Demonstrating Natural Gas Heat Pumps for Integrated Water Heating and Air Conditioning in Restaurants

This project demonstrated, measured, and verified an integrated gas commercial hot water and air conditioning prototype in two full-service restaurants in the Los Angeles Basin.

The team built two pre-commercial integrated gas heat pump systems for installation and commissioning at two full-service restaurants, undergoing ultra-low oxides of nitrogen certification in the process. The researchers monitored the two systems for 12 months and analyzed the resulting data with the integrated gas heat pump system sized as-installed at the two sites, using the performance of the gas heat pump to estimate a case where the gas heat pump component alone was sized properly to meet the total hot water load as a hypothetical and performance ceiling.

As California moves toward a decarbonized landscape over the next 20 years, this research will help reduce natural gas consumption and create a path towards technologies that will achieve these goals. For restaurants and other similar settings that struggle with electrification, the technology showed that NOx and GHG emissions were decreased by as much as half. The gas savings were 16 percent to 26 percent for the sites as-installed, with up to an estimated 44 percent to 46 percent savings if the gas heat pump system were “right-sized” for the individual sites. Both sites demonstrated a 14 percent reduction in total site electricity consumption due to supplemental cooling from the heat pump water heater. The gas heat pump prototypes received an “ultra low” NOx certification. The demonstrated heat pump used a natural refrigerant/absorbent, ammonia-water, which has both zero ozone depletion potential and zero global warming potential.

The research team solicited feedback from host sites and contractors and engaged in national market research to explore market barriers to adoption. Data analysis and modeling were done to estimate statewide potential for savings in energy, water, emissions, and operating costs. The team developed a simplified model of the low-cost gas heat pump system for commercial water heating and air conditioning. This model was incorporated into an informational water heater design guide for restaurants. In addition, the team developed a life-cycle/energy cost calculator tool for restaurants to determine both energy consumption and savings potential. Stakeholder outreach included educating prospective consumers, installation contractors, and other affected stakeholders; introducing the gas heat pump technology; and summarizing project findings.