Decarbonizing large commercial buildings through heat recovery

Building Decarbonization Resiliency, Health, and Safety Low-Carbon Process Heating

The Regents of the University of California, on behalf of the Berkeley Campus

Recipient

Berkeley, CA

Recipient Location

9th

Senate District

14th

Assembly District

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Active

Project Status

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Project Update

In 2025, the team met with Kaiser to vet and select another demonstration site—a hospital in South San Francisco. The data driven analysis task continues to clean and analyze data from 30 large commercial buildings. The advanced simulation task developed two approaches to modelling electrified HVAC plants using measured building data and conducted initial simulations. Market transformation activities included List of Electric Heating and Cooling Equipment for Large Commercial Buildings, a map of electric commercial building retrofits, the completion of a case study, and the alpha version of a simplified design webtool to provide estimated energy consumption and emissions for various HVAC options.

The Issue

Most all-electric systems for large commercial buildings rely on air-to-water heat pumps (AWHP) which have major limitations: high first costs, large space requirements, and generally poor energy efficiency. AWHPs can be difficult or even impossible to use for retrofitting large commercial buildings. An alternative is heat recovery chillers (HRCs), which generate chilled water and hot water simultaneously at much higher combined COPs, but require either simultaneous heating and cooling loads in the building or a separate heat source or sink. An overlooked opportunity for scalable decarbonization is partial electrification. The key is to deploy heat pumps appropriately and pair them effectively with other components in a system, prioritizing heat recovery and energy efficiency, thereby minimizing the need for heat pumps.

Project Innovation

The purpose of this project is to demonstrate a new large heat recovery chiller that uses an ultra-low GWP refrigerant at a Kaiser hospital building, as well as assess a range of other equipment combinations for other building types and site specific constraints through case studies, interviews with designers, energy modeling, and life cycle cost assessment. This project will demonstrate how hospitals can cost-effectively reduce carbon emissions using heat recovery chiller retrofits. The research team will shift the paradigm in this building type to save energy through simultaneous heat recovery opportunities that are currently not captured. Further, most large commercial building types do not have as much simultaneous heating and cooling load as hospitals, so decarbonizing them will require other combinations of equipment. This project will develop and evaluate decarbonization solutions using heat recovery chillers, AWHPs and thermal storage, while providing resources to help overcome barriers to applying these solutions to existing and new buildings at scale.

Project Goals

demonstrate a new large heat recovery chiller that uses a refrigerant with an ult-low GWP to reduce the emissions

acquire data, assess life cycle costs, perform simulations, and develop solutions and resources to aid designers

Project Benefits

This project will result in the ratepayer benefits of lower greenhouse gas emissions, reduced energy, and lower costs by demonstrating a cost-effective decarbonization strategy that offsets 70% of the existing gas-fired heating load in a hospital. The project will overcome substantial market barriers (e.g., such as lack of California Office of Statewide Health Planning and Development (now Department of Health Care Access and Information) Special Seismic Certification Preapproval (OSP)), conducting extensive analysis and simulation, and performing robust market transformation activities.

Consumer Appeal

Consumer appeal - The project also creates practical tools, guides, and case studies to help designers and building owners choose the best low‑carbon options. Overall, it aims to prove that cleaner, smarter heating and cooling systems can cut energy use, reduce carbon emissions, lower costs, and be easier for building owners to adopt at scale.