PURPOSE: To improve a result coefficient by lowering temperature raised for abolishing condensation heat and hence improve heat efficiency by reducing an engine heat by providing utilizing an absorption type refrigerator as a cooling heat source of a condenser of a mechanical refrigerator.

CONSTITUTION: An absorption type refrigerator 8 is actuated by heating a refrigerator with high temperature water prepared by the use of waste heat of an engine 2. The absorption type refrigerator 8 raises hot water discharged from the refrigerator 8 into high temperature one utilizing the waste heat of the engine and returns it to the refrigerator to heat an absorbed fluid, so that temperature of cold water produced by the present refrigerator can sufficiently be lowered. Cold water yielded from the absorption type refrigerator 8 is fed to a condenser 6 of a mechanical refrigerator by a pump 20, and it after taking condensation heat from the same is returned to the absorption type refrigerator 8 and again changed to cold water. Accordingly, the mechanical refrigerator 1 utilizes the low temperature cold water as the cooling heat source and hence efficiency (result efficiency) of the mechanical refrigerator is improved.