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Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Variable Speed Drive Volumetric Tracking (VSDVT) for Airflow Control in Variable Air Volume (VAV) Systems  

E-Print Network (OSTI)

An airflow control method has been developed for variable air volume (VAV) systems. This airflow control method is named VSD volumetric tracking (VSDVT) since both the supply and return airflows are determined using signals of the variable speed drives (VSD) instead of the flow stations. Its performance is studied and compared with the fan tracking (FT) method using model simulations. The VSDVT maintains a constant building pressure and the required outside airflow under all load conditions, reduces the annual return air fan energy by up to 50%, and the annual supply air fan energy by up to 30%. This paper presents the VSDVT method, the system models, and the simulation results.

Liu, M.

2002-01-01T23:59:59.000Z

2

Improving Control of a Dual-Duct Single-Fan Variable Air Volume Systems  

E-Print Network (OSTI)

This paper discusses improved control strategies for dual-duct single-fan variable air volume (VAV) systems. Common control strategy for supply air volume modulation is evaluated, and an improved air volume control strategy that maintains separate cold and hot air duct static pressure set points is presented. The paper also explores the interactions between the cold and hot deck temperatures and duct static pressures, and discusses the impact of non-ideal deck temperature settings on duct static pressures and overall system energy consumption. To compensate the negative impact of non-ideal cold and hot deck temperature set points, the authors propose using real-time duct static pressure readings as feedback signals to fine-tune the deck temperature set points. These new control schemes can reduce simultaneous cooling and heating while reducing fan power consumption.

Wei, G.; Martinez, J.; Minihan, T.; Brundidge, T.; Claridge, D. E.; Turner, W. D.

2003-01-01T23:59:59.000Z

3

Room Temperature Control During Season Switchover with Single Duct Variable Air Volume System Without Reheat  

E-Print Network (OSTI)

The Langford “A” building houses the College of Architecture on TAMU campus. There are ten singleduct variable air volume (VAV) air-handling units (AHUs) without reheat serving the building. The local pneumatic thermostats modulate the dampers of VAV boxes to maintain room temperature at their setpoints. The thermostat action is switched from direct acting (DA) to reverse acting (RA) when the season changes from fall to winter and vice versa from winter to spring, based on the out side air temperature, when season changes. This results in various parts of the building ether too cold or too hot during the season change. This paper presents that the thermostat action will be switched according to cooling loads or discharge air temperature, instead of outside air temperature. For the interior zone, thermostat action does not need to be switched at all. The comfort is improved and savings is achieved by the new control scheme. Because some air-handling units (AHUs) serve both interior and exterior zones, this system never worked as intended. The system must be modified to have zone reheat and the AHUs discharge air temperature is set below dew point for humidity control.

Liu, C.; Deng, S.; Claridge, D. E.; Turner, W. D.; Bruner, H.

2003-01-01T23:59:59.000Z

4

Optimized Fan Control In Variable Air Volume HVAC Systems Using Static Pressure Resets: Strategy Selection and Savings Analysis  

E-Print Network (OSTI)

The potential of static pressure reset (SPR) control to save fan energy in variable air volume HVAC systems has been well documented. Current research has focused on the creation of reset strategies depending on specific system features. As the commissioning process has begun to require the prediction of savings, knowledge of the extent to which various SPR control strategies impact fan energy has become increasingly important. This research aims to document existing SPR control strategies and utilize building data and simulation to estimate fan energy use. A comprehensive review of the literature pertaining to SPR control was performed and the results were organized into a top-down flow chart tool. Based on the type of feedback available from a particular system, or lack thereof, this tool will facilitate the selection of a SPR control strategy. A field experiment was conducted on a single duct variable air volume system with fixed discharge air temperature and static pressure setpoints. Finally, an air-side model of the experimental system was created using detailed building design information and calibrated using field measurements. This model was used to estimate the fan energy required to supply the trended airflow data using fixed static pressure (FSP) and SPR control based on zone demand, system demand, and outside air temperature. While utilizing trend data from November 1, 2008 to February 12, 2009, the FSP control of the experimental system was used as the baseline for ranking the energy savings potential of nine different forms of duct static pressure control. The highest savings (73-74%) were achieved using zonal demand based SPR control. System demand based SPR control yielded savings ranging from 59 to 76%, which increased when the duct sensor was positioned near the fan discharge and under similar zone load conditions. The outside air temperature based SPR control yielded savings of 65% since the experimental system supplied primarily perimeter zones. Finally, increasing the FSP setpoint from 2 to 3 inWG increased fan energy by 45%, while decreasing the setpoint from 2 to 1 inWG decreased fan energy by 41%.

Kimla, John

2009-12-01T23:59:59.000Z

5

Analysis and characterization of ancillary service demand response strategies for variable air volume HVAC systems  

E-Print Network (OSTI)

Output variability and prediction difficulties with respect to solar and wind electricity resources increase the requirement of grid-scale reserve capacity and add strain to existing firm generators used for reserves and ...

Blum, David H. (David Henry)

2013-01-01T23:59:59.000Z

6

Dynamic modeling and global optimal operation of multizone variable air volume HVAC systems.  

E-Print Network (OSTI)

??Energy conservation and indoor environment concerns have motivated extensive research on various aspects of control of Heating, Ventilating and Air-Conditioning (HVAC) and building systems. The… (more)

Zheng, Guo Rong

1997-01-01T23:59:59.000Z

7

96 ASHRAE Transactions: Research Current duct design methods for variable air volume  

E-Print Network (OSTI)

96 ASHRAE Transactions: Research ABSTRACT Current duct design methods for variable air volume (VAV in the 1997 ASHRAE Handbook--Fundamentals (ASHRAE 1997): equal friction, static regain, and the T Systems Taecheol Kim Jeffrey D. Spitler, Ph.D., P.E. Ronald D. Delahoussaye, Ph.D. Member ASHRAE Taecheol

8

ASHRAE Transactions: Research 105 Current duct design methods for variable air volume  

E-Print Network (OSTI)

ASHRAE Transactions: Research 105 ABSTRACT Current duct design methods for variable air volume (VAV for different design conditions are sought using a duct fitting database program as described in ASHRAE (1993 Jeffrey D. Spitler, Ph.D., P.E. Ronald D. Delahoussaye, Ph.D. Member ASHRAE Taecheol Kim is a Ph

9

Single-Duct Constant Air Volume System Supply Air Temperature Reset: Using Return Air Temperature or Outside Air Temperature?  

E-Print Network (OSTI)

The supply air temperature set point for a singleduct constant air volume air handling unit (AHU) system is often reset based on either return air temperature or outside air temperature in order to reduce simultaneous cooling and heating energy consumption. Both reset strategies make engineering sense as long as the reset schedules are reasonable. Quite often the decision to use one over the other is made with the assumption that they will all achieve some sorts of energy savings. However, the impact of these two strategies on AHU energy consumption could be very different. A comparison of these two commonly used supply air temperature reset strategies for a single-duct constant air volume system is presented in this paper. It is shown that from either the building energy consumption or building comfort point of view, the reset strategy based on outside air temperature is inherently better than that based on return air temperature. Significant amount of heating energy savings can be achieved by switching from return air temperature based reset to outside air temperature based reset. The reset strategy can also benefit variable air volume (VAV) AHUs. An improved supply air temperature set point reset control strategy is proposed by combining and staging the outside air and return air temperature based resets.

Wei, G.; Turner, W. D.; Claridge, D.; Liu, M.

2002-01-01T23:59:59.000Z

10

Control Humidity With Single-Duct, Single-Zone, Constant Air Volume System  

E-Print Network (OSTI)

The lecture hall of the Richardson Petroleum Building at Texas A&M University is a large lecture hall, with a total floor area of approximately 2500 ft^2. The lecture hall was served by a constant air volume (CAV) air handling unit (AHU) which had no reheat coil. This resulted in high room humidity levels although the room temperature was satisfied for part load conditions, especially when there was very little sensible load from the room. This paper presents Continuous Commissioning efforts (CC), which turned this inefficient, humid lecture hall into a comfortable learning environment. This case study also explores other possibilities to solve the humidity control problem with single-duct, single-zone constant air volume systems.

Chen, H.; Deng, S.; Bruner, H. L.; Claridge, D. E.

2000-01-01T23:59:59.000Z

11

Research on Fuzzy Regulation Strategies in the Constant Air Volume Air Conditioning System  

E-Print Network (OSTI)

The energy consumption of the constant air volume (CAV) system largely depends on the regulation strategies. Although some air conditioning systems are equipped with automatic regulation devices, others lack effective regulation strategies. To avoid wasting energy and presenting simple regulation methods, fuzzy regulation strategies for CAV systems are studied in this research. A CAV system of an office building is modeled and simulated with the Designer's Simulation Toolkit (DeST). The operating parameters are calculated based on the instantaneous load obtained from simulation. The operation of the system is divided into five stages according to different conception of “cold” or “hot” in different seasons. The relationship between the outdoor air temperature and the fresh air volume, and the supply air temperature is presented in the form of fuzzy rules. Then the building is simulated under different load conditions and the operating parameters are obtained from fuzzy reasoning. Finally, the effect of fuzzy strategies on energy consumption is analyzed and compared with the effects of the operating parameters obtained from simulation. The results show that energy consumption using a fuzzy regulation strategy is close to the energy consumption of knowing the exact load of the building, while the fuzzy regulation strategy can largely simplify the regulation of the air conditioning system.

Bai, T.; Zhang, J.; Ning, N.; Tong, K.; Wu, Y.; Wang, H.

2006-01-01T23:59:59.000Z

12

Supply Fan Control for Constant Air Volume Air Handling Units  

E-Print Network (OSTI)

Since terminal boxes do not have a modulation damper in constant volume (CV) air handling unit (AHU) systems, zone reheat coils have to be modulated to maintain the space temperature with constant supply airflow. This conventional control sequence causes a significant amount of reheat and constant fan power under partial load conditions. Variable Frequency Drives (VFDs) can be installed on these constant air volume systems. The fan speed can be modulated based on the maximum zone load. This paper present the procedure to control the supply fan speed and analyzes the thermal performance and major fan energy and thermal energy savings without expensive VAV retrofit through the actual system operation.

Cho, Y.; Wang, G.; Liu, M.

2007-01-01T23:59:59.000Z

13

Energy Savings for Occupancy-Based Control (OBC) of Variable-Air-Volume (VAV) Systems  

SciTech Connect

This study evaluates the savings potential of occupancy based control (OBC) for large office buildings with VAV terminal boxes installed.

Zhang, Jian; Lutes, Robert G.; Liu, Guopeng; Brambley, Michael R.

2013-01-24T23:59:59.000Z

14

CALIFORNIA ENERGY Advanced Variable Air Volume  

E-Print Network (OSTI)

who started me on programming the remote control of digital oscilloscopes, which later became the main Solyom from the Biology Division fixed a few chillers and vacuum pumps for me. I also enjoyed our long broadening most likely results from rapid IVR induced by the high density of states in protonated PAHs

15

System dynamics based models for selecting HVAC systems for office buildings: a life cycle assessment from carbon emissions perspective.  

E-Print Network (OSTI)

??This study aims to explore the life cycle environmental impacts of typical heating ventilation and air condition (HVAC) systems including variable air volume (VAV) system,… (more)

Chen, S

2011-01-01T23:59:59.000Z

16

A standard simulation testbed for the evaluation of control algorithms & strategies related to variable air volume HVAC systems  

E-Print Network (OSTI)

The parameters for a dynamic, computer simulation model were developed. The parameters characterize the physical and geometric properties of a building shell, the internal and external building loads, the buildings secondary ...

DeSimone, Mark

1995-01-01T23:59:59.000Z

17

Variable buoyancy system metric  

E-Print Network (OSTI)

Over the past 20 years, underwater vehicle technology has undergone drastic improvements, and vehicles are quickly gaining popularity as a tool for numerous oceanographic tasks. Systems used on the vehicle to alter buoyancy, ...

Jensen, Harold Franklin

2009-01-01T23:59:59.000Z

18

Variable frequency microwave furnace system  

DOE Patents (OSTI)

A variable frequency microwave furnace system designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity for testing or other selected applications. The variable frequency microwave furnace system includes a microwave signal generator or microwave voltage-controlled oscillator for generating a low-power microwave signal for input to the microwave furnace. A first amplifier may be provided to amplify the magnitude of the signal output from the microwave signal generator or the microwave voltage-controlled oscillator. A second amplifier is provided for processing the signal output by the first amplifier. The second amplifier outputs the microwave signal input to the furnace cavity. In the preferred embodiment, the second amplifier is a traveling-wave tube (TWT). A power supply is provided for operation of the second amplifier. A directional coupler is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter is provided for measuring the power delivered to the microwave furnace. A second power meter detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load. 5 figs.

Bible, D.W.; Lauf, R.J.

1994-06-14T23:59:59.000Z

19

Module Development and Simulation of the Variable Refrigerant Flow Air Conditioning System under Cooling Conditions in Energyplus  

E-Print Network (OSTI)

As a high-efficiency air conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way into medium-sized office buildings. Based on a generic dynamic building energy simulation environment, EnergyPlus, a new module is developed and the energy usage of the VRF system is investigated. This paper compares the energy consumption of the VRF system with that of two conventional air-conditioning systems, namely, the variable air volume (VAV) system and the fan-coil plus fresh air (FPFA) system. A generic office building is used to accommodate the different types of heating, ventilating, and air conditioning (HVAC) systems. Our objective is to examine the energy consumption of the VRF system applied to office buildings and make suggestions for evaluating and making decisions on HVAC systems in the early stages of building design. Simulation results show that the energy-saving potential of the VRF system is expected to achieve 22.2 percent and 11.7 percent, compared to the VAV system and the FPFA system, respectively. An energy-usage breakdown of electricity end-users in various systems is also presented.

Zhou, Y.; Wu, J.; Wang, R.; Shiochi, S.

2006-01-01T23:59:59.000Z

20

Bond Graph Modeling Of Variable Structure Systems  

E-Print Network (OSTI)

The problem of describing variable structure models in a compact, object--oriented fashion is revisited and analyzed from the perspective of bond graph modeling. Traditionally, bond graphs have always been used to describe continuous-- time physical processes with a fixed structure. Yet, this paper shall demonstrate that bond graphs are equally suitable to describe variable structure models as fixed structure models. Moreover, a bond graph description of variable structure models can teach us a lot about the essential properties of variable structure models, properties that are not easily visible when other modeling approaches are taken. The paper discusses issues related to causality reassignment and conditional index changes as a consequence of switching in a physical system. Keywords: Bond graphs, variable structure system, computational causality, conditional index change, switching, object--oriented modeling, Dymola. INTRODUCTION When the causality strokes were added to the forme...

François E. Cellier; Martin Otter; Hilding Elmqvist

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Variables optimization of building air conditioning system  

Science Conference Proceedings (OSTI)

A heating and climatizer system based on selective absorption of solar energy by a selective collector. The experimental study shows that the performance of this system depends on several variables: the nature of the colporteur fluid, the flow of the ... Keywords: heating and climatisation, modelation and optimization, solar energy

Marius-Constantin Popescu; Cornelia Aida Bulucea; Gheorghe Manolea; Cristian Vladu

2009-10-01T23:59:59.000Z

22

Variability of PV on Distribution Systems  

Science Conference Proceedings (OSTI)

In 2010, the Electric Power Research Institute (EPRI) along with several utilities began collecting high-resolution monitoring data on distributed solar photovoltaic (PV) systems throughout the United States. Included in these monitoring data are single-module PV systems distributed along selected feeders as well as several larger PV systems (up to 1.4 MW). Utilizing data from these sites, this report focuses specifically on examining the measured variability of solar PV distributed throughout a ...

2012-12-13T23:59:59.000Z

23

Development of an isothermal 2D zonal air volume model with impulse  

NLE Websites -- All DOE Office Websites (Extended Search)

Development of an isothermal 2D zonal air volume model with impulse Development of an isothermal 2D zonal air volume model with impulse conservation Title Development of an isothermal 2D zonal air volume model with impulse conservation Publication Type Conference Paper Year of Publication 2010 Authors Victor, Norrefeldt, Thierry Stephane Nouidui, and Gunnar Gruen Conference Name Clima 2010, 10th Rehva World Congress "Sustainable Energy Use in Buildings" Conference Location Antalya, Turkey Abstract This paper presents a new approach to model air flows with a zonal model. The aim of zonal models is to perform quick simulations of the air distribution in rooms. Therefore an air volume is subdivided into several discrete zones, typically 10 to 100. The zones are connected with flow elements computing the amount of air exchanged between them. In terms of complexity and needed computational time zonal models are a compromise between CFDcalculations and the approximation of perfect mixing. In our approach the air flow velocity is used as property of the zones. Thus the distinction between normal zones and jet or plume influenced zones becomes obsolete. The model is implemented in the object oriented and equation based language Modelica. A drawback of the new formulation is that the calculated flow pattern depends on the discretization. Nevertheless, the results show that the new zonal model performs well and is a useful extension to existing models.

24

Variable pressure power cycle and control system  

DOE Patents (OSTI)

A variable pressure power cycle and control system that is adjustable to a variable heat source is disclosed. The power cycle adjusts itself to the heat source so that a minimal temperature difference is maintained between the heat source fluid and the power cycle working fluid, thereby substantially matching the thermodynamic envelope of the power cycle to the thermodynamic envelope of the heat source. Adjustments are made by sensing the inlet temperature of the heat source fluid and then setting a superheated vapor temperature and pressure to achieve a minimum temperature difference between the heat source fluid and the working fluid.

Goldsberry, Fred L. (Spring, TX)

1984-11-27T23:59:59.000Z

25

Analysis of the Energy Consumption of VAV System in Different Supply Air Control Strategies  

Science Conference Proceedings (OSTI)

Variable air volume (VAV) system has been widely applied due to its characteristics of eminent energy saving and thermal comfort. Because of its above characteristics, sophisticated automatic control systems are required to support its operation. While ... Keywords: VAV A/C system, supply air control strategy, energy consumption analysis

Junjie Guo, Xiangxin Cheng

2012-07-01T23:59:59.000Z

26

Mobile Variable Depth Sampling System Design Study  

Science Conference Proceedings (OSTI)

A design study is presented for a mobile, variable depth sampling system (MVDSS) that will support the treatment and immobilization of Hanford LAW and HLW. The sampler can be deployed in a 4-inch tank riser and has a design that is based on requirements identified in the Level 2 Specification (latest revision). The waste feed sequence for the MVDSS is based on Phase 1, Case 3S6 waste feed sequence. Technical information is also presented that supports the design study.

BOGER, R.M.

2000-08-25T23:59:59.000Z

27

Energy Efficient Single Stack Exhaust Fan Systems (E3S3F)  

E-Print Network (OSTI)

This paper first investigates the fan energy performance of a constant air volume exhaust system. Two single stack energy efficient exhaust fan systems (E3S3F) are presented. The E3S3F-I has the static pressure sensor located at the inlet of the exhaust fan. It has been found to consume up to 15% less fan power than conventional constant air volume exhaust systems. The E3S3F-II uses a variable speed device to maintain the static pressure at the entrance of the stack. It consumes up to 60% less fan power than conventional constant volume exhaust systems.

Wang, G.; Liu, M.

2001-01-01T23:59:59.000Z

28

Variable temperature seat climate control system  

DOE Patents (OSTI)

A temperature climate control system comprises a variable temperature seat, at least one heat pump, at least one heat pump temperature sensor, and a controller. Each heat pump comprises a number of Peltier thermoelectric modules for temperature conditioning the air in a main heat exchanger and a main exchanger fan for passing the conditioned air from the main exchanger to the variable temperature seat. The Peltier modules and each main fan may be manually adjusted via a control switch or a control signal. Additionally, the temperature climate control system may comprise a number of additional temperature sensors to monitor the temperature of the ambient air surrounding the occupant as well as the temperature of the conditioned air directed to the occupant. The controller is configured to automatically regulate the operation of the Peltier modules and/or each main fan according to a temperature climate control logic designed both to maximize occupant comfort during normal operation, and minimize possible equipment damage, occupant discomfort, or occupant injury in the event of a heat pump malfunction.

Karunasiri, Tissa R. (Van Nuys, CA); Gallup, David F. (Pasadena, CA); Noles, David R. (Glendale, CA); Gregory, Christian T. (Alhambra, CA)

1997-05-06T23:59:59.000Z

29

Empowering Variable Renewables: Options for Flexible Electricity Systems |  

Open Energy Info (EERE)

Empowering Variable Renewables: Options for Flexible Electricity Systems Empowering Variable Renewables: Options for Flexible Electricity Systems Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Empowering Variable Renewables: Options for Flexible Electricity Systems Agency/Company /Organization: International Energy Agency Sector: Energy Focus Area: Renewable Energy Topics: Market analysis, Technology characterizations Resource Type: Publications Website: www.iea.org/g8/2008/Empowering_Variable_Renewables.pdf Empowering Variable Renewables: Options for Flexible Electricity Systems Screenshot References: Empowering Variable Renewables: Options for Flexible Electricity Systems[1] Summary "Increasing the share of renewables in energy portfolios is a key tool in the drive to reduce anthropogenic carbon dioxide emissions, as well as

30

Quantifying decoherence in continuous variable systems  

E-Print Network (OSTI)

We present a detailed report on the decoherence of quantum states of continuous variable systems under the action of a quantum optical master equation resulting from the interaction with general Gaussian uncorrelated environments. The rate of decoherence is quantified by relating it to the decay rates of various, complementary measures of the quantum nature of a state, such as the purity, some nonclassicality indicators in phase space and, for two-mode states, entanglement measures and total correlations between the modes. Different sets of physically relevant initial configurations are considered, including one- and two-mode Gaussian states, number states, and coherent superpositions. Our analysis shows that, generally, the use of initially squeezed configurations does not help to preserve the coherence of Gaussian states, whereas it can be effective in protecting coherent superpositions of both number states and Gaussian wave packets. 1

A. Serafini; M. G. A. Paris; F. Illuminati; S. De Siena

2005-01-01T23:59:59.000Z

31

Quantifying decoherence in continuous variable systems  

E-Print Network (OSTI)

We present a detailed report on the decoherence of quantum states of continuous variable systems under the action of a quantum optical master equation resulting from the interaction with general Gaussian uncorrelated environments. The rate of decoherence is quantified by relating it to the decay rates of various, complementary measures of the quantum nature of a state, such as the purity, some nonclassicality indicators in phase space and, for two-mode states, entanglement measures and total correlations between the modes. Different sets of physically relevant initial configurations are considered, including one- and two-mode Gaussian states, number states, and coherent superpositions. Our analysis shows that, generally, the use of initially squeezed configurations does not help to preserve the coherence of Gaussian states, whereas it can be effective in protecting coherent superpositions of both number states and Gaussian wave packets.

A. Serafini; M. G. A. Paris; F. Illuminati; S. De Siena

2005-01-28T23:59:59.000Z

32

Fuzzy logic system for variable message signs in Kuala Lumpur  

Science Conference Proceedings (OSTI)

Intelligent Transportation Systems refer to a wide variety of advanced and emerging technology applications designed mainly to reduce traffic congestion and emissions, and to improve highway efficiency, safety, and convenience. Variable message signs ... Keywords: fuzzy controller, fuzzy logic, intelligent transportation systems, variable message signs

Arash Moradkhani Roshandeh; Majid Joshani; Othman Che Puan

2009-06-01T23:59:59.000Z

33

Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems  

E-Print Network (OSTI)

Comparison of energy efficiency between variable refrigeranttheir superior energy efficiency. The variable refrigerantfew studies reporting the energy efficiency of VRF systems

Hong, Tainzhen

2010-01-01T23:59:59.000Z

34

Variable emissivity laser thermal control system  

DOE Patents (OSTI)

A laser thermal control system for a metal vapor laser maintains the wall mperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser.

Milner, Joseph R. (Livermore, CA)

1994-01-01T23:59:59.000Z

35

South Atlantic Multidecadal Variability in the Climate System Model  

Science Conference Proceedings (OSTI)

Strong multidecadal variability is detected in a 300-yr integration of the NCAR Climate System Model in the South Atlantic region, through the application of two signal recognition techniques: the multitaper method and singular spectrum analysis. ...

Ilana Wainer; Silvia A. Venegas

2002-06-01T23:59:59.000Z

36

Variable emissivity laser thermal control system  

DOE Patents (OSTI)

A laser thermal control system for a metal vapor laser maintains the wall temperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser. 8 figs.

Milner, J.R.

1994-10-25T23:59:59.000Z

37

Variable-Speed Wind System Design : Final Report.  

SciTech Connect

Almost from the onset of the development of wind energy conversion systems (WECS), it was known that variable-speed operation of the turbine would maximize energy capture. This study was commissioned to assess the cost, efficiency gain, reduction of the cost of energy (COE), and other operating implications of converting the existing hardware of a modern fixed-speed wind energy conversion system to variable-speed operation. The purpose of this study was to develop a preliminary design for the hardware required to allow variable-speed operation using a doubly-fed generator with an existing fixed-speed wind turbine design. The turbine selected for this study is the AWT-26 designed and built by Advanced Wind Turbines Inc. of Redmond, Washington. The lowest projected COE using this variable-speed generation system is projected to be $0.0499/kWh, compared to the lowest possible COE with fixed-speed generation which is projected to be $0.0546/kWh. This translates into a 8.6% reduction of the COE using this variable-speed generation option. The preliminary system design has advanced to where the printed circuit boards can be physically laid out based on the schematics and the system software can be written based on the control flow-charts. The core of hardware and software has been proven to be successful in earlier versions of VSG systems. The body of this report presents the results of the VSWG system development. Operation under normal and fault conditions is described in detail, the system performance for variable-speed operation is estimated and compared to the original fixed-speed system performance, and specifications for all system components (generator, power electronic converter, and system controller) are given. Costs for all components are estimated, and incremental system cost is compared to incremental energy production. Finally, operational features of the VSWG which are not available in the existing FSWG system are outlined.

Lauw, Hinan K.; Weigand, Claus H.; Marckx, Dallas A.; Electronic Power Conditioning, Inc.

1993-10-01T23:59:59.000Z

38

Best Practices for Energy Efficient Cleanrooms Efficient HVAC Systems: Variable-Speed-Drive Chillers  

E-Print Network (OSTI)

resource/24/ ASHRAE handbook – HVAC systems and equipments.Efficient Cleanrooms Efficient HVAC Systems: Variable-Speed-Efficient Cleanrooms Efficient HVAC Water Systems: Variable-

Xu, Tengfang

2005-01-01T23:59:59.000Z

39

Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems  

E-Print Network (OSTI)

comparison of VAV and VRF air conditioning systems in anThe variable refrigerant flow (VRF) and ground source heatthe energy efficiency of VRF systems compared with GSHP

Hong, Tainzhen

2010-01-01T23:59:59.000Z

40

A variable voltage MPPT control method for photovoltaic generation system  

Science Conference Proceedings (OSTI)

To increase the output efficiency of a photovoltaic (PV) generation system it is important to have an efficient maximum power point tracking (MPPT) technique. This paper describes the analysis, design and implementation of an efficient tracking method ... Keywords: maximum power point tracking (MPPT), photovoltaic generation system, pulse-width-modulation (PWM), solar energy, variable voltage

Liu Liqun; Wang Zhixin

2009-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Continuous variable tangle, monogamy inequality, and entanglement sharing in Gaussian states of continuous variable systems  

E-Print Network (OSTI)

For continuous-variable systems, we introduce a measure of entanglement, the continuous variable tangle ({\\em contangle}), with the purpose of quantifying the distributed (shared) entanglement in multimode, multipartite Gaussian states. This is achieved by a proper convex roof extension of the squared logarithmic negativity. We prove that the contangle satisfies the Coffman-Kundu-Wootters monogamy inequality in all three--mode Gaussian states, and in all fully symmetric $N$--mode Gaussian states, for arbitrary $N$. For three--mode pure states we prove that the residual entanglement is a genuine tripartite entanglement monotone under Gaussian local operations and classical communication. We show that pure, symmetric three--mode Gaussian states allow a promiscuous entanglement sharing, having both maximum tripartite residual entanglement and maximum couplewise entanglement between any pair of modes. These states are thus simultaneous continuous-variable analogs of both the GHZ and the $W$ states of three qubits: in continuous-variable systems monogamy does not prevent promiscuity, and the inequivalence between different classes of maximally entangled states, holding for systems of three or more qubits, is removed.

Gerardo Adesso; Fabrizio Illuminati

2004-10-06T23:59:59.000Z

42

Strategies and Decision Support Systems for Integrating Variable Energy  

Open Energy Info (EERE)

Strategies and Decision Support Systems for Integrating Variable Energy Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations: Global Best Practices, Examples of Excellence and Lessons Learned Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations: Global Best Practices, Examples of Excellence and Lessons Learned Agency/Company /Organization: United States Department of Energy Sector: Climate, Energy Focus Area: Renewable Energy, Grid Assessment and Integration, Wind Topics: Best Practices Resource Type: Lessons learned/best practices, Publications, Technical report Website: www1.eere.energy.gov/wind/pdfs/doe_wind_integration_report.pdf

43

Quantum state conversion between continuous variable and qubits systems  

E-Print Network (OSTI)

We investigate how quantum state can be converted between continuous variable and qubits systems. Non-linear Jaynes-Cumings interaction Hamiltonian is introduced to accomplish the conversion. Detail analysis on the conversion of thermal state exhibits that pretty good fidelity can be achieved.

Xiao-yu Chen; Liang Han; Li-zhen Jiang

2006-10-31T23:59:59.000Z

44

Quantifying the Variable Effects of Systems with Demand Response Resources  

E-Print Network (OSTI)

Quantifying the Variable Effects of Systems with Demand Response Resources Anupama Kowli and George, USA Abstract--The growing environmental concerns and increasing electricity prices have led to wider implementation of demand- side activities and created a new class of consumers, called de- mand response

Gross, George

45

Quantification and scaling of multipartite entanglement in continuous variable systems  

E-Print Network (OSTI)

We present a theoretical method to determine the multipartite entanglement between different partitions of multimode, fully or partially symmetric Gaussian states of continuous variable systems. For such states, we determine the exact expression of the logarithmic negativity and show that it coincides with that of equivalent two--mode Gaussian states. Exploiting this reduction, we demonstrate the scaling of the multipartite entanglement with the number of modes and its reliable experimental estimate by direct measurements of the global and local purities.

Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

2004-06-09T23:59:59.000Z

46

Extremal entanglement and mixedness in continuous variable systems  

E-Print Network (OSTI)

We investigate the relationship between mixedness and entanglement for Gaussian states of continuous variable systems. We introduce generalized entropies based on Schatten $p$-norms to quantify the mixedness of a state, and derive their explicit expressions in terms of symplectic spectra. We compare the hierarchies of mixedness provided by such measures with the one provided by the purity (defined as ${\\rm tr} \\varrho^2$ for the state $\\varrho$) for generic $n$-mode states. We then review the analysis proving the existence of both maximally and minimally entangled states at given global and marginal purities, with the entanglement quantified by the logarithmic negativity. Based on these results, we extend such an analysis to generalized entropies, introducing and fully characterizing maximally and minimally entangled states for given global and local generalized entropies. We compare the different roles played by the purity and by the generalized $p$-entropies in quantifying the entanglement and the mixedness of continuous variable systems. We introduce the concept of average logarithmic negativity, showing that it allows a reliable quantitative estimate of continuous variable entanglement by direct measurements of global and marginal generalized $p$-entropies.

Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

2004-02-18T23:59:59.000Z

47

Extremal entanglement and mixedness in continuous variable systems  

Science Conference Proceedings (OSTI)

We investigate the relationship between mixedness and entanglement for Gaussian states of continuous variable systems. We introduce generalized entropies based on Schatten p norms to quantify the mixedness of a state and derive their explicit expressions in terms of symplectic spectra. We compare the hierarchies of mixedness provided by such measures with the one provided by the purity (defined as tr {rho}{sup 2} for the state {rho}) for generic n-mode states. We then review the analysis proving the existence of both maximally and minimally entangled states at given global and marginal purities, with the entanglement quantified by the logarithmic negativity. Based on these results, we extend such an analysis to generalized entropies, introducing and fully characterizing maximally and minimally entangled states for given global and local generalized entropies. We compare the different roles played by the purity and by the generalized p entropies in quantifying the entanglement and the mixedness of continuous variable systems. We introduce the concept of average logarithmic negativity, showing that it allows a reliable quantitative estimate of continuous variable entanglement by direct measurements of global and marginal generalized p entropies.

Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio [Dipartimento di Fisica 'E. R. Caianiello', Universita di Salerno, INFM UdR di Salerno, INFN Sezione di Napoli, Gruppo Collegato di Salerno, Via S. Allende, 84081 Baronissi, SA (Italy)

2004-08-01T23:59:59.000Z

48

Commercial thermal distribution systems, Final report for CIEE/CEC  

E-Print Network (OSTI)

Design." Atlanta, American Society of Heating, Refrigeration, andRefrigeration, and Air Conditioning Engineers Brake horsepower Building Management System Constant air volume Center for Environmental Design

Xu, T.

2011-01-01T23:59:59.000Z

49

Entanglement, Purity, and Information Entropies in Continuous Variable Systems  

E-Print Network (OSTI)

Quantum entanglement of pure states of a bipartite system is defined as the amount of local or marginal ({\\em i.e.}referring to the subsystems) entropy. For mixed states this identification vanishes, since the global loss of information about the state makes it impossible to distinguish between quantum and classical correlations. Here we show how the joint knowledge of the global and marginal degrees of information of a quantum state, quantified by the purities or in general by information entropies, provides an accurate characterization of its entanglement. In particular, for Gaussian states of continuous variable systems, we classify the entanglement of two--mode states according to their degree of total and partial mixedness, comparing the different roles played by the purity and the generalized $p-$entropies in quantifying the mixedness and bounding the entanglement. We prove the existence of strict upper and lower bounds on the entanglement and the existence of extremally (maximally and minimally) entang...

Adesso, G; Illuminati, F; Adesso, Gerardo; Serafini, Alessio; Illuminati, Fabrizio

2005-01-01T23:59:59.000Z

50

Best Practices for Energy Efficient Cleanrooms Efficient HVAC Systems: Variable-Speed-Drive Chillers  

E-Print Network (OSTI)

LBNL-58636 Best Practices for Energy Efficient Cleanrooms Efficient HVAC Systems: Variable Efficient Cleanrooms Efficient HVAC Water Systems: Variable-Speed-Drive Chillers Tengfang Xu Contents HVAC.................................................................................................................................... 6 #12;HVAC Water Systems Variable-Speed-Drive Chillers Summary Cleanroom energy benchmarking data

51

Measuring advances in HVAC distribution system designs  

Science Conference Proceedings (OSTI)

Substantial commercial building energy savings have been achieved by improving the performance of the HVAC distribution system. The energy savings result from distribution system design improvements, advanced control capabilities, and use of variable-speed motors. Yet, much of the commercial building stock remains equipped with inefficient systems. Contributing to this is the absence of a definition for distribution system efficiency as well as the analysis methods for quantifying performance. This research investigates the application of performance indices to assess design advancements in commercial building thermal distribution systems. The index definitions are based on a first and second law of thermodynamics analysis of the system. The second law or availability analysis enables the determination of the true efficiency of the system. Availability analysis is a convenient way to make system efficiency comparisons since performance is evaluated relative to an ideal process. A TRNSYS simulation model is developed to analyze the performance of two distribution system types, a constant air volume system and a variable air volume system, that serve one floor of a large office building. Performance indices are calculated using the simulation results to compare the performance of the two systems types in several locations. Changes in index values are compared to changes in plant energy, costs, and carbon emissions to explore the ability of the indices to estimate these quantities.

Franconi, Ellen

1998-07-01T23:59:59.000Z

52

Measuring Advances in HVAC Distribution System Design  

SciTech Connect

Substantial commercial building energy savings have been achieved by improving the performance of the HV AC distribution system. The energy savings result from distribution system design improvements, advanced control capabilities, and use of variable-speed motors. Yet, much of the commercial building stock remains equipped with inefficient systems. Contributing to this is the absence of a definition for distribution system efficiency as well as the analysis methods for quantifying performance. This research investigates the application of performance indices to assess design advancements in commercial building thermal distribution systems. The index definitions are based on a first and second law of thermodynamics analysis of the system. The second law or availability analysis enables the determination of the true efficiency of the system. Availability analysis is a convenient way to make system efficiency comparisons since performance is evaluated relative to an ideal process. A TRNSYS simulation model is developed to analyze the performance of two distribution system types, a constant air volume system and a variable air volume system, that serve one floor of a large office building. Performance indices are calculated using the simulation results to compare the performance of the two systems types in several locations. Changes in index values are compared to changes in plant energy, costs, and carbon emissions to explore the ability of the indices to estimate these quantities.

Franconi, E.

1998-05-01T23:59:59.000Z

53

Entanglement, Purity, and Information Entropies in Continuous Variable Systems  

E-Print Network (OSTI)

Quantum entanglement of pure states of a bipartite system is defined as the amount of local or marginal ({\\em i.e.}referring to the subsystems) entropy. For mixed states this identification vanishes, since the global loss of information about the state makes it impossible to distinguish between quantum and classical correlations. Here we show how the joint knowledge of the global and marginal degrees of information of a quantum state, quantified by the purities or in general by information entropies, provides an accurate characterization of its entanglement. In particular, for Gaussian states of continuous variable systems, we classify the entanglement of two--mode states according to their degree of total and partial mixedness, comparing the different roles played by the purity and the generalized $p-$entropies in quantifying the mixedness and bounding the entanglement. We prove the existence of strict upper and lower bounds on the entanglement and the existence of extremally (maximally and minimally) entangled states at fixed global and marginal degrees of information. This results allow for a powerful, operative method to measure mixed-state entanglement without the full tomographic reconstruction of the state. Finally, we briefly discuss the ongoing extension of our analysis to the quantification of multipartite entanglement in highly symmetric Gaussian states of arbitrary $1 \\times N$-mode partitions.

Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

2005-06-06T23:59:59.000Z

54

High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems  

SciTech Connect

In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling converter provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling engine. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140 deg. C while the heat losses caused by the addition of the VCHP are 1.8 W.

Tarau, Calin; Walker, Kara L.; Anderson, William G. [Advanced Cooling Technologies, Inc. 1046 New Holland Ave. Lancaster, PA 17601 (United States)

2009-03-16T23:59:59.000Z

55

Dynamical paths and universality in continuous variables open systems  

E-Print Network (OSTI)

We address the dynamics of quantum correlations in continuous variable open systems and analyze the evolution of bipartite Gaussian states in independent noisy channels. In particular, upon introducing the notion of dynamical path through a suitable parametrization for symmetric states, we focus attention on phenomena that are common to Markovian and non-Markovian Gaussian maps under the assumptions of weak coupling and secular approximation. We found that the dynamical paths in the parameter space are universal, that is they do depend only on the initial state and on the effective temperature of the environment, with non Markovianity that manifests itself in the velocity of running over a given path. This phenomenon allows one to map non-Markovian processes onto Markovian ones and it may reduce the number of parameters needed to study a dynamical process, e.g. it may be exploited to build constants of motions valid for both Markovian and non-Markovian maps. Universality is also observed in the value of Gaussian discord at the separability threshold, which itself is a function of the sole initial conditions in the limit of high temperature. We also prove the existence of excluded regions in the parameter space, i.e. of sets of states which cannot be linked by any Gaussian dynamical map.

Andrea Cazzaniga; Sabrina Maniscalco; Stefano Olivares; Matteo G. A. Paris

2012-11-27T23:59:59.000Z

56

Entanglement in continuous variable systems: Recent advances and current perspectives  

E-Print Network (OSTI)

We review the theory of continuous-variable entanglement with special emphasis on foundational aspects, conceptual structures, and mathematical methods. Much attention is devoted to the discussion of separability criteria and entanglement properties of Gaussian states, for their great practical relevance in applications to quantum optics and quantum information, as well as for the very clean framework that they allow for the study of the structure of nonlocal correlations. We give a self-contained introduction to phase-space and symplectic methods in the study of Gaussian states of infinite-dimensional bosonic systems. We review the most important results on the separability and distillability of Gaussian states and discuss the main properties of bipartite entanglement. These include the extremal entanglement, minimal and maximal, of two-mode mixed Gaussian states, the ordering of two-mode Gaussian states according to different measures of entanglement, the unitary (reversible) localization, and the scaling of bipartite entanglement in multimode Gaussian states. We then discuss recent advances in the understanding of entanglement sharing in multimode Gaussian states, including the proof of the monogamy inequality of distributed entanglement for all Gaussian states, and its consequences for the characterization of multipartite entanglement. We finally review recent advances and discuss possible perspectives on the qualification and quantification of entanglement in non Gaussian states, a field of research that is to a large extent yet to be explored.

Gerardo Adesso; Fabrizio Illuminati

2007-01-29T23:59:59.000Z

57

Development of Clemson variable-rate lateral irrigation system  

Science Conference Proceedings (OSTI)

Crops in the Southern United States are generally produced in fields which are known to have a high degree of variability in soil type, water holding capacity, infiltration rates, and other major factors which affect crop production. In these fields, ... Keywords: Instrumentation, Irrigation, Lateral-move, Precision agriculture, Variable-rate irrigation

Young J. Han; Ahmad Khalilian; Tom O. Owino; Hamid J. Farahani; Sam Moore

2009-08-01T23:59:59.000Z

58

Performance Assessment of a Variable Refrigerant Flow Heat Pump Air Conditioning System  

Science Conference Proceedings (OSTI)

Variable refrigerant flow (VRF) technology uses smart integrated controls, variable speed drives, and refrigerant piping to provide energy efficiency, flexible operation, ease of installation, low noise, zone control, and comfort through all-electric technology. This report describes and documents the construction, performance, and application of a heat pump air conditioning system that uses VRF technology8212the Daikin VRV system. This variable refrigerant volume (VRV) system is manufactured by Daikin I...

