Patent ID: 7919209

Claim:
A fuel cell system comprising: a fuel cell stack; an anode input line; a hydrogen source providing fresh hydrogen gas to the anode input line; an anode re-circulation line for re-circulating anode exhaust gas from the stack to the anode input line; an anode heat exchanger receiving the re-circulated anode exhaust gas and the fresh hydrogen gas from the source, said anode heat exchanger heating both the re-circulated anode exhaust gas and the fresh hydrogen gas; a cooling fluid line directing a cooling fluid through the stack, where heated cooling fluid exits the stack and cooled cooling fluid enters the stack from the cooling fluid line, said cooling fluid line directing at least a portion of the heated cooling fluid from the stack to the anode heat exchanger to heat the re-circulated anode exhaust gas and the fresh hydrogen gas; and an isolation heat exchanger receiving the portion of the cooling fluid after the portion of the cooling fluid flows through the anode heat exchanger, said isolation heat exchanger cooling the cooling fluid.