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Title: Energy performance evaluation of variable-speed packaged rooftop units using field measurements and building energy simulation

Abstract

Packaged air-conditioning units are widely used in commercial buildings. Most packaged units in the field are equipped with constant-speed supply fans and constant-speed compressors. Many efforts have been made to increase the operational efficiency of packaged air conditioners by retrofitting existing units with improved controls or developing innovative products with advanced designs. This paper evaluates the energy performance of a packaged unit with all variable-speed components, including the supply fan, the compressor, and the condenser fan. Both a field test and energy simulation are used to quantify the potential of energy savings from the variable-speed unit (VSU) against reference units. In the field test, the reference is a six-year-old existing unit. It was determined through monitoring for one year that the VSU had a 31% higher cooling efficiency than the reference unit. In the simulation, a retail building model was used to compare the performance between the VSU and two reference units—one representing existing units in the field and the other representing units meeting the latest energy code requirements by ASHRAE Standard 90.1. Simulation results showed that depending on the climate, the VSU can save electricity consumption (including both cooling and fan) by 45%–54% relative to the first reference andmore » by 22%–29% relative to the second reference. These findings are valuable for building designers and con- tractors in selecting packaged rooftop units for both new constructions and retrofits.« less

Authors:
; ORCiD logo; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1501832
Report Number(s):
PNNL-SA-139774
Journal ID: ISSN 0378-7788
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Energy and Buildings
Additional Journal Information:
Journal Volume: 183; Journal Issue: C; Journal ID: ISSN 0378-7788
Publisher:
Elsevier
Country of Publication:
United States
Language:
English

Citation Formats

Wang, Weimin, Katipamula, Srinivas, Ngo, Hung, and Underhill, Ronald. Energy performance evaluation of variable-speed packaged rooftop units using field measurements and building energy simulation. United States: N. p., 2019. Web. doi:10.1016/j.enbuild.2018.10.031.
Wang, Weimin, Katipamula, Srinivas, Ngo, Hung, & Underhill, Ronald. Energy performance evaluation of variable-speed packaged rooftop units using field measurements and building energy simulation. United States. doi:10.1016/j.enbuild.2018.10.031.
Wang, Weimin, Katipamula, Srinivas, Ngo, Hung, and Underhill, Ronald. Tue . "Energy performance evaluation of variable-speed packaged rooftop units using field measurements and building energy simulation". United States. doi:10.1016/j.enbuild.2018.10.031.
@article{osti_1501832,
title = {Energy performance evaluation of variable-speed packaged rooftop units using field measurements and building energy simulation},
author = {Wang, Weimin and Katipamula, Srinivas and Ngo, Hung and Underhill, Ronald},
abstractNote = {Packaged air-conditioning units are widely used in commercial buildings. Most packaged units in the field are equipped with constant-speed supply fans and constant-speed compressors. Many efforts have been made to increase the operational efficiency of packaged air conditioners by retrofitting existing units with improved controls or developing innovative products with advanced designs. This paper evaluates the energy performance of a packaged unit with all variable-speed components, including the supply fan, the compressor, and the condenser fan. Both a field test and energy simulation are used to quantify the potential of energy savings from the variable-speed unit (VSU) against reference units. In the field test, the reference is a six-year-old existing unit. It was determined through monitoring for one year that the VSU had a 31% higher cooling efficiency than the reference unit. In the simulation, a retail building model was used to compare the performance between the VSU and two reference units—one representing existing units in the field and the other representing units meeting the latest energy code requirements by ASHRAE Standard 90.1. Simulation results showed that depending on the climate, the VSU can save electricity consumption (including both cooling and fan) by 45%–54% relative to the first reference and by 22%–29% relative to the second reference. These findings are valuable for building designers and con- tractors in selecting packaged rooftop units for both new constructions and retrofits.},
doi = {10.1016/j.enbuild.2018.10.031},
journal = {Energy and Buildings},
issn = {0378-7788},
number = C,
volume = 183,
place = {United States},
year = {2019},
month = {1}
}