2008-12-17T23:59:59.000Z

59

Intrinsic intraday variability in the gravitational lens system B0218+357  

E-Print Network (OSTI)

Radio monitoring of the gravitational lens system B0218+357 reveals it to be a highly variable source with variations on timescales of a few days correlated in both images. This shows that the variability is intrinsic to the background lensed source and suggests that similar variations in other intraday variable sources can also be intrinsic in origin.

A. D. Biggs; I. W. A. Browne; P. N. Wilkinson

2000-12-22T23:59:59.000Z

60

Low-Frequency Variability in the Arctic Atmosphere, Sea Ice, and Upper-Ocean Climate System  

Science Conference Proceedings (OSTI)

The low-frequency natural variability of the arctic climate system is modeled using a single-column, energy balance model of the atmosphere. sea ice, and upper-ocean system. Variability in the system is induced by forcing with realistic, random ...

C. M. Bitz; D. S. Battisti; R. E. Moritz; J. A. Beesley

1996-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems  

E-Print Network (OSTI)

Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems B. Beltran, T. Ahmed power generation in variable speed wind energy conversion systems (VS-WECS). These systems have two (National Renewable Energy Laboratory) wind turbine simulator FAST (Fatigue, Aerodynamics, Structures

Brest, Université de

62

Experimental Analysis of Variable Capacity Heat Pump Systems equipped with a liquid-cooled frequency inverter.  

E-Print Network (OSTI)

?? Using an inverter-driven compressor in variable capacity heat pump systems has a main drawback, which is the extra loss in the inverter. The present… (more)

Ebraheem, Thair

2013-01-01T23:59:59.000Z

63

The Coordinated Control of a Central Air Conditioning System Based on Variable Chilled Water Temperature and Variable Chilled Water Flow  

E-Print Network (OSTI)

At present, regulation of water flow by means of pump frequency conversion is one of the major methods for power-saving in central air conditioning systems. In this article, optimization regulation for central air conditioning system on the basis of coordinative optimization control for variable chilled water temperature and variable chilled water flow to obtain better power savings is put forward. According to typical meteorological year data, hourly air conditioning load of whole year for every typical room has been calculated with the transmission function method. In order to guarantee each typical room, the highest cooling load rate is used as an input parameter for optimization calculation. Based on the surface cooler check model, the smallest energy consumption of chiller and chiller water pump was taken as the objective function of the optimization model. The performance characteristics of a chiller, water pump, regulation valve and pipeline are taken into account, and the optimization chilled water temperature and chilled water flow were carried out. The case study for a commercial building in Guangzhou showed that the annual power consumption of the chillers and pumps of the air conditioning system is lower by 17% only with employment of variable water flow regulation by pump frequency conversion. In the case of optimization control with coordinative control of variable chilled water temperature and variable chilled water flow, the annual power consumption of the chillers and pumps of the air conditioning system is reduced by 22% in presence of remarkable power saving effects. Increasing the chilled water temperature will reduce the dehumidified capability of the air cooler, and the indoor relative humidity will increase. The simulation showed that the adjustment optimized process meets the comfort of each typical room. The lower the cooling load rate is, the more obvious the effect of power-saving is. The highest power-saving rate appears in December, which is 36.7%. Meanwhile, the least rate appears in July, which is only 14.5%.

Liu, J.; Mai, Y.; Liu, X.

2006-01-01T23:59:59.000Z

64

Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems  

E-Print Network (OSTI)

Amarnath, M. Blatt, Variable refrigerant flow: where, why,simulation in the variable refrigerant flow air-conditioningsimulation of the variable refrigerant flow air conditioning

Hong, Tainzhen

2010-01-01T23:59:59.000Z

65

Modeling the Variability of the Greater Agulhas Current System  

Science Conference Proceedings (OSTI)

An eddy-permitting, regional ocean model has been used to examine the variability in the source regions of the Agulhas Current on a range of time scales. These source regions are the East Madagascar Current, the flow through the Mozambique ...

J. C. Hermes; C. J. C. Reason; J. R. E. Lutjeharms

2007-07-01T23:59:59.000Z

66

Mixed Variable Optimization of the Number and Composition of Heat Intercepts in a Thermal Insulation System  

E-Print Network (OSTI)

: In the literature, thermal insulation systems with a xed number of heat intercepts have been optimized with respect to intercept locations and temperatures. The number of intercepts and the types of insulators that surround them were chosen by parametric studies. This was because the optimization methods used could not treat such categorical variables. Discrete optimization variables are categorical if the objective function or the constraints can not be evaluated unless the variables take one of a prescribed enumerable set of values. The key issue is that categorical variables can not be treated as ordinary discrete variables are treated by relaxing them to continuous variables with a side constraint that they be discrete at the solution. A new mixed variable programming (MVP) algorithm makes it possible to optimize directly with respect to mixtures of discrete, continuous, and categorical decision variables. The result of applying MVP is shown here to give a 65% reduction in the ...

Michael Kokkolaras; Charless Audet; J. E. Dennis, Jr.

2000-01-01T23:59:59.000Z

67

Impact of the Variable Refrigerant Volume Air Conditioning System on Building Energy Efficiency  

E-Print Network (OSTI)

The application of the variable refrigerant volume multi-zone air conditioning systems has met with mixed results since the publication of the Design Standard for Energy Efficiency of Public Buildings. This paper analyzes the characteristics of the variable refrigerant volume multi-zone air conditioning system, and discusses the advantages of its application.

Zhu, H.

2006-01-01T23:59:59.000Z

68

Control system and method for a power delivery system having a continuously variable ratio transmission  

DOE Patents (OSTI)

A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine. 4 figs.

Frank, A.A.

1984-07-10T23:59:59.000Z

69

Control system and method for a power delivery system having a continuously variable ratio transmission  

DOE Patents (OSTI)

A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine.

Frank, Andrew A. (1034 Hillside Ave., Madison, WI 53705)

1984-01-01T23:59:59.000Z

70

Assimilation Variability in the GEOS-1 Data Assimilation System  

Science Conference Proceedings (OSTI)

Ensembles of assimilation runs were used to assess the sensitivity of the GEOS-1 (Goddard Earth Observing System—Version 1) data assimilation system to data gaps and changes in initial conditions. Perturbations from a “control” assimilation were ...

Meta E. Sienkiewicz; James Pfaendtner

1997-04-01T23:59:59.000Z

71

The Effect of Pressure Difference Control on Hydraulic Stability in a Variable Flow Air Conditioning System  

E-Print Network (OSTI)

This paper analyzes the effects of different pressure difference control methods on hydraulic stability in a variable flow air conditioning system when it is applied to different air conditioning water systems. According to control method and water system, it can be divided into direct return system pass-by control, direct return system terminal control, reversed return system pass-by control and reversed return system terminal control. The results indicate that reversed return system terminal control has the best hydraulic stability.

Zhang, Z.; Fu, Y.; Chen, Y.

2006-01-01T23:59:59.000Z

72

www.eia.gov  

U.S. Energy Information Administration (EIA)

HVAC Conservation Features Variable Air-Volume System ... Economizer Cycle ..... HVAC Maintenance ..... Energy Management and Equipment Usage Reduced ...

73

Research of Speed Ratio Matching Strategies of Hydro-Mechanical Continuously Variable Transmission System for Tractor  

Science Conference Proceedings (OSTI)

To realize the optimal power and best fuel economy performance of engine, the speed ratio matching strategies of tractor with hydro-mechanical continuously variable transmission (HMCVT) system are studied. The engine output torque model and fuel consumption ... Keywords: Tractor, Hydro-mechanical continuously variable transmission, Speed ratio, Matching strategies

Liyou Xu; Zhili Zhou; Fuyi Cao; Mingzhu Zhang

2009-10-01T23:59:59.000Z

74

Entanglement, Purity, and Information Entropies in Continuous Variable Systems  

Science Conference Proceedings (OSTI)

Quantum entanglement of pure states of a bipartite system is defined as the amount of local or marginal (i.e. referring to the subsystems) entropy. For mixed states this identification vanishes, since the global loss ...

Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

2005-01-01T23:59:59.000Z

75

A Systemic Analysis of Multiscale Deep Convective Variability over the Tropical Pacific  

Science Conference Proceedings (OSTI)

The multiscale tropical deep convective variability over the Pacific Ocean is examined with the 4-month high-resolution deep convection index (ITBB) derived from satellite imagery. With a systemic view, the complex phenomenon is described with ...

Wen-wen Tung; Mitchell W. Moncrieff; Jian-Bo Gao

2004-07-01T23:59:59.000Z

76

Understanding Variability and Uncertainty of Photovoltaics for Integration with the Electric Power System  

E-Print Network (OSTI)

area of photovoltaic and other clean energy technologies.Energy recently hosted a day-long public workshop on the variability of photovoltaic (photovoltaic power plants into the utility system. Nicholas Miller is Director, Energy

Mills, Andrew

2010-01-01T23:59:59.000Z

77

Plenary lecture 3: variable structure control and time-delay systems: a survey  

Science Conference Proceedings (OSTI)

It is well known that the variable structure control is now recognized as one of the powerful robust tools for solving control problems of uncertain linear and nonlinear dynamical systems subject to parameter perturbations, unmodeled dynamics, external ...

Elbrous M. Jafarov

2010-05-01T23:59:59.000Z

78

Data Assimilation as Synchronization of Truth and Model: Experiments with the Three-Variable Lorenz System  

Science Conference Proceedings (OSTI)

The potential use of chaos synchronization techniques in data assimilation for numerical weather prediction models is explored by coupling a Lorenz three-variable system that represents “truth” to another that represents “the model.” By adding ...

Shu-Chih Yang; Debra Baker; Hong Li; Katy Cordes; Morgan Huff; Geetika Nagpal; Ena Okereke; Josue Villafańe; Eugenia Kalnay; Gregory S. Duane

2006-09-01T23:59:59.000Z

79

Links between Snow Cover, Surface Skin Temperature, and Rainfall Variability in the North American Monsoon System  

Science Conference Proceedings (OSTI)

The influence of land–atmosphere interactions on the variability of the North American monsoon system (NAMS) is investigated using the Television Infrared Observation Satellite (TIROS) Operational Vertical Sounder (TOVS) Pathfinder, the Climate ...

Toshi Matsui; Venkat Lakshmi; Eric Small

2003-06-01T23:59:59.000Z

80

ENSO and Pacific Decadal Variability in the Community Climate System Model Version 4  

Science Conference Proceedings (OSTI)

This study presents an overview of the El Nińo–Southern Oscillation (ENSO) phenomenon and Pacific decadal variability (PDV) simulated in a multicentury preindustrial control integration of the NCAR Community Climate System Model version 4 (CCSM4) ...

Clara Deser; Adam S. Phillips; Robert A. Tomas; Yuko M. Okumura; Michael A. Alexander; Antonietta Capotondi; James D. Scott; Young-Oh Kwon; Masamichi Ohba

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Climate Variability and Radiocarbon in the CM2Mc Earth System Model  

Science Conference Proceedings (OSTI)

The distribution of radiocarbon (14C) in the ocean and atmosphere has fluctuated on time scales ranging from seasons to millennia. It is thought that these fluctuations partly reflect variability in the climate system, offering a rich potential ...

Eric D. Galbraith; Eun Young Kwon; Anand Gnanadesikan; Keith B. Rodgers; Stephen M. Griffies; Daniele Bianchi; Jorge L. Sarmiento; John P. Dunne; Jennifer Simeon; Richard D. Slater; Andrew T. Wittenberg; Isaac M. Held

2011-08-01T23:59:59.000Z

82

Method and system to estimate variables in an integrated gasification combined cycle (IGCC) plant  

DOE Patents (OSTI)

System and method to estimate variables in an integrated gasification combined cycle (IGCC) plant are provided. The system includes a sensor suite to measure respective plant input and output variables. An extended Kalman filter (EKF) receives sensed plant input variables and includes a dynamic model to generate a plurality of plant state estimates and a covariance matrix for the state estimates. A preemptive-constraining processor is configured to preemptively constrain the state estimates and covariance matrix to be free of constraint violations. A measurement-correction processor may be configured to correct constrained state estimates and a constrained covariance matrix based on processing of sensed plant output variables. The measurement-correction processor is coupled to update the dynamic model with corrected state estimates and a corrected covariance matrix. The updated dynamic model may be configured to estimate values for at least one plant variable not originally sensed by the sensor suite.

Kumar, Aditya; Shi, Ruijie; Dokucu, Mustafa

2013-09-17T23:59:59.000Z

83

Enhanced Recovery Utilizing Variable Frequency Drives and a Distributed Power System  

Science Conference Proceedings (OSTI)

This report describes complete results of the project entitled ''Enhanced Recovery Utilizing Variable Frequency Drives and a Distributed Power System''. This demonstration project was initiated in July 2003 and completed in March 2005. The objective of the project was to develop an integrated power production/variable frequency drive system that could easily be deployed in the oil field that would increase production and decrease operating costs. This report describes all the activities occurred and documents results of the demonstration.

Randy Peden; Sanjiv Shah

2005-07-26T23:59:59.000Z

84

A computational method to extract macroscopic variables and their dynamics in multiscale systems  

E-Print Network (OSTI)

A systematic method to identify and extract the slow variables from a high-dimensional complex multiscale system is developed. The slow subspace is unravelled by employing the transfer operator and the Koopman operator the eigenfunctions of which are used to define a projection onto a slow subspace. The full system is then reformulated in terms of those slow variables, and we present and effective multiscale integrator, which allows for a large macro time step to propagate forward the slow variables. We illustrate our method with several examples and show how the reduced slow dynamics faithfully represents statistical features of the full dynamics which are not coordinate dependent.

Gary Froyland; Georg A. Gottwald; Andy Hammerlindl

2013-10-30T23:59:59.000Z

85

Variable-delay feedback control of unstable steady states in retarded time-delayed systems  

E-Print Network (OSTI)

We study the stability of unstable steady states in scalar retarded time-delayed systems subjected to a variable-delay feedback control. The important aspect of such a control problem is that time-delayed systems are already infinite-dimensional before the delayed feedback control is turned on. When the frequency of the modulation is large compared to the system's dynamics, the analytic approach consists of relating the stability properties of the resulting variable-delay system with those of an analogous distributed delay system. Otherwise, the stability domains are obtained by a numerical integration of the linearized variable-delay system. The analysis shows that the control domains are significantly larger than those in the usual time-delayed feedback control, and that the complexity of the domain structure depends on the form and the frequency of the delay modulation.

Aleksandar Gjurchinovski; Viktor Urumov

2010-07-06T23:59:59.000Z

86

System for throttling and compensation for variable feedstock properties  

DOE Patents (OSTI)

Apparatus is shown for adjusting the feed rate of pulverized feed material into a pressurized container. The apparatus also has utility for compensating for variations in the permeability of the feed material. A rotor that includes sprues with provision for controlling the pressure distribution along the sprues is located within the pressurized container. The rotor hub is connected to a drive means and a material supply means which extend through the wall of the container. A line for controlling pressure along the sprues by gas injection is connected to a chamber between sections of the sprue for controlling gas pressure at that point. The gas pressure control line is connected to a pressurized gas source and a control system external to the rotor.

Meyer, John W. (Palo Alto, CA)

1981-01-01T23:59:59.000Z

87

Fuzzy Inductive Reasoning for Variable Selection Analysis and Modeling of Biological Systems  

E-Print Network (OSTI)

Fuzzy Inductive Reasoning (FIR) is a qualitative inductive modeling and simulation methodology for dealing with dynamical systems. It has proven to be a powerful tool for qualitative model identification and prediction of future behavior of various kinds of dynamical systems, especially from the soft sciences, such as biology, biomedicine, and ecology. This paper focuses on modeling aspects of the FIR methodology. It is shown that the FIR variable selection analysis is a useful tool not only for FIR but also for other classical quantitative methodologies such as NARMAX (Nonlinear AutoRegressive Moving Average modeling with eXternal inputs). The tool allows to obtain models that interpret a system under study in optimal ways, in the sense that these models are well suited for predicting the future behavior of the system they represent. The FIR variable selection analysis turns out to work well even in those applications where standard statistical variable selection analysis does not pro...

Angela Nebot; Francois E. Cellier; Ra' ul Carvajal V

1997-01-01T23:59:59.000Z

88

Dispersion and variability in Catalan five and six peripheral vowel systems  

Science Conference Proceedings (OSTI)

This study compares F1 and F2 for the vowels of the five and six peripheral vowel systems of four minor dialects of Catalan (Felanitxer, Gironi, Sitgeta, Rossellones), with those of the seven peripheral vowel systems of the major dialects those minor ... Keywords: Acoustic analysis, Catalan, Contextual variability, Mid vowel neutralization, Near-mergers, Vowel space

Daniel Recasens; Aina Espinosa

2009-03-01T23:59:59.000Z

89

Integration of Variable Generation Forecasting into System Operations: Current Practices and Future Requirements  

Science Conference Proceedings (OSTI)

This project update provides the first output of the EPRI Bulk Renewable Integration Program Project P173-010, “Integration of Variable Generation Forecasts into System Operations.” This project, begun in 2013, aims to improve existing methods utilities/independent system operators (ISOs) use to integrate forecasts into system operations and develop new methods. This year’s goal was to identify current practices and future requirements. This was done by interacting with a wide ...

2013-12-11T23:59:59.000Z

90

Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems  

E-Print Network (OSTI)

Performance of ground source heat pump system in a near-zerosimulation tool for ground- source heat pump system designflow systems and ground source heat pump systems Abstract

Hong, Tainzhen

2010-01-01T23:59:59.000Z

91

Aquifer Vulnerability Assessment to Petroleum Contaminants Based on Fuzzy Variable Set Theory and Geographic Information System  

Science Conference Proceedings (OSTI)

It is a common environmental and hydro-geological problem that groundwater system is contaminated by petroleum hydrocarbons. An important step of pollution control and treatment is aquifer vulnerability assessment. In this paper, a karst fissure groundwater ... Keywords: fuzzy variable set, GIS, aquifer, petroleum contamination, vulnerability, assessment

Li Qingguo; Ma Zhenmin; Fang Yunzhi; Chen Shouyu

2009-07-01T23:59:59.000Z

92

Performance simulation of R410A air conditioning system with variable speeds  

Science Conference Proceedings (OSTI)

With the implementation of "Montreal protocol on substances that deplete the ozone layer", HCFCs especially R22 will be phased out. R410A (R32/R125,50/50wt%), as one alternative of R22, is a promising refrigerant for air conditioning ... Keywords: R410A, air conditioning, electronic expansion valve, performance, refrigerants, system simulation, variable speeds

Zaoxiao Zhang; Yongzhang Yu; Leping Zhang

2004-12-01T23:59:59.000Z

93

Improving Performance of Power Systems with Large-scale Variable Generation Additions  

Science Conference Proceedings (OSTI)

A power system with large-scale renewable resources, like wind and solar generation, creates significant challenges to system control performance and reliability characteristics because of intermittency and uncertainties associated with variable generation. It is important to quantify these uncertainties, and then incorporate this information into decision-making processes and power system operations. This paper presents three approaches to evaluate the flexibility needed from conventional generators and other resources in the presence of variable generation as well as provide this flexibility from a non-traditional resource – wide area energy storage system. These approaches provide operators with much-needed information on the likelihood and magnitude of ramping and capacity problems, and the ability to dispatch available resources in response to such problems.

Makarov, Yuri V.; Etingov, Pavel V.; Samaan, Nader A.; Lu, Ning; Ma, Jian; Subbarao, Krishnappa; Du, Pengwei; Kannberg, Landis D.

2012-07-22T23:59:59.000Z

94

Development of HVAC System Performance Criteria Using Factorial Design and DOE-2 Simulation  

E-Print Network (OSTI)

A new approach is described for the development of Heating, Ventilating, and Air-conditioning (HVAC) System Performance Criteria for the Texas Building Energy Design Standard. This approach integrates a design of experimental methodology and DOE-2 simulation to identify the effects of control parameters on HVAC system energy performance. Three new criteria - transport, plant, and system performance factors-are used as measures of system performance. The procedure has been applied to the development of criteria for a variable-air-volume (VAV) and a constant-air-volume (CAV) system in three Texas climates. The results show that the air distribution system pressure loss, cooling coil exit temperature set-pint, operation of an economizer, and use of dead band controls have significant effects on air transport energy use and total system performance. The selection of control strategies and set-points have a clear impact on energy use. There is also a great energy-saving potential of converting from a CAV to a VAV system.

Hou, D.; Jones, J. W.; Hunn, B. D.; Banks, J. A.

1996-01-01T23:59:59.000Z

95

Multiple-Zone Variable Refrigerant Flow System Modeling and Equipment Performance Mapping  

Science Conference Proceedings (OSTI)

We developed a variable refrigerant flow (VRF) vapor compression system model, which has five indoor units, one outdoor unit and one water heater. The VRF system can run simultaneous space conditioning (cooling or heating) and water heating. The indoor units and outdoor unit use fin-&-tube coil heat exchangers, and the water heater uses a tube-in-tube heat exchanger. The fin-&-tube coil heat exchangers are modeled using a segment-by-segment approach and the tube-in-tube water heater is modeled using a phase-by-phase approach. The compressor used is a variable-speed rotary design. We calibrated our model against a manufacturer s product literature. Based on the vapor compression system model, we investigated the methodology for generating VRF equipment performance maps, which can be used for energy simulations in TRNSYS and EnergyPlus, etc. In the study, the major independent variables for mapping are identified and the deviations between the simplified performance map and the actual equipment system simulation are quantified.

Shen, Bo [ORNL; Rice, C Keith [ORNL

2012-01-01T23:59:59.000Z

96

Modeling and design of control system for variable speed wind turbine in all operating region  

Science Conference Proceedings (OSTI)

In order to get the maximum power from the wind, the variable-speed wind turbine should run at different speed when wind speed changes. In this paper a control system is introduced to get this purpose base on establishing the three-mass model of the ... Keywords: doubly-fed induction generator (DFIG), feed-forward compensator, loop-shaping, pitch controller, speed controller, three-mass model, wind turbine

Wu Dingguo; Wang Zhixin

2008-05-01T23:59:59.000Z

97

Model of variable speed constant frequency double fed wind power generation system and analysis of its operating performance  

Science Conference Proceedings (OSTI)

Structure of variable speed constant frequency double fed wind power generation system (WPGS) was analyzed, and its model was established. Maximum power point tracking (MPPT) control, constant power control and vector control for WPGS were discussed. ... Keywords: operating performance, variable speed constant frequency, vector control, wind power generation system

Pan Tinglong; Ji Zhicheng

2009-06-01T23:59:59.000Z

98

A simple model to assess the sensitivity of grassland dairy systems to scenarios of seasonal biomass production variability  

Science Conference Proceedings (OSTI)

In recent decades, dairy herds of the peri-Mediterranean area have coped with high climatic variability, which has contributed to weakening their economic equilibrium. Survey studies highlighted that climatic impact depends on the strategies of farmers, ... Keywords: Biomass production variability, Cattle farming system, Modelling, System sensitivity

A. Lurette; C. Aubron; C. -H. Moulin

2013-04-01T23:59:59.000Z

99

Commissioning and Diagnosis of VAV Air-Conditioning Systems  

E-Print Network (OSTI)

This paper presents a fault detection and diagnosis (FDD) strategy based on system knowledge, qualitative states and object-oriented statistical process control (SPC) models for typical pressure-independent variable air volume (VAV) air-conditioning systems. Eight FDD schemes are built to detect the eleven pre-defined VAV faults using the qualitative and quantitative FDD approaches within the strategy at two steps. The ten hard faults, which would affect the system operation, are analyzed at Step 1. The soft fault, which would not affect the basic system operation but would impact the supervisory controls, is analyzed at Step 2. The strategy is tested and validated on typical VAV systems involving multiple faults, both in simulation and in-situ tests. A software package is developed as a BMS-assisted automatic commissioning tool based on the FDD strategy. Off-line tests were conducted in both the simulated building and the real building.

Qin, J.; Wang, S.; Chan, C.; Xiao, F.

2006-01-01T23:59:59.000Z

100

High Frequency Effects of Variable Frequency Drives (VFD) on Electrical Submersible Pump (ESP) Systems  

E-Print Network (OSTI)

Variable frequency drives (VFD) and subsea (umbilical) cables are frequently used in electrical submersible pump (ESP) systems for offshore platforms. There are two basic system configurations for ESP systems; VFD can be installed on the platform and the motor is connected to it through an umbilical cable, and VFD and the motor are installed closely and they are connected to the system through an umbilical cable. In this thesis, the pros and cons of each configuration are mentioned, but the focus is on the system with a VFD controlled motor through a long umbilical cable. A 36-pulse VFD is studied. Since multilevel VFDs have high frequency harmonics, high frequency modeling of the umbilical cable is used, and skin effect is also taken into consideration in the cable. The effect of the interactions between the umbilical cable and high frequency harmonics on the motor terminal voltage is explored.

Ozkentli, Esra

2012-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Variable Renewable Generation can Provide Balancing Control to the Electric Power System (Fact Sheet)  

DOE Green Energy (OSTI)

As wind and solar plants become more common in the electric power system, they may be called on to provide grid support services to help maintain system reliability. For example, through the use of inertial response, primary frequency response, and automatic generation control (also called secondary frequency response), wind power can provide assistance in balancing the generation and load on the system. These active power (i.e., real power) control services have the potential to assist the electric power system in times of disturbances and during normal conditions while also potentially providing economic value to consumers and variable renewable generation owners. This one-page, two-sided fact sheet discusses the grid-friendly support and benefits renewables can provide to the electric power system.

Not Available

2013-09-01T23:59:59.000Z

102

Quantum key distribution over 25 km with an all-fiber continuous-variable system  

E-Print Network (OSTI)

We report on the implementation of a reverse-reconciliated coherent-state continuous-variable quantum key distribution system, with which we generated secret keys at a rate of more than 2 kb/s over 25 km of optical fiber. Time multiplexing is used to transmit both the signal and phase reference in the same optical fiber. Our system includes all experimental aspects required for a field implementation of a quantum key distribution setup. Real-time reverse reconciliation is achieved by using fast and efficient LDPC error correcting codes.

Jerome Lodewyck; Matthieu Bloch; Raul Garcia-Patron; Simon Fossier; Evgueni Karpov; Eleni Diamanti; Thierry Debuisschert; Nicolas J. Cerf; Rosa Tualle-Brouri; Steven W. McLaughlin; Philippe Grangier

2007-06-28T23:59:59.000Z

103

Performance of thermal distribution systems in large commercial buildings  

NLE Websites -- All DOE Office Websites (Extended Search)

Performance of thermal distribution systems in large commercial buildings Performance of thermal distribution systems in large commercial buildings Title Performance of thermal distribution systems in large commercial buildings Publication Type Journal Article LBNL Report Number LBNL-44331 Year of Publication 2002 Authors Xu, Tengfang T., François Rémi Carrié, Darryl J. Dickerhoff, William J. Fisk, Jennifer A. McWilliams, Duo Wang, and Mark P. Modera Journal Energy and Buildings Volume 34 Start Page Chapter Pagination 215-226 Abstract This paper presents major findings of a field study on the performance of five thermal distribution systems in four large commercial buildings. The five systems studied are typical single-duct or dual-duct constant air volume (CAV) systems and variable air volume (VAV) systems, each of which serves an office building or a retail building with floor area over 2,000 m2. The air leakage from ducts are reported in terms of effective leakage area (ELA) at 25 Pa reference pressure, the ASHRAE-defined duct leakage class, and air leakage ratios. The specific ELAs ranged from 0.7 to 12.9 cm2 per m2 of duct surface area, and from 0.1 to 7.7 cm2 per square meter of floor area served. The leakage classes ranged from 34 to 757 for the five systems and systems sections tested. The air leakage ratios are estimated to be up to one-third of the fan- supplied airflow in the constant-air-volume systems. The specific ELAs and leakage classes indicate that air leakage in large commercial duct systems varies significantly from system to system, and from system section to system section even within the same thermal distribution system. The duct systems measured are much leakier than the ductwork specified as "unsealed ducts" by ASHRAE. Energy losses from supply ducts by conduction (including convection and radiation) are found to be significant, on the scale similar to the losses induced by air leakage in the duct systems. The energy losses induced by leakage and conduction suggest that there are significant energy-savings potentials from duct-sealing and insulation practice in large commercial buildings

104

Mixed variable optimization of a load-bearing thermal insulation system  

E-Print Network (OSTI)

categorical variables, mixed variable programming, pattern search algorithm, filter algorithm, nonlinear constraints Abstract: This paper describes the optimization of a load-bearing thermal insulation system characterized by hot and cold surfaces with a series of heat intercepts and insulators between them. The optimization problem is represented as a mixed variable programming (MVP) problem with nonlinear constraints, in which the objective is to minimize the power required to maintain the heat intercepts at fixed temperatures so that one surface is kept sufficiently cold. MVP problems are more general than mixed integer nonlinear programming (MINLP) problems in that the discrete variables are categorical; i.e., they must always take on values from a predefined enumerable set or list. Thus, traditional approaches that use branch and bound techniques cannot be applied. In a previous paper, a linearly constrained version of this problem was solved numerically using the Audet-Dennis generalized pattern search (GPS) method for MVP problems. However, this algorithm may not work for problems with general nonlinear constraints. A new algorithm that extends that of Audet and Dennis by incorporating a filter to handle nonlinear constraints makes it possible to solve the more general problem. Additional nonlinear constraints on stress, May 5, 2003 2 mass, and thermal contraction are added to that of the previous work in an effort to find a more realistic feasible design. Several computational experiments show a substantial improvement in power required to maintain the system, as compared to the previous literature. The addition of the new constraints leads to a very different design without significantly changing the power required. The results demonstrate that the new algorithm can be applied to a very broad class of optimization problems, for which no previous algorithm with provable convergence results could be applied. 1

Mark A. Abramson

2002-01-01T23:59:59.000Z

105

Energy Simulation of Integrated Multiple-Zone Variable Refrigerant Flow System  

Science Conference Proceedings (OSTI)

We developed a detailed steady-state system model, to simulate the performance of an integrated five-zone variable refrigerant flow (VRF)heat pump system. The system is multi-functional, capable of space cooling, space heating, combined space cooling and water heating, and dedicated water heating. Methods were developed to map the VRF performance in each mode, based on the abundant data produced by the equipment system model. The performance maps were used in TRNSYS annual energy simulations. Using TRNSYS, we have successfully setup and run cases for a multiple-split, VRF heat pump and dehumidifier combination in 5-zone houses in 5 climates that control indoor dry-bulb temperature and relative humidity. We compared the calculated energy consumptions for the VRF heat pump against that of a baseline central air source heat pump, coupled with electric water heating and the standalone dehumidifiers. In addition, we investigated multiple control scenarios for the VRF heat pump, i.e. on/off control, variable indoor air flow rate, and using different zone temperature setting schedules, etc. The energy savings for the multiple scenarios were assessed.

Shen, Bo [ORNL; Rice, C Keith [ORNL; Baxter, Van D [ORNL

2013-01-01T23:59:59.000Z

106

Analysis of national pay-as-you-drive insurance systems and other variable driving charges  

SciTech Connect

Under Pay as You Drive insurance (PAYD), drivers would pay part of their automobile insurance premium as a per-gallon surcharge every time they filled their gas tank. By transfering a portion of the cost of owning a vehicle from a fixed cost to a variable cost, PAYD would discourage driving. PAYD has been proposed recently in California as a means of reforming how auto insurance is provided. PAYD proponents claim that, by forcing drivers to purchase at least part of their insurance every time they refuel their car, PAYD would reduce or eliminate the need for uninsured motorist coverage. Some versions of PAYD proposed in California have been combined with a no-fault insurance system, with the intention of further reducing premiums for the average driver. Other states have proposed PAYD systems that would base insurance premiums on annual miles driven. In this report we discuss some of the qualitative issues surrounding adoption of PAYD and other policies that would convert other fixed costs of driving (vehicle registration, safety/emission control system inspection, and driver license renewal) to variable costs. We examine the effects of these policies on two sets of objectives: objectives related to auto insurance reform, and those related to reducing fuel consumption, CO{sub 2} emissions, and vehicle miles traveled. We pay particular attention to the first objective, insurance reform, since this has generated the most interest in PAYD to date, at least at the state level.

Wenzel, T.

1995-07-01T23:59:59.000Z

107

Combined transmission distribution load flow model employing system reduction and voltage variable load representation  

SciTech Connect

In the few decades since its introduction the digital computer has found widespread application within the electric power industry. One of the more fruitful areas for its utilization has been in the determination of the steady-state voltage conditions throughout the system. A power system naturally breaks down into two very distinct parts: transmission and distribution, and traditionally, the voltage problem has been separated the same way. In the transmission system it is referred to as a load flow problem, and in the distribution part it is called a voltage profile. In addition, the loads are often treated differently. Transmission loads are usually considered to be constant power, and the equations that result are therefore nonlinear. In the distribution portion the loads, though specified in terms of power, are sometimes handled as constant impedances, with linear equations. This work produced a new model wherein a mesh transmission system is combined with a radial distribution system and they are solved simultaneously. A system reduction technique is used to eliminate part of the transmission system from consideration, and thereby keep the problem at a manageable size. The solution algorithm incorporates a voltage variable load model which approximates the behavior of real loads more nearly than the common representations.

Enouen, P.W.

1985-01-01T23:59:59.000Z

108

Application of Coulomb wave function discrete variable representation to atomic systems in strong laser fields  

SciTech Connect

We present an efficient and accurate grid method for solving the time-dependent Schroedinger equation for an atomic system interacting with an intense laser pulse. Instead of the usual finite difference (FD) method, the radial coordinate is discretized using the discrete variable representation (DVR) constructed from Coulomb wave functions. For an accurate description of the ionization dynamics of atomic systems, the Coulomb wave function discrete variable representation (CWDVR) method needs three to ten times fewer grid points than the FD method. The resultant grid points of the CWDVR are distributed unevenly so that one has a finer grid near the origin and a coarser one at larger distances. The other important advantage of the CWDVR method is that it treats the Coulomb singularity accurately and gives a good representation of continuum wave functions. The time propagation of the wave function is implemented using the well-known Arnoldi method. As examples, the present method is applied to multiphoton ionization of both the H atom and the H{sup -} ion in intense laser fields. The short-time excitation and ionization dynamics of H by an abruptly introduced static electric field is also investigated. For a wide range of field parameters, ionization rates calculated using the present method are in excellent agreement with those from other accurate theoretical calculations.

Peng, L.-Y.; Starace, Anthony F. [Department of Physics and Astronomy, The University of Nebraska-Lincoln, Nebraska 68588-0111 (United States)

2006-10-21T23:59:59.000Z

109

Radar Observations of Convective System Variability in Relationship to African Easterly Waves during the 2006 AMMA Special Observing Period  

E-Print Network (OSTI)

A radar-based analysis of the structure, motion, and rainfall variability of westward-propagating squall-line mesoscale convective systems (SLMCSs) in Niamey, Niger, during the African Monsoon Multidisciplinary Activities ...

Williams, Earle R.

110

Radar Observations of Convective System Variability in Relationship to African Easterly Waves during the 2006 AMMA Special Observing Period  

Science Conference Proceedings (OSTI)

A radar-based analysis of the structure, motion, and rainfall variability of westward-propagating squall-line mesoscale convective systems (SLMCSs) in Niamey, Niger, during the African Monsoon Multidisciplinary Activities (AMMA) 2006 special ...

Rosana Nieto Ferreira; Thomas Rickenbach; Nick Guy; Earle Williams

2009-12-01T23:59:59.000Z

111

Origin of Pacific Multidecadal Variability in Community Climate System Model, Version 3 (CCSM3): A Combined Statistical and Dynamical Assessment  

Science Conference Proceedings (OSTI)

Observations indicate that Pacific multidecadal variability (PMV) is a basinwide phenomenon with robust tropical–extratropical linkage, though its genesis remains the topic of much debate. In this study, the PMV in the Community Climate System ...

Yafang Zhong; Zhengyu Liu; R. Jacob

2008-01-01T23:59:59.000Z

112

Soft x-ray array system with variable filters for the DIII-D tokamak  

Science Conference Proceedings (OSTI)

Recent upgrades to the soft x-ray (SXR) array system on the DIII-D tokamak are described. The system consists of two 32-channel arrays at one toroidal location and three toroidally distributed 12-channel arrays. The 32-channel arrays have been completely rebuilt to allow the switching of SXR filters without breaking vacuum. The 12-channel arrays have had upgrades performed to detectors, view slits, and data acquisition. Absolute extreme ultraviolet (AXUV) photodiodes are used as detectors in all arrays, allowing detection of photons ranging in energy from 2 eV to 10 keV. In the fixed-filter arrays, 127 {mu}m Be filters are used. In the variable-filter arrays, filter wheels are used to switch between five different possible pinhole/filter combinations.

Hollmann, E. M.; Chousal, L.; Hernandez, R. [University of California, San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States); Fisher, R. K.; Jackson, G. L.; Pidcoe, S. V.; Taussig, D. A. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Lanctot, M. J. [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States); Shankara, J. [Institute for Plasma Research, Bhat, Gandhinagar (India)

2011-11-15T23:59:59.000Z

113

Probabilistic Approach to Quantifying the Contribution of Variable Generation and Transmission to System Reliability: Preprint  

SciTech Connect

The increasing electrical load served by variable generation (VG), such as wind and solar energy, in the United States and many other countries has stimulated an interesting line of research to better quantify the capacity value of these resources. Methods applied traditionally to thermal units based on their average outage rates do not apply to VG because of their uncertain and non-dispatchable nature. The North American Electric Reliability Corporation's Integration of Variable Generation Task Force recently released a report that highlighted the need to develop and benchmark underlying loss-of-load expectation and related metrics that reasonably and fairly calculate the contribution to planning reserves, or capacity value, of solar and wind power. As the fraction of generation coming from VG becomes more significant, their estimated capacity value will have a larger impact on system planning. In this paper, we provide a method to include VG in traditional probabilistic-based adequacy methods. This method has been implemented in the Renewable Energy Probabilistic Resource Assessment tool developed at the National Renewable Energy Laboratory. Through an example based on the U.S. Western Interconnection, this method is applied to assess the effect that transmission can have on resource adequacy. We also analyze the interactions between available transmission and capacity value for VG.

Ibanez, E.; Milligan, M.

2012-09-01T23:59:59.000Z

114

Probabilistic Approach to Quantifying the Contribution of Variable Generation and Transmission to System Reliability: Preprint  

DOE Green Energy (OSTI)

The increasing electrical load served by variable generation (VG), such as wind and solar energy, in the United States and many other countries has stimulated an interesting line of research to better quantify the capacity value of these resources. Methods applied traditionally to thermal units based on their average outage rates do not apply to VG because of their uncertain and non-dispatchable nature. The North American Electric Reliability Corporation's Integration of Variable Generation Task Force recently released a report that highlighted the need to develop and benchmark underlying loss-of-load expectation and related metrics that reasonably and fairly calculate the contribution to planning reserves, or capacity value, of solar and wind power. As the fraction of generation coming from VG becomes more significant, their estimated capacity value will have a larger impact on system planning. In this paper, we provide a method to include VG in traditional probabilistic-based adequacy methods. This method has been implemented in the Renewable Energy Probabilistic Resource Assessment tool developed at the National Renewable Energy Laboratory. Through an example based on the U.S. Western Interconnection, this method is applied to assess the effect that transmission can have on resource adequacy. We also analyze the interactions between available transmission and capacity value for VG.

Ibanez, E.; Milligan, M.

2012-09-01T23:59:59.000Z

115

Analysis and Simulation of Mechanical Trains Driven by Variable Frequency Drive Systems  

E-Print Network (OSTI)

Induction motors and Variable Frequency Drives (VFDs) are widely used in industry to drive machinery trains. However, some mechanical trains driven by VFD-motor systems have encountered torsional vibration problems. This vibration can induce large stresses on shafts and couplings, and reduce the lifetime of these mechanical parts. Long before the designed lifetime, the mechanical train may encounter failure. This thesis focuses on VFDs with voltage source rectifiers for squirrel-cage induction motors of open-loop Volts/Hertz and closed-loop Field Oriented Control (FOC). First, the torsional vibration problems induced by VFDs are introduced. Then, the mathematical model for a squirrel-cage induction motor is given. Two common control methods used in VFD are discussed - open-loop Volts/Hertz and closed-loop FOC. SimPowerSystems and SimMechanics are used as the modeling software for electrical systems and mechanical systems respectively. Based on the models and software, two interface methods are provided for modeling the coupled system. A simple system is tested to verify the interface methods. The study of open-loop Volts/Hertz control method is performed. The closed-form of electromagnetic torque sideband frequency due to Pulse Width Modulation is given. A torsional resonance case is illustrated. The effects of non-ideal power switches are studied, which shows little in uence on the system response but which uses little energy consumption. A study of a non-ideal DC bus indicates that a DC bus voltage ripple can also induce a big torsional vibration. Next, the study of the closed-loop FOC control method is presented. Simulation for a complete VFD machinery train is performed. With the recti er and DC bus dynamic braking, the system shows a better performance than the ideal-DC bus case. Lastly, a parametric study of the FOC controller is performed. The effects of primary parameters are discussed. The results indicate that some control parameters (i.e. speed ramps, proportional gain in speed PI controller) are also responsible for the mechanical torsional vibration.

Han, Xu

2010-12-01T23:59:59.000Z

116

Second law analysis of advanced power generation systems using variable temperature heat sources  

SciTech Connect

Many systems produce power using variable temperature (sensible) heat sources. The Heat Cycle Research Program is currently investigating the potential improvements to such power cycles utilizing moderate temperature geothermal resources to produce electrical power. It has been shown that mixtures of saturated hydrocarbons (alkanes) or halogenated hydrocarbons operating with a supercritical Rankine cycle gave improved performance over boiling Rankine cycles with the pure working fluids for typical applications. Recently, in addition to the supercritical Rankine Cycle, other types of cycles have been proposed for binary geothermal service. This paper explores the limits on efficiency of a feasible plant and discusses the methods used in these advanced concept plants to achieve the maximum possible efficiency. The advanced plants considered appear to be approaching the feasible limit of performance so that the designer must weigh all considerations to fine the best plant for a given service. These results would apply to power systems in other services as well as to geothermal power plants. 17 refs., 15 figs.

