Drain water heat recovery (DWHR) as discussed in this report is the recovery of useful heat through a heat exchanger placed in the building drain system. This project was an effort to characterize the performance of drain water heat recovery systems as installed in commercial facilities. The concept was based on the observation that commercial occupancies can have hot water loads much larger than those in single family residences, and thus larger energy savings potential.
Drain water heat recovery systems can save a significant amount of energy in the right setting. In commercial building retrofits the technology can be a challenge, but new construction applications show promise for easier installation.
This project was supported in part (or in whole) by a grant from the Minnesota Department of Commerce, Division of Energy Resources through the Conservation Applied Research and Development (CARD program, which is funded by Minnesota ratepayers.