Absorption heat pumps use an ammonia-h2o absorption cycle, rather than a vapor-compression cycle, to transfer heat. Ammonia may be the refrigerant, and drinking water would be the absorber. The ammonia condenses at among the list of system’s coils to release heat and evaporates at the other coil to absorb heat. https://purethermal.co.uk/media-news/can-gas-absorption-heat-pumps-provide-an-alternative-heat-pump-option-in-2025/