Patent ID: 7504168

Claim:
A fuel cell electricity generating system, comprising: a fuel cell configured to allow the reaction of a fuel gas with an oxidizer gas to generate electricity, a fuel gas supplying unit configured to supply the fuel gas into said fuel cell, an oxidizer gas supplying unit configured to supply the oxidizer gas into said fuel cell, a state detecting unit configured to detect the temperature of cooling water to be supplied into said fuel cell, a cooling water heater configured to heat the cooling water to said fuel cell, an operation controlling unit configured to detect abnormalities with respect to rising of the temperature of the cooling water by utilizing the results detected by said state detecting unit, a cooling water path in which the cooling water for cooling said fuel cell flows, a heat exchanger which is provided on said cooling water path, an exhaust heat recovery path in which flow a water of heat exchanging with the cooling water of said cooling water path via said heat exchanger, a hot water storage tank configured to store hot water of said exhaust heat recovery path, the hot water being heated by heat transfer from the cooling water via said heat exchanger during electricity generation, and an operation mode switching unit configured to switch an operation mode to heat the cooling water by heat transfer from the hot water of said exhaust heat recovery path via said heat exchanger, wherein in the switched operation mode the direction of heat transfer is an opposite direction during the electricity generation.