Project Info

Project Title 
Evaluation of and Algorithm Development for the IAPMO Test Protocol for Horizontal Drain Water Heat Recovery Devices
Project Number 
C&S PG&E 2019_2
Investor Owned Utilities 
Water Heating
Project Year(s) 

This project created algorithms predicting the performance of drain water heat recovery devices as a function of their installed angle. The algorithms use the same process as previous Pacific Gas and Electric (PG&E) drain water heat recovery projects1. Four representative DWHR devices, two horizontal and two vertical, were installed at the PG&E Applied Technology Services (ATS) laboratory. Tests identified the steady state effectiveness of these devices at different installation angles. Based on recommendations from device manufacturers, the horizontal devices were tested at a range from 3 to 30 degrees from horizontal, and the vertical units were tested at a range from 70 to 87 degrees from horizontal. Tests on horizontal devices started at 3 degrees, not fully horizontal, because plumbing codes typically stipulate a minimum slope of ~3 degrees to ensure proper drainage.

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