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