Abstract: An engine or heat pump for a refrigeration system employing a first elongated expansion-compression device defining a pair of chambers, each having a linearly movable piston therein which are axially interconnected by a hollow cylinder. A second expansion-compression device is mounted within the cylinder. Conduit means are provided, one extending into each end of the first device, through the associated piston and into the cylinder. The first device forces working fluid received through the device to provide fluid under relatively high pressure to the power and work loops of a refrigeration system, while the second device actuated by the first device draws relatively low pressure fluid from the system and returns it under pressure to a source.

Abstract: A thermally powered heat transfer system employing a boiler for producing a refrigerant in vaporized form at relatively high pressure, the output of the boiler being connected to a pump, aspirator or compressor which may comprise a single cylinder, double piston structure functioning as a power source for moving the refrigerant and a pumping source for creating a low pressure for drawing refrigerant vapor form from an evaporator and into the condenser where the refrigerant vapor gives up its heat. The condenser is coupled in circuit with receiver means which holds liquid refrigerant and delivers same to the boiler and evaporator under control of suitable valving means.