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Dual Source Integrated Heat Pump Having Thermo-Storage


Invention Reference Number



Bo Shen
Buildings & Transportation Science Division

Licensing Contact

Andreana C Leskovjan
(865) 341-0433


Scientists at Oak Ridge National Laboratory have invented a dual-source heat pump for buildings that increases energy efficiency by using two sources– air source and ground source – which combine to deliver comfort, energy savings, and reduced cost over traditional single-source heat pumps.


About 40 percent of total U.S. energy consumption is consumed by buildings. Buildings can serve as an infinite reservoir enabling distributed resource integration and new non-traditional energy storage technologies, to shift peak load and increase energy efficiency. This licensable technology produces a dual-source integrated heat pump with the ability to store energy for future use. It is multi-functional, capable of indoor space cooling and heating, dehumidification, water heating and thermos-storage for a variety of uses. Dual-source heat pumps utilize both outdoor air source and ground source. The air source is used for a cooling operation when the ambient temperature is low and heating operation when the ambient temperature is high. The ground source is used when the resultant efficiency is higher than using the air source. This results in superior performance, cost savings, and energy efficiency, and reduce the size and cost of ground source heat exchanger

Applications and Industries

  • Heating, ventilation, air conditioning (HVAC) industry
  • Residential, single family homes
  • Commercial buildings
  • Anywhere energy storage is useful


  • One device offers symmetric indoor and outdoor heat exchangers to facilitate better refrigerant charge balance than typical heat pumps
  • Thermo-storage function charges a storage tank when electricity cost is low. It stores cooling/heating energy to be used during peak hours to reduce total utility cost and benefit grid resilience
  • Multi-functional, capable of space cooling and heating, water heating and thermo-storage
  • Provides hot water using the indoor refrigerant-to-water heat exchanger, achieving flexibility and energy savings
  • Two indoor and two outdoor heat exchangers can be individually controlled, increasing efficiency
  • All components can be independently controlled to optimize performance in a wide range of operating conditions