Absorption heat pumps use an ammonia-h2o absorption cycle, rather then a vapor-compression cycle, to transfer heat. Ammonia will be the refrigerant, and water may be the absorber. The ammonia condenses at one of several process’s coils to launch heat and evaporates at the other coil to soak up heat. Applicable https://purethermal.co.uk/media-news/can-gas-absorption-heat-pumps-provide-an-alternative-heat-pump-option-in-2025/