a refrigerating cycle having a compressor device, a condenser device, a depressurizing device, and an evaporator, wherein refrigerant is circulated in the refrigerating cycle to perform a cooling operation;

a Rankine cycle having a pump for pumping out the refrigerant, a heating device for heating the refrigerant by use of waste heat from a heat generating device, an expansion device, and the condenser device, wherein the refrigerant is circulated in the Rankine cycle to generate a driving force at the expansion device by expansion of the refrigerant heated by the heating device; and

a heat pump cycle having a pump bypass passage bypassing the pump and an orifice provided in the pump bypass passage, wherein the refrigerant is circulated from the compressor device through the heating device, the pump bypass passage and the condenser device to perform a heat absorbing operation at the condenser device and to perform a heating operation at the heating device, so that the heat generating device is heated by the heating operation at the heating device; wherein

the condenser device comprises;

a main condenser;

a gas-liguid separator connected to the main condenser and separating the refrigerant from the main condenser into gas phase and liguid phase refrigerant, when the Rankine cycle is in its operation;

a sub-cool condenser connected to the gas-liguid separator for further cooling down the liguid phase refrigerant from the gas-liguid separator; and

one end of the pump bypass passage is connected to a refrigerant passage between the main condenser and the sub-cool condenser, so that the refrigerant bypasses the sub-cool condenser and flows into the main condenser when the heat pump cycle is in its operation.