Bliem, C.J.; Mines, G.L.

1990-01-01T23:59:59.000Z

117

Recent Developments of the Modelica"Buildings" Library for Building Energy and Control Systems  

Science Conference Proceedings (OSTI)

At the Modelica 2009 conference, we introduced the Buildings library, a freely available Modelica library for building energy and control systems. This paper reports the updates of the library and presents example applications for a range of heating, ventilation and air conditioning (HVAC) systems. Over the past two years, the library has been further developed. The number of HVAC components models has been doubled and various components have been revised to increase numerical robustness.The paper starts with an overview of the library architecture and a description of the main packages. To demonstrate the features of the Buildings library, applications that include multizone airflow simulation as well as supervisory and local loop control of a variable air volume (VAV) system are briefly described. The paper closes with a discussion of the current development.

Wetter, Michael; Zuo, Wangda; Nouidui, Thierry Stephane

2011-04-01T23:59:59.000Z

118

Theoretical Study of a Novel Control Method of VAV Air-conditioning System Based on MATLAB  

E-Print Network (OSTI)

The main purpose of this study is to put forward a novel nonlinear feedback control strategy on controlling indoor air temperature by variable air volume. A dynamic model of a typical room for a VAV air-conditioning system is established. The performance of the novel control strategy is investigated. Simulation of the controlling air temperature, on which the novel strategy is adopted, was carried out based on MATLAB in the VAV system. In order to show that the novel control strategy outperforms conventional PID control, a comparison is made between the performance of conventional PID and the novel nonlinear feedback control strategy. The results show that nonlinear feedback control strategy outperforms a conventional PID control system in terms of celerity, stability and other aspects.

Shi, Z.; Hu, S.; Wang, G.; Li, A.

2006-01-01T23:59:59.000Z

119

Analysis of the electrical harmonic characteristics of a slip recovery variable speed generating system for wind turbine applications  

SciTech Connect

Variable speed electric generating technology can enhance the general use of wind energy in electric utility applications. This enhancement results from two characteristic properties of variable speed wind turbine generators: an improvement in drive train damping characteristics, which results in reduced structural loading on the entire wind turbine system, and an improvement in the overall efficiency by using a more sophisticated electrical generator. Electronic converter systems are the focus of this investigation -- in particular, the properties of a wound-rotor induction generator with the slip recovery system and direct-current link converter. Experience with solid-state converter systems in large wind turbines is extremely limited. This report presents measurements of electrical performances of the slip recovery system and is limited to the terminal characteristics of the system. Variable speed generating systems working effectively in utility applications will require a satisfactory interface between the turbine/generator pair and the utility network. The electrical testing described herein focuses largely on the interface characteristics of the generating system. A MOD-O wind turbine was connected to a very strong system; thus, the voltage distortion was low and the total harmonic distortion in the utility voltage was less than 3% (within the 5% limit required by most utilities). The largest voltage component of a frequency below 60 Hz was 40 dB down from the 60-Hz< component. 8 refs., 14 figs., 8 tabs.

Herrera, J.I.; Reddoch, T.W.

1988-02-01T23:59:59.000Z

120

New Close Binary Systems from the SDSS-I (Data Release Five) and the Search for Magnetic White Dwarfs in Cataclysmic Variable Progenitor Systems  

E-Print Network (OSTI)

We present the latest catalog of more than 1200 spectroscopically-selected close binary systems observed with the Sloan Digital Sky Survey through Data Release Five. We use the catalog to search for magnetic white dwarfs in cataclysmic variable progenitor systems. Given that approximately 25% of cataclysmic variables contain a magnetic white dwarf, and that our large sample of close binary systems should contain many progenitors of cataclysmic variables, it is quite surprising that we find only two potential magnetic white dwarfs in this sample. The candidate magnetic white dwarfs, if confirmed, would possess relatively low magnetic field strengths (B_WD < 10 MG) that are similar to those of intermediate-Polars but are much less than the average field strength of the current Polar population. Additional observations of these systems are required to definitively cast the white dwarfs as magnetic. Even if these two systems prove to be the first evidence of detached magnetic white dwarf + M dwarf binaries, th...

Silvestri, Nicole M; Hawley, Suzanne L; West, Andrew A; Schmidt, Gary D; Liebert, James; Szkody, Paula; Mannikko, Lee; Wolfe, Michael A; Barentine, J C; Brewington, Howard J; Harvanek, Michael; Krzesinski, Jurik; Long, Dan; Schneider, Donald P; Snedden, Stephanie A

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Controlled operation of variable speed driven permanent magnet synchronous generator for wind energy conversion systems  

Science Conference Proceedings (OSTI)

The introduction of distributed generation through renewable sources of energy has opened a challenging area for power engineers. As these sources are intermittent in nature, variable speed electric generators are employed for harnessing electrical energy ... Keywords: permanent magnet synchronous generator, power conditioners, power quality, variable speed generators, wind energy

Rajveer Mittal; K. S. Sandhu; D. K. Jain

2009-02-01T23:59:59.000Z

122

Application of partial mutual information variable selection to ANN forecasting of water quality in water distribution systems  

Science Conference Proceedings (OSTI)

Recent trends in the management of water supply have increased the need for modelling techniques that can provide reliable, efficient, and accurate representation of the complex, non-linear dynamics of water quality within water distribution systems. ... Keywords: Artificial neural networks, Chlorine disinfection, Chlorine residual forecasting, Input variable selection, Partial mutual information, Water quality modelling

Robert J. May; Graeme C. Dandy; Holger R. Maier; John B. Nixon

2008-10-01T23:59:59.000Z

123

HEAT PUMP AND AIR CONDITIONING SYSTEM ANALYSIS BASED ON VARIABLE SPEED COMPRESSOR.  

E-Print Network (OSTI)

??Mechanical Engineering M.S.E. Experiments were carried out to investigate the effect of ambient air temperatures on the heat pump performance using a variable speed compressor.… (more)

Zhang, Hao

2010-01-01T23:59:59.000Z

124

Modeling the Biosphere–Atmosphere System: The Impact of the Subgrid Variability in Rainfall Interception  

Science Conference Proceedings (OSTI)

Subgrid variability in rainfall distribution has been widely recognized as an important factor to include in the representation of land surface hydrology within climate models. In this paper, using West Africa as a case study, the impact of the ...

Guiling Wang; Elfatih A. B. Eltahir

2000-08-01T23:59:59.000Z

125

Mechanisms of Decadal Arctic Climate Variability in the Community Climate System Model, Version 2 (CCSM2)  

Science Conference Proceedings (OSTI)

Several mechanisms have been proposed to explain natural climate variability in the Arctic. These include processes related to the influence of the North Atlantic Oscillation/Arctic Oscillation (NAO/AO), anticyclonic/cyclonic regimes, changes in ...

Hugues Goosse; Marika M. Holland

2005-09-01T23:59:59.000Z

126

Performance of variable bit rate wireless communication systems over Nakagami fading channels  

Science Conference Proceedings (OSTI)

Currently, several wireless standards, both for voice and data communications as well as wireless local area networks, achieve a variable bit rate by different combinations of either binary or non-binary modulation and convolutional codes having different ...

Patrick Count; Clark Robertson

2003-10-01T23:59:59.000Z

127

Effects of Weather Variability and Soil Parameter Uncertainty on the Soil-Crop-Climate System  

Science Conference Proceedings (OSTI)

The variability of crop and soil states due to uncertain climatic inputs and soil properties is quantified using a mathematical representation of the physiological, biochemical, hydrological, and physical processes related to plant growth. The ...

Angelos L. Protopapas; Rafael L. Bras

1993-04-01T23:59:59.000Z

128

Tests with a line-commutated converter as a variable inductive load on the Bonneville Power Administration transmission system  

DOE Green Energy (OSTI)

A twelve-pulse, line-commutated converter, with a steady-state rating of 2.5 kV and 5.5 kA, formerly used for charging and discharging a superconducting magnet, was reconfigured as a static reactive power load. Tests staged at the Tacoma, WA, substation of the Bonneville Power Administration (BPA) revealed that the converter could be used as a variable inductive load, provided a stable current controller was installed. The unit was modulated as a variable VAR load following a sinusoidal VAR demand signal with an amplitude up to 14.8 MVAR. The total losses at maximum VAR output were 370 kW. This paper explains the necessary modifications of the converter to operate as a variable reactive load. Measured current waveshapes are analyzed. The effects of such a load on the BPA transmission system are presented.

Boenig, H.J.; Hauer, J.F.; Nielsen, R.G.

1986-01-01T23:59:59.000Z

129

Ota City : characterizing output variability from 553 homes with residential PV systems on a distribution feeder.  

DOE Green Energy (OSTI)

This report describes in-depth analysis of photovoltaic (PV) output variability in a high-penetration residential PV installation in the Pal Town neighborhood of Ota City, Japan. Pal Town is a unique test bed of high-penetration PV deployment. A total of 553 homes (approximately 80% of the neighborhood) have grid-connected PV totaling over 2 MW, and all are on a common distribution line. Power output at each house and irradiance at several locations were measured once per second in 2006 and 2007. Analysis of the Ota City data allowed for detailed characterization of distributed PV output variability and a better understanding of how variability scales spatially and temporally. For a highly variable test day, extreme power ramp rates (defined as the 99th percentile) were found to initially decrease with an increase in the number of houses at all timescales, but the reduction became negligible after a certain number of houses. Wavelet analysis resolved the variability reduction due to geographic diversity at various timescales, and the effect of geographic smoothing was found to be much more significant at shorter timescales.

Stein, Joshua S.; Miyamoto, Yusuke (Kandenko, Ibaraki, Japan); Nakashima, Eichi (Kandenko, Ibaraki, Japan); Lave, Matthew

2011-11-01T23:59:59.000Z

130

New Close Binary Systems from the SDSS-I (Data Release Five) and the Search for Magnetic White Dwarfs in Cataclysmic Variable Progenitor Systems  

E-Print Network (OSTI)

We present the latest catalog of more than 1200 spectroscopically-selected close binary systems observed with the Sloan Digital Sky Survey through Data Release Five. We use the catalog to search for magnetic white dwarfs in cataclysmic variable progenitor systems. Given that approximately 25% of cataclysmic variables contain a magnetic white dwarf, and that our large sample of close binary systems should contain many progenitors of cataclysmic variables, it is quite surprising that we find only two potential magnetic white dwarfs in this sample. The candidate magnetic white dwarfs, if confirmed, would possess relatively low magnetic field strengths (B_WD < 10 MG) that are similar to those of intermediate-Polars but are much less than the average field strength of the current Polar population. Additional observations of these systems are required to definitively cast the white dwarfs as magnetic. Even if these two systems prove to be the first evidence of detached magnetic white dwarf + M dwarf binaries, there is still a large disparity between the properties of the presently known cataclysmic variable population and the presumed close binary progenitors.

Nicole M. Silvestri; Mara P. Lemagie; Suzanne L. Hawley; Andrew A. West; Gary D. Schmidt; James Liebert; Paula Szkody; Lee Mannikko; Michael A. Wolfe; J. C. Barentine; Howard J. Brewington; Michael Harvanek; Jurik Krzesinski; Dan Long; Donald P. Schneider; Stephanie A. Snedden

2007-04-05T23:59:59.000Z

131

A variable speed wind generator maximum power tracking based on adaptative neuro-fuzzy inference system  

Science Conference Proceedings (OSTI)

The power from wind varies depending on the environmental factors. Many methods have been proposed to locate and track the maximum power point (MPPT) of the wind, such as the fuzzy logic (FL), artificial neural network (ANN) and neuro-fuzzy. In this ... Keywords: ANFIS, MPPT, Power generation, Variable speed wind generator, Wind energy

A. Meharrar; M. Tioursi; M. Hatti; A. Boudghčne Stambouli

2011-06-01T23:59:59.000Z

132

Study on Matching Strategies and Simulation of Hydro-mechanical Continuously Variable Transmission System of Tractor  

Science Conference Proceedings (OSTI)

In this paper, the engine output torque model and fuel consumption model are established based on engine test results. The engine rotary speed feature denotes the relationship between the engine rotary speed and the throttle opening when engine works ... Keywords: Tractor, Hydro-mechanical continuously variable transmission, Matching strategies, Simulation

Xu Liyou; Zhou Zhili; Cao Qingmei; Zhang Mingzhu

2010-05-01T23:59:59.000Z

133

Energy studies on central and variable refrigerant flow air-conditioning systems  

Science Conference Proceedings (OSTI)

Air-conditioning is a major contributor to energy end-use in commercial buildings. Different types of airconditioning systems are installed in commercial buildings including packaged systems

2012-01-01T23:59:59.000Z

134

Final report on LDRD project: Simulation/optimization tools for system variability analysis  

SciTech Connect

>This work was conducted during FY98 (Proposal Number 98-0036) and FY99 (Proposal Number 99-0818) under the auspices of the Sandia National Laboratories Laboratory-Directed Research and Development (LDRD) program. Electrical simulation typically treats a single data point in the very large input space of component properties. For electrical simulation to reach its full potential as a design tool, it must be able to address the unavoidable variability and uncertainty in component properties. Component viability is strongly related to the design margin (and reliability) of the end product. During the course of this project, both tools and methodologies were developed to enable analysis of variability in the context of electrical simulation tools. Two avenues to link relevant tools were also developed, and the resultant toolset was applied to a major component.

R. L. Bierbaum; R. F. Billau; J. E. Campbell; K. D. Marx; R. J. Sikorski; B. M. Thompson; S. D. Wix

1999-10-01T23:59:59.000Z

135

Performance Variability  

NLE Websites -- All DOE Office Websites (Extended Search)

Variability Variability of Highly Parallel Architectures William T.C. Kramer 1 and Clint Ryan 2 1 Department of Computing Sciences, University of California at Berkeley and the National Energy Research Scientific Computing Center, Lawrence Berkeley National Laboratory 2 Department of Computing Sciences, University of California at Berkeley Abstract. The design and evaluation of high performance computers has concentrated on increasing computational speed for applications. This performance is often measured on a well configured dedicated sys- tem to show the best case. In the real environment, resources are not always dedicated to a single task, and systems run tasks that may influ- ence each other, so run times vary, sometimes to an unreasonably large extent. This paper explores the amount of variation seen across four large distributed memory systems in a systematic manner. It then

136

Boussinesq systems in two space dimensions over a variable bottom for the generation and propagation of tsunami waves  

E-Print Network (OSTI)

Considered here are Boussinesq systems of equations of surface water wave theory over a variable bottom. A simplified such Boussinesq system is derived and solved numerically by the standard Galerkin-finite element method. We study by numerical means the generation of tsunami waves due to bottom deformation and we compare the results with analytical solutions of the linearized Euler equations. Moreover, we study tsunami wave propagation in the case of the Java 2006 event, comparing the results of the Boussinesq model with those produced by the finite difference code MOST, that solves the shallow water wave equations.

Mitsotakis, Dimitrios

2009-01-01T23:59:59.000Z

137

Multipartite entanglement in three-mode Gaussian states of continuous variable systems: Quantification, sharing structure and decoherence  

E-Print Network (OSTI)

We present a complete analysis of multipartite entanglement of three-mode Gaussian states of continuous variable systems. We derive standard forms which characterize the covariance matrix of pure and mixed three-mode Gaussian states up to local unitary operations, showing that the local entropies of pure Gaussian states are bound to fulfill a relationship which is stricter than the general Araki-Lieb inequality. Quantum correlations will be quantified by a proper convex roof extension of the squared logarithmic negativity (the contangle), satisfying a monogamy relation for multimode Gaussian states, whose proof will be reviewed and elucidated. The residual contangle, emerging from the monogamy inequality, is an entanglement monotone under Gaussian local operations and classical communication and defines a measure of genuine tripartite entanglement. We analytically determine the residual contangle for arbitrary pure three-mode Gaussian states and study the distribution of quantum correlations for such states. This will lead us to show that pure, symmetric states allow for a promiscuous entanglement sharing, having both maximum tripartite residual entanglement and maximum couplewise entanglement between any pair of modes. We thus name these states GHZ/$W$ states of continuous variable systems because they are simultaneous continuous-variable counterparts of both the GHZ and the $W$ states of three qubits. We finally consider the action of decoherence on tripartite entangled Gaussian states, studying the decay of the residual contangle. The GHZ/$W$ states are shown to be maximally robust under both losses and thermal noise.

Gerardo Adesso; Alessio Serafini; Fabrizio Illuminati

2005-12-16T23:59:59.000Z

138

Coexistence of unlimited bipartite and genuine multipartite entanglement: Promiscuous quantum correlations arising from discrete to continuous variable systems  

E-Print Network (OSTI)

Quantum mechanics imposes 'monogamy' constraints on the sharing of entanglement. We show that, despite these limitations, entanglement can be fully 'promiscuous', i.e. simultaneously present in unlimited two-body and many-body forms in states living in an infinite-dimensional Hilbert space. Monogamy just bounds the divergence rate of the various entanglement contributions. This is demonstrated in simple families of N-mode (N >= 4) Gaussian states of light fields or atomic ensembles, which therefore enable infinitely more freedom in the distribution of information, as opposed to systems of individual qubits. Such a finding is of importance for the quantification, understanding and potential exploitation of shared quantum correlations in continuous variable systems. We discuss how promiscuity gradually arises when considering simple families of discrete variable states, with increasing Hilbert space dimension towards the continuous variable limit. Such models are somehow analogous to Gaussian states with asymptotically diverging, but finite squeezing. In this respect, we find that non-Gaussian states (which in general are more entangled than Gaussian states), exhibit also the interesting feature that their entanglement is more shareable: in the non-Gaussian multipartite arena, unlimited promiscuity can be already achieved among three entangled parties, while this is impossible for Gaussian, even infinitely squeezed states.

Gerardo Adesso; Marie Ericsson; Fabrizio Illuminati

2006-09-22T23:59:59.000Z

139

Coexistence of unlimited bipartite and genuine multipartite entanglement: Promiscuous quantum correlations arising from discrete to continuous-variable systems  

SciTech Connect

Quantum mechanics imposes 'monogamy' constraints on the sharing of entanglement. We show that, despite these limitations, entanglement can be fully 'promiscuous', i.e., simultaneously present in unlimited two-body and many-body forms in states living in an infinite-dimensional Hilbert space. Monogamy just bounds the divergence rate of the various entanglement contributions. This is demonstrated in simple families of N-mode (N{>=}4) Gaussian states of light fields or atomic ensembles, which therefore enable infinitely more freedom in the distribution of information, as opposed to systems of individual qubits. Such a finding is of importance for the quantification, understanding, and potential exploitation of shared quantum correlations in continuous variable systems. We discuss how promiscuity gradually arises when considering simple families of discrete variable states, with increasing Hilbert space dimension towards the continuous variable limit. Such models are somehow analogous to Gaussian states with asymptotically diverging, but finite, squeezing. In this respect, we find that non-Gaussian states (which in general are more entangled than Gaussian states) exhibit also the interesting feature that their entanglement is more shareable: in the non-Gaussian multipartite arena, unlimited promiscuity can be already achieved among three entangled parties, while this is impossible for Gaussian, even infinitely squeezed states.

Adesso, Gerardo [Dipartimento di Fisica 'E. R. Caianiello', Universita degli Studi di Salerno, Via S. Allende, I-84081 Baronissi (Italy); CNR-INFM Coherentia , Naples (Italy) and INFN Sezione di Napoli-Gruppo Collegato di Salerno (Italy); Grup d'Informacio Quantica, Universitat Autonoma de Barcelona, E-08193 Bellaterra (Barcelona) (Spain); Ericsson, Marie [Centre for Quantum Computation, DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Illuminati, Fabrizio [CNR-INFM Coherentia , Naples (Italy) and INFN Sezione di Napoli-Gruppo ollegato di Salerno (Italy); Dipartimento di Matematica e Informatica Universita degli Studi di Salerno, Via Ponte don Melillo, I-84084 Fisciano (Italy); ISI Foundation for Scientific Interchange, Viale Settimio Severo 65, I-10133 Turin (Italy)

2007-08-15T23:59:59.000Z

140

Climate Variability over the Tropical Indian Ocean Sector in the NSIPP Seasonal Forecast System  

Science Conference Proceedings (OSTI)

Prospects for forecasting Indian dipole mode (IDM) events with lead times of a season or more are examined using the NASA Seasonal-to-Interannual Prediction Project (NSIPP) coupled-model forecast system. The mean climatology of the system over ...

Roxana C. Wajsowicz

2004-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Multiscale Diagnosis of the North American Monsoon System Using a Variable-Resolution GCM  

Science Conference Proceedings (OSTI)

The onset and evolution of the North American monsoon system during the summer of 1993 were examined from regional to large scales using the National Aeronautics and Space Administration (NASA) Goddard Earth Observing System (GEOS) stretched-grid ...

Ernesto Hugo Berbery; Michael S. Fox-Rabinovitz

2003-06-01T23:59:59.000Z

142

Optimizing the operation of an urban district heating system by means of variable speed drives  

Science Conference Proceedings (OSTI)

In this work is presenting an urban district heating system which is subjected to a modernization process. The urban district heating system is composed by the pumping station of the primary heat carrier and the district heating stations. The modernization ... Keywords: district heating system, energetic efficiency, pumping station, static frequency converter, testing

Sorin Ioan Deaconu; Gabriel Nicolae Popa; Iosif Popa

2008-07-01T23:59:59.000Z

143

Multipartite entanglement in three-mode Gaussian states of continuous-variable systems: Quantification, sharing structure, and decoherence  

Science Conference Proceedings (OSTI)

We present a complete analysis of the multipartite entanglement of three-mode Gaussian states of continuous-variable systems. We derive standard forms which characterize the covariance matrix of pure and mixed three-mode Gaussian states up to local unitary operations, showing that the local entropies of pure Gaussian states are bound to fulfill a relationship which is stricter than the general Araki-Lieb inequality. Quantum correlations can be quantified by a proper convex roof extension of the squared logarithmic negativity, the continuous-variable tangle, or contangle. We review and elucidate in detail the proof that in multimode Gaussian states the contangle satisfies a monogamy inequality constraint [G. Adesso and F. Illuminati, New J. Phys8, 15 (2006)]. The residual contangle, emerging from the monogamy inequality, is an entanglement monotone under Gaussian local operations and classical communications and defines a measure of genuine tripartite entanglements. We determine the analytical expression of the residual contangle for arbitrary pure three-mode Gaussian states and study in detail the distribution of quantum correlations in such states. This analysis yields that pure, symmetric states allow for a promiscuous entanglement sharing, having both maximum tripartite entanglement and maximum couplewise entanglement between any pair of modes. We thus name these states GHZ/W states of continuous-variable systems because they are simultaneous continuous-variable counterparts of both the GHZ and the W states of three qubits. We finally consider the effect of decoherence on three-mode Gaussian states, studying the decay of the residual contangle. The GHZ/W states are shown to be maximally robust against losses and thermal noise.

Adesso, Gerardo [Dipartimento di Fisica 'E. R. Caianiello', Universita degli Studi di Salerno, CNR-Coherentia, Gruppo di Salerno, and INFN Sezione di Napoli-Gruppo Collegato di Salerno, Via S. Allende, 84081 Baronissi (Saudi Arabia) (Italy); Centre for Quantum Computation, DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Serafini, Alessio [Institute for Mathematical Sciences, Imperial College, London, London SW7 2PE, United Kingdom and QOLS, Blackett Laboratory, Imperial College, London, Prince Consort Road, London SW7 2BW (United Kingdom); Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Illuminati, Fabrizio [Dipartimento di Fisica 'E. R. Caianiello', Universita degli Studi di Salerno, CNR-Coherentia, Gruppo di Salerno, and INFN Sezione di Napoli-Gruppo Collegato di Salerno, Via S. Allende, 84081 Baronissi (Saudi Arabia) (Italy)

2006-03-15T23:59:59.000Z

144

Non-invasive energy meter for fixed and variable flow systems ...  

An energy metering method and apparatus for liquid flow systems comprising first and second segments of one or more conduits through which a liquid flows, comprising ...

145

Coping with Variability in Model-Based Systems Engineering: An Experience in Green Energy  

E-Print Network (OSTI)

ML, a leading MBSE language, for developing a product line of wind turbine systems used for the generationML and how it has been applied to an ongoing project on wind turbine systems for the generation of electricity. We summarize the lessons learned during the modeling and development of a family of wind turbine

Egyed, Alexander

146

A Taxonomy of Antecedents of Information Systems Success: Variable Analysis Studies  

Science Conference Proceedings (OSTI)

Research in the information systems (IS) field has often been characterized as fragmented. This paper builds on a belief that for the field to move forward and have an impact on practitioners and other academic fields, the existing work must be examined ... Keywords: Antecedents Of Success, Information Systems Implementation, Quantitative Research, Taxonomies

Kai R. T. Larsen

2003-10-01T23:59:59.000Z

147

Dynamics of the accelerator-driven system as a variable gain amplifier  

Science Conference Proceedings (OSTI)

Historically, subcritical accelerator-driven systems have been called electronuclear devices. Interest in these devices has been revived for numerous nuclear applications, such as boron neutron capture therapy, accelerator transmutation of waste (ATW), and accelerator-based conversion (ABC). The latter systems are being investigated at Los Alamos National Laboratory for energy production and radioactive waste transmutation. The ATW and ABC in particular are accelerator-(source)-driven subcritical fluid-fueled systems. System dynamics are affected by movement of delayed neutron precursors and poisons into and out of the active multiplying region, giving both a reactivity effect and reduced {Beta} (called {Beta}{sub eff}). A salient dynamic characteristic of the system is that the neutron population (power) is very sensitive to the level of subcritical reactivity, which can depend on poisoning, depletion, and thermal feedback over short operational time scales. Ruby has pointed out that the dynamic behavior of systems containing sources is not fully appreciated. It is our purpose here to illustrate some of the more interesting dynamic characteristics of systems like ATW or ABC.

Woosley, M.L. Jr.; Rydin, R.A. [Univ. of Virginia, Charlottesville, VA (United States)

1995-12-31T23:59:59.000Z

148

Brazilian experience with self-adjusting fuel system for variable alcohol-gasoline blends  

DOE Green Energy (OSTI)

A fuel control system has been developed which allows fuels of various stoichiometries to be used interchangeably without suffering a fuel consumption penalty, allowing a more efficient use of the combustion energy. This Adaptive Lean Limit Control system uses a single, digital sensor and an electronic circuit to detect lean limit engine operation, and feeds back information to the fuel system to maintain the best economy mixture, regardless of the fuel blend being used. The hardware is described, and the results of extensive vehicle testing, using 20% and 50% ethanol-gasoline blends, are included.

Leshner, M.D.; Luengo, C.A.; Calandra, F.

1980-01-01T23:59:59.000Z

149

Assessing and Understanding the Impact of Stratospheric Dynamics and Variability on the Earth System  

Science Conference Proceedings (OSTI)

Advances in weather and climate research have demonstrated the role of the stratosphere in the Earth system across a wide range of temporal and spatial scales. Stratospheric ozone loss has been identified as a key driver of Southern Hemisphere ...

Edwin P. Gerber; Amy Butler; Natalia Calvo; Andrew Charlton-Perez; Marco Giorgetta; Elisa Manzini; Judith Perlwitz; Lorenzo M. Polvani; Fabrizio Sassi; Adam A. Scaife; Tiffany A. Shaw; Seok-Woo Son; Shingo Watanabe

2012-06-01T23:59:59.000Z

150

Global Variability of Mesoscale Convective System Anvil Structure from A-Train Satellite Data  

Science Conference Proceedings (OSTI)

Mesoscale convective systems (MCSs) in the tropics produce extensive anvil clouds, which significantly affect the transfer of radiation. This study develops an objective method to identify MCSs and their anvils by combining data from three A-...

Jian Yuan; Robert A. Houze Jr.

2010-11-01T23:59:59.000Z

151

Power System Operational and Planning Impacts of Generator Cycling Due to Increased Penetration of Variable Generation  

Science Conference Proceedings (OSTI)

This technical update describes work done in the second and final year of the EPRI Bulk Renewable Integration Program project, “Operational and Planning Impacts of Generator Cycling.” This project takes a system perspective in examining the issue of generator cycling behavior, which is likely to increase with increased renewable penetration. To better understand system impacts, researchers developed new modeling algorithms and used them in two case studies to investigate issues related ...

2013-12-22T23:59:59.000Z

152

The study of multimode power control system for MW variable-speed wind turbine  

Science Conference Proceedings (OSTI)

Wind energy is a viable option to complement other types of pollution-free generation. In the past constant-speed wind turbine is used for the limitation of the control technology and manufacturing technology. But this kind wind turbine has low efficiency ... Keywords: feed-forward compensator, loop-shaping, multimode power control system, pitch controller, speed controller, the shaft system model, wind turbine

Dingguo Wu; Zhixin Wang

2008-10-01T23:59:59.000Z

153

Fieldable Fourier Transform Spectrometer: System Construction, Background Variability Measurements, and Chemical Attack Warning Experiments  

SciTech Connect

The infrared sensors task at the Pacific Northwest National Laboratory (PNNL) is focused on the science and technology of remote and in-situ chemical sensors for detecting proliferation and countering terrorism. Missions to be addressed by remote chemical sensor development will include detecting proliferation of nuclear or chemical weapons, and providing warning of terrorist use of chemical weapons. Missions to be addressed by in-situ chemical sensor development include countering terrorism by screening luggage, personnel, and shipping containers for explosives, firearms, narcotics, chemical weapons, or chemical weapons residues, and mapping contaminated areas. The science and technology relevant to these primary missions is also likely to be useful for battlefield chemical weapons defense, air operations support, monitoring emissions from chemical weapons destruction facilities or industrial chemical plants, and law enforcement applications. PNNL will seek to serve organizations with direct interest in these missions through collaborative research and development efforts approved by NA-22. During FY02, PNNL began assembling a remote IR detection capability that would allow field experiments to be conducted. The capability consists of a commercially available FTIR (Fourier Transform Infrared) emission spectrometer and a frequency-modulation differential-absorption LIDAR (FM-DIAL) system being developed at PNNL. To provide environmental protection for these systems, a large, well insulated, temperature controlled trailer was specified and procured. While the FTIR system was field-ready, the FM-DIAL system required many modifications to prepare for field deployment. This document provides an overview of the FTIR system, summarizes the modifications made to the FM-DIAL system, and describes the salient features of the remote systems trailer.

Hatchell, Brian K.; Harper, Warren W.; Batishko, Charles R.; Johnson, Timothy J.; Sheen, David M.; Stewart, Timothy L.; Schultz, John F.

2002-10-01T23:59:59.000Z

154

Thermal Resources for Load Management: Understanding Variable Capacity HVAC Systems as a Load Management Resource  

Science Conference Proceedings (OSTI)

Space conditioning accounts for a major portion of the energy consumption in U.S. residences and commercial buildings and is a primary driver of summer and winter peak demand for electric utility companies. The most common type of space conditioning system in the U.S. is some form of an air-source, fixed speed, direct expansion system. For several decades utilities have implemented efficiency and demand response programs involving fixed speed air conditioning. Over the years, there has been a steady rise ..

2013-12-17T23:59:59.000Z

155

Global Sensitivity Analysis for the Short-term Prediction of System Variables  

E-Print Network (OSTI)

into or withdrawal from the transmission grid. The short-term prediction of LMPs in these regions is important. It is next established analytically that there is a fixed linear-affine mapping between bus load patterns piecewise linear-affine mapping can be used to predict system patterns corresponding to forecasted load

Tesfatsion, Leigh

156

A new battery energy storage system control method based on SOC and variable filter time constant  

Science Conference Proceedings (OSTI)

Because of large fluctuations and strong randomness of active power generated by renewable energy resources, taking into account the constraints such as battery life cycle, a new battery energy storage system control method based on real-time state-of-charge ...

Li Guo; Ye Zhang; Cheng Shan Wang

2012-01-01T23:59:59.000Z

157

Analysis of a variable speed vapor compression system using artificial neural networks  

Science Conference Proceedings (OSTI)

An artificial neural network (ANN) is a mathematical model that is inspired by the operation of biological neural networks. However, this is typically considered a computational model. An ANN can easily adapt to multiple situations and extract information ... Keywords: Artificial neural network, Energetic performance, Hidden neurons, Mapping configuration, Simulated annealing, Vapor compression system

J. M. Belman-Flores; S. E. Ledesma; M. G. Garcia; J. Ruiz; J. L. RodríGuez-MuńOz

2013-09-01T23:59:59.000Z

158

Sensible and Latent Cooling Load Control Using Centrally-Ducted, Variable-Capacity Space Conditioning Systems in Low Sensible Load Environments  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Sensible and Latent Cooling Load Control Using Centrally-Ducted, Variable-Capacity Space Conditioning Systems in Low Sensible Load Environments James Cummings BA-PIRC; Florida Solar Energy Center Presented at BA Summer Meeting, July 26, 2012 The gist of my message * Fixed capacity AC systems generally provide good RH control in typical residences. * In low-load homes, they may be less effective in achieving good RH control. * On the other hand, variable capacity AC systems have several characteristics which can provide improved RH control in homes. - Both Nordyne and Carrier have variable capacity units, varying from about 40% to 100% of nominal full capacity. - What is variable capacity? -- condenser fan, compressor speed, and AHU fan speed. The gist, continued

159

Global Classical Solutions of the Relativistic Vlasov-Darwin System with Small Cauchy Data: the Generalized Variables Approach  

E-Print Network (OSTI)

We show that a smooth, small enough Cauchy datum launches a unique classical solution of the relativistic Vlasov-Darwin (RVD) system globally in time. A similar result is claimed in Comm. Math. Sci. 6, 749-764 (2008) following the work in Int. Mat. Res. Not. 57191, 1-31 (2006). Our proof does not require estimates derived from the conservation of the total energy, nor those previously given on the transverse component of the electric field. These estimates are crucial in the references cited above. Instead, we exploit the formulation of the RVD system in terms of the generalized space and momentum variables. By doing so, we produce a simple a-priori estimate on the transverse component of the electric field. We widen the functional space required for the Cauchy datum to extend the solution globally in time, and we improve decay estimates given in Comm. Math. Sci. 6, 749-764 (2008) on the electromagnetic field and its space derivatives. Our method extends the constructive proof presented in "Collisionless kinetic equations from astrophysics: The Vlasov-Poisson system. Handbook of Differential Equations: Evolutionary Equations, Vol.3, Elsevier, 2007" to solve the Cauchy problem for the Vlasov-Poisson system with a small initial datum.

Reinel Sospedra-Alfonso; Martial Agueh; Reinhard Illner

2011-07-05T23:59:59.000Z

160

Investigation of a rotary valving system with variable valve timing for internal combustion engines: Final technical report  

DOE Green Energy (OSTI)

The objective of the program was to provide a functional demonstration of the Hansen Rotary Valving System with Variable Valve timing (HRVS/VVT), capable of throttleless inlet charge control, as an alternative to conventional poppet-valves for use in spark ignited internal combustion engines. The goal of this new technology is to secure benefits in fuel economy, broadened torque band, vibration reduction, and overhaul accessibility. Additionally, use of the variable valve timing capability to vary the effective compression ratio is expected to improve multi-fuel tolerance and efficiency. Efforts directed at the design of HRVS components proved to be far more extensive than had been anticipated, ultimately requiring that proof-trial design/development work be performed. Although both time and funds were exhausted before optical or ion-probe types of in-cylinder investigation could be undertaken, a great deal of laboratory data was acquired during the course of the design/development work. This laboratory data is the basis for the information presented in this Final Report.

Cross, P.C.; Hansen, C.N.

1994-11-18T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Sub-Hour Solar Data for Power System Modeling From Static Spatial Variability Analysis: Preprint  

Science Conference Proceedings (OSTI)

High penetration renewable integration studies need high quality solar power data with spatial-temporal correlations that are representative of a real system. This paper will summarize the research relating sequential point-source sub-hour global horizontal irradiance (GHI) values to static, spatially distributed GHI values. This research led to the development of an algorithm for generating coherent sub-hour datasets that span distances ranging from 10 km to 4,000 km. The algorithm, in brief, generates synthetic GHI values at an interval of one-minute, for a specific location, using SUNY/Clean Power Research, satellite-derived, hourly irradiance values for the nearest grid cell to that location and grid cells within 40 km.

Hummon, M.; Ibanez, E.; Brinkman, G.; Lew, D.

2012-12-01T23:59:59.000Z

162

Multipartite entanglement in three-mode Gaussian states of continuous variable systems: Quantification, sharing structure and decoherence  

E-Print Network (OSTI)

We present a complete analysis of multipartite entanglement of three-mode Gaussian states of continuous variable systems. We derive standard forms which characterize the covariance matrix of pure and mixed three-mode Gaussian states up to local unitary operations, showing that the local entropies of pure Gaussian states are bound to fulfill a relationship which is stricter than the general Araki-Lieb inequality. Quantum correlations will be quantified by a proper convex roof extension of the squared logarithmic negativity (the contangle), satisfying a monogamy relation for multimode Gaussian states, whose proof will be reviewed and elucidated. The residual contangle, emerging from the monogamy inequality, is an entanglement monotone under Gaussian local operations and classical communication and defines a measure of genuine tripartite entanglement. We analytically determine the residual contangle for arbitrary pure three-mode Gaussian states and study the distribution of quantum correlations for such states. ...

Adesso, G; Serafini, A; Adesso, Gerardo; Illuminati, Fabrizio; Serafini, Alessio

2005-01-01T23:59:59.000Z

163

Comparison on control strategies of the grid-side converter of variable speed constant frequency doubly-fed wind power generation system  

Science Conference Proceedings (OSTI)

Direct power control, vector control based on d-q synchronous rotating reference frame and ?-? static reference frame for the grid-side converter of variable speed constant frequency doubly-fed wind turbines are analyzed. System simulation ... Keywords: ?-? static reference frame, d-q rotating reference frame, direct power control, doubly-fed wind power generation system, grid-side converter

Xian-Ming Zhou; Ting-Long Pan; Zhi-Cheng Ji

2009-06-01T23:59:59.000Z

164

Abstract--Heart rate variability (HRV) is frequently used to measure autonomic nervous system (ANS) activity. However,  

E-Print Network (OSTI)

1 of 4 Abstract--Heart rate variability (HRV) is frequently used to measure autonomic nervous frequency (HF) ratio with little change in mean heart rate. Results suggest that nicotine affects both components may yield erroneous results. Keywords--Autonomic regulation, heart rate variability, Lomb

165

Duct Leakage Impacts on VAV System Performance in Large Commercial  

NLE Websites -- All DOE Office Websites (Extended Search)

Duct Leakage Impacts on VAV System Performance in Large Commercial Duct Leakage Impacts on VAV System Performance in Large Commercial Buildings Title Duct Leakage Impacts on VAV System Performance in Large Commercial Buildings Publication Type Report LBNL Report Number LBNL-53605 Year of Publication 2003 Authors Wray, Craig P., and Nance Matson Abstract The purpose of this study is to evaluate the variability of duct leakage impacts on air distribution system performance for typical large commercial buildings in California. Specifically, a hybrid DOE-2/TRNSYS sequential simulation approach was used to model the energy use of a low-pressure terminal-reheat variable-air-volume (VAV) HVAC system with six duct leakage configurations (tight to leaky) in nine prototypical large office buildings (representing three construction eras in three California climates where these types of buildings are common). Combined fan power for the variable-speed-controlled supply and return fans at design conditions was assumed to be 0.8 W/cfm. The VAV system that we simulated had perfectly insulated ducts, and maintained constant static pressure in the ducts upstream of the VAV boxes and a constant supply air temperature at the air-handler. Further evaluations of duct leakage impacts should be carried out in the future after methodologies are developed to deal with duct surface heat transfer effects, to deal with airflows entering VAV boxes from ceiling return plenums (e.g., to model parallel fan-powered VAV boxes), and to deal with static pressure reset and supply air temperature reset strategies.

166

How effective is new variable modified Chaplygin gas to play the role of dark energy- A dynamical system analysis in RS II Brane model  

E-Print Network (OSTI)

Motivated by some previous works of Rudra et al we set to explore the background dynamics when dark energy in the form of New Variable Modified Chaplygin gas is coupled to dark matter with a suitable interaction in the universe described by brane cosmology. The main idea is to find out the efficiency of New variable modified Chaplygin gas to play the role of DE. As a result we resort to the technique of comparison with standard dark energy models. Here the RSII brane model have been considered as the gravity theory. An interacting model is considered in order to search for a possible solution of the cosmic coincidence problem. A dynamical system analysis is performed because of the high complexity of the system . The statefinder parameters are also calculated to classify the dark energy model. Graphs and phase diagrams are drawn to study the variations of these parameters and get an insight into the effectiveness of the dark energy model. It is also seen that the background dynamics of New Variable Modified Chaplygin gas is consistent with the late cosmic acceleration. After performing an extensive mathematical analysis, we are able to constrain the parameters of new variable modified Chaplygin gas as $mgas. Our investigation leads us to the fact that New Variable Modified Chaplygin gas is not as effective as other Chaplygin gas models to play the role of dark energy.

Prabir Rudra; Chayan Ranjit; Sujata Kundu

2013-03-19T23:59:59.000Z

167

Dynamics and Practical Predictability of Extratropical Wintertime Low-Frequency Variability in a Low-Dimensional System  

Science Conference Proceedings (OSTI)

Dynamics and practical predictability of extratropical low-frequency variability (LFV) in Northern Hemisphere winter are examined in the framework of a two-dimensional (2D) stochastic differential equation (SDE) on the phase space spanned by two ...

Masaru Inatsu; Naoto Nakano; Hitoshi Mukougawa

2013-03-01T23:59:59.000Z

168

Predictability of Linear Coupled Systems. Part II: An Application to a Simple Model of Tropical Atlantic Variability  

Science Conference Proceedings (OSTI)

A predictability analysis developed within a general framework of linear stochastic dynamics in a companion paper is applied to a simple coupled climate model of tropical Atlantic variability (TAV). The simple model extends the univariate ...

