Patent attributes
A fuel cell module has a hydrogen recirculation pump and a controller. The controller receives a signal indicating the response of the pump to changes in the density or humidity of gasses in the hydrogen recirculation loop. The controller is programmed to consider the signal in controlling one or more balance of plant elements that effect the removal of water from the stack. In a process for operating the fuel cell module, the signal is considered when controlling one or more balance of plant elements that effect the removal of water from the stack. For example, an increase in current drawn from a constant speed or voltage recirculation pump indicates an increase in humidity and suggests that water should be removed from the stack, for example by increasing a coolant temperature set point.