Gas-Fired Binary-Fluid Sorption-Assisted Ejector Heat Pump

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Diagram of the mechanisms of a hot water tank.

Lead Performer: Oak Ridge National Laboratory – Oak Ridge, TN
Partners:
-- University of Missouri – Columbia, MO
-- Gas Technology Institute - Des Plaines, IL
-- ThermAvant Technologies, LLC - Columbia, MO
DOE Total Funding: $2,000,000
Cost Share: $504,000
Project Term: May 19, 2020 – May 19, 2023
Funding Type: Buildings Energy Efficiency Frontiers & Innovation Technologies (BENEFIT) 2019 Funding Opportunity

Project Objective

Oak Ridge National Laboratory (ORNL) will lead the project team to develop a fuel-fired ejector heat pump for water heating (GFEHP). The heat pump will have a gas coefficient of performance (gCOP) of 2 at the DOE standard rating conditions for water heating. The heat pump combines binary fluid ejector and sorption into a single cycle. The use of binary fluid in the ejector relaxes the performance requirements of the ejector. Sorption will be used to control the back pressure of the ejector while maintaining high temperature. Ejector back pressure control enables the heat pump to maintain high efficiency over the whole range of operating conditions. This overcomes a major technical barrier that has limited adoption of ejector heat pumps. At the end of the project, an alpha prototype will be built and its performance will be evaluated in a controlled laboratory environment.

Project Impact

The residential sector consumes 1 Quad of natural gas for only water heating. This translates to a fuel cost of $9.5 billion annually. Commercially available state-of-the-art fuel-fired water heaters are 98% efficient. The proposed heat pump is twice as efficient, with technical potential savings of 500 TBtu and monetary savings of $4.75 billion in fuel costs to consumers.

Contacts

DOE Technology Manager: Antonio Bouza  
Lead Performer: Ahmad Abu-Heiba, Oak Ridge National Laboratory