Patent ID: 8286423

Claim:
A cogeneration system comprising: an engine; a generator driven by the engine to generate electric energy; a waste-heat heat exchanger configured to heat cold water to thereby produce hot water by using waste heat from the engine as a first heat source; a hot water storage tank for storing therein the hot water output from the waste-heat heat exchanger; an auxiliary heating device disposed in a hot water circulation path extending between the waste-heat heat exchanger and the hot water storage tank; a hot air heater having a hot air passage for circulating outside air through the hot air passage in order to generate hot air inside the hot air heater by using the hot water output from the waste-heat heat exchanger as a second heat source; a cooling water circulation path extending between the engine and the waste-heat heat exchanger for circulation therethrough of cooling water; a hot water circulation pipe extending between the hot water storage tank and the hot air heater for circulation therethrough of the hot water; a first auxiliary heating device disposed in said hot water circulation pipe extending between the hot water storage tank and the hot air heater; at least one of a first cooling device and a second cooling device, the first cooling device is disposed in the cooling water circulation path and the second cooling device is disposed in the hot water circulation pipe; and a controller configured to activate said first cooling device, to cool the cooling water, when the temperature of the hot water stored in the hot water storage tank exceeds a first predetermined value, and activate said second cooling device, to cool the hot water, when the temperature of the hot air inside the hot air heater exceeds a second predetermined value.