Patent ID: 7600695

Claim:
A cogeneration system comprising: an engine; a generator connected to an output shaft of the engine to generate electricity; a heat pump type air conditioner including a compressor, a directional valve, an outdoor heat exchanger, an expansion device, and an indoor heat exchanger; a pre-heater to pre-heat outdoor air blown toward the outdoor heat exchanger; a compressor discharge line heater to heat a refrigerant discharged from the compressor; and a waste heat controller to transfer waste heat from the engine to at least one of the pre-heater and the compressor discharge line heater while controlling the amount of the waste heat transferred to the preheater and the compressor discharge line heater, wherein the waste heat controller comprises: a cooling water heat exchanger to absorb heat from cooling water used to cool the engine; an exhaust gas heat exchanger to absorb heat from exhaust gas discharged from the engine; a first heat medium circulation conduit to guide a first heat medium to be circulated through the cooling water heat exchanger and the pre-heater; a first circulation pump to pump the first heat medium for circulation of the first heat medium; a second heat medium circulation conduit to guide a second heat medium to be circulated through the exhaust gas heat exchanger and the compressor discharge line heater; a second circulation pump to pump the second heat medium for circulation of the second heat medium; a heat medium heater arranged at the first heat medium circulation conduit to heat the first heat medium emerging from the cooling water heat exchanger; and an exhaust gas path switching means for selectively supply the exhaust gas discharged from the engine to the heat medium heater or to the exhaust gas heat exchanger; and wherein the exhaust gas path switching means comprises: an exhaust conduit to guide the exhaust gas discharged from the engine to the exhaust gas heat exchanger; a branched conduit to guide the exhaust gas discharged from the engine to the heat medium heater; and a control valve to alternately open/close the exhaust conduit and the branched conduit.