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Title: Using Solar Hot Water to Address Piping Heat Losses in Multifamily Buildings

Solar thermal water heating is most cost effective when applied to multifamily buildings and some states offer incentives or other inducements to install them. However, typical solar water heating designs do not allow the solar generated heat to be applied to recirculation losses, only to reduce the amount of gas or electric energy needed for hot water that is delivered to the fixtures. For good reasons, hot water that is recirculated through the building is returned to the water heater, not to the solar storage tank. The project described in this report investigated the effectiveness of using automatic valves to divert water that is normally returned through the recirculation piping to the gas or electric water heater instead to the solar storage tank. The valves can be controlled so that the flow is only diverted when the returning water is cooler than the water in the solar storage tank.
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  1. Alliance for Residential Building Innovation, Davis, CA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Resource Type:
Technical Report
Research Org:
Alliance for Residential Building Innovation, Davis, CA (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Building Technologies Office (EE-5B)
Country of Publication:
United States
residential; Residential Buildings; ARBI; Building America; TRNSYS; multifamily; domestic hot water; solar water heater; recirculation