Ping Chang; R. Saravanan; Faming Wang; Link Ji

2004-04-01T23:59:59.000Z

169

Physics of the 9-Month Variability in the Gulf Stream Region: Combining Data and Dynamical Systems Analyses  

Science Conference Proceedings (OSTI)

Using nonseasonal altimeter data and SST observations of the North Atlantic, and more specifically the Gulf Stream region, dominant patterns of variability are determined using multivariate time series analyses. A statistically significant ...

Maurice J. Schmeits; Henk A. Dijkstra

2000-08-01T23:59:59.000Z

170

Variable Screw Compressor, Variable Screw Compressor Suppliers ...  

U.S. Energy Information Administration (EIA)

Variable Screw Compressor Suppliers & air compressor Manufacturers Directory. Source Top Quality Variable Screw Compressor Suppliers, air ...

171

Understanding Biomass Feedstock Variability  

SciTech Connect

If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that due to inherent species variabilities, production conditions, and differing harvest, collection, and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture, and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

Kevin L. Kenney; William A. Smith; Garold L. Gresham; Tyler L. Westover

2013-01-01T23:59:59.000Z

172

Interannual Variability of the Global Radiation Budget  

Science Conference Proceedings (OSTI)

Interannual variability of the global radiation budget, regions that contribute to its variability, and what limits albedo variability are investigated using Clouds and the Earth’s Radiant Energy System (CERES) data taken from March 2000 through ...

Seiji Kato

2009-09-01T23:59:59.000Z

173

A computer simulation appraisal of non-residential low energy cooling systems in California  

SciTech Connect

An appraisal of the potential performance of different Low Energy Cooling (LEC) systems in nonresidential buildings in California is being conducted using computer simulation. The paper presents results from the first phase of the study, which addressed the systems that can be modeled, with the DOE-2.1E simulation program. The following LEC technologies were simulated as variants of a conventional variable-air-volume system with vapor compression cooling and mixing ventilation in the occupied spaces: Air-side indirect and indirect/direct evaporative pre-cooling. Cool beams. Displacement ventilation. Results are presented for four populous climates, represented by Oakland, Sacramento, Pasadena and San Diego. The greatest energy savings are obtained from a combination of displacement ventilation and air-side indirect/direct evaporative pre-cooling. Cool beam systems have the lowest peak demand but do not reduce energy consumption significantly because the reduction in fan energy is offse t by a reduction in air-side free cooling. Overall, the results indicate significant opportunities for LEC technologies to reduce energy consumption and demand in nonresidential new construction and retrofit.

Bourassa, Norman; Haves, Philip; Huang, Joe

2002-05-17T23:59:59.000Z

174

A BEMS-Assisted Commissioning Tool to Improve the Energy Performance of HVAC Systems  

E-Print Network (OSTI)

The evolving capabilities of Building Energy Management Systems (BEMS) offer new opportunities to automate some parts of the commissioning process and can generate benefits over the entire life of a building. These benefits include a reduction of process cost and manual effort on site, improved quality assurance process and the adoption of automated energy audit capabilities to improve overall building performance. This paper presents the concept for a new automated commissioning tool that verifies and optimizes the performance of building HVAC systems using the capabilities of BEMS. The tool is applicable mainly to commercial and institutional buildings. In its simplest form, the tool monitors building control data and stores it in a structured database to be used online or upon request. Data resulting from standardized test procedures invoked manually or automatically are also stored in the database. A reasoning algorithm performs an intelligent analysis of the monitored data and also performs additional automated commissioning of HVAC components and systems, identifying faults, diagnosing them, and evaluating the potential energy efficiency improvements. The process is completed by sending detailed comprehensive reports to the user. This paper also includes an example showing how an automated BEMS-assisted commissioning tool can potentially be applied to improve the energy performance of variable-air-volume fan systems.

Choiniere, D.; Corsi, M.

2003-01-01T23:59:59.000Z

175

Numerical Analysis of a Cold Air Distribution System  

E-Print Network (OSTI)

Cold air distribution systems may reduce the operating energy consumption of air-conditioned air supply system and improve the outside air volume percentages and indoor air quality. However, indoor temperature patterns and velocity field are easily non-uniform so that residents usually feel uncomfortable. The distribution of indoor airflow by cold air distribution is researched in this paper. We study indoor air distribution under different low temperature air supply conditions by numerical simulation. The simulated results agree well with the experiments.

Zhu, L.; Li, R.; Yuan, D.

2006-01-01T23:59:59.000Z

176

Modelica-based Modeling and Simulation to Support Research and Development in Building Energy and Control Systems  

SciTech Connect

Traditional building simulation programs possess attributes that make them difficult to use for the design and analysis of building energy and control systems and for the support of model-based research and development of systems that may not already be implemented in these programs. This article presents characteristic features of such applications, and it shows how equation-based object-oriented modelling can meet requirements that arise in such applications. Next, the implementation of an open-source component model library for building energy systems is presented. The library has been developed using the equation-based object-oriented Modelica modelling language. Technical challenges of modelling and simulating such systems are discussed. Research needs are presented to make this technology accessible to user groups that have more stringent requirements with respect to the numerical robustness of simulation than a research community may have. Two examples are presented in which models from the here described library were used. The first example describes the design of a controller for a nonlinear model of a heating coil using model reduction and frequency domain analysis. The second example describes the tuning of control parameters for a static pressure reset controller of a variable air volume flow system. The tuning has been done by solving a non-convex optimization problem that minimizes fan energy subject to state constraints.

Wetter, Michael

2009-02-12T23:59:59.000Z

177

Dynamic Analysis of Hybrid Energy Systems under Flexible Operation and Variable Renewable Generation -- Part I: Dynamic Performance Analysis and Part II: Dynamic Cost  

SciTech Connect

Dynamic analysis of hybrid energy systems (HES) under flexible operation and variable renewable generation is considered in order to better understand various challenges and opportunities associated with the high system variability arising from the integration of renewable energy into the power grid. Unique consequences are addressed by devising advanced HES solutions in which multiple forms of energy commodities, such as electricity and chemical products, may be exchanged. Dynamic models of various unit operations are developed and integrated within two different HES options. One HES option, termed traditional, produces electricity only and consists of a primary heat generator (PHG) (e.g., a small modular reactor), a steam turbine generator, a wind farm, and a battery storage. The other HES option, termed advanced, includes not only the components present in the traditional option but also a chemical plant complex to repurpose excess energy for non-electricity services, such as for the production of chemical goods (e.g., transportation fuel). In either case, a given HES is connected to the power grid at a point of common coupling and requested to deliver a certain electricity generation profile as dictated by a regional power grid operator based on a predicted demand curve. Dynamic analysis of these highly-coupled HES are performed to identify their key dynamical properties and limitations and to prescribe solutions for best managing and mitigating the high variability introduced from incorporating renewable energy into the energy mix. A comparative dynamic cost analysis is also conducted to determine best HES options. The cost function includes a set of metrics for computing fixed costs, such as fixed operations and maintenance (O&M) and overnight capital costs, and also variable operational costs, such as cost of variability, variable O&M cost, and cost of environmental impact, together with revenues. Assuming different options for implementing PHG (e.g., natural gas, coal, nuclear), preliminary results identify the level of renewable penetration at which a given advanced HES option (e.g., a nuclear hybrid) becomes increasingly more economical than a traditional electricity-only generation solution. Conditions are also revealed under which carbon resources may be better utilized as carbon sources for chemical production rather than as combustion material for electricity generation.

Humberto E. Garcia; Amit Mohanty; Wen-Chiao Lin; Robert S. Cherry

2013-04-01T23:59:59.000Z

178

Impacts of Static Pressure Reset on VAV System Air Leakage, Fan Power and Thermal Energy - Part I: Theoretical Model and Simulation  

E-Print Network (OSTI)

As for a variable air volume (VAV) system, the air duct static pressure is a typical control variable maintained by modulating supply fan speed. The static pressure equals to the summation of the duct pressure loss downstream of the sensor to the terminal box and box inlet static pressure. Typically, the air duct static pressure is set as a constant set point based on the system design information and sensor location. However, under partial load conditions, the terminal box dampers have to be closed more since either required airflow is less than the design airflow which directly leads to much less pressure loss. Thus the static pressure set point should be reset lower in order to reduce fan power, avoid noise at terminal box dampers and box damper malfunction due to excessive pressure. Different static pressure reset schedules are reviewed and compared, considering the influence of outside air temperature on the building load, availability of the VAV box damper positions, the airflow ratio based static pressure reset has also applicable advantages over the existing constant static pressure set point and two typical reset methods. This paper present the theoretical models to express the impacts of static pressure reset on fan airflow, fan head, air leakage, fan power and thermal energy for both pressure independent and pressure dependent boxes. The impacts are also demonstrated using the parametric analysis and numerical results to show the benefits of the static pressure reset including reducing fan power, cooling energy and heating energy.

Liu, M.; Feng, J.; Wang, Z.; Wu, L.; Zheng, K.; Pang, W.

2007-01-01T23:59:59.000Z

179

Final Project Report: Self-Correcting Controls for VAV System Faults Filter/Fan/Coil and VAV Box Sections  

SciTech Connect

This report addresses original research by the Pacific Northwest National Laboratory for the California Institute for Energy and Environment on self-correcting controls for variable-air-volume (VAV) heating, ventilating and air-conditioning systems and focuses specifically on air handling and VAV box components of the air side of the system. A complete set of faults for these components was compiled and a fault mode analysis performed to understand the detectable symptoms of the faults and the chain of causation. A set of 26 algorithms was developed to facilitate the automatic correction of these faults in typical commercial VAV systems. These algorithms include training tests that are used during commissioning to develop models of normal system operation, passive diagnostics used to detect the symptoms of faults, proactive diagnostics used to diagnose the cause of a fault, and finally fault correction algorithms. Ten of the twenty six algorithms were implemented in a prototype software package that interfaces with a test bed facility at PNNL's Richland, WA, laboratory. Measurement bias faults were instigated in the supply-air temperature sensor and the supply-air flow meter to test the algorithms developed. The algorithms as implemented in the laboratory software correctly detected, diagnosed and corrected these faults. Finally, an economic and impact assessment was performed for the State of California for deployment of self-correcting controls. Assuming 15% HVAC energy savings and a modeled deployment profile, 3.1-5.8 TBu of energy savings are possible by year 15.

Brambley, Michael R.; Fernandez, Nicholas; Wang, Weimin; Cort, Katherine A.; Cho, Heejin; Ngo, Hung; Goddard, James K.

2011-05-01T23:59:59.000Z

180

Managing Your Energy: An ENERGY STAR(R) Guide for Identifying Energy Savings in Manufacturing Plants  

E-Print Network (OSTI)

and the need for demineralization. Employ solar air heatingSolar air heating systems, such as Solarwall ® , useDuct leakage repair Solar air heating Variable-air-volume

Worrell, Ernst

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Determining Critical Pressure and Duct Leakage in VAV Air-Handling...  

NLE Websites -- All DOE Office Websites (Extended Search)

for moving air in buildings use a significant amount of energy. It is well known that fan energy use in variable-air-volume (VAV) systems can be reduced by resetting the supply...

182

Simulation of the Post-Retrofit Thermal Energy Use for the Perry-Castaneda Library Building with the Use of Simplified System Models  

E-Print Network (OSTI)

Several state owned buildings with dual-duct constant volume (DDCV) systems are being retrofitted with energy efficient variable air volume (VAV) systems as part of Texas LoanSTAR Program. One method of determining the energy savings resulting from energy conserving retrofits relies on the use of a model for the daily whole building consumption, Epre, in the pre-retrofit configuration. Epre is typically a function of primary influencing parameters such as ambient temperature, humidity, building internal gains and others (Figure 1). Following the retrofit, the energy saved, E,av is determined using measured daily consumption, Emea3 as shown in Figure 1. This method is being used in the Texas LoanSTAR monitoring and analysis program for buildings that have adequate pre-retrofit monitored data. Unfortunately, in the Perry-Castaneda Library (PCL) building, the retrofits were completed before the monitoring instrumentation was installed. Therefore, no pre-retrofit monitored data are available for this building. Hence another method to estimate savings is needed. Such a method was developed and tested (Katipamula and Claridge 1991). This method was based on the use of the ASHRAE TC 4.7 simplified energy analysis procedure (SEAP). It involved developing one model each for the VAV (post-retrofit system) and the DDCV (pre-retrofit system) systems.

Katipamula, S.; Claridge, D. E.

1991-01-01T23:59:59.000Z

183

Simulation of the Post-Retrofit Thermal Energy Use for the University Teaching Center (UTC) Building with the Use of Simplified System Models  

E-Print Network (OSTI)

Several state owned buildings with dual-duct constant volume (DDCV) systems have been retrofitted with energy efficient variable air volume systems (VAV) as part of the Texas LoanSTAR Program. One method of determining the energy savings resulting from energy conserving retrofits relies on the use of a model for the daily whole building consumption, Epre, in the pre-retrofit configuration. Epre is typically a function of primary influencing parameters such as ambient temperature, humidity, building internal gains and others (Figure 1). Following the retrofit, the energy saved, Esav is determined using measured daily consumption, Emea3 as shown in Figure 1. This method is being used in the Texas LoanSTAR monitoring and analysis program for buildings that have adequate pre-retrofit monitored data (Kelly et al., 1992). Unfortunately, in the University Teaching Center (UTC) the retrofits were completed before the monitoring instrumentation was installed. Therefore, no pre-retrofit monitored data are available. Hence another method to estimate savings was needed. Such a method was developed and tested on a large engineering center (Katipamula and Claridge 1991). This method was based on the use of the ASHRAE TC 4.7 simplified energy analysis procedure (SEAP). It involved developing one model each for the VAV (post-retrofit system) and the DDCV (pre-retrofit system) systems.

Katipamula, S.; Claridge, D. E.

1991-01-01T23:59:59.000Z

184

Regional and Diurnal Variability of the Vertical Structure of Precipitation Systems in Africa Based on Spaceborne Radar Data  

Science Conference Proceedings (OSTI)

The Tropical Rainfall Measuring Mission (TRMM) 2A25 radar reflectivity profiles and derived surface rain rates are used to describe the vertical structure of precipitation systems in Africa. Five years of data are used in both the boreal and ...

Bart Geerts; Teferi Dejene

2005-04-01T23:59:59.000Z

185

High-Resolution Atmospheric Sensing of Multiple Atmospheric Variables Using the DataHawk Small Airborne Measurement System  

Science Conference Proceedings (OSTI)

The DataHawk small airborne measurement system provides in situ atmospheric measurement capabilities for documenting scales as small as 1 m and can access reasonably large volumes in and above the atmospheric boundary layer at low cost. The design ...

Dale A. Lawrence; Ben B. Balsley

2013-10-01T23:59:59.000Z

186

Variability in natural gas fuel composition and its effects on the performance of catalytic combustion systems. Final report for period September 18, 1998 - September 17, 2000  

SciTech Connect

Natural gas is composed primarily of methane with small amounts of higher hydrocarbons and diluents, which vary by region and over time. Compositions of natural gas from domestic and worldwide sources were surveyed with respect to content of higher hydrocarbons and diluents. The survey showed slight compositional variability between most of the gases, with a small fraction of them containing significantly larger contents of higher hydrocarbons than the mean. As gas-fired turbines will be used for power generation all over the world, they will need to tolerate operation with fuels with a wide variety of compositions, particularly with respect to the concentration of higher hydrocarbons and diluents. Subscale catalytic combustion modules typical of those used in gas turbine power generation with ultra low emissions of pollutants were tested in a subscale test system with natural gas alone and with added known levels of hydrocarbon compounds and diluents. The range of compositions tested contained the range observed in the survey. Test results were used to calculate the effect of composition on catalyst performance. The compositional variability is of little consequence to the catalyst for most of the gases in the survey, including nearly all of the gases delivered in the U.S. To accommodate the remaining gases, the catalyst inlet temperature must be lowered to maintain combustor durability. These results support commercial acceptance of catalytic combustion systems for use in natural gas fired turbines in distributed power generation with ultra low NO{sub x} emissions.

Ginter, David; Simchick, Chuck; Schlatter, Jim

2002-03-01T23:59:59.000Z

187

vol. 172, no. 3 the american naturalist september 2008 Sex-Specific Variability in the Immune System  

E-Print Network (OSTI)

abstract: Organisms theoretically manage their immune systems optimally across their life spans to maximize when laying while receiving a high-quality (HQ) diet; how- ever, laying while receiving a low immune response in females who were raising offspring while receiving an HQ diet suggests a residual

188

High-Resolution Atmospheric Sensing of Multiple Atmospheric Variables Using the DataHawk Small Airborne Measurement System  

Science Conference Proceedings (OSTI)

The DataHawk small airborne measurement system provides in-situ atmospheric measurement capabilities for documenting scales as small as 1 m and can access reasonably large volumes in and above the atmospheric boundary layer at low cost. The design ...

Dale A. Lawrence; Ben B. Balsley

189

Variable Definitions  

Gasoline and Diesel Fuel Update (EIA)

Data System CSV File Documentation Data System CSV File Documentation Energy Source Tables This document explains the contents of the comma-separated value (CSV) files by energy source located on the State Energy Data System (SEDS) web page at http://www.eia.gov/state/seds/seds-data-fuel.cfm. There is a CSV file for the most recent year's data for each energy source as shown in the HTML and PDF data tables. In some cases there is one data file for two tables. The first record in each file contains the column headings. The first data field is the state code (2 characters), followed by the data identifier (5-character mnemonic code, or MSN), and then the estimates for the latest year. Detailed descriptions of the state codes, data identifiers, and units are listed in the latter part of this documentation.

190

New Low Accretion-Rate Magnetic Binary Systems and their Significance for the Evolution of Cataclysmic Variables  

E-Print Network (OSTI)

Discoveries of two new white dwarf plus M star binaries with striking optical cyclotron emission features from the Sloan Digital Sky Survey (SDSS) brings to six the total number of X-ray faint, magnetic accretion binaries that accrete at rates 3 hr. Optical surveys for the cyclotron harmonics appear to be the only means of discovery, so the space density of pre-Polars could rival that of Polars, and the binaries provide an important channel of progenitors (in addition to the asynchronous Intermediate Polars). Both physical and SDSS observational selection effects are identified that may help to explain the clumping of all six systems in a narrow range of magnetic field strength around 60 MG.

Schmidt, G D; Vanlandingham, K M; Anderson, S F; Barentine, J C; Brewington, H J; Hall, P B; Harvanek, M; Kleinman, S J; Krzesínski, J; Long, D; Margon, B; Neilsen, E H; Newman, P R; Nitta, A; Schneider, D P; Snedden, S A

2005-01-01T23:59:59.000Z

191

New Low Accretion-Rate Magnetic Binary Systems and their Significance for the Evolution of Cataclysmic Variables  

E-Print Network (OSTI)

Discoveries of two new white dwarf plus M star binaries with striking optical cyclotron emission features from the Sloan Digital Sky Survey (SDSS) brings to six the total number of X-ray faint, magnetic accretion binaries that accrete at rates 3 hr. Optical surveys for the cyclotron harmonics appear to be the only means of discovery, so the space density of pre-Polars could rival that of Polars, and the binaries provide an important channel of progenitors (in addition to the asynchronous Intermediate Polars). Both physical and SDSS observational selection effects are identified that may help to explain the clumping of all six systems in a narrow range of magnetic field strength around 60 MG.

G. D. Schmidt; P. Szkody; K. M. Vanlandingham; S. F. Anderson; J. C. Barentine; H. J. Brewington; P. B. Hall; M. Harvanek; S. J. Kleinman; J. Krzesinski; D. Long; B. Margon; E. H. Neilsen; P. R. Newman; A. Nitta; D. P. Schneider; S. A. Snedden

2005-05-18T23:59:59.000Z

192

Sources of Variability of Evapotranspiration in California  

Science Conference Proceedings (OSTI)

The variability (1990–2002) of potential evapotranspiration estimates (ETo) and related meteorological variables from a set of stations from the California Irrigation Management System (CIMIS) is studied. Data from the National Climatic Data ...

Hugo G. Hidalgo; Daniel R. Cayan; Michael D. Dettinger

2005-02-01T23:59:59.000Z

193

Evaluating the influence of antecedent soil moisture on variability of the North American Monsoon precipitation in the coupled MM5/VIC modeling system  

SciTech Connect

The influence of antecedent soil moisture on North American monsoon system (NAMS) precipitation variability was explored using the MM5 mesoscale model coupled with the Variable Infiltration Capacity (VIC) land surface model. Sensitivity experiments were performed with extreme wet and dry initial soil moisture conditions for both the 1984 wet monsoon year and the 1989 dry year. The MM5-VIC model reproduced the key features of NAMS in 1984 and 1989 especially over northwestern Mexico. Our modeling results indicate that the land surface has memory of the initial soil wetness prescribed at the onset of the monsoon that persists over most of the region well into the monsoon season (e.g. until August). However, in contrast to the classical thermal contrast concept, where wetter soils lead to cooler surface temperatures, less land-sea thermal contrast, weaker monsoon circulations and less precipitation, the coupled model consistently demonstrated a positive soil moisture – precipitation feedback. Specifically, anomalously wet premonsoon soil moisture always lead to enhanced monsoon precipitation, and the reverse was also true. The surface temperature changes induced by differences in surface energy flux partitioning associated with pre-monsoon soil moisture anomalies changed the surface pressure and consequently the flow field in the coupled model, which in turn changed moisture convergence and, accordingly, precipitation patterns. Both the largescale circulation change and local land-atmospheric interactions in response to premonsoon soil moisture anomalies play important roles in the coupled model’s positive soil moisture monsoon precipitation feedback. However, the former may be sensitive to the strength and location of the thermal anomalies, thus leaving open the possibility of both positive and negative soil moisture precipitation feedbacks.

Zhu, Chunmei; Leung, Lai R.; Gochis, David; Qian, Yun; Lettenmaier, Dennis P.

2009-11-29T23:59:59.000Z

194

Performance analysis of a two-stage variable capacity air source heat pump and a horizontal loop coupled ground source heat pump system.  

E-Print Network (OSTI)

??The thermal performance of a new two-stage variable capacity air source heat pump (ASHP) and a horizontal ground loop ground source heat pump (GSHP) was… (more)

Safa, Amir Alizadeh

2012-01-01T23:59:59.000Z

195

Strategy Guideline: Compact Air Distribution Systems  

SciTech Connect

This Strategy Guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. Traditional systems sized by 'rule of thumb' (i.e., 1 ton of cooling per 400 ft2 of floor space) that 'wash' the exterior walls with conditioned air from floor registers cannot provide appropriate air mixing and moisture removal in low-load homes. A compact air distribution system locates the HVAC equipment centrally with shorter ducts run to interior walls, and ceiling supply outlets throw the air toward the exterior walls along the ceiling plane; alternatively, high sidewall supply outlets throw the air toward the exterior walls. Potential drawbacks include resistance from installing contractors or code officials who are unfamiliar with compact air distribution systems, as well as a lack of availability of low-cost high sidewall or ceiling supply outlets to meet the low air volumes with good throw characteristics. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.

Burdick, A.

2013-06-01T23:59:59.000Z

196

Operating Reserves and Variable Generation  

DOE Green Energy (OSTI)

This report tries to first generalize the requirements of the power system as it relates to the needs of operating reserves. It also includes a survey of operating reserves and how they are managed internationally in system operations today and then how new studies and research are proposing they may be managed in the future with higher penetrations of variable generation.

Ela, E.; Milligan, M.; Kirby, B.

2011-08-01T23:59:59.000Z

197

Atmospheric Carbon Dioxide Variability in the Community Earth System Model: Evaluation and Transient Dynamics during the Twentieth and Twenty-First Centuries  

Science Conference Proceedings (OSTI)

Changes in atmospheric CO2 variability during the twenty-first century may provide insight about ecosystem responses to climate change and have implications for the design of carbon monitoring programs. This paper describes changes in the three-...

Gretchen Keppel-Aleks; James T. Randerson; Keith Lindsay; Britton B. Stephens; J. Keith Moore; Scott C. Doney; Peter E. Thornton; Natalie M. Mahowald; Forrest M. Hoffman; Colm Sweeney; Pieter P. Tans; Paul O. Wennberg; Steven C. Wofsy

2013-07-01T23:59:59.000Z

198

The spatial and temporal subsidence variability of the East Mesa Geothermal Field, California, USA, and its potential impact on the All American Canal System  

Science Conference Proceedings (OSTI)

The spatiotemporal variability of subsidence around the East Mesa Geothermal Field (EMGF) near the All American Canal (AAC) has been measured using 30 temporally averaged interferograms from 1992 to 2000. Deformation rate maps from two shorter time periods ...

Joo-Yup Han; R. R. Forster; D. E. Moser; A. L. J. Ford; J. Ramirez-Hernandez; K. F. Tiampo

2011-06-01T23:59:59.000Z

199

High Air Volume to Low Liquid Volume Aerosol Collector Technology  

Giving animals in need a HOME. November 14, 2013. LLNL, Intel, Cray produce big data machine. ... for the Department of Energy's National Nuclear Security Administration

200

Monitoring of Photovoltaic Plant Output and Variability  

Science Conference Proceedings (OSTI)

The performance of photovoltaic (PV) systems, including variability characteristics, is of increasing interest to utilities as they integrate more solar energy onto the electric grid. This study is part of a multi-year research series to investigate influencing factors that affect PV plant output, variability, and approaches to system management. It explores PV variability both from a grid perspective and through examination of project design aspects that can affect annual power production. ...

2012-12-12T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Duct leakage impacts on VAV system performance in California large commercial buildings  

SciTech Connect

The purpose of this study is to evaluate the variability of duct leakage impacts on air distribution system performance for typical large commercial buildings in California. Specifically, a hybrid DOE-2/TRNSYS sequential simulation approach was used to model the energy use of a low-pressure terminal-reheat variable-air-volume (VAV) HVAC system with six duct leakage configurations (tight to leaky) in nine prototypical large office buildings (representing three construction eras in three California climates where these types of buildings are common). Combined fan power for the variable-speed-controlled supply and return fans at design conditions was assumed to be 0.8 W/cfm. Based on our analyses of the 54 simulation cases, the increase in annual fan energy is estimated to be 40 to 50% for a system with a total leakage of 19% at design conditions compared to a tight system with 5% leakage. Annual cooling plant energy also increases by about 7 to 10%, but reheat energy decreases (about 3 to 10%). In combination, the increase in total annual HVAC site energy is 2 to 14%. The total HVAC site energy use includes supply and return fan electricity consumption, chiller and cooling tower electricity consumption, boiler electricity consumption, and boiler natural gas consumption. Using year 2000 average commercial sector energy prices for California ($0.0986/kWh and $7.71/Million Btu), the energy increases result in 9 to 18% ($7,400 to $9,500) increases in HVAC system annual operating costs. Normalized by duct surface area, the increases in annual operating costs are 0.14 to 0.18 $/ft{sup 2}. Using a suggested one-time duct sealing cost of $0.20 per square foot of duct surface area, these results indicate that sealing leaky ducts in VAV systems has a simple payback period of about 1.3 years. Even with total leakage rates as low as 10%, duct sealing is still cost effective. This suggests that duct sealing should be considered at least for VAV systems with 10% or more total duct leakage. The VAV system that we simulated had perfectly insulated ducts, and maintained constant static pressure in the ducts upstream of the VAV boxes and a constant supply air temperature at the airhandler. Further evaluations of duct leakage impacts should be carried out in the future after methodologies are developed to deal with duct surface heat transfer effects, to deal with airflows entering VAV boxes from ceiling return plenums (e.g., to model parallel fan-powered VAV boxes), and to deal with static pressure reset and supply air temperature reset strategies.

Wray, Craig P.; Matson, Nance E.

2003-10-01T23:59:59.000Z

202

Energy Savings of Variable Speed Motors  

E-Print Network (OSTI)

This paper investigates the energy savings available by utilizing variable speed motors on pump and fan applications. Conventional control of flow or pressure in process plants is normally accomplished by throttling the various streams with control valves. Depending on the system and the actual operating conditions, this throttling may consume a considerable amount of energy. The hydraulics of different systems are investigated to generalize high energy saving applications. Typical pump characteristics at varying speeds are investigated since most performance curves are only available at a constant speed. The various types of variable speed electric motors are discussed. However, the primary variable speed system recommended is a variable frequency speed system which utilizes standard induction motors. Specific cases of centrifugal pump applications and cooling tower fan service are presented. Turndown frequencies, stream factors, and electric rates are included in the evaluation. The energy savings of a variable speed system becomes significant when flow rates vary widely and the electrical rates are high.

Fishel, F. D.

1979-01-01T23:59:59.000Z

203

Assimilation of Screen-Level Variables in ECMWF’s Integrated Forecast System: A Study on the Impact on the Forecast Quality and Analyzed Soil Moisture  

Science Conference Proceedings (OSTI)

In many operational numerical weather prediction applications, the soil moisture analysis is based on the modeled first-guess and screen-level variables; that is, 2-m temperature and 2-m relative humidity. A set of two global 61-day analysis/...

Matthias Drusch; Pedro Viterbo

2007-02-01T23:59:59.000Z

204

Development of a Laboratory Verified Single-Duct VAV System Model with Fan Powered Terminal Units Optimized Using Computational Fluid Dynamics  

E-Print Network (OSTI)

Single Duct Variable Air Volume (SDVAV) systems use series and parallel Fan Powered Terminal Units to control the air flow in conditioned spaces. This research developed a laboratory verified model of SDVAV systems that used series and parallel fan terminal units where the fan speeds were controlled by either Silicon Controlled Rectifiers (SCR) or Electronically Commutated Motors (ECM) motors. As part of the research, the model was used to compare the performance of the systems and to predict the harmonics generated by ECM systems. All research objectives were achieved. The CFD model, which was verified with laboratory measurements, showed the potential to identify opportunities for improvement in the design of the FPTU and accurately predicted the static pressure drop as air passed through the unit over the full operating range of the FPTU. Computational fluid dynamics (CFD) models of typical a FPTU were developed and used to investigate opportunities for optimizing the design of FPTUs. The CFD model identified key parameters required to conduct numerical simulations of FPTU and some of the internal components used to manufacture the units. One key internal component was a porous baffle used to enhance mixing when primary air and induced air entered the mixing chamber. The CFD analysis showed that a pressure-drop based on face velocity model could be used to accurately predict the performance of the FPTU. The SDVAV simulation results showed that parallel FPTUs used less energy overall than series systems that used SCR motors as long as primary air leakage was not considered. Simulation results also showed that series ECM FPTUs used about the same amount of energy, within 3 percent, of parallel FPTU even when leakage was not considered. A leakage rate of 10 percent was enough to reduce the performance of the parallel FPTU to the level of the series SCR system and the series ECM FPTUs outperformed the parallel FPTUs at all weather locations used in the study.

Davis, Michael A.

2010-08-01T23:59:59.000Z

205

Variable Renewable Generation Can Provide Balancing Control to...  

NLE Websites -- All DOE Office Websites (Extended Search)

Variable Renewable Generation Can Provide Balancing Control to the Electric Power System e Active Power Control Helps Maintain System Frequency As wind and solar plants become more...

206

Variable orifice using an iris shutter  

DOE Patents (OSTI)

A variable orifice forming mechanism utilizing an iris shutter arrangement adapted to control gas flow, conductance in vacuum systems, as a heat shield for furnace windows, as a beam shutter in sputtering operations, and in any other application requiring periodic or continuously-variable control of material, gas, or fluid flow.

Beeman, Raymond (El Cerrito, CA); Brajkovich, Steven J. (Fremont, CA)

1978-01-01T23:59:59.000Z

207

VARIABLE TIME DELAY MEANS  

DOE Patents (OSTI)

An electrically variable time delay line is described which may be readily controlled simuitaneously with variable impedance matching means coupied thereto such that reflections are prevented. Broadly, the delay line includes a signal winding about a magnetic core whose permeability is electrically variable. Inasmuch as the inductance of the line varies directly with the permeability, the time delay and characteristic impedance of the line both vary as the square root of the permeability. Consequently, impedance matching means may be varied similariy and simultaneously w:th the electrically variable permeability to match the line impedance over the entire range of time delay whereby reflections are prevented.

Clemensen, R.E.

1959-11-01T23:59:59.000Z

208

Nine New Variable Stars in Camelopardalis  

E-Print Network (OSTI)

Nine new short period variable stars have been discovered in the direction of the open cluster Cr464 in Camelopardalis. The field was observed using Tzec Maun Observatory's telescope AP180. Two new variable stars were classified as pulsating stars (RRab and RRc types). The other seven stars are binary systems. One of them is of ELL-type, four binaries were recognized as EW-type, and two systems are rather short period EA-type binaries. All new variables were registered in the VSX catalogue.

Virnina, Natalia A

2013-01-01T23:59:59.000Z

209

Wireless Demand Response Controls for HVAC Systems  

E-Print Network (OSTI)

ASHRAE: American Society of Heating, Refrigerating, and Air-Conditioning Engineers Btu: British thermal unit CAV: constant air volume CCZ: California climate zone

Federspiel, Clifford

2010-01-01T23:59:59.000Z

210

Wireless Demand Response Controls for HVAC Systems  

E-Print Network (OSTI)

data from California Climate Zone (CCZ) 12, which includesdesign day using California Climate Zone 12 weather data (air volume CCZ: California climate zone CDMA: Code Division

Federspiel, Clifford

2010-01-01T23:59:59.000Z

211

Estimated Global Hydrographic Variability  

Science Conference Proceedings (OSTI)

An estimate is made of the three-dimensional global oceanic temperature and salinity variability, omitting the seasonal cycle, both as a major descriptive element of the ocean circulation and for use in the error estimates of state estimation. ...

Gaël Forget; Carl Wunsch

2007-08-01T23:59:59.000Z

212

Design and Test of DC Voltage Link Conversion System and Brushless Doubly-Fed Induction Generator for Variable-Speed Wind Energy Applications: August 1999--May 2003  

SciTech Connect

This report describes four low-cost alternative power converters for processing the power developed by a doubly fed wound-rotor induction generator for wind energy conversion systems.

Lipo, T.A.; Panda, D.; Zarko, D.

2005-11-01T23:59:59.000Z

213

Dirac equation in terms of hydrodynamic variables  

E-Print Network (OSTI)

The distributed system $\\mathcal{S}_D$ described by the Dirac equation is investigated simply as a dynamic system, i.e. without usage of quantum principles. The Dirac equation is described in terms of hydrodynamic variables: 4-flux $j^{i}$, pseudo-vector of the spin $S^{i}$, an action $\\hbar \\phi $ and a pseudo-scalar $\\kappa $. In the quasi-uniform approximation, when all transversal derivatives (orthogonal to the flux vector $j^i$) are small, the system $\\mathcal{S}_D$ turns to a statistical ensemble of classical concentrated systems $\\mathcal{S}_{dc}$. Under some conditions the classical system $\\mathcal{S}_{dc}$ describes a classical pointlike particle moving in a given electromagnetic field. In general, the world line of the particle is a helix, even if the electromagnetic field is absent. Both dynamic systems $\\mathcal{S}_D$ and $\\mathcal{S}_{dc}$ appear to be non-relativistic in the sense that the dynamic equations written in terms of hydrodynamic variables are not relativistically covariant with respect to them, although all dynamic variables are tensors or pseudo-tensors. They becomes relativistically covariant only after addition of a constant unit timelike vector $f^{i}$ which should be considered as a dynamic variable describing a space-time property. This "constant" variable arises instead of $\\gamma $-matrices which are removed by means of zero divizors in the course of the transformation to hydrodynamic variables. It is possible to separate out dynamic variables $\\kappa $, $\\kappa ^i$ responsible for quantum effects. It means that, setting $\\kappa ,\\kappa ^i\\equiv 0$, the dynamic system $\\mathcal{S}_D$ described by the Dirac equation turns to a statistical ensemble $\\mathcal{E}_{Dqu}$ of classical dynamic systems $\\mathcal{S}_{dc}$.

Yuri A. Rylov

2011-01-31T23:59:59.000Z

214

Investigations into the effects of environmental and physical variables on the growth of natural and transplanted populations of Ruppia maritima L. s.l. in the Galveston Bay System, Texas  

E-Print Network (OSTI)

The effects of sixteen environmental and physical variables on the growth of six natural populations and on the establishment and growth of transplanted populations of widgeon grass, Ruppia maritima L. s.l., were evaluated in the Galveston Bay System, Texas. Growth differences in natural populations among different basin morphologies and tidal regimes were examined. Sediment texture influenced the percent cover of widgeon grass the greatest of the variables studied. High silt content and low sand content in the sediments resulted in greater percent cover of widgeon grass than sediments with low silt and high sand content. Water temperature significantly influenced the stem lengths of widgeon grass; warm temperatures stimulated longer plant lengths, while cold water temperatures resulted in reduced stem lengths. Marshes and tidal habitats exhibited perennial growth patterns of widgeon grass as compared to annual growth patterns found in ponds, lakes, and semitidal habitats. Ponds, lakes, and semitidal habitats generally had significantly higher percent cover and stem lengths than marshes and tidal habitats; except in periods of drought. The effects of sixteen environmental and physical variables on the growth and establishment of transplanted widgeon grass, Ruppia maritima L. s.l., in the Galveston Bay System, were analyzed. Growth differences between different transplant spacings (1 meter, 0.5 meters and 0.25 meters) also were studied. Various fetch distances had the greatest significant influence on the establishment and growth of transplanted widgeon grass. Greater fetch distances resulted in reduced growth of transplants due to increased wave action that the transplants were subjected to. There was no significant difference in widgeon grass growth among the transplant spacings. In conclusion, I found that widgeon grass can be successfully transplanted onto submerged bare sediments in areas of low fetch distances. Transplanting widgeon grass into internal open water areas designed with low fetch distances in saltmarsh restoration projects can increase habitat diversity and function. Efforts should concentrate on designing suitable habitat into restoration plans rather than transplanting large quantities of plant material.

Schubert, William James

2002-01-01T23:59:59.000Z

215

Quantum computation and hidden variables  

E-Print Network (OSTI)

Many physicists limit oneself to an instrumentalist description of quantum phenomena and ignore the problems of foundation and interpretation of quantum mechanics. This instrumentalist approach results to "specialization barbarism" and mass delusion concerning the problem, how a quantum computer can be made. The idea of quantum computation can be described within the limits of quantum formalism. But in order to understand how this idea can be put into practice one should realize the question: "What could the quantum formalism describe?", in spite of the absence of an universally recognized answer. Only a realization of this question and the undecided problem of quantum foundations allows to see in which quantum systems the superposition and EPR correlation could be expected. Because of the "specialization barbarism" many authors are sure that Bell proved full impossibility of any hidden-variables interpretation. Therefore it is important to emphasize that in reality Bell has restricted to validity limits of the no- hidden-variables proof and has shown that two-state quantum system can be described by hidden variables. The later means that no experimental result obtained on two-state quantum system can prove the existence of superposition and violation of the realism. One should not assume before unambiguous experimental evidence that any two-state quantum system is quantum bit. No experimental evidence of superposition of macroscopically distinct quantum states and of a quantum bit on base of superconductor structure was obtained for the present. Moreover same experimental results can not be described in the limits of the quantum formalism.

V. V. Aristov; A. V. Nikulov

2010-07-12T23:59:59.000Z

216

Adaptive variable structure control law for a variable speed wind turbine  

Science Conference Proceedings (OSTI)

The efficiency of the wind power conversions systems can be greatly improved using an appropriate control algorithm. In this work, an adaptive robust control for a doubly feed induction generator drive for variable speed wind power generation is described. ... Keywords: modeling and simulation, variable structure control, wind turbine control

Oscar Barambones; Jose Maria Gonzalez De Durana; Patxi Alkorta; Jose Antonio Ramos; Manuel De La Sen

2011-05-01T23:59:59.000Z

217

Georeactor Variability and Integrity  

E-Print Network (OSTI)

As a deep-Earth energy source, the planetocentric nuclear-fission georeactor concept is on a more secure scientific footing than the previous idea related to the assumed growth of the inner core. Unlike previously considered deep-Earth energy sources, which are essentially constant on a human time-scale, variability in nuclear fission reactors can arise from changes in composition and/or position of fuel, moderators, and neutron absorbers. Tantalizing circumstantial evidence invites inquiry into the possibility of short-term planetocentric nuclear fission reactor variability. This brief communication emphasizes the importance of scientific integrity and highlights the possibility of variable georeactor power output so that these might be borne in mind in future investigations, especially those related to the Earth's heat flux.

J. Marvin Herndon

2005-10-04T23:59:59.000Z

218

Georeactor Variability and Integrity  

E-Print Network (OSTI)

As a deep-Earth energy source, the planetocentric nuclear-fission georeactor concept is on a more secure scientific footing than the previous idea related to the assumed growth of the inner core. Unlike previously considered deep-Earth energy sources, which are essentially constant on a human time-scale, variability in nuclear fission reactors can arise from changes in composition and/or position of fuel, moderators, and neutron absorbers. Tantalizing circumstantial evidence invites inquiry into the possibility of short-term planetocentric nuclear fission reactor variability. This brief communication emphasizes the importance of scientific integrity and highlights the possibility of variable georeactor power output so that these might be borne in mind in future investigations, especially those related to the Earth's heat flux.

Herndon, J M

2005-01-01T23:59:59.000Z

219

Free piston variable-stroke linear-alternator generator ...  

A free-piston variable stroke linear-alternator AC power generator for a combustion engine. An alternator mechanism and oscillator system generates AC current. The ...

220

Modeling 18° Water Variability  

Science Conference Proceedings (OSTI)

Variability of 18° Water formation is investigated with an isopycnic-coordinate model of the North Atlantic. A 30-year spinup integration is used as a “control” experiment in which the upper water column in the Sargasso Sea is shown to be in ...

