Patent ID: 7892685

Claim:
A fuel cell system comprising: a plurality of fuel cell units; a common-use reforming unit configured to supply hydrogen to the plurality of fuel cell units; each fuel cell unit comprising: a stack unit configured to generate electricity by an electrochemical reaction between air and the hydrogen supplied from the common-use reforming unit; an air supplying unit configured to supply the air to the stack unit; an integral heat exchange unit configured to cool the stack unit by recovering heat generated by the stack unit, the integral heat exchange unit also being configured to store the recovered heat; a hot-water supplying unit configured to receive the heat stored by the integral heat exchange unit, the hot-water supplying unit also being configured to provide heat and hot water external to the fuel cell unit; an auxiliary heat supplying unit configured to generate heat by reacting air supplied from the air supplying unit and hydrogen supplied from the common-use reforming unit or hydrogen discharged from the stack unit, the auxiliary heat supplying unit also being configured to selectively supply the generated heat to the hot-water supplying unit; and an electric output unit configured to convert the electricity generated in the stack unit into a utility power, wherein the integral heat exchange unit includes: a heat exchange module body connected with a cooling-water line which is configured to allow a cooling water to pass through the inside of the stack unit so as to cool the stack unit, and comprise a first line coupled from the common-use reforming unit to the stack unit, a second hot-water line connected from one portion of a hot-water storage tank to another portion of the hot-water storage tank through the inside of the electric output unit, and an air supplying line connected from the air supplying unit to the stack unit; and an auxiliary heater positioned inside the heat exchange module body.