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Title: Gas Engine-Driven Heat Pump with Desiccant Dehumidification

Abstract

About 40% of total U.S. energy consumption was consumed in residential and commercial buildings. Improved air-conditioning technology has by far the greatest potential impact on the electric industry compared to any other technology that uses electricity. This paper describes the development of an innovative natural gas, propane, LNG or bio-gas IC engine-driven heat pump (GHP) with desiccant dehumidification (GHP/DD). This integrated system has higher overall efficiencies than conventional equipment for space cooling, addresses both new and existing commercial buildings, and more effectively controls humidity in humid areas. Waste heat is recovered from the GHP to provide energy for regenerating the desiccant wheel and to augment heating capacity and efficiency. By combining the two technologies, an overall source COP of greater that 1.5 (hot, humid case) can be achieved by utilizing waste heat from the engine to reduce the overall energy required to regenerate the desiccant. Moreover, system modeling results show that the sensible heat ratio (SHR- sensible heat ratio) can be lowered to less 60% in a dedicated outdoor air system application with hot, humid cases.

Authors:
 [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Building Technologies Research and Integration Center (BTRIC)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1338549
DOE Contract Number:
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: Second International Conference on Energy and Indoor Environment for Hot Climates February 26 - 27, 2017, Doha, Qatar, 20170226, 20170227
Country of Publication:
United States
Language:
English
Subject:
gas engine driven heat pump; dessicant coupled air conditioning system

Citation Formats

Shen, Bo, and Abu-Heiba, Ahmad. Gas Engine-Driven Heat Pump with Desiccant Dehumidification. United States: N. p., 2017. Web.
Shen, Bo, & Abu-Heiba, Ahmad. Gas Engine-Driven Heat Pump with Desiccant Dehumidification. United States.
Shen, Bo, and Abu-Heiba, Ahmad. Sun . "Gas Engine-Driven Heat Pump with Desiccant Dehumidification". United States. doi:.
@article{osti_1338549,
title = {Gas Engine-Driven Heat Pump with Desiccant Dehumidification},
author = {Shen, Bo and Abu-Heiba, Ahmad},
abstractNote = {About 40% of total U.S. energy consumption was consumed in residential and commercial buildings. Improved air-conditioning technology has by far the greatest potential impact on the electric industry compared to any other technology that uses electricity. This paper describes the development of an innovative natural gas, propane, LNG or bio-gas IC engine-driven heat pump (GHP) with desiccant dehumidification (GHP/DD). This integrated system has higher overall efficiencies than conventional equipment for space cooling, addresses both new and existing commercial buildings, and more effectively controls humidity in humid areas. Waste heat is recovered from the GHP to provide energy for regenerating the desiccant wheel and to augment heating capacity and efficiency. By combining the two technologies, an overall source COP of greater that 1.5 (hot, humid case) can be achieved by utilizing waste heat from the engine to reduce the overall energy required to regenerate the desiccant. Moreover, system modeling results show that the sensible heat ratio (SHR- sensible heat ratio) can be lowered to less 60% in a dedicated outdoor air system application with hot, humid cases.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2017},
month = {Sun Jan 01 00:00:00 EST 2017}
}

