Low-GWP Mechanical Modules for Rapid Deployment Project

Alteration to a building’s interior to accommodate replacement systems is often one of the greatest barriers to an electrification retrofit. This rework is often very time-consuming, disruptive, bespoke, and costly. Heating, ventilation, and air conditioning, and domestic hot water systems can pose particular challenges because the system components are often spread throughout the building and installed in inaccessible locations. Combining the systems that deliver these major mechanical end uses could offer advantages for retrofits to achieve building electrification. As heat pumps take an increasing size of the mechanical system market, more refrigerant is being used in buildings. This report shares learnings and outcomes from studying three combined mechanical systems that use low-global warming potential refrigerant, and evaluate their suitability for California’s existing multifamily building market, especially affordable multifamily housing. Each product evaluated represents a type of combined mechanical system whose advantages and disadvantages were measured through design and demonstration research. The findings share what types of products suit the target building market and why, and how system design can be considered going forward. Combined mechanical system products whose configuration allows for reuse of existing system locations and infrastructure, and are developed with specific retrofit applications in mind, are most primed for market development and most likely to be successful retrofit solutions. Ultimately, the research seeks to identify possible solutions for existing buildings to reduce greenhouse gas emissions, utility costs, and retrofit costs and invasiveness, to support pursuit of California’s legislative and climate goals.