Robert Marsh; Adrian L. New

1996-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Field Test and Performance Verification: Integrated Active Desiccant Rooftop Hybrid System Installed in a School - Final Report: Phase 4A  

SciTech Connect

This report summarizes the results of a field verification pilot site investigation that involved the installation of a hybrid integrated active desiccant/vapor-compression rooftop heating, ventilation, and air-conditioning (HVAC) unit at an elementary school in the Atlanta Georgia area. For years, the school had experienced serious humidity and indoor air quality (IAQ) problems that had resulted in occupant complaints and microbial (mold) remediation. The outdoor air louvers of the original HVAC units had been closed in an attempt to improve humidity control within the space. The existing vapor compression variable air volume system was replaced by the integrated active desiccant rooftop (IADR) system that was described in detail in an Oak Ridge National Laboratory (ORNL) report published in 2004 (Fischer and Sand 2004). The IADR system and all space conditions have been monitored remotely for more than a year. The hybrid system was able to maintain both the space temperature and humidity as desired while delivering the outdoor air ventilation rate required by American Society of Heating, Refrigerating and Air-Conditioning Engineers Standard 62. The performance level of the IADR unit and the overall system energy efficiency was measured and found to be very high. A comprehensive IAQ investigation was completed by the Georgia Tech Research Institute before and after the system retrofit. Before-and-after data resulting from this investigation confirmed a significant improvement in IAQ, humidity control, and occupant comfort. These observations were reported by building occupants and are echoed in a letter to ORNL from the school district energy manager. The IADR system was easily retrofitted in place of the original rooftop system using a custom curb adapter. All work was completed in-house by the school's maintenance staff over one weekend. A subsequent cost analysis completed for the school district by the design engineer of record concluded that the IADR system being investigated was actually less expensive to install than other less-efficient options, most of which were unable to deliver the required ventilation while maintaining the desired space humidity levels.

Fischer, J

2005-12-21T23:59:59.000Z

222

Variable percentage sampler  

DOE Patents (OSTI)

A remotely operable sampler is provided for obtaining variable percentage samples of nuclear fuel particles and the like for analyses. The sampler has a rotating cup for a sample collection chamber designed so that the effective size of the sample inlet opening to the cup varies with rotational speed. Samples of a desired size are withdrawn from a flowing stream of particles without a deterrent to the flow of remaining particles.

Miller, Jr., William H. (Knoxville, TN)

1976-01-01T23:59:59.000Z

223

Variable laser attenuator  

DOE Patents (OSTI)

The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

Foltyn, S.R.

1987-05-29T23:59:59.000Z

224

Variable laser attenuator  

SciTech Connect

The disclosure relates to low loss, high power variable attenuators comprng one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength.

Foltyn, Stephen R. (Los Alamos, NM)

1988-01-01T23:59:59.000Z

225

Solar-type Variables  

E-Print Network (OSTI)

The rich acoustic oscillation spectrum in solar-type variables make these stars particularly interesting for studying fluid-dynamical aspects of the stellar interior. I present a summary of the properties of solar-like oscillations, how they are excited and damped and discuss some of the recent progress in using asteroseismic diagnostic techniques for analysing low-degree acoustic modes. Also the effects of stellar-cycle variations in low-mass main-sequence stars are addressed.

Houdek, Gunter

2009-01-01T23:59:59.000Z

226

Errors in all variables  

SciTech Connect

We present a thorough derivation of the posterior for the straight line fit employing the hyper-plane prior. For the example of the parabola we enlarge the scope to nonlinear problems, however simplify it to be solved resembling the straight line solution. Finally we come to the problem of determining the exponents of a scaling law, where in logarithmic form the scaling exponents are linear coefficients of logarithmic variables.

Preuss, R.; Dose, V. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)

2005-11-23T23:59:59.000Z

227

Integrating Variable Renewable Energy: Challenges and Solutions  

SciTech Connect

In the U.S., a number of utilities are adopting higher penetrations of renewables, driven in part by state policies. While power systems have been designed to handle the variable nature of loads, the additional supply-side variability and uncertainty can pose new challenges for utilities and system operators. However, a variety of operational and technical solutions exist to help integrate higher penetrations of wind and solar generation. This paper explores renewable energy integration challenges and mitigation strategies that have been implemented in the U.S. and internationally, including forecasting, demand response, flexible generation, larger balancing areas or balancing area cooperation, and operational practices such as fast scheduling and dispatch.

Bird, L.; Milligan, M.; Lew, D.

2013-09-01T23:59:59.000Z

228

ZonePAC: Zonal Power Estimation and Control via HVAC Metering and Occupant Feedback  

Science Conference Proceedings (OSTI)

Heating Ventillation and Air Conditioning (HVAC) systems account for nearly 40% of primary energy consumption by commercial buildings. Yet, these systems by and large operate in an open-loop with the building occupants. While the monitoring and feedback ... Keywords: Energy Estimation, HVAC, Thermostat, User Interface, Variable Air Volume

Bharathan Balaji, Hidetoshi Teraoka, Rajesh Gupta, Yuvraj Agarwal

2013-11-01T23:59:59.000Z

229

Energy conservation measures in an institutional building by dynamic simulation using designbuilder  

Science Conference Proceedings (OSTI)

In this study, various energy conservation measures (ECMs) on heating, ventilating and air conditioning (HVAC) and lighting systems for a 4-storied building in subtropical (hot and humid climate) Central Queensland, Australia are evaluated using the ... Keywords: designbuilder, energy conservation measures, energy efficient lighting and day light control, energy simulation, hot-humid climate, variable air volume system

M. M. Rahman; M. G. Rasul; M. M. K. Khan

2008-02-01T23:59:59.000Z

230

Jets with Variable R  

E-Print Network (OSTI)

We introduce a new class of jet algorithms designed to return conical jets with a variable Delta R radius. A specific example, in which Delta R scales as 1/pT, proves particularly useful in capturing the kinematic features of a wide variety of hard scattering processes. We implement this Delta R scaling in a sequential recombination algorithm and test it by reconstructing resonance masses and kinematic endpoints. These test cases show 10-20% improvements in signal efficiency compared to fixed Delta R algorithms. We also comment on cuts useful in reducing continuum jet backgrounds.

David Krohn; Jesse Thaler; Lian-Tao Wang

2009-03-02T23:59:59.000Z

231

Simultaneous Equation Systems Involving Binary Choice Variables  

E-Print Network (OSTI)

of car and ownership train andbus usage,respectively. The#aBUS USAGE,ANDCAROWNERSHIP (source:DutchMobility Panel) CARowned,1 = 1 + cars owned). T, Train-usage (0= no usage, 1 =

van Wissen, Leo J.; Golob, Thomas F.

1990-01-01T23:59:59.000Z

232

Solar Irradiance Variability  

E-Print Network (OSTI)

The Sun has long been considered a constant star, to the extent that its total irradiance was termed the solar constant. It required radiometers in space to detect the small variations in solar irradiance on timescales of the solar rotation and the solar cycle. A part of the difficulty is that there are no other constant natural daytime sources to which the Sun's brightness can be compared. The discovery of solar irradiance variability rekindled a long-running discussion on how strongly the Sun affects our climate. A non-negligible influence is suggested by correlation studies between solar variability and climate indicators. The mechanism for solar irradiance variations that fits the observations best is that magnetic features at the solar surface, i.e. sunspots, faculae and the magnetic network, are responsible for almost all variations (although on short timescales convection and p-mode oscillations also contribute). In spite of significant progress important questions are still open. Thus there is a debat...

Solanki, Sami K

2012-01-01T23:59:59.000Z

233

Mesoscale Time and Space Wind Variability  

Science Conference Proceedings (OSTI)

The results of a program to study the time and space variability of the wind field below 5 km are presented. Wind data were collected using pilot balloons tracked with the METRAC positioning system. Balloons were launched at 10-30 min intervals ...

W. H. Jasperson

1982-06-01T23:59:59.000Z

234

Climate Variability, Fish, and Fisheries  

Science Conference Proceedings (OSTI)

Fish population variability and fisheries activities are closely linked to weather and climate dynamics. While weather at sea directly affects fishing, environmental variability determines the distribution, migration, and abundance of fish. ...

P. Lehodey; J. Alheit; M. Barange; T. Baumgartner; G. Beaugrand; K. Drinkwater; J.-M. Fromentin; S. R. Hare; G. Ottersen; R. I. Perry; C. Roy; C. D. van der Lingen; F. Werner

2006-10-01T23:59:59.000Z

235

Colorado River Basin Hydroclimatic Variability  

Science Conference Proceedings (OSTI)

An analysis of annual hydroclimatic variability in the Upper Colorado River basin (UCRB) for the period of 1906–2006 was performed to understand the dominant modes of multidecadal variability. First, wavelet-based spectral analysis was employed ...

Kenneth Nowak; Martin Hoerling; Balaji Rajagopalan; Edith Zagona

2012-06-01T23:59:59.000Z

236

Initial testing of a variable-stroke Stirling engine  

SciTech Connect

In support of the US Department of Energy's Stirling Engine Highway Vehicle Systems Program, NASA Lewis Research Center is evaluating variable-stroke control for Stirling engines. The engine being tested is the Advenco Stirling engine; this engine was manufactured by Philips Research Laboratories of the Netherlands and uses a variable-angle swash-plate drive to achieve variable stroke operation. This report describes the engine, presents initial steady-state test data taken at Lewis, and describes a major drive system failure and subsequent modifications. Computer simulation results are presented to show potential part-load efficiency gains with variable-stroke control.

Thieme, L.G.

1985-02-01T23:59:59.000Z

237

Scalable analysis of variable software  

Science Conference Proceedings (OSTI)

The advent of variability management and generator technology enables users to derive individual variants from a variable code base based on a selection of desired configuration options. This approach gives rise to the generation of possibly billions ... Keywords: C Preprocessor, Liveness Analysis, Software Product Lines, Type Checking, Variability-aware Analysis

Jörg Liebig; Alexander von Rhein; Christian Kästner; Sven Apel; Jens Dörre; Christian Lengauer

2013-08-01T23:59:59.000Z

238

Variability within Modeling Language Definitions  

Science Conference Proceedings (OSTI)

We present a taxonomy of the variability mechanisms offered by modeling languages. The definition of a formal language encompasses a syntax and a semantic domain as well as the mapping that relates them, thus language variabilities are classified according ... Keywords: Modeling languages, UML, formal semantics, variability

María Victoria Cengarle; Hans Grönniger; Bernhard Rumpe

2009-10-01T23:59:59.000Z

239

Symmetrization Of Binary Random Variables  

E-Print Network (OSTI)

A random variable Y is called an independent symmetrizer of a given random variable X if (a) it is independent of X and (b) the distribution of X Y is symmetric about 0. In cases where the distribution of X is symmetric about its mean, it is easy to see that the constant random variable Y is a minimum-variance independent symmetrizer. Taking

Abram Kagan; Colin Mallows; Larry Shepp; Robert J. Vanderbei; Yehuda Vardi

1999-01-01T23:59:59.000Z

240

Appendix A. Measure Category Definitions ESCOs applying for NAESCO accreditation are asked to indicate the measures installed  

E-Print Network (OSTI)

· piping/steam distribution · pumps & priming systems · steam/heat traps · variable air volume · airflow) Distribution/ventilation · air handling units · ducts/fittings (also duct insulation) · heat exchangers heaters · oil-fired water heaters · solar water heaters · hot water piping/distribution · water heater

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research  

E-Print Network (OSTI)

model of an HVAC system using support vector regression (SVR). Online control signals improving control-objective optimization Particle swarm optimization Variable-air-volume Reheat process Model predictive control Energy the optimization model. A model predictive control strategy is used to generate controls minimizing the reheat

Kusiak, Andrew

242

NERC Presentation: Accommodating High Levels of Variable Generation,  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

NERC Presentation: Accommodating High Levels of Variable NERC Presentation: Accommodating High Levels of Variable Generation, October 29, 2010 NERC Presentation: Accommodating High Levels of Variable Generation, October 29, 2010 North American Electric Reliability Corporation (NERC) presentation to the Electricity Advisory Committee, October 29, 2010, on accommodating high levels of variable electricity eneration. Variable resources are types of electric power generation that rely on an uncontrolled, "variable" fuel (e.g. wind, sunlight, waves, tidal forces, and some types of rivers) to generate electricity. Most renewablesfall into this category. Reliably integrating these resources into the bulk power system will require significant changes to traditional methods used for system planning and operation. Ongoing efforts brought together by NERC and its stakeholders

243

Temperature Variability over Africa  

Science Conference Proceedings (OSTI)

The variation of near-surface air temperature anomalies in Africa between 1979 and 2010 is investigated primarily using Microwave Sounding Unit (MSU) total lower-tropospheric temperature data from the Remote Sensing Systems (RSS) and the ...

Jennifer M. Collins

2011-07-01T23:59:59.000Z

244

Development of In-Situ Fan Curve Measurement with One Airflow Measurement  

E-Print Network (OSTI)

Fan airflow is the key parameter for air volume tracking control in variable air volume systems. One of the airflow measurement methods is to determine airflow using the fan speed, fan head, and fan curve. Both fan speed and fan head can be measured accurately. Therefore, the accuracy of the fan airflow depends on the accuracy of the fan curve. An experimental method has been developed to determine the in-situ fan curve with only one airflow measurement. This paper presents the theoretical background, experimental procedures, and verification results.

Liu, G.; Joo, I. S.; Song, L.; Liu, M.

2003-01-01T23:59:59.000Z

245

VARIABLE TIME-INTERVAL GENERATOR  

DOE Patents (OSTI)

This patent relates to a pulse generator and more particularly to a time interval generator wherein the time interval between pulses is precisely determined. The variable time generator comprises two oscillators with one having a variable frequency output and the other a fixed frequency output. A frequency divider is connected to the variable oscillator for dividing its frequency by a selected factor and a counter is used for counting the periods of the fixed oscillator occurring during a cycle of the divided frequency of the variable oscillator. This defines the period of the variable oscillator in terms of that of the fixed oscillator. A circuit is provided for selecting as a time interval a predetermined number of periods of the variable oscillator. The output of the generator consists of a first pulse produced by a trigger circuit at the start of the time interval and a second pulse marking the end of the time interval produced by the same trigger circuit.

Gross, J.E.

1959-10-31T23:59:59.000Z

246

RESEARCH ARTICLE Empirical assessment of short-term variability from  

E-Print Network (OSTI)

RESEARCH ARTICLE Empirical assessment of short-term variability from utility-scale solar PV plants grid because additional system resources are required to maintain the grid's reliability. In this study-term variability; PV plant ramp rate; daily aggregate ramp rate; inverter shells *Correspondence Rob van Haaren

247

The Variability of Seasonality  

Science Conference Proceedings (OSTI)

Seasons are the complex nonlinear response of the physical climate system to regular annual solar forcing. There is no a priori reason why they should remain fixed/invariant from year to year, as is often assumed in climate studies when ...

S. Pezzulli; D. B. Stephenson; A. Hannachi

2005-01-01T23:59:59.000Z

248

CDIAC Climate Data: Available Variables  

NLE Websites -- All DOE Office Websites (Extended Search)

Climate Variables Available in CDIAC Data Products Temperature Precipitation Cloudiness Sunshine Duration Snowfall and Snow Depth Atmospheric Pressure Atmospheric Moisture Surface...

249

Solar energy: some variables influencing increased utilization  

SciTech Connect

The mid 1970s energy crisis encouraged the growth of alternative fuels. Through the late 1970s and 1980s, solar energy was the primary alternative fuel. Federal and state programs encouraged the growth of residential solar installations through the use of tax credits. This dissertation used data from the eleven western states to assess tax credits' influence on residential solar installations. A Spearman's r was used to evaluate the role of tax credits on the percent increase in solar systems from 1980 to 1984. The r/sub s/ was .93. The second portion of the analysis used contingency tables to see if variables other than tax credits influence solar installations; the results showed tax credits + solar radiation and fuel mix are the significant variables. The final chapter looks at municipal solar utilities, tax on excessive energy use, a public/private solar research lab, and building rating system as means to supplement solar energy tax credits.

Born, B.E.

1986-01-01T23:59:59.000Z

250

Modeling Semidiurnal Internal Tide Variability in the Southern California Bight  

Science Conference Proceedings (OSTI)

The Regional Oceanic Modeling System (ROMS) is applied in a nested configuration with realistic forcing to the Southern California Bight (SCB) to analyze the variability in semidiurnal internal wave generation and propagation. The SCB has a ...

M. C. Buijsman; Y. Uchiyama; J. C. McWilliams; C. R. Hill-Lindsay

2012-01-01T23:59:59.000Z

251

The Choice of Variable for Atmospheric Moisture Analysis  

Science Conference Proceedings (OSTI)

The implications of using different control variables for the analysis of moisture observations in a global atmospheric data assimilation system are investigated. A moisture analysis based on either mixing ratio or specific humidity is prone to ...

Dick P. Dee; Arlindo M. da Silva

2003-01-01T23:59:59.000Z

252

Projection of Climate Change onto Modes of Atmospheric Variability  

Science Conference Proceedings (OSTI)

Two possible interpretations of forced climate change view it as projecting, either linearly or nonlinearly, onto the dominant modes of variability of the climate system. An evaluation of these two interpretations is performed using annual mean ...

DáithíA. Stone; Andrew J. Weaver; Ronald J. Stouffer

2001-09-01T23:59:59.000Z

253

Sliding mode control strategy for variable speed wind turbine  

Science Conference Proceedings (OSTI)

The efficiency of the wind power conversions systems can be greatly improved using an appropriate control algorithm. In this work, a robust control for variable speed wind power generation that incorporates a doubly feed induction generator is described. ...

Oscar Barambones; Jose Maria Gonzalez De Durana

2009-09-01T23:59:59.000Z

254

Impact of Gravity Waves on Marine Stratocumulus Variability  

Science Conference Proceedings (OSTI)

The impact of gravity waves on marine stratocumulus is investigated using a large-eddy simulation model initialized with sounding profiles composited from the Variability of American Monsoon Systems (VAMOS) Ocean–Cloud–Atmosphere–Land Study ...

Qingfang Jiang; Shouping Wang

2012-12-01T23:59:59.000Z

255

Variables Influencing HRSG Designs  

E-Print Network (OSTI)

Heat Recovery Steam Generators (HRSG's) are widely used in chemical plants, refineries, incineration and cogeneration systems and in general for recovering energy from waste gas streams. In applications such as hydrogen or sulfuric acid plants, the duty and exit gas temperature from the HRSG are set by process considerations while the energy recovery potential in other applications is impacted by considerations of efficiency. In addition, low or high temperature corrosion, space availability, duty, size and maintenance aspects play a vital role in the design and sizing of HRSG's. This paper will address a few of the above considerations.

Ganapathy, V.; Rentz, J.

1990-06-01T23:59:59.000Z

256

Decadal Climate Variability in the North Pacific during the Recent Decades  

Science Conference Proceedings (OSTI)

Decadal wintertime variability in the North Pacific climate system observed over the last few decades is documented. The decadal sea surface temperature (SST) variability is found to be concentrated around two major oceanic fronts. The ...

H. Nakamura; G. Lin; T. Yamagata

1997-10-01T23:59:59.000Z

257

Analysis Methods for Characterizing Salinity Variability from Multivariate Time Series Applied to the Apalachicola Bay Estuary  

Science Conference Proceedings (OSTI)

Statistical analysis methods are developed to quantify the impacts of multiple forcing variables on the hydrographic variability within an estuary instrumented with an enduring observational system. The methods are applied to characterize the ...

Steven L. Morey; Dmitry S. Dukhovskoy

2012-04-01T23:59:59.000Z

258

Examining Internal and External Contributors to Greenland Climate Variability Using CCSM3  

Science Conference Proceedings (OSTI)

Greenland climate variability is connected to internal and external sources of global climate variability in six millennium simulations using Community Climate System Model 3. Simulation forcings are consistent with the PaleoClimate Model Inter-...

Heather J. Andres; W. R. Peltier

259

On Sub-ENSO Variability  

Science Conference Proceedings (OSTI)

Multichannel singular spectrum analysis (MSSA) of surface zonal wind, sea surface temperature (SST), 20° isotherm depth, and surface zonal current observations (between 1990 and 2004) identifies three coupled ocean–atmosphere modes of variability ...

Noel S. Keenlyside; Mojib Latif; Anke Dürkop

2007-07-01T23:59:59.000Z

260

Review of Variable Generation Integration Charges  

DOE Green Energy (OSTI)

The growth of wind and solar generation in the United States, and the expectation of continued growth of these technologies, dictates that the future power system will be operated in a somewhat different manner because of increased variability and uncertainty. A small number of balancing authorities have attempted to determine an 'integration cost' to account for these changes to their current operating practices. Some balancing authorities directly charge wind and solar generators for integration charges, whereas others add integration charges to projected costs of wind and solar in integrated resource plans or in competitive solicitations for generation. This report reviews the balancing authorities that have calculated variable generation integration charges and broadly compares and contrasts the methodologies they used to determine their specific integration charges. The report also profiles each balancing authority and how they derived wind and solar integration charges.

Porter, K.; Fink, S.; Buckley, M.; Rogers, J.; Hodge, B. M.

2013-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

A triple hot-wire system for indoor air flow measurements  

SciTech Connect

The application of a home made, triple hot-wire system in indoor air flow measurements is presented. Both the anemometer and sensor have been developed at Athens University with the aim to provide a reliable, research tool of reasonable cost, simple construction, and satisfactory performance. All three velocity components above a threshold of 10 cm s{sup {minus}1} can be measured. The system is also equipped with two thermometers for measuring the mean and fluctuating air temperature and for providing a means of temperature compensation of the hot wires` signal. After evaluation of the system in the laboratory, it was used in the measurement of the velocity profile of flows driven by the temperature difference between two internal zones. The implied accuracy of the method allows for its integration with measurements of air volume exchange rates between internal zones, as estimated by tracer gas techniques.

Papadopoulos, K.H.; Soilemes, A.T.; Helmis, C.G.; Santamouris, M.; Dascalaki, E. [Univ. of Athens (Greece); Asimakopoulos, D.N. [Univ. of Athens (Greece)]|[National Observatory of Athens (Greece). Inst. of Meteorology and Physics of the Atmospheric Environment; Argiriou, A. [National Observatory of Athens (Greece). Inst. of Meteorology and Physics of the Atmospheric Environment

1996-08-01T23:59:59.000Z

262

Variable focal length deformable mirror  

DOE Patents (OSTI)

A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.

Headley, Daniel (Albuquerque, NM); Ramsey, Marc (Albuquerque, NM); Schwarz, Jens (Albuquerque, NM)

2007-06-12T23:59:59.000Z

263

Advanced Variable Speed Air-Source Integrated Heat Pump  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

variable speed air-source variable speed air-source integrated heat pump (AS-IHP) - CRADA Van D. Baxter Oak Ridge National Laboratory vdb@ornl.gov; 865-574-2104 April 3, 2013 Development of advanced HVAC/WH system options for efficient residential or small commercial buildings, new const. or retrofit * ET R&D project in support of DOE/BTO Goal of 50% Reduction in Building Energy Use by 2030 IHP concept - all HVAC & WH services integrated into

264

Advanced Variable Speed Air-Source Integrated Heat Pump  

NLE Websites -- All DOE Office Websites (Extended Search)

variable speed air-source variable speed air-source integrated heat pump (AS-IHP) - CRADA Van D. Baxter Oak Ridge National Laboratory vdb@ornl.gov; 865-574-2104 April 3, 2013 Development of advanced HVAC/WH system options for efficient residential or small commercial buildings, new const. or retrofit * ET R&D project in support of DOE/BTO Goal of 50% Reduction in Building Energy Use by 2030 IHP concept - all HVAC & WH services integrated into

265

Visualizing Spatial and Temporal Variability in Coastal Observatories  

Science Conference Proceedings (OSTI)

In this paper, we describe a set of 3D and 4D visualization tools and techniques for CORIE, a complex environmental observation and forecasting system (EOFS) for the Columbia River. The Columbia River, a complex and highly variable estuary, is the target ... Keywords: coastal observatories, environmental observation and forecasting systems, coasts, estuaries, Columbia River

Walter H. Jimenez; Wagner T. Correa; Claudio T. Silva; Baptista Baptista

2003-10-01T23:59:59.000Z

266

ANSI/ASHRAE/IES Standard 90.1-2010 Final Qualitative Determination  

NLE Websites -- All DOE Office Websites (Extended Search)

m - updates chiller efficiency requirements. 6. Addendum n - extends variable air volume fan control requirements. 1 IESNA and IES refer to the same organization. The title "IESNA"...

267

Satellite attitude control using environmental forces based on variable structure control.  

E-Print Network (OSTI)

??The present thesis examines the use of environmental forces for satellite attitude control using variable structure control. The system comprises of a satellite with control… (more)

Patel, Tarunkumar

2008-01-01T23:59:59.000Z

268

Market Characteristics for Efficient Integration of Variable Generation in the Western Interconnection  

DOE Green Energy (OSTI)

The overriding purpose of this report is to establish the physical requirements of a power system that can accommodate high levels of variable generation.

Milligan, M.; Kirby, B.

2010-08-01T23:59:59.000Z

269

Searching for Variability in the Globular Cluster Messier 4  

E-Print Network (OSTI)

Time-series data taken with the Hubble Space Telescope of a field six core radii (~5') from the center of the globular cluster Messier 4, and covering a period of about 10 weeks in early 2001, have been analyzed in search of variable objects. Various criteria were employed to select candidate variable stars. Period searches were performed on the selected candidates using phase dispersion minimization (PDM). The reliability of the PDM search results was tested using synthetic light curves of eclipsing binary stars and sinusoidal light curves of different periods. Results from this analysis showed that there are probably no eclipsing binary stars or periodic variables in our field with periods on the order of a few hours to a few days, down to limiting magnitudes of V~25 and I~24, which is consistent with the absence of contact binaries such as W Ursae Majoris systems. However, one candidate variable star does show an increase in brightness of ~0.1 magnitudes in both bandpasses, which seems to last for a few days. Possible explanations concerning the nature of this object include a binary system with a white dwarf primary and a low-mass main sequence secondary, or a BY Draconis variable star. We are able to set an upper limit to the observed fraction of photometric variability in this dataset of 0.05%.

Robert D. Ferdman; Harvey B. Richer; James Brewer; Greg G. Fahlman; Brad K. Gibson; Brad M. S. Hansen; Mark E. Huber; Rodrigo A. Ibata; Jasonjot S. Kalirai; Jaymie M. Matthews; R. Michael Rich; Jason F. Rowe; Michael M. Shara; Peter B. Stetson

2003-04-25T23:59:59.000Z

270

Massive Variability Surveys from Venezuela  

E-Print Network (OSTI)

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ? 180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community. 1.

C. D. Impey; C. E. Petry; César Briceńo

2003-01-01T23:59:59.000Z

271

Massive Variability Surveys from Venezuela  

E-Print Network (OSTI)

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

Briceńo, C

2003-01-01T23:59:59.000Z

272

Massive Variability Surveys from Venezuela  

E-Print Network (OSTI)

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

Cesar Briceno

2003-04-03T23:59:59.000Z

273

Free piston variable-stroke linear-alternator generator  

DOE Patents (OSTI)

A free-piston variable stroke linear-alternator AC power generator for a combustion engine. An alternator mechanism and oscillator system generates AC current. The oscillation system includes two oscillation devices each having a combustion cylinder and a flying turnbuckle. The flying turnbuckle moves in accordance with the oscillation device. The alternator system is a linear alternator coupled between the two oscillation devices by a slotted connecting rod.

Haaland, Carsten M. (Dadeville, AL)

1998-01-01T23:59:59.000Z

274

Lecture 2227 Continuous Random Variables  

E-Print Network (OSTI)

-x/100 dx = -e-x/100 100 0 = 1 - e-1 = .632 text typo Example 3 (Light Bulb): The lifetime X, in hours, of a certain kind of light bulb is a continuous random variable with density f(x) = 1500 x2 I(1500,) Check = 1 4 = p Let B denote the number of failures before 2000 hours among 5 light bulbs. Then P(B 1) = P

Scholz, Fritz

275

Lecture 2227 Continuous Random Variables  

E-Print Network (OSTI)

) = 100 0 1 100 e-x/100 dx = -e-x/100 100 0 = 1 - e-1 = .632 text typo Example 3 (Light Bulb): The lifetime X, in hours, of a certain kind of light bulb is a continuous random variable with density f 2000 1500 = 1 - 3 4 = 1 4 = p Let B denote the number of failures before 2000 hours among 5 light bulbs

Scholz, Fritz

276

Systems  

E-Print Network (OSTI)

Abstract Developing usable and robust mixed reality systems requires unique human–computer interaction techniques and customized hardware systems. The design of the hardware is directed by the requirements of the rich 3D interactions that can be performed using immersive mobile MR systems. Geometry modeling and capture, navigational annotations, visualizations, and training simulations are all enhanced using augmented computer graphics. We present the design guidelines that have led us through 10 years of evolving mobile outdoor MR hardware systems.

Benjamin Avery; Ross T. Smith; Wayne Piekarski; Bruce H. Thomas

2009-01-01T23:59:59.000Z

277

Climatic variability within an equilibrium greenhouse simulation  

SciTech Connect

A simulation of the possible consequences of a doubling of the CO{sub 2} content of the atmosphere has been performed with a low resolution global climatic model. The model included the diurnal and seasonal computed sea ice amount and cloud cover, and used implied oceanic heat fluxes to represent transport processes in the oceans. A highly responsive 2-layer soil moisture formulation was also incorporated. Twenty year equilibrated simulations for control (1xCO{sub 2}) and greenhouse (2xCO{sub 2}) conditions were generated. The major emphasis of the analysis presented here is on the intra-annual and interannual variability of the greenhouse run with respect to the control run. This revealed considerable differences from the time-averaged results with occasions of marked positive and negative temperature deviations. Of particular interest were the periods of negative temperature departures compared to the control run which were identified, especially over the Northern Hemisphere continents. Temporal and spatial precipitation and soil moisture anomalies also occurred, some of which were related to the surface temperature changes. Substantial sea surface temperature anomalies were apparent in the greenhouse run, indicating that a source of climatic forcing existed in addition to that due to doubling of the CO{sub 2}. Comparison of the intra-annual and interannual variability of the control run with that of the greenhouse run suggests that, in many situations, it will be difficult to identify a greenhouse signal against the intrinsic natural variability of the climatic system. 35 refs., 20 figs., 1 tab.

Gordon, H.B.; Hunt, B.G. [CSIRO Division of Atmospheric Research, Victoria (Austria)

1994-01-01T23:59:59.000Z

278

The Value of a Variable Resolution Approach to Numerical Weather Prediction  

Science Conference Proceedings (OSTI)

It is shown that a numerical weather prediction system with variable resolution, higher in the early forecast range and lower afterward, provides more skilful forecasts than a system with constant resolution. Results indicate that the advantage ...

Roberto Buizza

2010-04-01T23:59:59.000Z

279

A Comparative Analysis of the Temporal Variability of Lightning Observations and GOES Imagery  

Science Conference Proceedings (OSTI)

Lightning Positioning and Tracking System (LPATS) data received by the Cooperative Institute for Research in the Atmosphere via a real-time weather data network were used to study the temporal variability of lightning for a frontal system and ...

P. B. Roohr; T. H. Vonder Haar

1994-11-01T23:59:59.000Z

280

Nonferromagnetic linear variable differential transformer  

DOE Patents (OSTI)

A nonferromagnetic linear variable differential transformer for accurately measuring mechanical displacements in the presence of high magnetic fields is provided. The device utilizes a movable primary coil inside a fixed secondary coil that consists of two series-opposed windings. Operation is such that the secondary output voltage is maintained in phase (depending on polarity) with the primary voltage. The transducer is well-suited to long cable runs and is useful for measuring small displacements in the presence of high or alternating magnetic fields.

Ellis, James F. (Powell, TN); Walstrom, Peter L. (Oak Ridge, TN)

1977-06-14T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

DETECTING VARIABILITY IN MASSIVE ASTRONOMICAL TIME-SERIES DATA. II. VARIABLE CANDIDATES IN THE NORTHERN SKY VARIABILITY SURVEY  

SciTech Connect

We present variability analysis of data from the Northern Sky Variability Survey (NSVS). Using the clustering method, which defines variable candidates as outliers from large clusters, we cluster 16,189,040 light curves having data points at more than 15 epochs as variable and non-variable candidates in 638 NSVS fields. Variable candidates are selected depending on how strongly they are separated from the largest cluster and how rarely they are grouped together in eight-dimensional space spanned by variability indices. All NSVS light curves are also cross-correlated with IRAS, AKARI, Two Micron All Sky Survey, Sloan Digital Sky Survey (SDSS), and GALEX objects, as well as known objects in the SIMBAD database. The variability analysis and cross-correlation results are provided in a public online database, which can be used to select interesting objects for further investigation. Adopting conservative selection criteria for variable candidates, we find about 1.8 million light curves as possible variable candidates in the NSVS data, corresponding to about 10% of our entire NSVS sample. Multi-wavelength colors help us find specific types of variability among the variable candidates. Moreover, we also use morphological classification from other surveys such as SDSS to suppress spurious cases caused by blending objects or extended sources due to the low angular resolution of the NSVS.

Shin, Min-Su [Department of Astronomy, The University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Yi, Hahn; Kim, Dae-Won; Chang, Seo-Won [Department of Astronomy, Yonsei University, Seoul 120-749 (Korea, Republic of); Byun, Yong-Ik, E-mail: msshin@umich.edu, E-mail: yihahn@galaxy.yonsei.ac.kr, E-mail: dakim@cfa.harvard.edu, E-mail: seowony@galaxy.yonsei.ac.kr, E-mail: ybyun@yonsei.ac.kr [Department of Astronomy and University Observatory, Yonsei University, Seoul 120-749 (Korea, Republic of)

2012-03-15T23:59:59.000Z

282

Modeling the Effect of Land Surface Evaporation Variability on Precipitation Variability. Part I: General Response  

Science Conference Proceedings (OSTI)

This is the first of a two-part article that investigates the impact of land surface evaporation variability on the interannual variability of precipitation and compares it with the impact caused by sea surface temperature variability. Previous ...

Oreste Reale; Paul Dirmeyer

2002-08-01T23:59:59.000Z

283

Variable Average Absolute Percent Differences  

U.S. Energy Information Administration (EIA) Indexed Site

Variable Variable Average Absolute Percent Differences Percent of Projections Over- Estimated Gross Domestic Product Real Gross Domestic Product (Average Cumulative Growth)* (Table 2) 1.0 42.6 Petroleum Imported Refiner Acquisition Cost of Crude Oil (Constant $) (Table 3a) 35.2 18.6 Imported Refiner Acquisition Cost of Crude Oil (Nominal $) (Table 3b) 34.7 19.7 Total Petroleum Consumption (Table 4) 6.2 66.5 Crude Oil Production (Table 5) 6.0 59.6 Petroleum Net Imports (Table 6) 13.3 67.0 Natural Gas Natural Gas Wellhead Prices (Constant $) (Table 7a) 30.7 26.1 Natural Gas Wellhead Prices (Nominal $) (Table 7b) 30.0 27.1 Total Natural Gas Consumption (Table 8) 7.8 70.2 Natural Gas Production (Table 9) 7.1 66.0 Natural Gas Net Imports (Table 10) 29.3 69.7 Coal Coal Prices to Electric Generating Plants (Constant $)** (Table 11a)

284

SLUDGE BATCH VARIABILITY STUDY WITH FRIT 418  

SciTech Connect

The Defense Waste Processing Facility (DWPF) initiated processing Sludge Batch 6 (SB6) in the summer of 2010. In support of processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frit 418 to process SB6. This recommendation was based on assessments of the compositional projections for SB6 available at the time from the Liquid Waste Organization (LWO) and SRNL (using a model-based approach). To support qualification of SB6, SRNL executed a variability study to assess the applicability of the current durability models for SB6. The durability models were assessed over the expected Frit 418-SB6 composition range. Seventeen glasses were selected for the variability study based on the sludge projections used in the frit recommendation. Five of the glasses are based on the centroid of the compositional region, spanning a waste loading (WL) range of 32 to 40%. The remaining twelve glasses are extreme vertices (EVs) of the sludge region of interest for SB6 combined with Frit 418 and are all at 36% WL. These glasses were fabricated and characterized using chemical composition analysis, X-ray diffraction (XRD) and the Product Consistency Test (PCT). After initiating the SB6 variability study, the measured composition of the SB6 Tank 51 qualification glass produced at the SRNL Shielded Cells Facility indicated that thorium was present in the glass at an appreciable concentration (1.03 wt%), which made it a reportable element for SB6. This concentration of ThO{sub 2} resulted in a second phase of experimental studies. Five glasses were formulated that were based on the centroid of the new sludge compositional region combined with Frit 418, spanning a WL range of 32 to 40%. These glasses were fabricated and characterized using chemical composition analysis and the PCT. Based on the measured PCT response, all of the glasses (with and without thorium) were acceptable with respect to the Environmental Assessment (EA) reference glass regardless of thermal history. All of the normalized boron releases were less than 1 g/L. While all of the targeted glass compositions were predictable with respect to the Product Composition Control System (PCCS) models for durability, a small number of the measured glass compositions were located outside of the lower prediction limit indicating poorer durability than what was actually measured. These unpredictable glasses were in the same lithium metaborate (LM) preparation block during the chemical analyses, which resulted in measured compositions that were not representative of the target compositions. A review of the data did not indicate a clear cause for the problem. Re-digestion and re-measurement of three glasses from this preparation block yielded glass compositions closer to the target values and predicted PCT responses within the PCCS model uncertainty. Therefore, it is believed that the glasses were correctly fabricated and the targeted compositions are closer representations of the true compositions. Per the requirements of the DWPF Glass Product Control Program, the PCCS durability models have been shown to be applicable for the SB6/Frit 418 glass system. PCT results from the glasses fabricated as part of the variability study were shown to be predictable and/or acceptable with respect to the DWPF PCCS models. In addition, the inclusion of ThO{sub 2} was shown to have minimal impact on the acceptability and predictability of the variability study glasses.

Johnson, F.; Edwards, T.

2010-11-29T23:59:59.000Z

285

A Simulation of Variability of ENSO Forecast Skill  

Science Conference Proceedings (OSTI)

In many prediction schemes, the skill of long-range forecasts of ENSO events depends on the time of year. Such variability could be directly due to seasonal changes in the basic ocean-atmosphere system or due to the state of ENSO itself.

M. K. Davey; D. L. T. Anderson; S. Lawrence

1996-01-01T23:59:59.000Z

286

A scalable goal-oriented approach to software variability recovery  

Science Conference Proceedings (OSTI)

Software reuse approaches, such as software product lines, can help to achieve considerable effort and cost savings in product development for sets of software systems with a significant overlap in functionality. However, in the practice many organizations ... Keywords: product lines, reverse engineering, software reuse, source code mining, variability, variant, visualization

Slawomir Duszynski

2011-08-01T23:59:59.000Z

287

Variable-energy drift-tube linear accelerator  

SciTech Connect

A linear accelerator system includes a plurality of post-coupled drift-tubes wherein each post coupler is bistably positionable to either of two positions which result in different field distributions. With binary control over a plurality of post couplers, a significant accumlative effect in the resulting field distribution is achieved yielding a variable-energy drift-tube linear accelerator.

Swenson, Donald A. (Los Alamos, NM); Boyd, Jr., Thomas J. (Los Alamos, NM); Potter, James M. (Los Alamos, NM); Stovall, James E. (Los Alamos, NM)

1984-01-01T23:59:59.000Z

288

Variable-reluctance motors for electric vehicle propulsion  

SciTech Connect

This paper discusses the design, operation, and expected performance of a 60-kW variable-reluctance motor and inverter-designed for electric vehicle propulsion. To substantiate the performance of this system, experimental data obtained with a prototype 3.8-kW motor and inverter are provided.

Vallese, F.J.; Lang, J.H.

1985-01-01T23:59:59.000Z

289

Incremental Closure of Free Variable Tableaux  

Science Conference Proceedings (OSTI)

This paper presents a technique for automated theorem proving with free variable tableaux that does not require backtracking. Most existing automated proof procedures using free variable tableaux require iterative deepening and backtracking over applied ...

Martin Giese

2001-06-01T23:59:59.000Z

290

Thermocline Variability in Different Dynamic Regions  

Science Conference Proceedings (OSTI)

The response of thermocline circulation to a variable wind forcing is investigated with quasigeostrophic models. The physical mechanism responsible for the different variability features in various dynamic regions has been highlighted. Special ...

Zhengye Liu

1996-08-01T23:59:59.000Z

291

Complex Variability of the H? Emission Line Pro le of the T Tauri Binary System KH 15D: The In uence of Orbital Phase, Occultation by the Circumbinary Disk, and Accretion Phenomenae  

E-Print Network (OSTI)

We have obtained 48 high-resolution echelle spectra of the pre-main-sequence eclipsing binary system KH 15D (V582 Mon, P = 48.37 days, e ~ 0.6, M[subscript A] = 0.6 M [subscript ?], MB = 0.7 M [subscript ?]). The eclipses ...

Hamilton, Catrina M.

292

Studies on selection of controlled variables  

E-Print Network (OSTI)

Studies on selection of controlled variables by Vidar Alstad A Thesis Submitted for the Degree. Thus, the selection of controlled variables integrates the optimization and the control layer. Selecting the right controlled variables can be of paramount importance. Many chem­ ical processes

Skogestad, Sigurd

293

Studies on selection of controlled variables  

E-Print Network (OSTI)

Studies on selection of controlled variables by Vidar Alstad A Thesis Submitted for the Degree. Thus, the selection of controlled variables integrates the optimization and the control layer. Selecting the right controlled variables can be of paramount importance. Many chem- ical processes

Skogestad, Sigurd

294

Adaptive sampling for Bayesian variable selection  

E-Print Network (OSTI)

Adaptive sampling for Bayesian variable selection DAVID J. NOTT Department of Statistics for variable selection and for dealing with model un- certainty have become increasingly popular in recent consider adaptive Markov chain Monte Carlo schemes for Bayesian variable selection in Gaussian linear

Blennerhassett, Peter

295

Variable ratio regenerative braking device  

DOE Patents (OSTI)

Disclosed is a regenerative braking device (10) for an automotive vehicle. The device includes an energy storage assembly (12) having a plurality of rubber rollers (26, 28) mounted for rotation between an input shaft (36) and an output shaft (42), clutches (38, 46) and brakes (40, 48) associated with each shaft, and a continuously variable transmission (22) connectable to a vehicle drivetrain and to the input and output shafts by the respective clutches. The rubber rollers are torsionally stressed to accumulate energy from the vehicle when the input shaft is clutched to the transmission while the brake on the output shaft is applied, and are torsionally relaxed to deliver energy to the vehicle when the output shaft is clutched to the transmission while the brake on the input shaft is applied. The transmission ratio is varied to control the rate of energy accumulation and delivery for a given rotational speed of the vehicle drivetrain.

