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Title: Development of 20 IEER Rooftop Units System Modeling and Building Energy Simulations

Abstract

Based on detailed steady-state system and component modeling, we developed a rooftop unit system design, which is able to achieve IEER (Integrated Energy Efficiency Ratio) higher than 20. We modeled fin-&-tube and micro-channel heat exchangers using segment-to-segment approach, and use AHRI 10-coefficient compressor map to simulate compressor performance. The system modeling is based on a component-based modeling approach, which facilitates flexible simulation of complicated system configurations. Starting with a baseline system having IEER of 16.6, we extensively investigated numerous technical options, i.e. varying compressor sizes, heat exchanger fin densities, fin-&-tube or micro-channel heat exchanger, suction line heat exchanger, desiccant wheel, tandem compressor, variable-speed compressor, and condenser evaporative pre-cooling; and developed an innovative system configuration combining a tandem compression system with a variable-speed compression system. The combined system can achieve high IEER as well as process the outdoor ventilation air over an extensive range. We successfully evaluated the design concept for a 20-ton (70.4 kW) unit as well as a 10-ton (35.2 kW) unit. All the selected components are readily accessible on the market, and we validated the performance predictions against existing Rooftop Unit (RTU) products at the rating condition. This paper illustrates a potentially cost-effective high IEER RTU design. Inmore » addtion, we conducted extensive building energy simulations using EnergyPlus to predict seasonal energy saving potentials and peak power reductions using the High IEER RTU in sixteen US cities, in comparison to a RTU with a minimum efficiency.« less

Authors:
 [1];  [1];  [2]
  1. ORNL
  2. Oak Ridge National Laboratory (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:
1093068
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
HVAC & R Research
Additional Journal Information:
Journal Volume: 19; Journal Issue: 7
Country of Publication:
United States
Language:
English
Subject:
Rooftop Air Conditioner; Modeling

Citation Formats

Shen, Bo, Rice, C Keith, and Vineyard, Edward. Development of 20 IEER Rooftop Units System Modeling and Building Energy Simulations. United States: N. p., 2013. Web.
Shen, Bo, Rice, C Keith, & Vineyard, Edward. Development of 20 IEER Rooftop Units System Modeling and Building Energy Simulations. United States.
Shen, Bo, Rice, C Keith, and Vineyard, Edward. Tue . "Development of 20 IEER Rooftop Units System Modeling and Building Energy Simulations". United States.
@article{osti_1093068,
title = {Development of 20 IEER Rooftop Units System Modeling and Building Energy Simulations},
author = {Shen, Bo and Rice, C Keith and Vineyard, Edward},
abstractNote = {Based on detailed steady-state system and component modeling, we developed a rooftop unit system design, which is able to achieve IEER (Integrated Energy Efficiency Ratio) higher than 20. We modeled fin-&-tube and micro-channel heat exchangers using segment-to-segment approach, and use AHRI 10-coefficient compressor map to simulate compressor performance. The system modeling is based on a component-based modeling approach, which facilitates flexible simulation of complicated system configurations. Starting with a baseline system having IEER of 16.6, we extensively investigated numerous technical options, i.e. varying compressor sizes, heat exchanger fin densities, fin-&-tube or micro-channel heat exchanger, suction line heat exchanger, desiccant wheel, tandem compressor, variable-speed compressor, and condenser evaporative pre-cooling; and developed an innovative system configuration combining a tandem compression system with a variable-speed compression system. The combined system can achieve high IEER as well as process the outdoor ventilation air over an extensive range. We successfully evaluated the design concept for a 20-ton (70.4 kW) unit as well as a 10-ton (35.2 kW) unit. All the selected components are readily accessible on the market, and we validated the performance predictions against existing Rooftop Unit (RTU) products at the rating condition. This paper illustrates a potentially cost-effective high IEER RTU design. In addtion, we conducted extensive building energy simulations using EnergyPlus to predict seasonal energy saving potentials and peak power reductions using the High IEER RTU in sixteen US cities, in comparison to a RTU with a minimum efficiency.},
doi = {},
journal = {HVAC & R Research},
number = 7,
volume = 19,
place = {United States},
year = {2013},
month = {1}
}