Abstract: An improved engine cooling system is combined with a jet-driven heat pump system for utilizing otherwise wasted heat from an engine to produce refrigeration and heating of cabin, charge air and other media without requiring additional shaft power from the engine. In a closed cycle, vaporized refrigerant fluid is conveyed via jet ejectors from the engine cooling jacket at a high pressure and temperature and from refrigerant evaporators at low pressures and temperatures to a radiator/condenser at an intermediate pressure and temperature. The greater portion of condensed refrigerant fluid is pumped back to the engine (boiler) and the balance is throttled into the evaporators (heat exchangers) to produce an evaporative cooling effect. The vapor resulting therefrom is evacuated by the ejectors and returned to the condenser/radiator.