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Title: Multifamily Heat Pump Water Heater Evaluation

Abstract

Although heat pump water heaters (HPWHs) have gained significant attention in recent years as a high efficiency electric water heating solution for single family homes, central HPWHs for commercial or multi-family applications are not as well documented in terms of measured performance and cost effectiveness. To evaluate this technology, the Alliance for Residential Building Innovation team monitored the performance of a 10.5 ton central HPWH installed on a student apartment building at the West Village Zero Net Energy Community in Davis, California. Monitoring data collected over a 16 month period were then used to validate a TRNSYS simulation model. The TRNSYS model was then used to project performance in different climates using local electric rates. Results of the study indicate that after some initial commissioning issues, the HPWH operated reliably with an annual average efficiency of 2.12 (Coefficient of Performance). The observed efficiency was lower than the unit's rated efficiency, primarily due to the fact that the system rarely operated under steady-state conditions. Changes in the system configuration, storage tank sizing, and control settings would likely improve the observed field efficiency. Modeling results suggest significant energy savings relative to electric storage water heating systems (typical annual efficiencies around 0.90) providingmore » for typical simple paybacks of six to ten years without any incentives. The economics versus gas water heating are currently much more challenging given the current low natural gas prices in much of the country. Increased market size for this technology would benefit cost effectiveness and spur greater technology innovation.« less

Authors:
 [1];  [1]
  1. Davis Energy Group, Davis, CA (United States). Alliance for Residential Building Innovation
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Building Technologies Office (EE-5B)
OSTI Identifier:
1349799
Report Number(s):
NREL/SR-5500-66430; DOE/GO-102017-4872
DOE Contract Number:  
AC36-08GO28308
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; residential; residential buildings; Building America; ARBI; water heating; field monitoring; computer modeling; multi-family; cost effectiveness

Citation Formats

Hoeschele, M., and Weitzel, E. Multifamily Heat Pump Water Heater Evaluation. United States: N. p., 2017. Web. doi:10.2172/1349799.
Hoeschele, M., & Weitzel, E. Multifamily Heat Pump Water Heater Evaluation. United States. doi:10.2172/1349799.
Hoeschele, M., and Weitzel, E. Fri . "Multifamily Heat Pump Water Heater Evaluation". United States. doi:10.2172/1349799. https://www.osti.gov/servlets/purl/1349799.
@article{osti_1349799,
title = {Multifamily Heat Pump Water Heater Evaluation},
author = {Hoeschele, M. and Weitzel, E.},
abstractNote = {Although heat pump water heaters (HPWHs) have gained significant attention in recent years as a high efficiency electric water heating solution for single family homes, central HPWHs for commercial or multi-family applications are not as well documented in terms of measured performance and cost effectiveness. To evaluate this technology, the Alliance for Residential Building Innovation team monitored the performance of a 10.5 ton central HPWH installed on a student apartment building at the West Village Zero Net Energy Community in Davis, California. Monitoring data collected over a 16 month period were then used to validate a TRNSYS simulation model. The TRNSYS model was then used to project performance in different climates using local electric rates. Results of the study indicate that after some initial commissioning issues, the HPWH operated reliably with an annual average efficiency of 2.12 (Coefficient of Performance). The observed efficiency was lower than the unit's rated efficiency, primarily due to the fact that the system rarely operated under steady-state conditions. Changes in the system configuration, storage tank sizing, and control settings would likely improve the observed field efficiency. Modeling results suggest significant energy savings relative to electric storage water heating systems (typical annual efficiencies around 0.90) providing for typical simple paybacks of six to ten years without any incentives. The economics versus gas water heating are currently much more challenging given the current low natural gas prices in much of the country. Increased market size for this technology would benefit cost effectiveness and spur greater technology innovation.},
doi = {10.2172/1349799},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Mar 03 00:00:00 EST 2017},
month = {Fri Mar 03 00:00:00 EST 2017}
}

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