Lead Performer: National Renewable Energy Laboratory – Golden, CO
June 20, 2023
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Lead Performer: National Renewable Energy Laboratory – Golden, CO
Partners:
-- Rheem Manufacturing Co.
-- Group 14 Engineering
DOE Total Funding: $2,027,000
Cost Share: $225,000
Project Term: October 1, 2022 – September 30, 2025
Funding Type: Lab Award
Project Objective
This project will work toward developing combination heat pumps with 20% lower installed cost for space and water heating in multifamily buildings. The project objective will be to develop a combination heat pump system capable of efficiently providing water outlet temperatures of 180 °F for space and water heating using a refrigerant with GWP < 750 and achieving DOE efficiency standards for heat pumps and heat pump water heaters. Expected outcomes include comprehensive modeling tools for optimization of high-temperature heat pump combination systems, prototype systems capable of meeting cost and efficiency targets, market assessments for targeted deployment, and control optimization to better meet occupant and grid needs.
This project will employ the use of two-phase refrigerant injection, cascaded heat recovery for hot water heating, and component material substitutions to achieve the high-temperature water delivery temperatures needed for lower-cost electric drop-in replacements for fossil fuel boilers. Experimental characterization of prototype equipment will be performed under steady state as well as dynamic conditions using hardware-in-the-loop infrastructure. By engaging with multiple stakeholders in the multifamily housing sector and those focused on addressing the needs of income qualified housing, this project will provide more equitable heating technologies by incorporating and understanding the barriers faced by these communities integrally into the design process. The National Renewable Energy Laboratory (NREL) will coordinate the project activities and use modeling and testing capabilities to aid in the evaluation and optimization of low-cost combination space and water heating technologies. Rheem Manufacturing Co. will provide support on product cost analysis and prototype development. Group14 Engineering will support stakeholder engagement and the identification of barrier and solutions to heat pump installed cost reduction in multifamily buildings.
Project Impact
Multifamily housing represents ~25% of all residential buildings in the United States. Being unable to readily integrate combination heat pumps with convective heat emitters greatly limits retrofitability of buildings that utilize steam or high-temperature liquid water radiators for space heating. This includes ~34% of all fossil fuel-based multifamily housing structures. Developing a lower-cost combination heat pump system suitable for convective heating will help promote building electrification within the U.S. in a more equitable manner. Such products will allow for drop-in replacements with lower installation cost by avoiding distribution system upgrades.
Contacts
DOE Technology Manager: Payam Delgoshaei
Lead Performer: Nelson James