Patent ID: 6916567

Claim:
A fuel cell system comprising: (a) a fuel cell having an anode with an anode inlet for receiving a fuel gas and an anode outlet, a cathode with a cathode inlet for receiving an incoming oxidant gas stream and a cathode outlet for discharging an outgoing oxidant gas stream, and an electrolyte between the anode and the cathode; (b) a plurality of dryers, each dryer in the plurality of dryers having a first mode of operation for recovering moisture from the outgoing oxidant gas stream and a second mode of operation for humidifying the incoming oxidant gas stream, and being connectable to the cathode outlet in the first mode and to the cathode inlet in the second mode; and (c) a first switch means for, for each dryer in the plurality of dryers, switching the dryer into and out of the second mode of operation in which the first switch means fluidly connects the dryer to the cathode inlet and obstructs fluid connection between the dryer and the cathode outlet, switching the dryer into and out of the first mode of operation in which the first switch means fluidly connects the dryer to the cathode outlet and obstructs fluid connection between the dryer and the cathode inlet, wherein, in use, the plurality of dryers includes at least one dryer in the first mode of operation, and at least one dryer in the second mode of operation.