Phase-change heat transfer coupling for aqua-ammonia absorption systems

In a process for operating an aqua-ammonia absorption cooling system or heating and/or cooling system for supplying cooling or heating to an indoor space, said system comprising:

• a heat exchange assembly having a first heat exchanger exterior to the indoor space to be heated and/or cooled, a second heat exchanger in heat transfer exposure with the interior of said indoor space, piping in flow communication with said first and second heat exchangers and having a phase-change refrigerant other than ammonia therein, and a pump for pumping the liquid phase-change refrigerant between said first and second heat exchangers,
• an improvement comprising pumping more of the liquid phase-change refrigerant from the heat exchanger in which refrigerant condensation occurs to the heat exchanger in which refrigerant vaporization occurs than is required to meet the heat load transfer in said heat exchanger for vaporizing said phase-change refrigerant alone.