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Energy Saving Absorption Heat Pump Water Heater

Oak Ridge National Laboratory

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Technology Marketing SummaryORNL’s new absorption heat pump and water heater technology offers substantial energy savings and can reduce the use of fossil fuels by buildings. While conventional heat pump water heater designs are limited to using toxic ammonia water systems, this system uses heat drawn from the ambient environment to achieve energy efficiency. This approach extends the application of the invention beyond industrial settings to residential and commercial use.DescriptionThe system features one assembly with a condenser and an evaporator, a second assembly with an absorber, a desorber, and a heat exchanger, and a thermal coupler. The system employs lithium bromide, which is now widely used in commercial air conditioning.

In current systems, however, efficiency has been limited by crystallization at the solution heat exchanger outlet and at the absorber. ORNL researchers found a way to avoid crystallization by increasing evaporating pressure. Further crystallization is averted by directing the process water first through the absorber and then through the condenser. The water flow direction can be changed at run-time to optimize performance.
  • Energy efficient and environmentally friendly
  • Substantial energy savings compared with conventional gas-fired water heaters
  • Lithium bromide water absorption, now commercialized for cooling applications, is easily available
Applications and Industries
  • Residential and commercial water heating
  • Alternative versions offer industrial process heat generation and boiler preheating
More InformationLead Inventor:
Omar Abdelaziz
Energy and Transportation Science Division
Oak Ridge National Laboratory
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Application 20120000221
An absorption heat pump system that can include a first assembly, a second assembly, and a thermal coupler is disclosed herein. The first assembly can include a condenser and an evaporator. The second assembly can include an absorber, a desorber, and a heat exchanger. The thermal coupler can include a first gas inlet, a second fluid inlet, and a mixed fluid outlet. The system can be configured with a first gas outlet of the desorber in fluid communication with the first gas inlet of the thermal coupler, and the mixed fluid outlet of the thermal coupler in fluid communication with a mixed fluid inlet of the evaporator. The system can also include a coolant absorber inlet and outlet on the absorber and a coolant condenser inlet and outlet on the condenser, with the coolant absorber outlet in fluid communication with the coolant condenser inlet.
Oak Ridge National Laboratory 07/02/2010
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
UT-B ID 201002389DevelopmentAvailable10/20/201012/08/2010

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To: David L. Sims<>