Abstract: Fuel Cell stack coolant water is processed by moving the two-phase water/steam coolant exhaust through a steam separator wherein the water phase is separated from the steam phase. The water phase is then moved through a heat exchanger where its temperature is lowered to a subcooled level which is below the coolant operating temperature in the stack. A flow control valve is associated with the coolant heat exchanger to regulate water flow through and/or around the heat exchanger depending on the temperature of the water which leaves the steam separator. By subcooling the coolant before it reenters the stack, a lessening of electrolyte loss through evaporation is achieved. By eliminating steam condensation as a form of system heat rejection, system engineering is simplified and construction costs are lowered.

Abstract: Coolant water is delivered to a fuel cell stack through a manifold which extends up the side of the stack and which communicates with the cooling plates in the stack by means of a plurality of outlet pipes or snivvies. The coolant exhausted from the stack is handled with a similar outlet manifold with corresponding outlet snivvies. The water is ducted into the inlet manifold via a conduit which opens into the inlet manifold at the top thereof and a bleed conduit extends from the inlet manifold at the bottom thereof, to an ion exchange bed polisher and then back to the cooling system bypassing the stack. In this manner, constriction of the snivvies by iron oxide and copper corrosion product is more uniformly distributed on the inlet side, and the corrosion products in the coolant water which settle to the bottom of the inlet manifold are carried around the stack to the polisher or ion exchange bed where particles are removed from the water, whereupon the water is returned to the coolant loop.