The Elizabeth James House CO2 HPWH Multifamily Retrofit case study demonstrated that multiple Sanden (CO2) heat pump water heaters (typically used in single-family residential applications), together with a novel “swing tank” design, can collectively serve the water heating and recirculation loop temperature maintenance needs of a 60-unit low-rise multifamily building in the Pacific Northwest. Field-collected data showed that the system delivered a coefficient of performance (COP) in excess of 3 and provided an average of 20 gallons of hot water per day per apartment.
Heat pump water heaters are an emerging technology in the domestic water heating market, especially in multifamily building applications. Because of this, installation costs have been high. However, with market growth, established design and installation practices and increased competition costs will come down. The Sanden CO2 HPWH is a versatile product and is very efficient. The novel “swing tank” design and applications require additional research but have demonstrated results for reducing water heating and temperature maintenance loads in multifamily buildings across Pacific Northwest climate zone.
Read the Elizabeth James House CO2 HPWH Multifamily Retrofit case study.
