Absorption heat pumps use an ammonia-h2o absorption cycle, in lieu of a vapor-compression cycle, to transfer heat. Ammonia could be the refrigerant, and drinking water may be the absorber. The ammonia condenses at one of many method’s coils to launch heat and evaporates at the opposite coil to absorb heat. https://purethermal.co.uk/media-news/can-gas-absorption-heat-pumps-provide-an-alternative-heat-pump-option-in-2025/