Hoppie, Lyle O. (Birmingham, MI)

1981-12-15T23:59:59.000Z

296

Variable residence time vortex combustor  

DOE Patents (OSTI)

A variable residence time vortex combustor including a primary combustion chamber for containing a combustion vortex, and a plurality of louvres peripherally disposed about the primary combustion chamber and longitudinally distributed along its primary axis. The louvres are inclined to impel air about the primary combustion chamber to cool its interior surfaces and to impel air inwardly to assist in driving the combustion vortex in a first rotational direction and to feed combustion in the primary combustion chamber. The vortex combustor also includes a second combustion chamber having a secondary zone and a narrowed waist region in the primary combustion chamber interconnecting the output of the primary combustion chamber with the secondary zone for passing only lower density particles and trapping higher density particles in the combustion vortex in the primary combustion chamber for substantial combustion.

Melconian, Jerry O. (76 Beaver Rd., Reading, MA 01867)

1987-01-01T23:59:59.000Z

297

Rapid Oscillations in Cataclysmic Variables  

E-Print Network (OSTI)

I give an overview of the rich phenomenology of dwarf nova oscillations (DNOs) and Quasi-periodic Oscillations (QPOs) observed in cataclysmic variable stars (CVs). The favoured interpretation of these rapid brightness modulations (3 - >1000 s time scales) is that they are magnetic in nature - magnetically channelled accretion from the inner accretion disc for DNOs and possible magnetically excited travelling waves in the disc for QPOs. There is increasing evidence for the magnetic aspects, which extend to lower field the well known properties of strong field (polars) and intermediate strength field (intermediate polars) CVs. The result is that almost all CVs show the presence of magnetic fields on their white dwarf primaries - though for many the intrinsic field may be locally enhanced by the accretion process itself. There are many parallel behaviours with the QPOs seen in X-Ray binaries, with high and low frequency X-Ray QPOs resembling respectively the DNOs and QPOs in CVs.

Brian Warner

2003-12-06T23:59:59.000Z

298

Mass Market Demand Response and Variable Generation Integration Issues: A Scoping Study  

NLE Websites -- All DOE Office Websites (Extended Search)

Mass Market Demand Response and Mass Market Demand Response and Mass Market Demand Response and Mass Market Demand Response and Variable Generation Integration Issues: Variable Generation Integration Issues: Variable Generation Integration Issues: Variable Generation Integration Issues: A Scoping Study A Scoping Study Peter Cappers, Andrew Mills, Charles Goldman, Ryan Wiser, Joseph H. Eto Report Summary October 2011 Energy Analysis Department  Electricity Markets and Policy Group 1 1 Presentation Overview Presentation Overview  Objectives and Approach  Variable Generation Resources and the Bulk Power System  Demand Response Opportunities  Demand Response as a Strategy to Integrate p gy g Variable Generation Resources  Comparison of Various Strategies to Integrate Variable Generation  Conclusions Energy Analysis Department  Electricity Markets and Policy Group

299

Advanced Variable Speed Air-Source Integrated Heat Pumps Research Project |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Advanced Variable Speed Air-Source Advanced Variable Speed Air-Source Integrated Heat Pumps Research Project Advanced Variable Speed Air-Source Integrated Heat Pumps Research Project The U.S. Department of Energy is currently conducting research into advanced variable speed air-source integrated heat pumps (AS-IHPs). Project Description This project seeks to develop AS-IHP products for the larger air-source system market. Development focuses on a fully variable capacity or variable speed AS-IHP option. Project Partners Research is being undertaken through a cooperative research and development agreement (CRADA) between the Department of Energy, Oak Ridge National Laboratory, and a CRADA partner. Project Goals The goal of this project is the development of a fully variable-speed version of an AS-IHP product that can provide heating, ventilation, and air

300

Integration of Variable Generation and Cost-Causation (Fact Sheet)  

DOE Green Energy (OSTI)

Variable renewable energy generation sources, such as wind and solar energy, provide benefits such as reduced environmental impact, zero fuel consumption, and low and stable costs. Advances in both technologies can reduce capital costs and provide significant control capabilities. However, their variability and uncertainty - which change with weather conditions, time of day, and season - can cause an increase in power system operating costs compared to a fully controllable power plant. Although a number of studies have assessed integration costs, calculating them correctly is challenging because it is difficult to accurately develop a baseline scenario without variable generation that properly accounts for the energy value. It is also difficult to appropriately allocate costs given the complex, nonlinear interactions between resources and loads.

Not Available

2012-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Application Performance Variability on Hopper  

NLE Websites -- All DOE Office Websites (Extended Search)

noise. All of the following graphs have been graphed against the minimum NERSCTIME in a job. The analysis also included a basic weighting system, which gives a penalty to the Y...

302

Variable stars in the field of the open cluster NGC 7789  

E-Print Network (OSTI)

We present the results of our search for variable stars in the intermediate-age open cluster NGC 7789. We have found 45 variable stars: 35 eclipsing binaries, five pulsating variables and five miscellaneous variables. Most of the eclipsing binaries show W UMa type of variability, with periods shorter than one day. Four systems exhibit unusual behavior: two, V4276 and V6698, are probably RS CVn stars, another, V3283, is a possible cataclysmic binary. The nature of the fourth binary, V2130, is unclear: the system exhibits assymetric maxima. Among the pulsating variables two, V3407C and V4805 are background RR Lyrae stars and one, V6736, is a delta Scuti variable which is a blue straggler belonging to the cluster. Some of the miscellaneous variables may have periods longer than the five day timespan of our observations. We also present a color-magnitude diagram for the NGC 7789 open cluster, fairly complete down to V ~ 20. The relatively large number of variables found in the comparison field (14 compared to 31 in the cluster field) implies that objects not associated physically with the cluster can account for a significant number of variables identified in the cluster field, as well as in other globular and open clusters observed on a dense background/foreground of disk stars.

B. J. Mochejska; J. Kaluzny

1999-07-20T23:59:59.000Z

303

Pulsating Variable Stars in the Coma Berenices dwarf spheroidal galaxy  

E-Print Network (OSTI)

We present B, V, I time-series photometry of the Coma Berenices dwarf spheroidal galaxy, a faint Milky Way satellite, recently discovered by the Sloan Digital Sky Survey. We have obtained V, B-V and V, V-I color-magnitude diagrams that reach V~23.0-23.2 mag showing the galaxy turnoff at V~21.7 mag, and have performed the first study of the variable star population of this new Milky Way companion. Two RR Lyrae stars (a fundamental-mode -RRab- and a first overtone -RRc- pulsator) and a short period variable with period P=0.12468 days were identified in the galaxy. The RRab star has a rather long period of P_ab=0.66971 days and is about 0.2 mag brighter than the RRc variable and other non-variable stars on the galaxy horizontal branch. In the period-amplitude diagram the RRab variable falls closer to the loci of Oosterhoff type-II systems and evolved fundamental-mode RR Lyrae stars in the Galactic globular cluster M3. The average apparent magnitude of the galaxy horizontal branch, =18.64+-0.04 mag, leads to a di...

Musella, I; Clementini, G; Dall'Ora, M; Kinemuchi, K; Di Fabrizio, L; Greco, C; Marconi, M; Smith, H; Radovich, M; Beers, T

2009-01-01T23:59:59.000Z

304

Hard X-ray Variability of AGN  

E-Print Network (OSTI)

Aims: Active Galactic Nuclei are known to be variable throughout the electromagnetic spectrum. An energy domain poorly studied in this respect is the hard X-ray range above 20 keV. Methods: The first 9 months of the Swift/BAT all-sky survey are used to study the 14 - 195 keV variability of the 44 brightest AGN. The sources have been selected due to their detection significance of >10 sigma. We tested the variability using a maximum likelihood estimator and by analysing the structure function. Results: Probing different time scales, it appears that the absorbed AGN are more variable than the unabsorbed ones. The same applies for the comparison of Seyfert 2 and Seyfert 1 objects. As expected the blazars show stronger variability. 15% of the non-blazar AGN show variability of >20% compared to the average flux on time scales of 20 days, and 30% show at least 10% flux variation. All the non-blazar AGN which show strong variability are low-luminosity objects with L(14-195 keV) < 1E44 erg/sec. Conclusions: Concerning the variability pattern, there is a tendency of unabsorbed or type 1 galaxies being less variable than the absorbed or type 2 objects at hardest X-rays. A more solid anti-correlation is found between variability and luminosity, which has been previously observed in soft X-rays, in the UV, and in the optical domain.

V. Beckmann; S. D. Barthelmy; T. J. -L. Courvoisier; N. Gehrels; S. Soldi; J. Tueller; G. Wendt

2007-09-14T23:59:59.000Z

305

Definition: Variable Peak Pricing | Open Energy Information  

Open Energy Info (EERE)

Variable Peak Pricing Variable Peak Pricing Jump to: navigation, search Dictionary.png Variable Peak Pricing Variable Peak Pricing (VPP) is a hybrid of time-of-use and real-time pricing where the different periods for pricing are defined in advance (e.g., on-peak=6 hours for summer weekday afternoon; off-peak= all other hours in the summer months), but the price established for the on-peak period varies by utility and market conditions.[1] Related Terms real-time pricing References ↑ https://www.smartgrid.gov/category/technology/variable_peak_pricing [[C LikeLike UnlikeLike You like this.Sign Up to see what your friends like. ategory: Smart Grid Definitionssmart grid,off-peak,on-peak,smart grid, |Template:BASEPAGENAME]]smart grid,off-peak,on-peak,smart grid, Retrieved from "http://en.openei.org/w/index.php?title=Definition:Variable_Peak_Pricing&oldid=50262

306

Thermal Testing of Tow-Placed Variable Stiffness Panels  

E-Print Network (OSTI)

Commercial systems for precise placement of pre-preg composite tows are enabling technology that allows fabrication of advanced composite structures in which the tows may be precisely laid down along curvilinear paths within a given ply. For laminates with curvilinear tow paths, the fiber orientation angle varies continuously throughout the laminate, and is not required to be straight and parallel in each ply as in conventional composite laminates. Hence, the stiffness properties vary as a function of location in the laminate, and the associated composite structure is called a Ňvariable stiffnessÓ composite structure. Previous analytical studies indicate that variable stiffness structures have great potential for improving the structural performance of composite structures. In the present research, an experimental program has been conducted to evaluate the thermal performance of two variable stiffness panels fabricated using the Viper Fiber Placement System developed by Cincinnati Machine. These variable stiffness panels have the same layup, but one panel has overlapping tows and the other panel does not. Results of thermal tests of the variable stiffness panels are presented and com-

K. Chauncey Wu; Zafer G˙rdal

2001-01-01T23:59:59.000Z

307

A Search for Rapid Photometric Variability in Symbiotic Binaries  

E-Print Network (OSTI)

We report on our survey for rapid (time scale of minutes) photometric variability in symbiotic binaries. These binaries are becoming an increasingly important place to study accretion onto white dwarfs since they are candidate Type Ia supernovae progenitors. Unlike in most cataclysmic variables, the white dwarfs in symbiotics typically accrete from a wind, at rates greater than or equal to 10^{-9} solar masses per year. In order to elucidate the differences between symbiotics and other white dwarf accretors, as well as search for magnetism in symbiotic white dwarfs, we have studied 35 primarily northern symbiotic binaries via differential optical photometry. Our study is the most comprehensive to date of rapid variability in symbiotic binaries. We have found one magnetic accretor, Z And, previously reported by Sokoloski & Bildsten (1999). In four systems (EG And, BX Mon, CM Aql, and BF Cyg), some evidence for flickering at a low level (roughly 10 mmag) is seen for the first time. These detections are, however, marginal. For 25 systems, we place tight upper limits (order of mmag) on both aperiodic and periodic variability, highlighting a major difference between symbiotics and cataclysmic variables. The remaining five of the objects included in our sample (the 2 recurrent novae RS Oph and T CrB, plus CH Cyg, o Ceti, and MWC 560) had previous detections of large-amplitude optical flickering, and we present our extensive observations of these systems in a separate paper. We discuss the impact of our results on the ``standard'' picture of wind-fed accretion, and speculate on the possibility that in most symbiotics, light from quasi-steady nuclear burning on the surface of the white dwarf hides the fluctuating emission from accretion.

J. L. Sokoloski; Lars Bildsten; Wynn C. G. Ho

2001-04-02T23:59:59.000Z

308

DESIGN OF SOFTWARE SENSORS FOR UNMEASURABLE VARIABLES OF ANAEROBIC DIGESTION PROCESSES  

E-Print Network (OSTI)

DESIGN OF SOFTWARE SENSORS FOR UNMEASURABLE VARIABLES OF ANAEROBIC DIGESTION PROCESSES Simeonov, I variables of anaerobic digestion processes. For this purpose, different mathematical models of anaerobic on a pilot-scale anaerobic bioreactor with computer monitoring system. Key words: Anaerobic digestion

Paris-Sud XI, Université de

309

Thermodynamics of the Universe Filled with Perfect Fluid Having Variable Equation of State  

E-Print Network (OSTI)

We study the thermodynamics of the universe containing perfect fluid with equation of state $p=\\omega\\rho,\\omega$ is variable. Here we choose $\\omega$ to be a function of the red shift variable $z$ and four different choices of $\\omega$ has been investigated. Also the laws of thermodynamics are examined considering the universe bounded by the horizon (apparent) as a thermodynamical system.

Mazumder, Nairwita

2009-01-01T23:59:59.000Z

310

Thermodynamics of the Universe Filled with Perfect Fluid Having Variable Equation of State  

E-Print Network (OSTI)

We study the thermodynamics of the universe containing perfect fluid with equation of state $p=\\omega\\rho,\\omega$ is variable. Here we choose $\\omega$ to be a function of the red shift variable $z$ and four different choices of $\\omega$ has been investigated. Also the laws of thermodynamics are examined considering the universe bounded by the horizon (apparent) as a thermodynamical system.

Nairwita Mazumder; Subenoy Chakraborty

2009-07-16T23:59:59.000Z

311

A simulation-and-regression approach for stochastic dynamic programs with endogenous state variables  

Science Conference Proceedings (OSTI)

We investigate the optimum control of a stochastic system, in the presence of both exogenous (control-independent) stochastic state variables and endogenous (control-dependent) state variables. Our solution approach relies on simulations and regressions ... Keywords: Approximate dynamic programming, Hydropower management, Least-squares Monte Carlo, Simulation and regression, Stochastic control

Michel Denault, Jean-Guy Simonato, Lars Stentoft

2013-11-01T23:59:59.000Z

312

NERC Presentation: Accommodating High Levels of Variable Generation...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

high levels of variable electricity eneration. Variable resources are types of electric power generation that rely on an uncontrolled, "variable" fuel (e.g. wind, sunlight,...

313

The use of 'race' as a variable in biomedical research  

E-Print Network (OSTI)

a variable in biomedical research but mainly to monitor thea Variable in Biomedical Research A dissertation submittedVariable in Biomedical Research…………. Manifest, Operative and

Efstathiou, Sophia

2009-01-01T23:59:59.000Z

314

Envera Variable Compression Ratio Engine  

DOE Green Energy (OSTI)

Aggressive engine downsizing, variable compression ratio and use of the Atkinson cycle are being combined to improve fuel economy by up to 40 percent relative to port fuel injected gasoline engines, while maintaining full engine power. Approach Engine downsizing is viewed by US and foreign automobile manufacturers as one of the best options for improving fuel economy. While this strategy has already demonstrated a degree of success, downsizing and fuel economy gains are currently limited. With new variable compression ratio technology however, the degree of engine downsizing and fuel economy improvement can be greatly increased. A small variable compression ratio (VCR) engine has the potential to return significantly higher vehicle fuel economy while also providing high power. Affordability and potential for near term commercialization are key attributes of the Envera VCR engine. VCR Technology To meet torque and power requirements, a smaller engine needs to do more work per stroke. This is typically accomplished by boosting the incoming charge with either a turbo or supercharger so that more energy is present in the cylinder per stroke to do the work. With current production engines the degree of engine boosting (which correlates to downsizing) is limited by detonation (combustion knock) at high boost levels. Additionally, the turbo or supercharger needs to be responsive and efficient while providing the needed boost. VCR technology eliminates the limitation of engine knock at high load levels by reducing compression ratio to {approx}9:1 (or whatever level is appropriate) when high boost pressures are needed. By reducing the compression ratio during high load demand periods there is increased volume in the cylinder at top dead center (TDC) which allows more charge (or energy) to be present in the cylinder without increasing the peak pressure. Cylinder pressure is thus kept below the level at which the engine would begin to knock. When loads on the engine are low the compression ratio can be raised (to as much as 18:1) providing high engine efficiency. It is important to recognize that for a well designed VCR engine cylinder pressure does not need to be higher than found in current production turbocharged engines. As such, there is no need for a stronger crankcase, bearings and other load bearing parts within the VCR engine. The Envera VCR mechanism uses an eccentric carrier approach to adjust engine compression ratio. The crankshaft main bearings are mounted in this eccentric carrier or 'crankshaft cradle' and pivoting the eccentric carrier 30 degrees adjusts compression ratio from 9:1 to 18:1. The eccentric carrier is made up of a casting that provides rigid support for the main bearings, and removable upper bearing caps. Oil feed to the main bearings transits through the bearing cap fastener sockets. The eccentric carrier design was chosen for its low cost and rigid support of the main bearings. A control shaft and connecting links are used to pivot the eccentric carrier. The control shaft mechanism features compression ratio lock-up at minimum and maximum compression ratio settings. The control shaft method of pivoting the eccentric carrier was selected due to its lock-up capability. The control shaft can be rotated by a hydraulic actuator or an electric motor. The engine shown in Figures 3 and 4 has a hydraulic actuator that was developed under the current program. In-line 4-cylinder engines are significantly less expensive than V engines because an entire cylinder head can be eliminated. The cost savings from eliminating cylinders and an entire cylinder head will notably offset the added cost of the VCR and supercharging. Replacing V6 and V8 engines with in-line VCR 4-cylinder engines will provide high fuel economy at low cost. Numerous enabling technologies exist which have the potential to increase engine efficiency. The greatest efficiency gains are realized when the right combination of advanced and new technologies are packaged together to provide the greatest gains at the least cost. Aggressive engine downsiz

Charles Mendler

2011-03-15T23:59:59.000Z

315

Natural Gas Variability In California: Environmental Impacts...  

NLE Websites -- All DOE Office Websites (Extended Search)

Natural Gas Variability In California: Environmental Impacts And Device Performance, Combustion Modeling of Pollutant Emissions From a Residential Cooking Range Title Natural Gas...

316

NREL: Transmission Grid Integration - Variability of Renewable...  

NLE Websites -- All DOE Office Websites (Extended Search)

as variable generation sources because their electricity production varies based on the availability of wind and sun. However, they are not the only source of variation in a...

317

Variable-Period Undulators for Synchrotron Radiation  

DOE Patents (OSTI)

A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

2005-02-22T23:59:59.000Z

318

Variability of Load and Net Load in Case of Large Scale Distributed Wind Power  

Science Conference Proceedings (OSTI)

Large scale wind power production and its variability is one of the major inputs to wind integration studies. This paper analyses measured data from large scale wind power production. Comparisons of variability are made across several variables: time scale (10-60 minute ramp rates), number of wind farms, and simulated vs. modeled data. Ramp rates for Wind power production, Load (total system load) and Net load (load minus wind power production) demonstrate how wind power increases the net load variability. Wind power will also change the timing of daily ramps.

Holttinen, H.; Kiviluoma, J.; Estanqueiro, A.; Gomez-Lazaro, E.; Rawn, B.; Dobschinski, J.; Meibom, P.; Lannoye, E.; Aigner, T.; Wan, Y. H.; Milligan, M.

2011-01-01T23:59:59.000Z

319

Coordinated Variable Structure Switching Attacks for Smart Grid  

E-Print Network (OSTI)

The effective modeling and analysis of large-scale power system disturbances especially those stemming from intentional attack represents an open engineering and research problem. Challenges stem from the need to develop intelligent models of cyber-physical attacks that produce salient disruptions and appropriately describe meaningful cyber-physical interdependencies such that they balance precision, scale and complexity. In our research, we present a foundation for the development of a class of intelligent cyber-physical attacks termed coordinated variable structure switching attacks whereby opponents aim to destabilize the power grid through con- trolled switching sequence. Such switching is facilitated by cyber-attack and corruption of communication channels and control signals of the associated switch(es). We provide methods and theorems to construct such attack models and demonstrate their utility in the simulation of extensive system disturbances. Our proposed class of cyber-physical switching attacks for smart grid systems has the potential to disrupt large-scale power system operation within a short interval of time. Through successful cyber intrusion, an opponent can remotely apply a state- dependent coordinated switching sequence on one or more relays and circuit breakers of a power system to disrupt operation. Existence of this switching vulnerability is dependent on the local structure of the power grid. Variable structure systems theory is employed to effectively model the cyber-physical aspects of a smart grid and determine the existence of the vulnerability and construct the destabilizing switching attack sequence. We illustrate the utility of the attack approach assess its impact on the different power system test cases including the single machine infinite bus power system model and the Western Electricity Coordinating Council (WECC) 3-machine 9-bus system through MATLAB/Simulink and PSCAD simulation environment. The results demonstrate the potential of our approach for practical attack. Moreover, we build on our work in several ways. First, we extend the research to demonstrate an approach to mitigation within the variable structure system frame- work. We demonstrate via small signal analysis how through persistent switching a stable sliding mode can be used to disrupt a dynamical system that seems stable. We also design an approach to vulnerability analysis to assess the feasibility of co-ordinated variable structure switching attacks. Moreover, we study the performance of our attack construction approach when the opponent has imperfect knowledge of the local system dynamics and partial knowledge of the generator state. Based on the system with modeling errors, we study the performance of coordinated variable structure switching attacks in the presence of state estimation. Finally, we illustrate the concepts of attack model within the multiple switching framework, the cascading failure analysis is employed in the New-England 10-machine, 39-bus power system using MATLAB/Simulink and DSATools simulation environment. Our results demonstrate the potential for coordinated variable structure switching attacks to enable large-scale power system disturbances.

Liu, Shan

2013-05-01T23:59:59.000Z

320

SLUDGE BATCH 7B GLASS VARIABILITY STUDY  

SciTech Connect

The Defense Waste Processing Facility (DWPF) is preparing to initiate processing Sludge Batch 7b (SB7b). In support of the upcoming processing, the Savannah River National Laboratory (SRNL) provided a recommendation to utilize Frits 418 with a 6% Na{sub 2}O addition (26 wt% Na{sub 2}O in sludge) and 702 with a 4% Na{sub 2}O addition (24 wt% Na{sub 2}O in sludge) to process SB7b. This recommendation was based on assessments of the compositional projections for SB7b available at the time from the Savannah River Remediation (SRR). To support qualification of SB7b, SRNL executed a variability study to assess the applicability of the current durability models for SB7b. The durability models were assessed over the expected composition range of SB7b, including potential caustic additions, combined with Frits 702 and 418 over a 32-40% waste loading (WL) range. Thirty four glasses were selected based on Frits 418 and 702 coupled with the sludge projections with an additional 4-6% Na{sub 2}O to reflect the potential caustic addition. Six of these glasses, based on average nominal sludge compositions including the appropriate caustic addition, were developed for both Frit 418 and Frit 702 at 32, 36 and 40% WL to provide coverage in the center of the anticipated SB7b glass region. All glasses were fabricated and characterized using chemical composition analysis, X-ray diffraction (XRD) and the Product Consistency Test (PCT). To comply with the DWPF Glass Product Control Program, a total of thirty four glasses were fabricated to assess the applicability of the current DWPF PCCS durability models. Based on the measured PCT response, all of the glasses were acceptable with respect to the Environmental Assessment (EA) benchmark glass regardless of thermal history. The NL[B] values of the SB7b variability study glasses were less than 1.99 g/L as compared to 16.695 g/L for EA. A small number of the D-optimally selected 'outer layer' extreme vertices (EV) glasses were not predictable using the current Product Composition Control System (PCCS) models for durability, but were acceptable compared to the EA glass when tested. These glasses fell outside of the lower 95% confidence band, which demonstrates conservatism in the model. A few of the glasses fell outside of the upper 95% confidence band; however, these particular glasses have normalized release values that were much lower than the values of EA and should be of no practical concern. Per the requirements of the DWPF Glass Product Control Program, the PCCS durability models have been shown to be applicable to the SB7b sludge system with a range of Na{sub 2}O concentrations blended with Frits 418 or 702. PCT results from the glasses fabricated as part of the variability study were shown to be predictable by the current DWPF PCCS models and/or acceptable with respect to the EA benchmark glass regardless of thermal history or compositional view.

Johnson, F.; Edwards, T.

2011-10-25T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Variable Stars in Large Magellanic Cloud Globular Clusters III: Reticulum  

E-Print Network (OSTI)

This is the third in a series of papers studying the variable stars in old globular clusters in the Large Magellanic Cloud. The primary goal of this series is to look at how the characteristics and behavior of RR Lyrae stars in Oosterhoff-intermediate systems compare to those of their counterparts in Oosterhoff-I/II systems. In this paper we present the results of our new time-series BVI photometric study of the globular cluster Reticulum. We found a total of 32 variables stars (22 RRab, 4 RRc, and 6 RRd stars) in our field of view. We present photometric parameters and light curves for these stars. We also present physical properties, derived from Fourier analysis of light curves, for some of the RR Lyrae stars. We discuss the Oosterhoff classification of Reticulum and use our results to re-derive the distance modulus and age of the cluster.

Kuehn, Charles A; Smith, Horace A; Catelan, Márcio; Jeon, Young-Beom; Nemec, James M; Walker, Alistair R; Kunder, Andrea; Pritzl, Barton J; De Lee, Nathan; Borissova, Jura

2013-01-01T23:59:59.000Z

322

Maximizing Energy Capture of Fixed-Pitch Variable-Speed Wind Turbines  

DOE Green Energy (OSTI)

Field tests of a variable-speed, stall-regulated wind turbine were conducted at a US Department of Energy Laboratory. A variable-speed generating system, comprising a doubly-fed generator and series-resonant power converter, was installed on a 275-kW, downwind, two-blade wind turbine. Gearbox, generator, and converter efficiency were measured in the laboratory so that rotor aerodynamic efficiency could be determined from field measurement of generator power. The turbine was operated at several discrete rotational speeds to develop power curves for use in formulating variable-speed control strategies. Test results for fixed-speed and variable-speed operation are presented along with discussion and comparison of the variable-speed control methodologies. Where possible, comparisons between fixed-speed and variable-speed operation are shown.

Pierce, K.; Migliore, P.

2000-08-01T23:59:59.000Z

323

MEXICAN CORN: Genetic Variability and Trade Liberalisation  

E-Print Network (OSTI)

It is now a well established fact that corn (Zea mays) originated in Mexico and that a great part of the evolution that may be observed in terms of this plant’s genetic variability took place in this country. 2 As the plant’s history unfolded, early forms of these races were taken by people into a wide variety of environments and ecological niches from which many distinct varieties developed in the relative isolation of these separated regions. Thus, Mexico also became a center of genetic diversity for corn, and its stock of germplasm has contributed in a decisive manner to global production of corn. Even the dented varieties of the U.S. Corn Belt are close descendants of the first Mexican landraces. The germplasm resources that are deposited in Mexico’s corn varieties, as well as in the wild relatives of this crop, are of prime importance for the world’s food production system of the next century. 3 Corn germplasm of Mexican origin has played a critical role in improvements for corn cultivated in tropical regions in relation to yield increments, plague resistance, short growth cycle, drought resistance and increases of protein content of grain. It has also been instrumental in increasing yields in the case of corn produced in temperate regions at high latitudes. Mexican 1

Alejandro Nadal; El Colegio De México; Alejandro Nadal; El Colegio De México

2000-01-01T23:59:59.000Z

324

Grassmann Variables in Jordan Matrix Models  

E-Print Network (OSTI)

Here we demonstrate the emergence of Grassmann variables in matrix models based on the exceptional Jordan algebra. The Grassmann algebras are built naturally using the octonion algebra. We argue the appearance of Grassmann variables solidifies the relationship between supersymmetry and triality.

Michael Rios

2005-03-02T23:59:59.000Z

325

THE MULTI-USE STEINEL VARIABLE TEMPERATURE  

E-Print Network (OSTI)

THE MULTI-USE STEINEL VARIABLE TEMPERATURE ELECTRONICALLY CONTROLLED HEAT GUNTEMPERATURE RANGE 212 COMBUSTIBLE LIQUIDS. DO NOT USE FOR: · Heating gas engines · Heating car batteries · Thawing refrigerator equipment Specifications Temperature Variable from 212° F to 1100° F Watts 1500W Weight 1.5 lbs. Supply

Kleinfeld, David

326

THE MULTI-USE STEINEL VARIABLE TEMPERATURE  

E-Print Network (OSTI)

THE MULTI-USE STEINEL VARIABLE TEMPERATURE ELECTRONICALLY CONTROLLED HEAT GUNTEMPERATURE RANGE 212 COMBUSTIBLE LIQUIDS. DO NOT USE FOR: · Heating gas engines · Heating car batteries · Thawing refrigerator equipment Specifications Temperature Variable from 212" F to 1100° F Watts 1500W Weight 1.5 lbs. Supply

Kleinfeld, David

327

Internal Variability of Indian Ocean SST  

Science Conference Proceedings (OSTI)

A 40-yr integration of an eddy-resolving numerical model of the tropical Indian Ocean is analyzed to quantify the interannual variability that is caused by the internal variability of ocean dynamics. It is found that along the equator in the ...

Markus Jochum; Raghu Murtugudde

2005-09-01T23:59:59.000Z

328

Gradient based variable forgetting factor RLS algorithm  

Science Conference Proceedings (OSTI)

An accurate new variable forgetting factor recursive least-square adaptive algorithm is derived. An improved mean square behaviour analysis is presented, which shows that the theoretical analysis and the simulation results are close to each other. The ... Keywords: RLS algorithm, adaptive filters, variable forgetting factor

C. F. So; S. C. Ng; S. H. Leung

2003-06-01T23:59:59.000Z

329

Examining Uncertainty in Demand Response Baseline Models and Variability in Automated Response to Dynamic Pricing  

Science Conference Proceedings (OSTI)

Controlling electric loads to deliver power system services presents a number of interesting challenges. For example, changes in electricity consumption of Commercial and Industrial (C&I) facilities are usually estimated using counterfactual baseline models, and model uncertainty makes it difficult to precisely quantify control responsiveness. Moreover, C&I facilities exhibit variability in their response. This paper seeks to understand baseline model error and demand-side variability in responses to open-loop control signals (i.e. dynamic prices). Using a regression-based baseline model, we define several Demand Response (DR) parameters, which characterize changes in electricity use on DR days, and then present a method for computing the error associated with DR parameter estimates. In addition to analyzing the magnitude of DR parameter error, we develop a metric to determine how much observed DR parameter variability is attributable to real event-to-event variability versus simply baseline model error. Using data from 38 C&I facilities that participated in an automated DR program in California, we find that DR parameter errors are large. For most facilities, observed DR parameter variability is likely explained by baseline model error, not real DR parameter variability; however, a number of facilities exhibit real DR parameter variability. In some cases, the aggregate population of C&I facilities exhibits real DR parameter variability, resulting in implications for the system operator with respect to both resource planning and system stability.

Mathieu, Johanna L.; Callaway, Duncan S.; Kiliccote, Sila

2011-08-15T23:59:59.000Z

330

Simulated Physical Mechanisms Associated with Climate Variability over Lake Victoria Basin in East Africa  

Science Conference Proceedings (OSTI)

A fully coupled regional climate, 3D lake modeling system is used to investigate the physical mechanisms associated with the multiscale variability of the Lake Victoria basin climate. To examine the relative influence of different processes on ...

Richard O. Anyah; Fredrick H. M. Semazzi; Lian Xie

2006-12-01T23:59:59.000Z

331

Analysis of Short Space–Time-Scale Variability of Oceanic Rain Using TOPEX/Jason  

Science Conference Proceedings (OSTI)

Information on the spatial and temporal variability of rain rate is important not only for meteorology and hydrology but also for the design of remote sensing and in situ measuring or of millimeter wave communication systems. The Ocean Topography ...

J. Tournadre; S. Bhandari

2009-01-01T23:59:59.000Z

332

The Role of Ice–Ocean Interactions in the Variability of the North Atlantic Thermohaline Circulation  

Science Conference Proceedings (OSTI)

The simulated influence of Arctic sea ice on the variability of the North Atlantic climate is discussed in the context of a global coupled ice–ocean–atmosphere model. This coupled system incorporates a general circulation ocean model, an ...

Marika M. Holland; Cecilia M. Bitz; Michael Eby; Andrew J. Weaver

2001-03-01T23:59:59.000Z

333

A Preliminary Analysis of Spatial Variability of Raindrop Size Distributions during Stratiform Rain Events  

Science Conference Proceedings (OSTI)

The spatial variability of raindrop size distributions (DSDs) and precipitation fields is investigated utilizing disdrometric measurements from the four Precipitation Occurrence Sensor Systems (POSS) and radar reflectivity fields from S-band dual-...

Choong Ke Lee; Gyu Won Lee; Isztar Zawadzki; Kyung-Eak Kim

2009-02-01T23:59:59.000Z

334

Coupled Variability and Predictability in a Stochastic Climate Model of the Tropical Atlantic  

Science Conference Proceedings (OSTI)

The coupled variability and predictability of the tropical Atlantic ocean–atmosphere system were analyzed within the framework of a linear stochastic climate model. Despite the existence of a meridional dipole as the leading mode, tropical ...

Faming Wang; Ping Chang

2008-12-01T23:59:59.000Z

335

Antarctic Sea Ice Climatology, Variability, and Late Twentieth-Century Change in CCSM4  

Science Conference Proceedings (OSTI)

A preindustrial control run and an ensemble of twentieth-century integrations of the Community Climate System Model, version 4 (CCSM4), are evaluated for Antarctic sea ice climatology, modes of variability, trends, and covariance with related ...

Laura Landrum; Marika M. Holland; David P. Schneider; Elizabeth Hunke

2012-07-01T23:59:59.000Z

336

Sensitivity of Arctic Climate Variability to Mean State: Insights from the Cretaceous  

Science Conference Proceedings (OSTI)

This study investigates Arctic climate variability during a period of extreme warmth using the Community Climate System Model, version 3 (CCSM3) coupled ocean–atmosphere general circulation model. Four mid-Cretaceous simulations were completed ...

Christopher J. Poulsen; Jing Zhou

2013-09-01T23:59:59.000Z

337

Analysis of Near-Surface Atmospheric Variables: Validation of the SAFRAN Analysis over France  

Science Conference Proceedings (OSTI)

Systčme d’analyse fournissant des renseignements atmosphériques ŕ la neige (SAFRAN) is a mesoscale atmospheric analysis system for surface variables. It produces an analysis at the hourly time step using ground data observations. One of SAFRAN’s ...

P. Quintana-Seguí; P. Le Moigne; Y. Durand; E. Martin; F. Habets; M. Baillon; C. Canellas; L. Franchisteguy; S. Morel

2008-01-01T23:59:59.000Z

338

The Influence of the AMOC Variability on the Atmosphere in CCSM3  

Science Conference Proceedings (OSTI)

The influence of the Atlantic meridional overturning circulation (AMOC) variability on the atmospheric circulation is investigated in a control simulation of the NCAR Community Climate System Model, version 3 (CCSM3), where the AMOC evolves from ...

Claude Frankignoul; Guillaume Gastineau; Young-Oh Kwon

2013-12-01T23:59:59.000Z

339

Do General Circulation Models Underestimate the Natural Variability in the Arctic Climate?  

Science Conference Proceedings (OSTI)

The authors examine the natural variability of the arctic climate system simulated by two very different models: the Geophysical Fluid Dynamics Laboratory (GFDL) global climate model, and an area-averaged model of the arctic atmosphere–sea ice–...

D. S. Battisti; C. M. Bitz; R. E. Moritz

1997-08-01T23:59:59.000Z

340

The Basic Effects of Atmosphere–Ocean Thermal Coupling on Midlatitude Variability  

Science Conference Proceedings (OSTI)

Starting from the assumption that the atmosphere is the primary source of variability internal to the midlatitude atmosphere–ocean system on intraseasonal to interannual timescales, the authors construct a simple stochastically forced, one-...

Joseph J. Barsugli; David S. Battisti

1998-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

U-097: PHP "php_register_variable_ex()" Code Execution Vulnerability |  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

097: PHP "php_register_variable_ex()" Code Execution 097: PHP "php_register_variable_ex()" Code Execution Vulnerability U-097: PHP "php_register_variable_ex()" Code Execution Vulnerability February 7, 2012 - 9:00am Addthis PROBLEM: PHP "php_register_variable_ex()" Code Execution Vulnerability PLATFORM: PHP 5.3.x ABSTRACT: Execution of arbitrary code via network as well as user access via network reference LINKS: PHP Security Archive SecurityTracker Alert ID: 1026631 Secunia Advisory SA47806 CVE-2012-0830 IMPACT ASSESSMENT: High Discussion: A vulnerability has been reported in PHP, which can be exploited by malicious people to compromise a vulnerable system. Impact: A remote user can send specially crafted data to trigger a memory error in php_register_variable_ex() and execute arbitrary code on the target system.

342

New Report: Integrating Variable Wind Energy into the Grid | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Report: Integrating Variable Wind Energy into the Grid Report: Integrating Variable Wind Energy into the Grid New Report: Integrating Variable Wind Energy into the Grid December 19, 2011 - 2:00pm Addthis The Energy Department and Alstom Grid announce the availability of a new report on integrating wind energy into the electrical grid. | Image source: The Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations Report. The Energy Department and Alstom Grid announce the availability of a new report on integrating wind energy into the electrical grid. | Image source: The Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations Report. Charlton I. Clark Integration Team Lead, Wind and Water Power Program

343

Extrinsic Radio Variability of JVAS/CLASS Gravitational Lenses  

E-Print Network (OSTI)

We present flux-ratio curves of the fold and cusp (i.e. close multiple) images of six JVAS/CLASS gravitational lens systems. The data were obtained over a period of 8.5 months in 2001 with the Multi-Element Radio-Linked Interferometer Network (MERLIN) at 5-GHz with 50 mas resolution, as part of a MERLIN Key-Project. Even though the time delays between the fold and cusp images are small (<~1 day) compared to the time-scale of intrinsic source variability, all six lens systems show evidence that suggests the presence of extrinsic variability. In particular, the cusp images of B2045+265 -- regarded as the strongest case of the violation of the cusp relation (i.e. the sum of the magnifications of the three cusp images add to zero) -- show extrinsic variations in their flux-ratios up to ~40 percent peak-to-peak on time scales of several months. Its low Galactic latitude of b=-10 degree and a line-of-sight toward the Cygnus superbubble region suggest that Galactic scintillation is the most likely cause. The cusp images of B1422+231 at b=+69 degree do not show strong extrinsic variability. Galactic scintillation can therefore cause significant scatter in the cusp and fold relations of some radio lens systems (up to 10 percent rms), even though these relations remain violated when averaged over a <~1 year time baseline.

