What is it?
An absorption heat pump is an HVAC device that provides heating just like any other heat pump; except absorption heat pumps can run on natural gas instead of electricity.
How does it work?
Absorption heat pumps use an absorption cycle instead of a vapor-compression cycle. The difference with absorption cycles is that heat, instead of a compressor, makes the whole system work.
What are the most appropriate applications?
Absorption heat pumps can be used in the same types of applications as electric heat pumps, furnaces, and boilers, but they are most cost-effective when access to electricity is difficult or expensive. Currently, only air-to-water gas absorption heat pumps are available in the marketplace. These heat pumps create hot water that can be used for heating radiators, in-floor heaters, or water coils in air handlers.
What are the savings?
Absorption heat pumps measure energy efficiency in terms of coefficient of performance (COP), where a higher number represents a better efficiency. A COP of 1.4 can be expected from an absorption heat pump. For comparison, a high-efficiency natural gas boiler or furnace may have a 0.95 COP equivalent level of efficiency.
What are the non-energy benefits?
The greatest benefit of natural gas heat pumps is that they do not require electricity and can be designed to run on nearly any heat source[1] with a high enough temperature. Additionally, absorption refrigeration systems are simple in comparison to vapor-compression refrigeration systems so maintenance is expected to be lower.
What is the cost?
Absorption heat pumps will be more expensive than electric heat pumps or gas-fired furnaces, but it is expected that the difference in cost can be recovered in a few years from the energy-cost savings that result from increased efficiency.
What is the status/availability of the technology?
Absorption heat pumps are just becoming available to the market with large commercial and industrial customers likely being the first audience for this technology. Currently, cooling only (gas absorption coolers) or heating only units, with an option for domestic water heating, are available in Europe. Units with combined heating and cooling capability are being explored.
What kinds of incentives/programs are available?
No specific incentives are available at this time, but large projects may be eligible for customized incentives from natural gas utilities.
[1] https://energy.gov/energysaver/absorption-heat-pumps
