Central Heat Pump Water Heating Control Optimization

Central heat pump water heating systems (CHPWH) are crucial for the greenhouse gas, decarbonization, and energy efficiency goals of California. This technology is relevant to a large portion of the multifamily and commercial building market and the earliest adopters are beginning to install these systems. Potential savings in the California multifamily market alone are around 1.7 million tons of greenhouse gas emissions per year. However, controls improvements and guidelines are needed to fully realize their benefits, including optimized energy costs, energy consumption, greenhouse gas emissions, and grid impacts.  A recent low-GWP CHPWH retrofit field demonstration at two low-income, multifamily buildings in San Francisco demonstrated system performance, emissions reductions, and reliability of the installed systems. However, the control scheme left room for improvement and energy costs increased over the natural gas system baseline. This project will implement controls to optimize energy cost and demand charge impacts while conducting full measurement and verification. The study will demonstrate the value of optimized controls to the building owner and utility while also providing recommendations for control sequences for CHPWH installations across the state. Guidelines and demonstrations such as this are paramount to the effective, equitable, beneficial adoption of CHPWH systems.