L. V. E. Koopmans; A. Biggs; R. D. Blandford; I. W. A. Browne; N. J. Jackson; S. Mao; P. N. Wilkinson; A. G. de Bruyn; J. Wambsganss

2003-02-11T23:59:59.000Z

344

Constraints for the design of variability-intensive service-oriented reference architectures - An industrial case study  

Science Conference Proceedings (OSTI)

Context: Service-oriented architecture has become a widely used concept in software industry. However, we currently lack support for designing variability-intensive service-oriented systems. Such systems could be used in different environments, without ... Keywords: Case study, Reference architectures, SOA, Service-oriented architecture, Variability, e-Government

Matthias Galster; Paris Avgeriou; Dan Tofan

2013-02-01T23:59:59.000Z

345

Fuzzy logic approach for spatially variable nitrogen fertilization of corn based on soil, crop and precipitation information  

Science Conference Proceedings (OSTI)

A fuzzy Inference System (FIS) was developed to generate recommendations for spatially variable applications of nitrogen (N) fertilizer using soil, plant and precipitation information. Experiments were conducted over three seasons (2005-2007) to assess ... Keywords: fuzzy inference systems, nitrogen sufficiency index, precipitations, soil electrical conductivity, variable nitrogen fertilization, water supply

Yacine Bouroubi; Nicolas Tremblay; Philippe Vigneault; Carl Bélec; Bernard Panneton; Serge Guillaume

2011-06-01T23:59:59.000Z

346

Mass Market Demand Response and Variable Generation Integration Issues: A  

NLE Websites -- All DOE Office Websites (Extended Search)

Mass Market Demand Response and Variable Generation Integration Issues: A Mass Market Demand Response and Variable Generation Integration Issues: A Scoping Study Title Mass Market Demand Response and Variable Generation Integration Issues: A Scoping Study Publication Type Report Refereed Designation Unknown Year of Publication 2011 Authors Cappers, Peter, Andrew D. Mills, Charles A. Goldman, Ryan H. Wiser, and Joseph H. Eto Pagination 76 Date Published 10/2011 Publisher LBNL City Berkeley Keywords demand response, electricity markets and policy group, energy analysis and environmental impacts department, renewable generation integration, smart grid Abstract The penetration of renewable generation technology (e.g., wind, solar) is expected to dramatically increase in the United States during the coming years as many states are implementing policies to expand this sector through regulation and/or legislation. It is widely understood, though, that large scale deployment of certain renewable energy sources, namely wind and solar, poses system integration challenges because of its variable and often times unpredictable production characteristics (NERC, 2009). Strategies that rely on existing thermal generation resources and improved wind and solar energy production forecasts to manage this variability are currently employed by bulk power system operators, although a host of additional options are envisioned for the near future. Demand response (DR), when properly designed, could be a viable resource for managing many of the system balancing issues associated with integrating large-scale variable generation (VG) resources (NERC, 2009). However, demand-side options would need to compete against strategies already in use or contemplated for the future to integrate larger volumes of wind and solar generation resources. Proponents of smart grid (of which Advanced Metering Infrastructure or AMI is an integral component) assert that the technologies associated with this new investment can facilitate synergies and linkages between demand-side management and bulk power system needs. For example, smart grid proponents assert that system-wide implementation of advanced metering to mass market customers (i.e., residential and small commercial customers) as part of a smart grid deployment enables a significant increase in demand response capability.1 Specifically, the implementation of AMI allows electricity consumption information to be captured, stored and utilized at a highly granular level (e.g., 15-60 minute intervals in most cases) and provides an opportunity for utilities and public policymakers to more fully engage electricity customers in better managing their own usage through time-based rates and near-real time feedback to customers on their usage patterns while also potentially improving the management of the bulk power system. At present, development of time-based rates and demand response programs and the installation of variable generation resources are moving forward largely independent of each other in state and regional regulatory and policy forums and without much regard to the complementary nature of their operational characteristics.2 By 2020, the electric power sector is expected to add ~65 million advanced meters3 (which would reach ~47% of U.S. households) as part of smart grid and AMI4 deployments (IEE, 2010) and add ~40-80 GW of wind and solar capacity (EIA, 2010). Thus, in this scoping study, we focus on a key question posed by policymakers: what role can the smart grid (and its associated enabling technology) play over the next 5-10 years in helping to integrate greater penetration of variable generation resources by providing mass market customers with greater access to demand response opportunities? There is a well-established body of research that examines variable generation integration issues as well as demand response potential, but the nexus between the two has been somewhat neglected by the industry. The studies that have been conducted are informative concerning what could be accomplished with strong broad-based support for the expansion of demand response opportunities, but typically do not discuss the many barriers that stand in the way of reaching this potential. This study examines how demand side resources could be used to integrate wind and solar resources in the bulk power system, identifies barriers that currently limit the use of demand side strategies, and suggests several factors that should be considered in assessing alternative strategies that can be employed to integrate wind and solar resources in the bulk power system. It is difficult to properly gauge the role that DR could play in managing VG integration issues in the near future without acknowledging and understanding the entities and institutions that govern the interactions between variable generation and mass market customers (see Figure ES-1). Retail entities, like load-serving entities (LSE) and aggregators of retail customers (ARC), harness the demand response opportunities of mass market customers through tariffs (and DR programs) that are approved by state regulatory agencies or local governing entities (in the case of public power). The changes in electricity consumption induced by DR as well as the changes in electricity production due to the variable nature of wind and solar generation technologies is jointly managed by bulk power system operators. Bulk power system operators function under tariffs approved by the Federal Energy Regulatory Commission (FERC) and must operate their systems in accordance with rules set by regional reliability councils. These reliability rules are derived from enforceable standards that are set by the North American Electric Reliability Corporation (NERC) and approved by federal regulators. Thus, the role that DR can play in managing VG integration issues is contingent on what opportunities state and local regulators are willing to approve and how customers' response to the DR opportunities can be integrated into the bulk power system both electrically (due to reliability rules) and financially (due to market rules).

347

Lithium battery management system  

SciTech Connect

Provided is a system for managing a lithium battery system having a plurality of cells. The battery system comprises a variable-resistance element electrically connected to a cell and located proximate a portion of the cell; and a device for determining, utilizing the variable-resistance element, whether the temperature of the cell has exceeded a predetermined threshold. A method of managing the temperature of a lithium battery system is also included.

Dougherty, Thomas J. (Waukesha, WI)

2012-05-08T23:59:59.000Z

348

Reducing variability in equipment availability at Intel using systems optimization  

E-Print Network (OSTI)

Equipment management is an important driver behind operational efficiency, since capital equipment makes up about 40% of the average semiconductor manufacturer's total assets. The main goal of this project is to reduce ...

Kwong, William W. M

2004-01-01T23:59:59.000Z

349

Strategies and Decision Support Systems for Integrating Variable...  

Open Energy Info (EERE)

understanding of the operational impacts of wind integration and how wind power forecast is being used today. The identified practices from a broad group of utilities can be...

350

On the Mechanism of Pacific Multidecadal Climate Variability in CCSM3: The Role of the Subpolar North Pacific Ocean  

Science Conference Proceedings (OSTI)

Previous analyses of the Community Climate System Model, version 3 (CCSM3) standard integration have revealed pronounced multidecadal variability in the Pacific climate system. The purpose of the present work is to investigate physical mechanism ...

Yafang Zhong; Zhengyu Liu

2009-09-01T23:59:59.000Z

351

Glossary | Building Energy Codes Program  

NLE Websites -- All DOE Office Websites (Extended Search)

Balancing, Air Balancing, Air Adjusting air flow rates through air distribution system devices, such as fans and diffusers, by manually adjusting the position of dampers, splitter vanes, extractors, etc., or by using automatic control devices, such as constant air volume or variable air volume boxes. Balancing, Hydronic Adjusting water flow rates through hydronic distribution system devices, such as pumps and coils, by manually adjusting the position valves, or by using automatic control devices, such as automatic flow control valves. Ballast A device used in conjunction with an electric-discharge lamp to cause the lamp to start and operate under the proper circuit conditions of voltage, current, wave form, electrode heat, etc. Basement Wall Basement walls that enclose heated spaces are part of the building

352

Energy Efficiency Improvement and Cost Saving Opportunities for the Dairy Processing Industry  

E-Print Network (OSTI)

air-volume systems Building insulation Adjustable-speedand wind shielding. Building insulation. Adding insulationguidelines for building insulation, for example, California’

Brush, Adrian

2012-01-01T23:59:59.000Z

353

Variability of EGRET Gamma-Ray Sources  

E-Print Network (OSTI)

The variability of the high-energy gamma ray sources in the Third EGRET catalog is analyzed by a new method. We re-analyze the EGRET data to calculate a likelihood function for the flux of each source in each observation, both for detections and upper limits. These functions can be combined in a uniform manner with a simple model of the flux distribution to characterize the flux variation by a confidence interval for the relative standard deviation of the flux. The main result is a table of these values for almost all the cataloged sources. As expected, the identified pulsars are steady emitters and the blazars are mostly highly variable. The unidentified sources are heterogeneous, with greater variation at higher Galactic latitude. There is an indication that pulsar wind nebulae are associated with variable sources. There is a population of variable sources along the Galactic plane, concentrated in the inner spiral arms.

P. L. Nolan; W. F. Tompkins; I. A. Grenier; P. F. Michelson

2003-07-10T23:59:59.000Z

354

Interannual Variability of Northwest Australian Tropical Cyclones  

Science Conference Proceedings (OSTI)

Tropical cyclone (TC) activity over the southeast Indian Ocean has been studied far less than other TC basins, such as the North Atlantic and northwest Pacific. The authors examine the interannual TC variability of the northwest Australian (NWAUS)...

Kevin H. Goebbert; Lance M. Leslie

2010-09-01T23:59:59.000Z

355

Variability of Southern Ocean Jets Near Topography  

Science Conference Proceedings (OSTI)

The interaction of jets with topography in the Southern Ocean is investigated using 19 years of altimetry data. In particular, the “jet jumping” mode of variability, by which two or more jets passing close to the same topographic feature show ...

Christopher C. Chapman; Rosemary Morrow

356

Weather Noise Forcing of Surface Climate Variability  

Science Conference Proceedings (OSTI)

A model-based method to evaluate the role of weather noise forcing of low-frequency variability of surface properties, including SST, surface currents, land surface temperature, and soil moisture, is presented. In this procedure, an “interactive ...

Edwin K. Schneider; Meizhu Fan

2007-09-01T23:59:59.000Z

357

Experiments Concerning Variability among Subjective Analyses  

Science Conference Proceedings (OSTI)

The variability of subjective (hand) analyses is explored by examining the results of two synoptic laboratory experiments. Two groups of analysts participated in the first experiment, one consisting of 13 senior meteorology students (1977), the ...

Dayton G. Vincent; Herbert Borenstein

1980-10-01T23:59:59.000Z

358

Tropical Convective Variability as 1/f Noise  

Science Conference Proceedings (OSTI)

Evidence is presented that the tropical convective variability behaves as 1/f noise for a 1–30-day period. This behavior is shown by analyzing the time series of convective available potential energy, which measures the degree of convective ...

Jun-Ichi Yano; Klaus Fraedrich; Richard Blender

2001-09-01T23:59:59.000Z

359

Optimizing Crop Insurance under Climate Variability  

Science Conference Proceedings (OSTI)

This paper studies the selection of optimal crop insurance under climate variability and fluctuating market prices. A model was designed to minimize farmers’ expected losses (including insurance costs) while using the conditional-value-at-risk ...

Juan Liu; Chunhua Men; Victor E. Cabrera; Stan Uryasev; Clyde W. Fraisse

2008-10-01T23:59:59.000Z

360

Variable volume architecture : expanding the boundary  

E-Print Network (OSTI)

Research into the creation of a Variable Volume Architecture is explored through a series of proposals and projects. An argument is established to develop the means and methods of achieving an architecture of transformation. ...

Saheba, Asheshh (Asheshh Mohit), 1972-

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Backscatter Differential Phase—Estimation and Variability  

Science Conference Proceedings (OSTI)

On the basis of simulations and observations made with polarimetric radars operating at X, C, and S bands, the backscatter differential phase ? has been explored; ? has been identified as an important polarimetric variable that should not be ...

Silke Trömel; Matthew R. Kumjian; Alexander V. Ryzhkov; Clemens Simmer; Malte Diederich

2013-11-01T23:59:59.000Z

362

Spatial Variability of Outgoing Longwave Radiation  

Science Conference Proceedings (OSTI)

Data from the Earth Radiation Budget Experiment scanning radiometer aboard the NOAA-9 operational meteorological satellite are used to investigate the spatial variability of outgoing longwave radiation (OLR). Daily and monthly radiation maps at ...

G. Louis Smith; David Rutan

1994-07-01T23:59:59.000Z

363

Climate Variability and Sugarcane Yield in Louisiana  

Science Conference Proceedings (OSTI)

This paper seeks to understand the role that climate variability has on annual yield of sugarcane in Louisiana. Unique features of sugarcane growth in Louisiana and nonclimatic, yield-influencing factors make this goal an interesting and ...

David Greenland

2005-11-01T23:59:59.000Z

364

Integrating Variable Renewable Energy: Challenges and Solutions  

NLE Websites -- All DOE Office Websites (Extended Search)

LLC This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.govpublications. Contract No. DE-AC36-08GO28308 Integrating Variable...

365

Anisotropic high temperature superconductors as variable resistors and switches  

Science Conference Proceedings (OSTI)

Several anisotropic high temperature superconductors show critical current densities which are strongly dependent on the direction of an applied external magnetic field. The resistance of a sample can change by several orders of magnitude by applying a magnetic field. The potential for using the field dependent variable resistor or switch for applications in power systems is evaluated. Test results with small samples are presented. The requirements for large scale applications are outlined. The magnetic field triggering requirement, the frequency response of the device, use in 60 Hz ac circuits and heat transfer consideration are investigated. Several application examples are discussed. Use of variable resistor as a fault current limiter, as a switching element in rectifier circuitry and as an improved dump resistor for a superconducting magnet is presented.

Boenig, H.J.; Daugherty, M.A.; Fleshler, S.; Maley, M.P.; Mueller, F.M.; Prenger, F.C.; Coulter, J.Y.

1994-12-01T23:59:59.000Z

366

FITDisk: A Cataclysmic Variable Accretion Disk Demonstration Tool  

E-Print Network (OSTI)

We present the software tool FITDisk, a precompiled-binary Windows GUI version of our smoothed particle hydrodynamics cataclysmic variable accretion disk research code. Cataclysmic variables are binary star systems in which a compact stellar remnant, typically a white dwarf star, is stripping mass from a lower-main-sequence companion star by way of an accretion disk. Typically the disk is the brightest component of the system, because the plasma is heated dramatically as it spirals down in the gravitational well of the primary white dwarf star. The shortest-period systems can display disk "superhump" oscillations driven by the rotating tidal field of the secondary star. FITDisk models these accretion disk phenomena using a fully three-dimensional hydrodynamics calculation, and data can be visualized as they are computed or stored to hard drive for later playback at a fast frame rate. Simulations are visualized using OpenGL graphics and the viewing angle can be changed interactively. Pseudo light curves of simulated systems can be plotted along with the associated Fourier amplitude spectrum. FITDisk is available for free download at www.astro.fit.edu/cv/fitdisk.html.

Matt A. Wood; Josh Dolence; James C. Simpson

2005-11-11T23:59:59.000Z

367

Potential Reductions in Variability with Alternative Approaches to Balancing Area Cooperation with High Penetrations of Variable Generation  

SciTech Connect

The work described in this report was performed by the National Renewable Energy Laboratory (NREL) and funded by the Office of the Energy Efficiency and Renewable Energy, U.S. Department of Energy (EERE DOE). This project is a joint project with the Pacific Northwest National Laboratory. This report evaluates the physical characteristics that improve the ability of the power system to absorb variable generation. It then uses evidence from electricity markets in the Eastern Interconnection of the United States to show how large, fast energy markets can help with integration. The concept of Virtual Balancing Area is introduced, a concept that covers a broad range of cooperative measures that can be undertaken by balancing areas to help manage variability.

Milligan, M.; Kirby, B.; Beuning, S.

2010-08-01T23:59:59.000Z

368

Computational Study on Thermal Properties of HVAC System with Building Structure Thermal Storage  

E-Print Network (OSTI)

Building structure thermal storage (BSTS) HVAC systems can store heat during nighttime thermal storage operation (nighttime operation hours) by using off-peak electricity and release it in the daytime air-conditioning operation (daytime operation hours) by utilizing a large amount of the thermal capacity of building structures such as beams, columns and floors composed of concrete. These BSTS systems have recently been considered as one method for leveling hourly electricity demands for HVAC on a day-to-day basis. Through a simulation using a model developed with experimental data, this paper describes how various factors for the design and operation of a BSTS quantitatively affect the charge/discharge performances of a HVAC system. As a result, the following was revealed: the thermal performance of the system is strongly influenced by the daily heat storage operation hours, supply air volume and supply air temperature during the nighttime operation hours, stored heat caused the total daytime cooling extraction to decrease by 11% to 58% and the daily total cooling extraction through nighttime to daytime to increase by 4% to 17% compared with the values of non- thermal storage HVAC system.

Sato, Y.; Sagara, N.; Ryu, Y.; Maehara, K.; Nagai, T.

2007-01-01T23:59:59.000Z

369

Variability in Automated Responses of Commercial Buildings and Industrial Facilities to Dynamic Electricity Prices  

Science Conference Proceedings (OSTI)

Changes in the electricity consumption of commercial buildings and industrial facilities (C&I facilities) during Demand Response (DR) events are usually estimated using counterfactual baseline models. Model error makes it difficult to precisely quantify these changes in consumption and understand if C&I facilities exhibit event-to-event variability in their response to DR signals. This paper seeks to understand baseline model error and DR variability in C&I facilities facing dynamic electricity prices. Using a regression-based baseline model, we present a method to compute the error associated with estimates of several DR parameters. We also develop a metric to determine how much observed DR variability results from baseline model error rather than real variability in response. We analyze 38 C&I facilities participating in an automated DR program and find that DR parameter errors are large. Though some facilities exhibit real DR variability, most observed variability results from baseline model error. Therefore, facilities with variable DR parameters may actually respond consistently from event to event. Consequently, in DR programs in which repeatability is valued, individual buildings may be performing better than previously thought. In some cases, however, aggregations of C&I facilities exhibit real DR variability, which could create challenges for power system operation.

Mathieu, Johanna L.; Callaway, Duncan S.; Kiliccote, Sila

2011-08-16T23:59:59.000Z

370

U-090: RSA enVision Discloses Environment Variable Information to Remote  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

0: RSA enVision Discloses Environment Variable Information to 0: RSA enVision Discloses Environment Variable Information to Remote Users U-090: RSA enVision Discloses Environment Variable Information to Remote Users January 27, 2012 - 6:00am Addthis PROBLEM: A vulnerability was reported in RSA enVision PLATFORM: Version(s): 4.0 prior to 4.0 SP4 P5, 4.1 prior to 4.1 P3 ABSTRACT: A remote user can view potentially sensitive data on the target system. reference LINKS: CVE-2011-4143 SecurityTracker Alert ID: 1026591 Secunia Advisory IMPACT ASSESSMENT: Medium Discussion: The security issue is caused due to the application disclosing certain environment variables containing web system setup information via the web interface. Further information about this resolution and other fixes can be found in the Release Notes associated with RSA enVision 4.1, Patch 3 and

371

The influence of a variable volume water heater on the domestic load profile  

SciTech Connect

In this paper a variable volume water heater and a load impact model is presented. The variable volume water heater is a unique system that can be implemented as a residential demand-side management tool. The variable volume water heater can shift the electrical energy consumption, used to heat water, to off-peak time periods. The electrical energy is shifted without influencing the hot water usage of the customer. The load impact model simulates the effect of controlling the volume of stored hot water on a domestic load. The model mathematics as well as the model verification are discussed. The paper ends with a comparative case study on two residential areas. The case study indicates that the variable volume water heater can reduce the system peak as well as increase the off-peak energy consumption.

Lemmer, E.F.; Delport, G.J.

1999-12-01T23:59:59.000Z

372

May 2013 PSERC Webinar: Managing Wind Variability with Self-Reserves and  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

May 2013 PSERC Webinar: Managing Wind Variability with May 2013 PSERC Webinar: Managing Wind Variability with Self-Reserves and Responsive Demand May 2013 PSERC Webinar: Managing Wind Variability with Self-Reserves and Responsive Demand April 9, 2013 - 10:40am Addthis The DOE-funded Power Systems Engineering Research Center (PSERC) is offering a free public webinar on managing wind variability in energy production. The webinar will be held Tuesday, May 7, 2013 from 2-3 p.m. No pre-registration is necessary. Using wind power to supply up to 20%, or more, of electrical demand is increasingly popular in policy mandates, yet is relatively untested in terms of actual system and market operations. This presentation will investigate the concept of self-reserves, wherein wind generators withhold a portion of forecasted energy production, via their hour-ahead schedule,

373

Variables et categories grammaticales dans un modele ariane  

Science Conference Proceedings (OSTI)

Toutes tes catégories grammaticales utilisées dans un modéle de traduction ariane sont formalisées et codées de faç mnémonique en tant que variables et valeurs de variables. L'ensemble des variables d'un ...

Jean-Phillippe Guilbaud

1986-08-01T23:59:59.000Z

374

Reversible Record Breaking and Variability: Temperature Distributions across the Globe  

Science Conference Proceedings (OSTI)

Based on counts of record highs and lows, and employing reversibility in time, an approach to examining natural variability is proposed. The focus is on intrinsic variability; that is, variance separated from the trend in the mean. A variability ...

Amalia Anderson; Alexander Kostinski

2010-08-01T23:59:59.000Z

375

U.S. Economic Sensitivity to Weather Variability  

Science Conference Proceedings (OSTI)

To estimate the economic effects of weather variability in the United States, the authors define and measure weather sensitivity as the variability in economic output that is attributable to weather variability, accounting for changes in technology and ...

Jeffrey K. Lazo; Megan Lawson; Peter H. Larsen; Donald M. Waldman

2011-06-01T23:59:59.000Z

376

Variable Refrigerant Flow Air Conditioners and Heat Pumps for Commercial Buildings  

Science Conference Proceedings (OSTI)

Multi-split heat pumps have evolved from a technology suitable for residential and light commercial buildings to variable refrigerant flow (VRF) systems that can provide efficient space conditioning for large commercial buildings. VRF systems are enhanced versions of ductless multi-split systems, permitting more indoor units to be connected to each outdoor unit and providing additional features such as simultaneous heating and cooling and heat recovery. VRF systems are very popular in Asia and Europe and...

2008-01-25T23:59:59.000Z

377

FITDisk: A Cataclysmic Variable Accretion Disk Demonstration Tool  

E-Print Network (OSTI)

We present the software tool FITDisk, a precompiled-binary Windows GUI version of our smoothed particle hydrodynamics cataclysmic variable accretion disk research code. Cataclysmic variables are binary star systems in which a compact stellar remnant, typically a white dwarf star, is stripping mass from a lower-main-sequence companion star by way of an accretion disk. Typically the disk is the brightest component of the system, because the plasma is heated dramatically as it spirals down in the gravitational well of the primary white dwarf star. The shortest-period systems can display disk "superhump" oscillations driven by the rotating tidal field of the secondary star. FITDisk models these accretion disk phenomena using a fully three-dimensional hydrodynamics calculation, and data can be visualized as they are computed or stored to hard drive for later playback at a fast frame rate. Simulations are visualized using OpenGL graphics and the viewing angle can be changed interactively. Pseudo light curves of sim...

Wood, M A; Simpson, J C; Wood, Matt A.; Dolence, Josh; Simpson, James C.

2005-01-01T23:59:59.000Z

378

An Assessment of Industry Data Related to Essential Variables for Fusing High Density Polyethylene Pipe  

Science Conference Proceedings (OSTI)

The Nuclear Regulatory Commission has expressed concern about the essential variables used for fusing safety-related nuclear power plant piping systems constructed of high density polyethylene (HDPE). The essential variables detailed in the American Society of Mechanical Engineers (ASME) Code Case N-755-1, “Use of Polyethylene (PE) Plastic Pipe,” were considered to be incomplete. In addition, there were questions about using data in the Plastic Pipe Institute (PPI) report TR-33 ...

2013-07-31T23:59:59.000Z

379

Large deviation properties of constant rate data streams sharing a buffer with variable rate cross traffic  

Science Conference Proceedings (OSTI)

We consider a constant rate data stream which shares a buffer with a variable rate data stream. A first come first serve service discipline is applied at the buffer. After service at the first buffer the variable rate traffic leaves the system, whereas ... Keywords: 68M20, 90B15, Markov-modulated fluid sources, fluid model, large buffer asymptotics, many sources asymptotics, on-off sources, primary 60F10, queueing network, secondary 60K25

Kurt Majewski

2008-10-01T23:59:59.000Z

380

Modeling and Model Validation for Variable Generation Technologies: Focus on Wind Generation  

Science Conference Proceedings (OSTI)

The influx of variable-generation technologies, particularly wind generation, into the bulk transmission grid has been tremendous over the past decade. This trend will likely continue, in light of national and state renewable portfolio standards. Thus, there is a need for generic, standard, and publicly available models for variable-generation technologies for power system planning studies. The Electric Power Research Institute (EPRI), in collaboration with the Western Electricity Coordinating Council (...

2010-12-14T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Variable Frequency Drives: Energy Savings and Impact on Motor Performance  

E-Print Network (OSTI)

Variable frequency drives (VFDs) have found widespread application in recent years. VFDs are valued for their potential to save energy and improve processes. Reliability has improved significantly, but there are still pitfalls to be addressed in properly applying VFDs. The benefits and pitfalls in applying VFDs that will be addressed by this paper include- Benefits: Energy Savings, Improved Process Control, “Soft Start” Reduced Mechanical Stress, Improved Electrical System Power Factor, and Pitfalls: Motor Acoustic Noise, Motor Heating. This paper is intended for plant engineers and maintenance personnel who have some practical experience with electrical and mechanical equipment, but are not VFD experts.

Petro, D.

1993-03-01T23:59:59.000Z

382

EFFECT OF PITCH CONTROL AND POWER CONDITIONING ON POWER QUALITY OF VARIABLE SPEED WIND TURBINE GENERATORS  

E-Print Network (OSTI)

Wind energy is considered as the most viable renewable energy options. In a renewable energy system more energy from the wind. One of the options is to use the variable speed wind turbine-speed wind turbine system for transient studies are discussed in this paper. The performance of wind energy

383

Flight Control Design for Rotorcraft with Variable Rotor Speed.  

E-Print Network (OSTI)

??Flight control design issues for rotorcraft with variable rotor speed are investigated, and new design methodologies are developed to deal with the challenges of variable… (more)

Guo, Wei

2009-01-01T23:59:59.000Z

384

Adaptation to Climate Variability and Change: A Guidance Manual...  

Open Energy Info (EERE)

Adaptation to Climate Variability and Change: A Guidance Manual for Development Planning Jump to: navigation, search Tool Summary Name: Adaptation to Climate Variability and...

385

2005 RECS Variable Response Code Labels - U.S. Energy ...  

U.S. Energy Information Administration (EIA)

7 concrete or concrete block 8 glass 9 other 10 indescribable : 1 . 2005 recs variable response code labels . variable response code label file number* cnfrmhuq .

386

GEOCHEMICAL MODELING OF F AREA SEEPAGE BASIN COMPOSITION AND VARIABILITY  

SciTech Connect

From the 1950s through 1989, the F Area Seepage Basins at the Savannah River Site (SRS) received low level radioactive wastes resulting from processing nuclear materials. Discharges of process wastes to the F Area Seepage Basins followed by subsequent mixing processes within the basins and eventual infiltration into the subsurface resulted in contamination of the underlying vadose zone and downgradient groundwater. For simulating contaminant behavior and subsurface transport, a quantitative understanding of the interrelated discharge-mixing-infiltration system along with the resulting chemistry of fluids entering the subsurface is needed. An example of this need emerged as the F Area Seepage Basins was selected as a key case study demonstration site for the Advanced Simulation Capability for Environmental Management (ASCEM) Program. This modeling evaluation explored the importance of the wide variability in bulk wastewater chemistry as it propagated through the basins. The results are intended to generally improve and refine the conceptualization of infiltration of chemical wastes from seepage basins receiving variable waste streams and to specifically support the ASCEM case study model for the F Area Seepage Basins. Specific goals of this work included: (1) develop a technically-based 'charge-balanced' nominal source term chemistry for water infiltrating into the subsurface during basin operations, (2) estimate the nature of short term and long term variability in infiltrating water to support scenario development for uncertainty quantification (i.e., UQ analysis), (3) identify key geochemical factors that control overall basin water chemistry and the projected variability/stability, and (4) link wastewater chemistry to the subsurface based on monitoring well data. Results from this study provide data and understanding that can be used in further modeling efforts of the F Area groundwater plume. As identified in this study, key geochemical factors affecting basin chemistry and variability included: (1) the nature or chemistry of the waste streams, (2) the open system of the basins, and (3) duration of discharge of the waste stream types. Mixing models of the archetype waste streams indicated that the overall basin system would likely remain acidic much of the time. Only an extended periods of predominantly alkaline waste discharge (e.g., >70% alkaline waste) would dramatically alter the average pH of wastewater entering the basins. Short term and long term variability were evaluated by performing multiple stepwise modeling runs to calculate the oscillation of bulk chemistry in the basins in response to short term variations in waste stream chemistry. Short term (1/2 month and 1 month) oscillations in the waste stream types only affected the chemistry in Basin 1; little variation was observed in Basin 2 and 3. As the largest basin, Basin 3 is considered the primary source to the groundwater. Modeling showed that the fluctuation in chemistry of the waste streams is not directly representative of the source term to the groundwater (i.e. Basin 3). The sequence of receiving basins and the large volume of water in Basin 3 'smooth' or nullify the short term variability in waste stream composition. As part of this study, a technically-based 'charge-balanced' nominal source term chemistry was developed for Basin 3 for a narrow range of pH (2.7 to 3.4). An example is also provided of how these data could be used to quantify uncertainty over the long term variations in waste stream chemistry and hence, Basin 3 chemistry.

Millings, M.; Denham, M.; Looney, B.

2012-05-08T23:59:59.000Z

387

Interannual Variability of Indian Ocean Heat Transport  

Science Conference Proceedings (OSTI)

The work in this paper builds upon the relatively well-studied seasonal cycle of the Indian Ocean heat transport by investigating its interannual variability over a 41-yr period (1958–98). An intermediate, two-and-a-half-layer thermodynamically ...

Galina Chirokova; Peter J. Webster

2006-03-01T23:59:59.000Z

388

The Interannual Variability of Tropical Cyclones  

Science Conference Proceedings (OSTI)

This paper examines the interannual variability of tropical cyclones in each of the earth’s cyclone basins using data from 1985 to 2003. The data are first analyzed using a Monte Carlo technique to investigate the long-standing myth that the ...

William M. Frank; George S. Young

2007-10-01T23:59:59.000Z

389

Reuse and variability in large software applications  

Science Conference Proceedings (OSTI)

Reuse has always been a major goal in software engineering, since it promises large gains in productivity, quality and time to market reduction. Practical experience has shown that substantial reuse has only successfully happened in two cases: libraries, ... Keywords: AOP, COTS, EAI, MDA, interoperability, model driven software engineering, process driven application, product families, product line, reuse, variability, workflow

Jacky Estublier; German Vega

2005-09-01T23:59:59.000Z

390

Cloud service selection based on variability modeling  

Science Conference Proceedings (OSTI)

The selection among Cloud services is a recent problem in research and practice. The diversity of decision-relevant criteria, configurability of Cloud services and the need to involve human decision-makers require holistic support through models, methodologies ... Keywords: cloud service selection, decision-making, feature modeling, variability modeling

Erik Wittern; Jörn Kuhlenkamp; Michael Menzel

2012-11-01T23:59:59.000Z

391

Anatomy of North Pacific Decadal Variability  

Science Conference Proceedings (OSTI)

A systematic analysis of North Pacific decadal variability in a full-physics coupled ocean–atmosphere model is executed. The model is an updated and improved version of the coupled model studied by Latif and Barnett. Evidence is sought for ...

Niklas Schneider; Arthur J. Miller; David W. Pierce

2002-03-01T23:59:59.000Z

392

Galactic Variable Sky with EGRET and GLAST  

Science Conference Proceedings (OSTI)

The characteristics of the largely-unidentified Galactic sources of gamma rays that were detected by EGRET are reviewed. Proposed source populations that may have the correct spatial, spectral, luminosity, and variability properties to be the origins of the EGRET sources are also presented. Finally, the prospects for studying Galactic gamma-ray sources with the GLAST LAT are reviewed.

Digel, S.W.; /SLAC

2006-11-28T23:59:59.000Z

393

A strain gage?variable area flowmeter  

Science Conference Proceedings (OSTI)

This article presents a unique hybrid flowmeter that combines the turndown ratio/low resistance benefits of a variable area differential pressure flowmeter with the low component simplicity of a target flowmeter. The design attaches a single element strain gage to the flexural membrane suspended in a fluid flow passage

D. W. Guillaume; D. DeVries

1990-01-01T23:59:59.000Z

394

Variation of Area Variables in Regge Calculus  

E-Print Network (OSTI)

We consider the possibility to use the areas of two-simplexes, instead of lengths of edges, as the dynamical variables of Regge calculus. We show that if the action of Regge calculus is varied with respect to the areas of two-simplexes, and appropriate constraints are imposed between the variations, the Einstein-Regge equations are recovered.

Jarmo Makela

1998-01-09T23:59:59.000Z

395

10 X-rays from Cataclysmic Variables  

E-Print Network (OSTI)

Cataclysmic Variables ? (CVs) are a distinct class of interacting binaries, transferring mass from a donor star to a degenerate accretor, a white dwarf (WD). In all observational determinations, and as is required by theory for stable mass transfer, the donor star is of lower mass than the accretor.

Erik Kuulkers; Andrew Norton; Axel Schwope; Brian Warner

2003-01-01T23:59:59.000Z

396

Investigation of determinism in heart rate variability  

Science Conference Proceedings (OSTI)

The article searches for the possible presence of determinism in heart rate variability (HRV) signals by using a new approach based on NARMA (nonlinear autoregressive moving average) modeling and free-run prediction. Thirty-three 256-point HRV time series obtained from Wistar rats submitted to different autonomic blockade protocols are considered

M. E. D. Gomes; A. V. P. Souza; H. N. Guimarăes; L. A. Aguirre

2000-01-01T23:59:59.000Z

397

The Kelastic variable wall mining machine. Interim final report  

SciTech Connect

This machine cuts coal along a longwall face extending up to 500 feet by a rotating auger with bits. The machine also transports the coal that is cut acting as screw conveyor. By virtue of an integral shroud comprising part of the conveyor the machine is also amenable to a separation of the zones where men work from air being contaminated by dust and methane gas by the cutting action. Beginning as single intake air courses, the air separates at the working section where one split provides fresh air to the Occupied Zone (OZ) for human needs and the other split purges and carries away dust and methane from face fragmentation in the Cutting Zone (CZ). The attractiveness of the Variable Wall Mining Machine is that it addresses the limitations of current longwall mining equipment: it can consistently out-produce continuous mining machines and most longwall shearing machines. It also is amenable to configuring an environment, the dual-duct system, where the air for human breathing is separated from dust-laden ventilating air with methane mixtures. The objective of the research was to perform a mathematical and experimental study of the interrelationships of the components of the system so that a computer model could demonstrate the workings of the system in an animation program. The analysis resulted in the compilation of the parameters for three different configurations of a dual aircourse system of ventilating underground mines. In addressing the goal of an inherently safe mining system the dual-duct adaptation to the Variable Wall Mining Machine appears to offer the path to solution. The respirable dust problem is solvable; the explosive dust problem is nearly solvable; and the explosive methane problem can be greatly reduced. If installed in a highly gassy mine, the dual duct models would also be considerably less costly.

1995-11-12T23:59:59.000Z

398

How to Avoid Overestimating Variable Speed Drive Savings  

E-Print Network (OSTI)

This paper addresses eight factors that can cause incorrect and often excessive savings estimates for pump and fan variable speed drive applications. To avoid overestimating savings: 1. Identify system elements that affect head pressure independently of flow rate. 2. Identify system elements that change head pressure in proportion to less than the square of flow rate. 3. Account for dynamic system elements, especially when in systems with minimum static pressure controls. 4. Consider changes in fan efficiency. 5. Account for decreases in motor efficiency at part load, particularly for smaller motors below about 35 percent load. 6. Recognize that existing part load controls may be more efficient than expected. 7. Account for drive losses. 8. Measure full flow power, rather than assuming it is the same as motor nameplate or design power. For many pump and fan systems, none of the eight factors will apply, or their effects will be negligible. However, analysts should consider their applicability when estimating savings for a particular system. This paper provides tools for accounting for the factors.

Maxwell, J. B.

2005-01-01T23:59:59.000Z

399

CHARACTERIZING THE OPTICAL VARIABILITY OF BRIGHT BLAZARS: VARIABILITY-BASED SELECTION OF FERMI ACTIVE GALACTIC NUCLEI  

SciTech Connect

We investigate the use of optical photometric variability to select and identify blazars in large-scale time-domain surveys, in part to aid in the identification of blazar counterparts to the {approx}30% of {gamma}-ray sources in the Fermi 2FGL catalog still lacking reliable associations. Using data from the optical LINEAR asteroid survey, we characterize the optical variability of blazars by fitting a damped random walk model to individual light curves with two main model parameters, the characteristic timescales of variability {tau}, and driving amplitudes on short timescales {sigma}-circumflex. Imposing cuts on minimum {tau} and {sigma}-circumflex allows for blazar selection with high efficiency E and completeness C. To test the efficacy of this approach, we apply this method to optically variable LINEAR objects that fall within the several-arcminute error ellipses of {gamma}-ray sources in the Fermi 2FGL catalog. Despite the extreme stellar contamination at the shallow depth of the LINEAR survey, we are able to recover previously associated optical counterparts to Fermi active galactic nuclei with E {>=} 88% and C = 88% in Fermi 95% confidence error ellipses having semimajor axis r < 8'. We find that the suggested radio counterpart to Fermi source 2FGL J1649.6+5238 has optical variability consistent with other {gamma}-ray blazars and is likely to be the {gamma}-ray source. Our results suggest that the variability of the non-thermal jet emission in blazars is stochastic in nature, with unique variability properties due to the effects of relativistic beaming. After correcting for beaming, we estimate that the characteristic timescale of blazar variability is {approx}3 years in the rest frame of the jet, in contrast with the {approx}320 day disk flux timescale observed in quasars. The variability-based selection method presented will be useful for blazar identification in time-domain optical surveys and is also a probe of jet physics.

Ruan, John J.; Anderson, Scott F.; MacLeod, Chelsea L.; Becker, Andrew C.; Davenport, James R. A.; Ivezic, Zeljko [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Burnett, T. H. [Department of Physics, University of Washington, Seattle, WA 98195-1560 (United States); Kochanek, Christopher S. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Plotkin, Richard M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Sesar, Branimir [Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA 91125 (United States); Stuart, J. Scott, E-mail: jruan@astro.washington.edu [Lincoln Laboratory, Massachusetts Institute of Technology, 244 Wood Street, Lexington, MA 02420-9108 (United States)

2012-11-20T23:59:59.000Z

400

Storage of LWR spent fuel in air. Volume 3, Results from exposure of spent fuel to fluorine-contaminated air  

SciTech Connect

The Behavior of Spent Fuel in Storage (BSFS) Project has conducted research to develop data on spent nuclear fuel (irradiated U0{sub 2}) that could be used to support design, licensing, and operation of dry storage installations. Test Series B conducted by the BSFS Project was designed as a long-term study of the oxidation of spent fuel exposed to air. It was discovered after the exposures were completed in September 1990 that the test specimens had been exposed to an atmosphere of bottled air contaminated with an unknown quantity of fluorine. This exposure resulted in the test specimens reacting with both the oxygen and the fluorine in the oven atmospheres. The apparent source of the fluorine was gamma radiation-induced chemical decomposition of the fluoro-elastomer gaskets used to seal the oven doors. This chemical decomposition apparently released hydrofluoric acid (HF) vapor into the oven atmospheres. Because the Test Series B specimens were exposed to a fluorine-contaminated oven atmosphere and reacted with the fluorine, it is recommended that the Test Series B data not be used to develop time-temperature limits for exposure of spent nuclear fuel to air. This report has been prepared to document Test Series B and present the collected data and observations.

Cunningham, M.E.; Thomas, L.E.

1995-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

A Bayesian decision theory approach to variable selection for discrimination  

Science Conference Proceedings (OSTI)

Motivated by examples in spectroscopy, we study variable selection for discrimination in problems with very many predictor variables. Assuming multivariate normal distributions with common variance for the predictor variables within groups, we develop ... Keywords: Bayes, decision theory, discriminant analysis, near infrared spectroscopy, simulated annealing, variable selection

T. Fearn; P. J. Brown; P. Besbeas

2002-07-01T23:59:59.000Z

402

Variable selection and ranking for analyzing automobile traffic accident data  

Science Conference Proceedings (OSTI)

Variable ranking and feature selection are important concepts in data mining and machine learning. This paper introduces a new variable ranking technique named Sum Max Gain Ratio (SMGR). The new technique is evaluated within the domain of traffic accident ... Keywords: decision tree, traffic accident data, variable and feature selection, variable ranking

Huanjing Wang; Allen Parrish; Randy K. Smith; Susan Vrbsky

2005-03-01T23:59:59.000Z

403

An examination of loads and responses of a wind turbine undergoing variable-speed operation  

DOE Green Energy (OSTI)

The National Renewable Energy Laboratory has recently developed the ability to predict turbine loads and responses for machines undergoing variable-speed operation. The wind industry has debated the potential benefits of operating wind turbine sat variable speeds for some time. Turbine system dynamic responses (structural response, resonance, and component interactions) are an important consideration for variable-speed operation of wind turbines. The authors have implemented simple, variable-speed control algorithms for both the FAST and ADAMS dynamics codes. The control algorithm is a simple one, allowing the turbine to track the optimum power coefficient (C{sub p}). The objective of this paper is to show turbine loads and responses for a particular two-bladed, teetering-hub, downwind turbine undergoing variable-speed operation. The authors examined the response of the machine to various turbulent wind inflow conditions. In addition, they compare the structural responses under fixed-speed and variable-speed operation. For this paper, they restrict their comparisons to those wind-speed ranges for which limiting power by some additional control strategy (blade pitch or aileron control, for example) is not necessary. The objective here is to develop a basic understanding of the differences in loads and responses between the fixed-speed and variable-speed operation of this wind turbine configuration.

Wright, A.D.; Buhl, M.L. Jr.; Bir, G.S.

1996-11-01T23:59:59.000Z

404

Variable-speed blower motors gaining ground in residential HVAC market  

SciTech Connect

Variable-speed blowers with electronically commutated permanent-magnet motors are gaining ground in the residential forced-air HVAC market. Variable-speed blower motors offer better comfort, better air mixing, lower noise, and tighter temperature and humidity control, as well as higher efficiency and lower peak demand than the constant-speed blower motors installed in most standard systems. Although these benefits cost considerably more up front, some homeowners think the extra cost is justified. Sales are increasing dramatically, and although variable-speed units made up less than three percent of the market in 1993, industry representatives predict that variable-speed blower motors may become the standard within ten to twenty years. The benefits of variable-speed gas furnaces also open up the potential for collaboration between gas and electric utilities. The best way for an electric utility to encourage customers to consider variable-speed gas furnaces may be through the gas utility, since homeowners look to the gas utility when it`s time to make a decision about a gas furnace purchase. Gas utilities can also benefit from variable speed by providing their customers better comfort, and possibly by reducing the customer`s gas bill (due to zoning or better control).

Gregerson, J.

