Abstract: A hot-water heating system for use by submarines, divers and the like in an underwater environment includes a heating-medium circuit and a hot-water circuit. The heating-medium circuit includes an electric-motor-driven compressor in a water-tight submersible housing for compressing a heating-medium fluid. The heating-medium circuit also includes a condenser heat exchanger, a throttle valve, and an evaporator heat exchanger connected in series between a discharge outlet and a suction inlet of the compressor. The evaporator heat exchanger can make thermal contact with water surrounding the water-tight housing to absorb heat from the water and the condenser heat exchanger make thermal contact with the water in the hot water circuit to transfer heat to the water.

Abstract: A heat extraction or reclamation system particularly adapted to recover otherwise rejected heat from the refrigerant gas flowing through air conditioning and refrigerating systems includes a counter-flow heat exchanger for transferring heat to a medium such as water, the heat exchanger being installed in the tubing upstream of the conventional condenser. The heat extraction system has a pump for circulating water or other medium to be heated, located on one side of the heat exchanger. Hot refrigerant gas, the so-called superheated gas flowing from the compressor of the air conditioning or refrigerating system, is circulated through the other side of the heat exchanger. The pump flow rate and the heat transfer area between the refrigerant gas and the water or other medium are chosen to ensure that the refrigerant gas outlet quality remains within limits which ensure flow continuity in operation. Refrigerant gas leaving the system will contain some liquid in the form of droplets or a small stream.