Packaged Central CO2 Heat Pump Water Heater Multifamily Demonstration

This report presents the background, methodology, and findings of a field demonstration of packaged, carbon dioxide (CO2) central heat pump water heaters installed at two neighboring multifamily buildings in Menlo Park, California. The project team added instrumentation to the systems for performance monitoring and implemented load shift controls. Assessment of the energy usage, greenhouse gas impacts, and total system benefit bolster previous findings of similar systems at other sites. The well-commissioned system reduced greenhouse gas emissions by 86 percent and provided total system benefits of 61 percent as compared to a natural gas code baseline alternative, with some room for additional improvement. These installs were among the very first instances of this new product. Since these were among the first, the project team was able to identify some opportunities for improvement which will yield even further benefit to building owners, utility programs, manufacturers, and installers.