Early Reverse Cycle Chiller Research

Pacific Northwest

Innovative garage-based heat pump systems for low-carbon multifamily water heating

Ecotope partnered with Bonneville Power Administration (BPA) to explore innovative applications of Reverse Cycle Chiller (RCC) heat pump technology for domestic water heating in multifamily buildings. The research focused on locating heat pump systems in below-grade parking garages, where they benefit from the stable ground temperatures and capture waste heat from lighting, vehicle engines, and exhaust air. This approach aimed to demonstrate scalable, cost-effective strategies for high-efficiency water heating within dense urban housing contexts.

As part of the research, pilot installations were completed in three Seattle multifamily buildings. Early monitoring results showed energy use for water heating was reduced by nearly a factor of three. These findings highlight RCC technology’s potential to cut total building energy use by up to 20%, offering a powerful tool for decarbonizing multifamily housing and supporting regional electrification goals.

Learn more about RCC here:

• Reverse Cycle Chillers for Multifamily Buildings in the Pacific Northwest: Phase I Final Report. Bonneville Power Administration, September 2009
• Reverse Cycle Chiller (RCC) Best Practices Design Guidelines. Seattle City Light, December 2015.