1994-12-31T23:59:59.000Z

405

Variable Stars in Large Magellanic Cloud Globular Clusters I: NGC 1466  

E-Print Network (OSTI)

This is the first in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to better understand how the RR Lyrae stars in Oosterhoff-intermediate systems compare to those in Oosterhoff I/II systems. In this paper we present the results of our new time-series BV photometric study of NGC 1466. A total of 62 variables were identified in the cluster, of which 16 are new discoveries. The variables include 30 RRab stars, 11 RRc's, 8 RRd's, 1 candidate RR Lyrae, 2 long-period variables, 1 potential anomalous Cepheid, and 9 variables of undetermined classification. We present photometric parameters for these variables. For the RR Lyrae stars physical properties derived from Fourier analysis of their light curves are presented. The RR Lyrae stars were used to determine a reddening-corrected distance modulus of (m-M)0 = 18.43 +/- 0.15. We discuss several different indicators of Oosterhoff type and find NGC 1466 to be an Oosterhoff-intermediate obj...

Kuehn, Charles A; Catelan, Márcio; Pritzl, Barton J; De Lee, Nathan; Borissova, Jura

2011-01-01T23:59:59.000Z

406

Variable Stars in Large Magellanic Cloud Globular Clusters II: NGC 1786  

E-Print Network (OSTI)

This is the second in a series of papers studying the variable stars in Large Magellanic Cloud globular clusters. The primary goal of this series is to study how RR Lyrae stars in Oosterhoff-intermediate systems compare to their counterparts in Oosterhoff I/II systems. In this paper, we present the results of our new time-series BV photometeric study of the globular cluster NGC 1786. A total of 65 variable stars were identified in our field of view. These variables include 53 RR Lyraes (27 RRab, 18 RRc, and 8 RRd), 3 classical Cepheids, 1 Type II Cepheid, 1 Anomalous Cepheid, 2 eclipsing binaries, 3 Delta Scuti/SX Phoenicis variables, and 2 variables of undetermined type. Photometeric parameters for these variables are presented. We present physical properties for some of the RR Lyrae stars, derived from Fourier analysis of their light curves. We discuss several different indicators of Oosterhoff type which indicate that the Oosterhoff classification of NGC 1786 is not as clear cut as what is scene in most gl...

Kuehn, Charles A; Catelan, Marcio; Pritzl, Barton J; De Lee, Nathan; Borissova, Jura

2012-01-01T23:59:59.000Z

407

Variables Affecting Economic Development of Wind Energy  

NLE Websites -- All DOE Office Websites (Extended Search)

Variables Affecting Economic Variables Affecting Economic Development of Wind Energy E. Lantz and S. Tegen National Renewable Energy Laboratory Presented at WINDPOWER 2008 Houston, Texas June 1-4, 2008 Conference Paper NREL/CP-500-43506 July 2008 NREL is operated by Midwest Research Institute â—Ź Battelle Contract No. DE-AC36-99-GO10337 NOTICE The submitted manuscript has been offered by an employee of the Midwest Research Institute (MRI), a contractor of the US Government under Contract No. DE-AC36-99GO10337. Accordingly, the US Government and MRI retain a nonexclusive royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for US Government purposes. This report was prepared as an account of work sponsored by an agency of the United States government.

408

Thermodynamics in variable speed of light theories  

SciTech Connect

The perfect fluid in the context of a covariant variable speed of light theory proposed by J. Magueijo is studied. On the one hand the modified first law of thermodynamics together with a recipe to obtain equations of state are obtained. On the other hand the Newtonian limit is performed to obtain the nonrelativistic hydrostatic equilibrium equation for the theory. The results obtained are used to determine the time variation of the radius of Mercury induced by the variability of the speed of light (c), and the scalar contribution to the luminosity of white dwarfs. Using a bound for the change of that radius and combining it with an upper limit for the variation of the fine structure constant, a bound on the time variation of c is set. An independent bound is obtained from luminosity estimates for Stein 2015B.

Racker, Juan [CONICET, Centro Atomico Bariloche, Avenida Bustillo 9500 (8400), San Carlos De Bariloche (Argentina); Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N (1900), La Plata (Argentina); Sisterna, Pablo [Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350 (7600), Mar del Plata (Argentina); Vucetich, Hector [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque S/N (1900), La Plata (Argentina)

2009-10-15T23:59:59.000Z

409

Discrete variable theory of triatomic photodissociation  

SciTech Connect

The coupled equations describing the photodissociation process are expressed in the discrete variable representation (DVR) in which the coupled equations are labeled by quadrature points rather than by internal basis functions. A large reduction in the dimensionality of the coupled equations can be realized since the spatially localized bound state nuclear wave function vanishes at most of the quadrature points, making only certain orientations of the fragments important in the region of strong interaction (small separation). The discrete variable theory of photodissociation is applied to the model dissociation of bent HCN in which the CN fragment is treated as a rigid rotor. The truncated DVR rotational distributions are compared with the exact close coupled rotational distributions, and excellent agreement with greatly reduced dimensionality of the equations is found.

Heather, R.W.; Light, J.C.

1983-07-01T23:59:59.000Z

410

Thermodynamics in variable speed of light theories  

E-Print Network (OSTI)

The perfect fluid in the context of a covariant variable speed of light theory proposed by J. Magueijo is studied. On the one hand the modified first law of thermodynamics together with a recipe to obtain equations of state are obtained. On the other hand the Newtonian limit is performed to obtain the nonrelativistic hydrostatic equilibrium equation for the theory. The results obtained are used to determine the time variation of the radius of Mercury induced by the variability of the speed of light ($c$), and the scalar contribution to the luminosity of white dwarfs. Using a bound for the change of that radius and combining it with an upper limit for the variation of the fine structure constant, a bound on the time variation of $c$ is set. An independent bound is obtained from luminosity estimates for Stein 2015B.

Juan Racker; Pablo Sisterna; Hector Vucetich

2007-11-06T23:59:59.000Z

411

CVcat: an interactive database on cataclysmic variables  

E-Print Network (OSTI)

CVcat is a database that contains published data on cataclysmic variables and related objects. Unlike in the existing online sources, the users are allowed to add data to the catalogue. The concept of an ``open catalogue'' approach is reviewed together with the experience from one year of public usage of CVcat. New concepts to be included in the upcoming AstroCat framework and the next CVcat implementation are presented. CVcat can be found at http://www.cvcat.org.

J. Kube; B. T. Gaensicke; F. Euchner; B. Hoffmann

2003-04-29T23:59:59.000Z

412

Bessel-Zernike Discrete Variable Representation Basis  

SciTech Connect

The connection between the Bessel discrete variable basis expansion and a specific form of an orthogonal set of Jacobi polynomials is demonstrated. These so-called Zernike polynomials provide alternative series expansions of suitable functions over the unit interval. Expressing a Bessel function in a Zernike expansion provides a straightforward method of generating series identities. Furthermore, the Zernike polynomials may also be used to efficiently evaluate the Hankel transform for rapidly decaying functions or functions with finite support.

Cerjan, C J

2005-10-24T23:59:59.000Z

413

Changes in heart rate variability during fainting  

Science Conference Proceedings (OSTI)

Studies of heart rate variability in people who faint may yield insights into normal physiologic mechanisms which probably are dynamic. These insights might be gained because fainting appears to be due to a breakdown of these mechanisms. Tilt table testing reliably induces fainting in patients with a history of fainting and can be used to study these mechanisms. During tilt tests ending in fainting heart rate changes markedly

Robert Sheldon; Kenneth Riff

1991-01-01T23:59:59.000Z

414

Monsoon Climate Variabilities International Pacific Research Center and Department of Meteorology, School of Ocean and Earth Science and Technology  

E-Print Network (OSTI)

Monsoon Climate Variabilities Tim Li International Pacific Research Center and Department, USA The Asian monsoon consists of three subcomponents, Indian monsoon (IM), East Asian monsoon (EAM), and western North Pacific monsoon (WNPM). All these submonsoon systems exhibit remarkable intraseasonal

Li, Tim

415

The Probability Distribution of Sea Surface Wind Speeds: Effects of Variable Surface Stratification and Boundary Layer Thickness  

Science Conference Proceedings (OSTI)

Air–sea exchanges of momentum, energy, and material substances of fundamental importance to the variability of the climate system are mediated by the character of the turbulence in the atmospheric and oceanic boundary layers. Sea surface winds ...

Adam Hugh Monahan

2010-10-01T23:59:59.000Z

416

A Joint Statistical and Dynamical Assessment of Atmospheric Response to North Pacific Oceanic Variability in CCSM3  

Science Conference Proceedings (OSTI)

Atmospheric response to North Pacific oceanic variability is assessed in Community Climate System Model, version 3 (CCSM3) using two statistical methods and one dynamical method. All methods identify an equivalent barotropic low response to a ...

Yafang Zhong; Zhengyu Liu

2008-11-01T23:59:59.000Z

417

HIGH LEVEL WASTE SLUDGE BATCH 4 VARIABILITY STUDY  

Science Conference Proceedings (OSTI)

The Defense Waste Processing Facility (DWPF) is preparing for vitrification of High Level Waste (HLW) Sludge Batch 4 (SB4) in early FY2007. To support this process, the Savannah River National Laboratory (SRNL) has provided a recommendation to utilize Frit 503 for vitrifying this sludge batch, based on the composition projection provided by the Liquid Waste Organization on June 22, 2006. Frit 418 was also recommended for possible use during the transition from SB3 to SB4. A critical step in the SB4 qualification process is to demonstrate the applicability of the durability models, which are used as part of the DWPF's process control strategy, to the glass system of interest via a variability study. A variability study is an experimentally-driven assessment of the predictability and acceptability of the quality of the vitrified waste product that is anticipated from the processing of a sludge batch. At the DWPF, the durability of the vitrified waste product is not directly measured. Instead, the durability is predicted using a set of models that relate the Product Consistency Test (PCT) response of a glass to the chemical composition of that glass. In addition, a glass sample is taken during the processing of that sludge batch, the sample is transmitted to SRNL, and the durability is measured to confirm acceptance. The objective of a variability study is to demonstrate that these models are applicable to the glass composition region anticipated during the processing of the sludge batch - in this case the Frit 503 - SB4 compositional region. The success of this demonstration allows the DWPF to confidently rely on the predictions of the durability/composition models as they are used in the control of the DWPF process.

Fox, K; Tommy Edwards, T; David Peeler, D; David Best, D; Irene Reamer, I; Phyllis Workman, P

2006-10-02T23:59:59.000Z

418

Temporal and spatial variability of surface temperature over Texas  

E-Print Network (OSTI)

Surface temperature is one of the most fundamental aspects of the climate system, and its study has been the focus of extensive research in the field of climatology for years. Examination of its temporal and spatial fluctuations can provide scientists with information on the behavior of the atmospheric circulation. Many researchers have also been interested in the physical processes and mechanisms at work in producing the observed distribution of the surface temperature field over the globe. Various analytical methods are used in the study of temperature variability on the Earth. White and Wallace (1978) documented the annual march of surface temperature by mapping amplitudes and phases of the seasonal cycle. The latter were obtained through Fourier analysis of the data. Kim and North (1991, 1992) routinely use second-moment statistics such as variance and spatial correlation to study the fluctuations of temperature in energy balance models as compared with observations. Empirical orthogonal function (EOF) analysis has become a popular and convenient method for representing the variability of climatic parameters since the groundbreaking work of Lorenz (1956). The first several EOFS, or patterns of covariability in a meteorological field, can sometimes be explained in a physical sense based on their shapes. While most previous efforts have concentrated on the global or hemispheric scale, this research examines the fluctuations of surface temperature on a regional scale, namely the state of Texas. Texas is an ideal location for a study of this type due to its vast areal extent, diverse topography, and expanse across different climatic regimes. Some of the methods used in the study of temperature variability are applied to the state of Texas.

Moninski, Anthony David

1995-01-01T23:59:59.000Z

419

Efficient Low-Lift Cooling with Radiant Distribution, Thermal Storage and Variable-Speed Chiller Controls Part I: Component and Subsystem Models  

DOE Green Energy (OSTI)

this paper develops component and subsystem models used to evaluat4e the performance of a low-lift cooling system with an air-colled chiller optimized for variable-speed and low-pressure-ratio operation, a hydronic radient distribution system, variable-speed transport miotor controls, and peak-shifting controls.

Armstrong, Peter; Jiang, Wei; Winiarski, David W.; Katipamula, Srinivas; Norford, L. K.; Willingham, ryan

2009-03-31T23:59:59.000Z

420

Natural Gas Variability In California: Environmental Impacts And Device  

NLE Websites -- All DOE Office Websites (Extended Search)

Natural Gas Variability In California: Environmental Impacts And Device Natural Gas Variability In California: Environmental Impacts And Device Performance - Experimental Evaluation Of Installed Cooking Exhaust Fan Performance Title Natural Gas Variability In California: Environmental Impacts And Device Performance - Experimental Evaluation Of Installed Cooking Exhaust Fan Performance Publication Type Report Year of Publication 2011 Authors Singer, Brett C., William W. Delp, and Michael G. Apte Publisher Lawrence Berkeley National Laboratory City Berkeley, CA Keywords energy analysis and environmental impacts department Abstract The installed performance of cooking exhaust fans was evaluated through residential field experiments conducted on a sample of 15 devices varying in design and other characteristics. The sample included two rear downdraft systems, two under-cabinet microwave over range units, three different installations of an under-cabinet model with grease screens across the bottom and no capture hood, two devices with grease screens covering the bottom of a large capture hood (one under-cabinet, one wall-mount chimney), four under-cabinet open hoods, and two open hoods with chimney mounts over islands. Performance assessment included measurement of airflow and sound levels across fan settings and experiments to quantify the contemporaneous capture efficiency for the exhaust generated by natural gas cooking burners. Capture efficiency is defined as the fraction of generated pollutants that are removed through the exhaust and thus not available for inhalation of household occupants. Capture efficiency was assessed for various configurations of burner use (e.g., single front, single back, combination of one front and one back, oven) and fan speed setting. Measured airflow rates were substantially lower than the levels noted in product literature for many of the units. This shortfall was observed for several units costing more than $1000. Capture efficiency varied widely (from < 5 percent to roughly 100 percent) across devices and across conditions for some devices. As expected, higher capture efficiencies were achieved with higher fan settings and the associated higher air flow rates. In most cases, capture efficiencies were substantially higher for rear burners than for front burners. The best and most consistent performance was observed for open hoods that covered all cooktop burners and operated at higher airflow rates. The lowest capture efficiencies were measured when a front burner was used with a rear backdraft system or with lowest fan setting for above-the-range systems that do not cover the front burners.

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Energy Systems Integration  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Systems Integration Systems Integration Ben Kroposki, PhD, PE Director, Energy Systems Integration National Renewable Energy Laboratory 2 Reducing investment risk and optimizing systems in a rapidly changing energy world * Increasing penetration of variable RE in grid * Increasing ultra high energy efficiency buildings and controllable loads * New data, information, communications and controls * Electrification of transportation and alternative fuels * Integrating energy storage (stationary and mobile) and thermal storage * Interactions between electricity/thermal/fuels/data pathways * Increasing system flexibility and intelligence Current Energy Systems Future Energy Systems Why Energy Systems Integration? 3 Energy Systems Integration Continuum Scale Appliance (Plug)

422

Design of a variable gain amplifier for an ultrawideband receiver  

E-Print Network (OSTI)

A fully differential CMOS variable gain amplifier (VGA) has been designed for an ultra-wideband receiver. The VGA comprises of two variable gain stages followed by a post amplifier stage. The interface between the digital control block and the analog VGA is formed by a digital-to-analog converter and an exponential voltage generator. The gain of the VGA varies dB-linearly from 0 to 52 dB with respect to the control voltage. The VGA is operated in open loop with a bandwidth greater than 500 MHz throughout the gain range to cater to the requirements of the ultra-wideband system. The noise-to-power ratio of the VGA is -23.9 dB for 1Vp-p differential input signal in the low gain setting, and the equivalent input referred noise is 1.01 V2 for the high gain setting. All three stages use common mode feedback to fix and stabilize the output DC levels at a particular voltage depending on the input common-mode requirement of the following stage. DC offset cancellation has also been incorporated to minimize the input referred DC offset caused by systematic and random mismatches in the circuit. Compensation schemes to minimize the effects of temperature, supply and process variations have been included in the design. The circuit has been designed in 0.18??m CMOS technology, and the post layout simulations are in good agreement with the schematic simulations.

Krishnanji, Sivasankari

2005-08-01T23:59:59.000Z

423

Variable speed wind turbine generator with zero-sequence filter  

DOE Patents (OSTI)

A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility. 14 figs.

Muljadi, E.

1998-08-25T23:59:59.000Z

424

Variable Speed Wind Turbine Generator with Zero-sequence Filter  

DOE Patents (OSTI)

A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility.

Muljadi, Eduard (Golden, CO)

1998-08-25T23:59:59.000Z

425

Variable speed wind turbine generator with zero-sequence filter  

DOE Patents (OSTI)

A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility.

Muljadi, Eduard (Golden, CO)

1998-01-01T23:59:59.000Z

426

Intelligent Switching System Methodology and Its Application in Complex Process Control System  

Science Conference Proceedings (OSTI)

The switching system can be viewed as a kind of hybrid systems because it with both continuous state variables and discrete state variables. Viewing the controller as hierarchical, then the switch strategy belongs to the higher hierarchy. It represents ... Keywords: intelligent switching system, hybrid systems, fuzzy logic, complex process control, coke oven

Junwei Gao; Yangdong Ye; Tianyun Shi; Qiuhua Jiang; Limin Jia

2002-09-01T23:59:59.000Z

427

Allocating Variability and Reserve Requirements (Presentation)  

SciTech Connect

This presentation describes how you could conceivably allocate variability and reserve requirements, including how to allocate aggregation benefits. Conclusions of this presentation are: (1) Aggregation provides benefits because individual requirements are not 100% correlated; (2) Method needed to allocate reduced requirement among participants; (3) Differences between allocation results are subtle - (a) Not immediately obvious which method is 'better'; (b) Many are numerically 'correct', they sum to the physical requirement; (c) Many are not 'fair', Results depend on sub-aggregation and/or the order individuals are included; and (4) Vector allocation method is simple and fair.

Kirby, B.; King, J.; Milligan, M.

2011-10-01T23:59:59.000Z

428

Long-Term Wind Power Variability  

DOE Green Energy (OSTI)

The National Renewable Energy Laboratory started collecting wind power data from large commercial wind power plants (WPPs) in southwest Minnesota with dedicated dataloggers and communication links in the spring of 2000. Over the years, additional WPPs in other areas were added to and removed from the data collection effort. The longest data stream of actual wind plant output is more than 10 years. The resulting data have been used to analyze wind power fluctuations, frequency distribution of changes, the effects of spatial diversity, and wind power ancillary services. This report uses the multi-year wind power data to examine long-term wind power variability.

Wan, Y. H.

2012-01-01T23:59:59.000Z

429

Allocating Variability and Reserve Requirements (Presentation)  

DOE Green Energy (OSTI)

This presentation describes how you could conceivably allocate variability and reserve requirements, including how to allocate aggregation benefits. Conclusions of this presentation are: (1) Aggregation provides benefits because individual requirements are not 100% correlated; (2) Method needed to allocate reduced requirement among participants; (3) Differences between allocation results are subtle - (a) Not immediately obvious which method is 'better'; (b) Many are numerically 'correct', they sum to the physical requirement; (c) Many are not 'fair', Results depend on sub-aggregation and/or the order individuals are included; and (4) Vector allocation method is simple and fair.

Kirby, B.; King, J.; Milligan, M.

2011-10-01T23:59:59.000Z

430

Constraints on Area Variables in Regge Calculus  

E-Print Network (OSTI)

We describe a general method of obtaining the constraints between area variables in one approach to area Regge calculus, and illustrate it with a simple example. The simplicial complex is the simplest tessellation of the 4-sphere. The number of independent constraints on the variations of the triangle areas is shown to equal the difference between the numbers of triangles and edges, and a general method of choosing independent constraints is described. The constraints chosen by using our method are shown to imply the Regge equations of motion in our example.

Jarmo Makela; Ruth M. Williams

2000-11-02T23:59:59.000Z

431

Constraints on Area Variables in Regge Calculus  

E-Print Network (OSTI)

We describe a general method of obtaining the constraints between area variables in one approach to area Regge calculus, and illustrate it with a simple example. The simplicial complex is the simplest tessellation of the 4-sphere. The number of independent constraints on the variations of the triangle areas is shown to equal the difference between the numbers of triangles and edges, and a general method of choosing independent constraints is described. The constraints chosen by using our method are shown to imply the Regge equations of motion in our example.

Mäkelä, J M; Makela, Jarmo; Williams, Ruth M.

2001-01-01T23:59:59.000Z

432

Performance variability of highly parallel architectures  

E-Print Network (OSTI)

that were part of the NERSC IBM running with 256-wayshare SMP nodes. The NERSC IBM SP system, “Seaborg,” is avariation present on the NERSC IBM SP system when it was ?

Kramer, William T.C.; Ryan, Clint

2003-01-01T23:59:59.000Z

433

User Participation, Management Support and System Types  

Science Conference Proceedings (OSTI)

This paper explores user participation in the systems development process and examines this variable in relation to the type of system under development. Prior user participation research has not shown conclusive support for its impact on system success. ...

Edward J. Garrity

1994-07-01T23:59:59.000Z

434

Variably insulating portable heater/cooler  

DOE Patents (OSTI)

A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

Potter, T.F.

1998-09-29T23:59:59.000Z

435

IS ACTIVE REGION CORE VARIABILITY AGE DEPENDENT?  

Science Conference Proceedings (OSTI)

The presence of both steady and transient loops in active region cores has been reported from soft X-ray and extreme-ultraviolet observations of the solar corona. The relationship between the different loop populations, however, remains an open question. We present an investigation of the short-term variability of loops in the core of two active regions in the context of their long-term evolution. We take advantage of the nearly full Sun observations of STEREO and Solar Dynamics Observatory spacecraft to track these active regions as they rotate around the Sun multiple times. We then diagnose the variability of the active region cores at several instances of their lifetime using EIS/Hinode spectral capabilities. We inspect a broad range of temperatures, including for the first time spatially and temporally resolved images of Ca XIV and Ca XV lines. We find that the active region cores become fainter and steadier with time. The significant emission measure at high temperatures that is not correlated with a comparable increase at low temperatures suggests that high-frequency heating is viable. The presence, however, during the early stages, of an enhanced emission measure in the ''hot'' (3.0-4.5 MK) and ''cool'' (0.6-0.9 MK) components suggests that low-frequency heating also plays a significant role. Our results explain why there have been recent studies supporting both heating scenarios.

Ugarte-Urra, Ignacio [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2012-12-10T23:59:59.000Z

436

Variably insulating portable heater/cooler  

DOE Green Energy (OSTI)

A compact vacuum insulation panel comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning "on" and "off" the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls.

Potter, Thomas F. (Denver, CO)

1998-01-01T23:59:59.000Z

437

Demand Response and Variable Generation Integration Scoping Study  

NLE Websites -- All DOE Office Websites (Extended Search)

Market and Policy Barriers for Demand Market and Policy Barriers for Demand Response Providing Ancillary Services in U.S. Electricity Markets Peter Cappers, Jason MacDonald, Charles Goldman April 2013 Report Summary 1 Energy Analysis Department  Electricity Markets and Policy Group Presentation Overview  Objectives and Approach  Wholesale and Retail Market Environments  Market and Policy Barrier Typology  Prototypical Regional Barrier Assessment 2 Energy Analysis Department  Electricity Markets and Policy Group A Role for Demand Response to Provide Ancillary Services  Increasing penetration of renewable energy generation in U.S. electricity markets means that bulk power system operators will need to manage the variable and uncertain nature of many renewable resources

438

Demand Response and Variable Generation Integration Scoping Study  

NLE Websites -- All DOE Office Websites (Extended Search)

The Impact of City-level Permitting The Impact of City-level Permitting Processes on Residential PV Installation Prices and Development Times An Empirical Analysis of Solar Systems in California Cities Ryan Wiser and CG Dong Lawrence Berkeley National Laboratory April 2013 This analysis was funded by the Solar Energy Technologies Office, Office of Energy Efficiency and Renewable Energy of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 Energy Analysis Department  Electricity Markets and Policy Group Presentation Overview * Questions and Objective * Literature Review * Data Sources and Processing * Variable Description and Summary * Regression Analysis Results * Interpretation and Predictions * Conclusions * Possible Future Extensions 2 Energy Analysis Department  Electricity Markets and Policy Group

439

Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients  

E-Print Network (OSTI)

In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtain a time-frequency representation of the signal, which provides better insight in the frequency distribution of the signal with time. A 6 level decomposition of HRV was achieved with db4 as mother wavelet, and the above two bands LF and HF were combined in 12 specialized frequencies sub-bands obtained in wavelet package transform. Features extracted from these coefficients can efficiently represent the characteristics of the original signal. ANOVA statistical test is used for the evaluation of proposed algorithm.

Kheder, G; Massoued, M Ben; Samet, M

2009-01-01T23:59:59.000Z

440

Comments on: 'Implementation of self-tuning regulators with variable forgetting factors'  

Science Conference Proceedings (OSTI)

The similarities are pointed out between the variable forgetting factor given in the paper by Fortescue, Kershenbaum and Ydstie and that given in Wellstead and Sanoff. Moreover, it is shown that the method of Fortescue, Kershenbaum and Ydstie can be ... Keywords: Adaptive control, stochastic control, time-varying systems

S. P. Sanoff; P. E. Wellstead

1983-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Brief paper: Implementation of self-tuning regulators with variable forgetting factors  

Science Conference Proceedings (OSTI)

A modified version of the self-tuning regulator having limited adaptability has been successfully implemented on a large-scale chemical pilot plant. The new algorithm uses a least-squares estimator with variable weighting of past data; at each step a ... Keywords: Adaptive control, chemical industry, computer control, process control, stochastic control, time-varying systems

T. R. Fortescue; L. S. Kershenbaum; B. E. Ydstie

1981-11-01T23:59:59.000Z

442

Multiple Equilibria, Natural Variability, and Climate Transitions in an Idealized Ocean–Atmosphere Model  

Science Conference Proceedings (OSTI)

An idealized coupled ocean–atmosphere is constructed to study climatic equilibria and variability. The model focuses on the role of large-scale fluid motions in the climate system. The atmospheric component is an eddy-resolving two-level global ...

R. Saravanan; James C. Mc Williams

1995-10-01T23:59:59.000Z

443

Variability of the Somali Current as Observed from Seasat Altimetry  

Science Conference Proceedings (OSTI)

Three methods of extraction of mesoscale variability from altimetry are compared in the Somali current area: crossover residuals after minimization to reduce orbit errors, along-track variability using quasi-repetitive tracks, and difference ...

C. Perigaud; J. F. Minster

1988-01-01T23:59:59.000Z

444

U-090: RSA enVision Discloses Environment Variable Information...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

0: RSA enVision Discloses Environment Variable Information to Remote Users U-090: RSA enVision Discloses Environment Variable Information to Remote Users January 27, 2012 - 6:00am...

445

Stochastic Forcing of Ocean Variability by the North Atlantic Oscillation  

Science Conference Proceedings (OSTI)

At middle and high latitudes, the magnitude of stochastic wind stress forcing of the ocean by atmospheric variability on synoptic time scales (i.e., “weather” related variability) is comparable to that of the seasonal cycle. Stochastic forcing ...

Kettyah C. Chhak; Andrew M. Moore; Ralph F. Milliff

2009-01-01T23:59:59.000Z

446

Spatial Variability of Shortwave Irradiance for Snowmelt in Forests  

Science Conference Proceedings (OSTI)

The spatial variation of melt energy can influence snow cover depletion rates and in turn be influenced by the spatial variability of shortwave irradiance to snow. The spatial variability of shortwave irradiance during melt under uniform and ...

John Pomeroy; Chad Ellis; Aled Rowlands; Richard Essery; Janet Hardy; Tim Link; Danny Marks; Jean Emmanuel Sicart

2008-12-01T23:59:59.000Z

447

West African Monsoon Intraseasonal Variability: A Precipitable Water Perspective  

Science Conference Proceedings (OSTI)

West African monsoon intraseasonal variability has important implications for food security and drought early warnings. In the present study, intraseasonal variability over the Sahel is assessed from the perspective of precipitable water, as ...

D. Emmanuel Poan; Romain Roehrig; Fleur Couvreux; Jean-Philippe Lafore

2013-04-01T23:59:59.000Z

448

Temporal Variability of Diapycnal Mixing in Shag Rocks Passage  

Science Conference Proceedings (OSTI)

Diapycnal mixing rates in the oceans have been shown to have a great deal of spatial variability, but the temporal variability has been little studied. Here results are presented from a method developed to calculate diapycnal diffusivity from ...

Gillian M. Damerell; Karen J. Heywood; David P. Stevens; Alberto C. Naveira Garabato

2012-03-01T23:59:59.000Z

449

Modeling the Variability of Sydney Harbor Wind Measurements  

Science Conference Proceedings (OSTI)

The time-dependent behavior in the variability of wind measurements is investigated using bivariate generalized autoregressive conditional heteroscedastic models. These models express the current level of short-timescale wind variability in terms ...

Edward Cripps; William T. M. Dunsmuir

2003-08-01T23:59:59.000Z

450

LPB Hydro-Climate Variability as Simulated by GCM Experiments...  

NLE Websites -- All DOE Office Websites (Extended Search)

LPB Hydro-Climate Variability as Simulated by GCM Experiments: Role of Remote SST Forcing Title LPB Hydro-Climate Variability as Simulated by GCM Experiments: Role of Remote SST...

451

Snowpack spatial variability: towards understanding its effect on remote sensing  

E-Print Network (OSTI)

Snowpack spatial variability: towards understanding its effect on remote sensing measurements spatial variability: towards understanding its effect on remote sensing mea- surements and snow slope large errors in these basin estimates. Remote sensing measurements offer a promising alternative, due

Marshall, Hans-Peter

452

Jet Jumping: Low-Frequency Variability in the Southern Ocean  

Science Conference Proceedings (OSTI)

The authors study intrinsic variability in the position of jets in a ?-plane channel ocean with simple topography using a quasigeostrophic numerical model. This study links the variability in jet position with abyssal anticyclones that form as a ...

Christopher C. Chapman; Andrew McC. Hogg

2013-05-01T23:59:59.000Z

453

Modeling Climate Variability in the Tropical Atlantic Atmosphere  

Science Conference Proceedings (OSTI)

Climate variability in the tropical Atlantic sector as represented in six atmospheric general circulation models is examined. On the annual mean, most simulations overestimate wind stress away from the equator although much of the variability can ...

Jiande Wang; James A. Carton

2003-12-01T23:59:59.000Z

454

Intraseasonal Variability over Tropical Africa during Northern Summer  

Science Conference Proceedings (OSTI)

The intraseasonal variability over Africa during northern summer was analyzed, using 25 years of NCEP– NCAR reanalysis and satellite data. The dominant pattern of variability was one of enhanced deep convection over the whole African monsoon ...

Adrian J. Matthews

2004-06-01T23:59:59.000Z

455

Tropical Cloud Feedbacks and Natural Variability of Climate  

Science Conference Proceedings (OSTI)

Simulations of natural variability by two GCMs are examined. One GCM is a sector model, allowing relatively rapid integration without simplification of the model physics, which would potentially exclude mechanisms of variability. Two mechanisms ...

R. L. Miller; A. D. Del Genio

1994-09-01T23:59:59.000Z

456

A search for chaotic behavior in Northern Hemisphere stratospheric variability  

Science Conference Proceedings (OSTI)

Northern Hemisphere stratospheric variability is investigated with respect to chaotic behavior using time series from three different variables extracted from four different re-analysis products and two numerical model runs with different forcing. ...

Gualtiero Badin; Daniela I.V. Domeisen

457

Role of Smarter Grids in Variable Renewable Resource Integration (Presentation)  

Science Conference Proceedings (OSTI)

This presentation discusses the role of smarter grids in variable renewable resource integration and references material from a forthcoming ISGAN issue paper: Smart Grid Contributions to Variable Renewable Resource Integration, co-written by the presenter and currently in review.

Miller, M.

2012-07-01T23:59:59.000Z

458

Holographic Dark Energy Scenario and Variable Modified Chaplygin Gas  

E-Print Network (OSTI)

In this letter, we have considered that the universe is filled with normal matter and variable modified Chaplygin gas. Also we have considered the interaction between normal matter and variable modified Chaplygin gas in FRW universe. Then we have considered a correspondence between the holographic dark energy density and interacting variable modified Chaplygin gas energy density. Then we have reconstructed the potential of the scalar field which describes the variable modified Chaplygin cosmology.

Surajit Chattopadhyay; Ujjal Debnath

2009-01-15T23:59:59.000Z

459

Bayesian Variable Selection and the Swendsen-Wang Algorithm  

E-Print Network (OSTI)

Bayesian Variable Selection and the Swendsen-Wang Algorithm David J. NOTT and Peter J. GREEN improvements in Markov chain Monte Carlo sampling algorithms for Bayesian variable selection. Currently used, this excludes the ith predictor from the model. The problem of variable selection is to decide which predictors

Green, Peter

460

Bayesian variable selection and the Swendsen-Wang algorithm  

E-Print Network (OSTI)

Bayesian variable selection and the Swendsen-Wang algorithm David J. Nott1 and Peter J. Green2 1 motivated improvements in Markov chain Monte Carlo sampling algorithms for Bayesian variable selection. Traditional sampling al- gorithms for Bayesian variable selection may perform poorly when there are severe

Barber, Stuart

Note: This page contains sample records for the topic "variable air-volume system" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Common multifractality in the heart rate variability and brain activity of healthy humans  

Science Conference Proceedings (OSTI)

The influence from the central nervous system on the human multifractal heart rate variability (HRV) is examined under the autonomic nervous system perturbation induced by the head-up-tilt body maneuver. We conducted the multifractal factorization analysis to factor out the common multifractal factor in the joint fluctuation of the beat-to-beat heart rate and electroencephalography data. Evidence of a central link in the multifractal HRV was found

D. C. Lin; A. Sharif

2010-01-01T23:59:59.000Z

462

The TAOS Project Stellar Variability II. Detection of 15 Variable Stars  

SciTech Connect

The Taiwanese-American Occultation Survey (TAOS) project has collected more than a billion photometric measurements since 2005 January. These sky survey data - covering timescales from a fraction of a second to a few hundred days - are a useful source to study stellar variability. A total of 167 star fields, mostly along the ecliptic plane, have been selected for photometric monitoring with the TAOS telescopes. This paper presents our initial analysis of a search for periodic variable stars from the time-series TAOS data on one particular TAOS field, No. 151 (RA = 17{sup h} 30{sup m} 6.67{sup s}, Dec = 27 degrees, 17 minutes, 30 seconds, J2000), which had been observed over 47 epochs in 2005. A total of 81 candidate variables are identified in the 3 square degree field, with magnitudes in the range 8 < R < 16. On the basis of the periodicity and shape of the lightcurves, 32 variables, 18 of which were previously unknown, are classified as RR Lyrae, Cepheid, {delta} Scuti, SX Phonencis, semi-regular and eclipsing binaries.

Mondal, S; Lin, C C; Zhang, Z W; Alcock, C; Axelrod, T; Bianco, F B; Byun, Y I; Coehlo, N K; Cook, K H; Dave, R; Kim, D W; King, S K; Lee, T; Lehner, M J; Lin, H C; Marshall, S L; Protopapas, P; Rice, J A; Schwamb, M E; Wang, J H; Wang, S Y; Wen, C Y

2010-01-28T23:59:59.000Z

463

Stochastic variability of effective properties via the generalized variability response function  

Science Conference Proceedings (OSTI)

Homogenization of randomly heterogeneous material properties into effective properties is an essential procedure in facilitating the analysis of a wide range of mechanics problems. Although formulas exist to calculate deterministic effective properties ... Keywords: Effective properties, Random fields, Uncertainty quantification, Variability response functions

Kirubel Teferra; Sanjay R. Arwade; George Deodatis

2012-11-01T23:59:59.000Z

464

Characterisation of soil texture variability using the apparent soil electrical conductivity at a highly variable site  

Science Conference Proceedings (OSTI)

The characterisation of the spatial distribution of clay, silt, and sand/gravel is one of the main objectives of soil surveys. Researchers as well as producers have an interest in characterising soil texture variability. The objective of our study was ... Keywords: Clay, EM38, Residual kriging, Sand/gravel, Silt, Spatial heterogeneity

K. Heil; U. Schmidhalter

2012-02-01T23:59:59.000Z

465

Variational estimates using a discrete variable representation  

SciTech Connect

The advantage of using a discrete variable representation (DVR) is that the Hamiltonian of two interacting particles can be constructed in a very simple form. However, the DVR Hamiltonian is approximate and, as a consequence, the results cannot be considered as variational ones. We will show that the variational character of the results can be restored by performing a reduced number of integrals. In practice, for a variational description of the lowest n bound states only n(n+1)/2 integrals are necessary whereas D(D+1)/2 integrals are enough for the scattering states (D is the dimension of the S matrix). Applications of the method to the study of dimers of He, Ne and Ar, for both bound and scattering states, are presented.

Lombardi, M.; Barletta, P.; Kievsky, A. [Istituto Nazionale di Fisica Nucleare, Via Buonarroti 2, 56100 Pisa (Italy); Dipartimento di Fisica, Universita di Pisa, 56100 Pisa (Italy)

2004-09-01T23:59:59.000Z

466

Variable selection in nonparametric additive models  

E-Print Network (OSTI)

We consider a nonparametric additive model of a conditional mean function in which the number of variables and additive components may be larger than the sample size but the number of nonzero additive components is "small" relative to the sample size. The statistical problem is to determine which additive components are nonzero. The additive components are approximated by truncated series expansions with B-spline bases. With this approximation, the problem of component selection becomes that of selecting the groups of coefficients in the expansion. We apply the adaptive group Lasso to select nonzero components, using the group Lasso to obtain an initial estimator and reduce the dimension of the problem. We give conditions under which the group Lasso selects a model whose number of components is comparable with the underlying model, and the adaptive group Lasso selects the nonzero components correctly with probability approaching one as the sample size increases and achieves the optimal rate of convergence. Th...

Huang, Jian; Wei, Fengrong; 10.1214/09-AOS781

2010-01-01T23:59:59.000Z

467

Forecasting neutron star temperatures: predictability and variability  

E-Print Network (OSTI)

It is now possible to model thermal relaxation of neutron stars after bouts of accretion during which the star is heated out of equilibrium by nuclear reactions in its crust. Major uncertainties in these models can be encapsulated in modest variations of a handful of fudge parameters that change the crustal thermal conductivity, specific heat, and heating rates. Observations of thermal relaxation constrain these fudge parameters and allow us to predict longer term variability in terms of the neutron star core temperature. We demonstrate this explicitly by modeling ongoing thermal relaxation in the neutron star XTE J1701-462. Its future cooling, over the next 5 to 30 years, is strongly constrained and depends mostly on its core temperature, uncertainties in crust physics having essentially been pinned down by fitting to the first three years of observations.

Dany Page; Sanjay Reddy

2013-07-17T23:59:59.000Z

468

Variable Interactions in Query-Driven Visualization  

SciTech Connect

One fundamental element of scientific inquiry is discoveringrelationships, particularly the interactions between different variablesin observed or simulated phenomena. Building upon our prior work in thefield of Query-Driven Visualization, where visual data analysisprocessing is focused on subsets of large data deemed to be"scientifically interesting," this new work focuses on a novel knowledgediscovery capability suitable for use with petascale class datasets. Itenables visual presentation of the presence or absence of relationships(correlations) between variables in data subsets produced by Query-Drivenmethodologies. This technique holds great potential for enablingknowledge discovery from large and complex datasets currently emergingfrom SciDAC and INCITE projects. It is sufficiently generally to beapplicable to any time of complex, time-varying, multivariate data fromstructured, unstructured or adaptive grids.

Bethel, E. Wes; Gosink, Luke J.; Anderson, John C.; Joy, Kenneth I.

2007-10-25T23:59:59.000Z

469

Cataclysmic Variables From the Sloan Digital Sky Survey. VI. the Sixth Year (2005)  

SciTech Connect

The 28 cataclysmic variables found in 2005 in the Sloan Digital Sky Survey are presented with their coordinates, magnitudes and spectra. Five of these systems are previously known CVs (HH Cnc, SX LMi, QZ Ser, RXJ1554.2+2721 and HS1016+3412) and the rest are new discoveries. Additional spectroscopic, photometric and/or polarimetric observations of 10 systems were carried out, resulting in estimates of the orbital periods for seven of the new binaries. The 23 new CVs include one eclipsing system, one new Polar and five systems whose spectra clearly reveal atmospheric absorption lines from the underlying white dwarf.

Szkody, Paula; /Washington U., Seattle, Astron. Dept.; Henden, Arne; /Naval Observ., Flagstaff /AAVSO, Cambridge; Mannikko, Lee; Mukadam, Anjum; /Washington U., Seattle,; Schmidt, Gary D.; /Arizona U., Astron. Dept. - Steward Observ.; Bochanski, John J.; Agueros, Marcel; Anderson, Scott F.; Silvestri, Nicole M.; /Washington U., Seattle,; Dahab, William E.; /Princeton U. Observ.; Oguri, Masamune; /Princeton U. Observ. /KIPAC, Menlo Park; Schneider, Donald P.; /Penn State U., Astron. Astrophys.; Shin,; Strauss, Michael A.; Knapp, Gillian R.; /Princeton U. Observ.; West, Andrew A.; /Washington U., Seattle, Astron. Dept.

2007-06-15T23:59:59.000Z

470

Integrating Variable Renewable Energy in Electric Power Markets: Best Practices from International Experience  

DOE Green Energy (OSTI)

Many countries -- reflecting very different geographies, markets, and power systems -- are successfully managing high levels of variable renewable energy on the electric grid, including that from wind and solar energy. This study documents the diverse approaches to effective integration of variable renewable energy among six countries -- Australia (South Australia), Denmark, Germany, Ireland, Spain, and the United States (Western region-Colorado and Texas)-- and summarizes policy best practices that energy ministers and other stakeholders can pursue to ensure that electricity markets and power systems can effectively coevolve with increasing penetrations of variable renewable ene