Patent ID: 7811713
Filing Date: 2010-10-12
Classification: H01M,Y02E

Abstract:
1. A method for thermal control of air flow in a fuel cell system, the method of comprising the steps: (a). providing a fuel cell stack, a fluid in a system coolant loop, a heat exchanger connected to at least one water vapor transfer unit, a first valve, a second valve, and a secondary cooling heat exchanger; (b). determining an actual temperature of an air flow at an inlet of the water vapor transfer unit; (c). determining a desired temperature of the air flow as a function of the temperature at which the water vapor transfer unit operates with maximum efficiency; and (d). controlling the flow of at least a portion of the fluid from the system coolant loop to the heat exchanger with the first valve and the second valve to achieve the desired temperature, wherein the first valve when open directs a portion of the fluid from the system coolant loop into the heat exchanger, and the second valve when open directs the fluid from the system coolant loop directly into the secondary cooling heat exchanger before the fluid enters the heat exchanger.