Conference:
Other availability
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  • This paper examines the merits of coupling a desiccant dehumidification subsystem to a gas-engine-driven vapor compression air conditioner. A system is identified that uses a rotary silicia-gel parallel-plate dehumidifier. Dehumidifier data and analysis are based on recent tests. The dehumidification subsystem processes the fresh air portion and handles the latent portion of the load. Adding the desiccant subsystem increases the gas-based coefficient of performance 40% and increases the cooling capacity 50%. Increased initial manufacturing costs are estimated at around $500/ton ($142/kW) for volume production. This cost level is expected to reduce the total initial cost per ton compared to amore » system without the desiccant subsystem. 19 refs., 8 figs., 5 tabs.« less
  • The Fort Sam Houston (San Antonio, Texas) New Technology Demonstration Program (NTDP) project is a field evaluation of a 3-ton gas-engine-driven residential heat pump. Comparative energy-performance results for the gas heat pump (GHP) and three other air-conditioner/furnace systems are presented from the San Antonio field testing. These energy results form the basis for a life-cycle cost comparison between the gas heat pump and other commercially available air-conditioner/furnace systems. A life-cycle cost analysis is presented for the GHP at Fort Sam Houston and is also projected to five other federal sites.
  • A new generation of natural gas engine-driven heat pump (GEHP) was introduced to the marketplace recently. While the units installed have performed exceptionally well and earned rave reviews for comfort and savings on utility bills, the higher initial cost and relatively long payback time have affected the wide commercialization of this advanced technology. According to a study done for the southeastern US in the Atlanta metropolitan area, the annual operating cost of the GEHP is less than that of a baseline system consisting of a 92% efficiency gas furnace and a SEER 12 air conditioner. The estimated payback time ismore » around 10 years to cover the difference in initial equipment price between the new and the baseline system. It has been projected that a liquid overfeed (LOF) recuperative cycle concept can simplify the hardware design of a GEHP, resulting in reduced cost and improved performance. Laboratory tests have shown that LOF would improve the energy efficiency of a vapor compression unit by 10%. In addition, LOF will reduce the compressor pressure ratio and thereby improve equipment reliability. Based on the assumed performance improvements and cost reduction, a simple payback calculation indicates LOF can reduce the payback time for an improved GEHP considerably in the Atlanta metropolitan area. Laboratory testing of an improved GEHP has been carried out at Oak Ridge National Laboratory. This paper reports on the equipment design modifications required to implement LOF and the results of performance tests at steady-state conditions. The preliminary cooling test results have indicated that the LOF in conjunction with orifice-type expander can be applied to GEHP for cost and performance enhancements. The improvements in energy efficiency will be dependent upon several controlling parameters including the proper refrigeration charge, the selected ambient temperature, and the system operating condition.« less
  • A new generation of natural gas engine-driven heat pumps (GEHPs) was introduced to the marketplace recently. While the units installed have performed exceptionally well and earned rave reviews for comfort and savings on utility bills, the higher initial cost and relatively long payback time have affected the wide commercialization of this advanced technology. According to a study done for the southeastern US in the Atlanta Metropolitan area, the annual operating cost of the GEHP is less than that of a baseline system consisting of a 92% efficiency gas furnace and a seasonal energy efficiency ratio (SEER) 12 air conditioner. Themore » estimated payback time is about ten years to cover the difference in initial equipment price between the new and the baseline system. It has been projected that a liquid overfeed (LOF) recuperative cycle concept can simplify the hardware design of a GEHP, resulting in reduced cost and improved performance. Laboratory tests have shown that LOF would improve the energy efficiency of a vapor compression unit by 10%. In addition, LOF will reduce the compressor pressure ratio and thereby improve equipment reliability. Based on the assumed performance improvements and cost reduction, a simple payback time for an improved GEHP considerably in the Atlanta metropolitan area. Laboratory testing of an improved GEHP has been carried out. This paper reports on the equipment design modifications required to implement LOF and the results of performance tests at steady-state conditions.« less
  • Building air-conditioning (cooling) is the single largest use of electricity, driving increases in summer peak electric demand in much of the United States. Increases in peak load on the utility grid lead to high electricity prices, power quality problems, and grid system inefficiencies and even failures. Improved air-conditioning technology thus has the greatest potential impact on the electric grid compared to other technologies that use electricity. Thermally-activated systems, such as natural gas engine-driven heat pumps, can provide overall peak load reduction and electric grid relief for summer peak demand. This study describes the performance of a 10 refrigeration ton (RT)more » natural gas engine-driven heat pump rooftop unit in a controlled environment over a wide range of operating conditions in heating and cooling modes. Results showed gas COP exceeding the goal of 1.6 at 47 F (8.3 C) rating condition. Gas COP in cooling mode also exceeded the goal of 1.2 at 95 F (35 C) rating condition. Future work will investigate additional applications for gas engine-driven equipment, such as residential space conditioning.« less