Abstract: Liquid refrigerant (1) is flashed-off by ultrasonic vibrations and/or diffuser plate (5) into saturated vapour that is static pressure reduced/velocity increased by the converging inlet tract and volute of turbine (4). The turbine wheel expansion cools (***) this saturated vapour—less a turbine efficiency loss heating effect and powers compressor (7). The % age free work of compressor (7) is the product of the efficiencies of turbine (4) and compressor (7). Valve (2) controls pump-down, superheat via sensors (10) & (11). Valve (16) controls hot gas bypass/turbine speed via sonic sensor (9). Compressor (13) can be any type of compressor with reduced compression and motor speed—horsepower reducing 55 to 75% plus. Exact required speed of an automobile A/C compressor is obtained via the belt drive.