BONNEVILLE POWER ADMINISTRATION
Heat pump water heater project receives industry innovation award

The American Society of Heating, Refrigerating and Air-Conditioning Engineers recognized BPA's Energy Efficiency emerging technologies team for its work on multifamily heat pump water heaters.

Designing and constructing a better-than-code building envelope reduces the energy demands significantly in our heating climate. - Rob Marks, senior energy management engineer with Snohomish PUD

A BPA-sponsored energy efficiency project received a regional technology innovation award from the American Society of Heating, Refrigerating and Air-Conditioning Engineers. The award recognizes several leading-edge energy efficiency improvements related to heat pump water heater design used in an Everett, Washington, multifamily facility.  

BPA and Snohomish PUD partnered with Ecotope Engineering to design, test, install and commission a variety of different heat pump water heater products with the goal to provide healthy, comfortable and energy efficient spaces. The result was an award-winning hot water system in the HopeWorks Station, an innovative campus that brings together high-performance, affordable housing with training programs to transition residents to high-skilled jobs and independence. See a virtual video tour of HopeWorks.

Advanced water heating initiatives are a cornerstone in combating climate change while also reducing energy consumption across the U.S. to improve overall electrical grid resilience. Well-designed electric heat pump solutions provide significant benefits to the region. For instance, new CO2 heat pump water heaters, like those used in this project, are up to four times more efficient than traditional electric resistance systems, free up capacity on the electrical grid and have the global warming potential of zero. Finding economical and efficient hot water solutions for multifamily buildings represents a significant opportunity for the Northwest while providing energy savings to an underserved market.
 
The HopeWorks Station tested a new design concept using a distributed hot water system. The Sanden heat pump water heater unit, originally designed for single-family homes, was adapted for this multifamily project by using a distributed heat trace design. The 65-unit HopeWorks Station uses multiple Sanden heat pumps located on the roof that are connected to 13 hot water storage tanks on the top floor of the facility. Each tank serves three to six apartment units. 

"Designing and constructing a better-than-code building envelope reduces the energy demands significantly in our heating climate," said Rob Marks, senior energy management engineer with Snohomish PUD. "Snohomish PUD was eager to help our customer and community partner HopeWorks take the next step in reducing energy consumption with the high-efficiency and innovative design of this heat pump water heating system. With ongoing HopeWorks resident training and mentoring, we anticipate a high level of energy saving success for this facility." 

The project went through a number of developmental stages, including a feasibility study to test the concept of using the individual heat pumps in a new configuration, followed by the final design, the field installation and long-term measurement and verification monitoring to quantify savings and document key learnings to apply to future projects. Field data showed that the heat pumps operated at a coefficient of performance of 3.3, which means they are more than three times more efficient than traditional heat pump water systems. 

ASHRAE, founded in 1894, is a global society advancing human well-being through sustainable technology for the built environment. The Society and its members focus on building systems, energy efficiency, indoor air quality, refrigeration and sustainability within the industry. Through research, standards writing, publishing and continuing education, ASHRAE shapes tomorrow's built environment today. ASHRAE recognizes successful application of innovative design which incorporates ASHRAE standards for effective energy management, indoor air quality and mechanical design management.