Demonstrating a new-to-market heat recovery chiller with ultra-low GWP in a large California hospital.
Status: Current
Project Objective
This project will demonstrate a large new-to-market heat recovery chiller that uses a refrigerant with an ultra-low greenhouse warming potential (GWP) to reduce the emissions from a hospital’s heating and cooling system, and make it easier to scale this demonstration to other hospitals. The research team will also acquire data, assess life-cycle costs, perform simulations, and develop solutions and resources to aid designers and owners to effectively decarbonize other building types. A key goal will also be to shift the paradigm in this building type to save energy through simultaneous heat recovery opportunities that are currently not captured.
Significance to Industry
Building owners are challenged to efficiently and cost-effectively heat and cool large buildings in light of a rapid shift toward decarbonization through electrification. Early all-electric heating plants for large commercial buildings have mostly deployed air-to-water heat pumps (AWHP) but these are expensive, require a large footprint, and are not efficient at generating heat in cold weather. For retrofits in large buildings, AWHPs are challenging because the hot water produced is often not hot enough for the existing terminal units, and roof space is often limited or comes with structural constraints. Further, existing heat pump equipment generally uses refrigerants with a high global warming potential (GWP). In contrast, heat recovery chillers can achieve higher efficiencies and higher temperatures, and can often be located in existing plant rooms, but require a simultaneous heat sink and a heat source (i.e., simultaneous heating and cooling loads) or thermal energy storage. Though there are many challenges to overcome, particularly for existing buildings, heat recovery is a cost-effective, energy- and space-efficient solution for decarbonization for many applications.
Research Approach
This project will develop and evaluate decarbonization solutions using heat recovery chillers, air-to-water heat pumps (AWHPs) and thermal storage, while providing resources to help overcome barriers to applying these solutions to existing and new buildings at scale. The team will measure the effects of the demonstration over a minimum of 12 months pre- and post- installation and leverage that information to estimate savings across our healthcare partner’s portfolio of hospitals in California. Measurement and verification will include heating, cooling, and electrical energy, which will be mapped to cost, air quality and marginal carbon emissions. More broadly, decarbonizing large commercial buildings faces many barriers, such as unfamiliarity with solutions and new equipment options, lack of existing case studies, system complexity, lack of effective simulation tools, and the high cost of sub-optimal solutions. To address these, the project will evaluate life cycle costs for a range of decarbonization options to identify appropriate solutions for different applications, provide generalized control strategies, and explore pathways with large equipment manufacturers to develop modular, packaged solutions to reduce project cost and complexity. Using cutting edge simulation tools (Modelica and EnergyPlus) the researchers will validate control strategies to maximize energy efficiency, avoided carbon, and grid impact.
Lastly, to provide feedback to the design community based on early installations, we interview designers to compile success stories and lessons learned from stakeholders. We will also perform case studies of operating all-electric and hybrid plants to better understand actual performance. The project efforts will culminate in a design tool, a new design guide, and other resources to help industry successfully tackle these new challenges.
CBE is partnering with the California Institute for Energy Efficiency (CIEE), Taylor Engineers, Lawrence Berkeley National Laboratory, and a large healthcare partner that will provide the hospital demonstration site. We expect this multi-year project to result in numerous papers, tools and resources that can inform and influence design teams, building owners and operators to adopt heat recovery as a cost-effective, energy efficient, and space-efficient solution for decarbonization. The work will also serve as a valuable training ground for a number of future building industry leaders, the MS and PhD students in Berkeley’s Building Science, Technology and Sustainability Program.
Illustrative image above was AI generated and does not represent the demonstration site.