Absorption heat pumps use an ammonia-drinking water absorption cycle, rather than a vapor-compression cycle, to transfer heat. Ammonia may be the refrigerant, and drinking water is definitely the absorber. The ammonia condenses at among the method’s coils to release heat and evaporates at the opposite coil to soak up heat. https://purethermal.co.uk/media-news/can-gas-absorption-heat-pumps-provide-an-alternative-heat-pump-option-in-2025/