Freeze tolerant fuel cell power plant

A method of operating and storing a freeze tolerant fuel cell power plant in sub-freezing ambient conditions wherein the power plant includes a fuel cell and a coolant loop having a water transport plate secured within the fuel cell that directs a water coolant through the fuel cell, and coolant circulating means secured to a coolant passage for circulating the water coolant through the coolant loop, comprising the steps of:

• a. providing a freeze tolerant accumulator means for storing the water coolant and a water immiscible fluid, a water immiscible fluid feed line secured between the accumulator means and the coolant loop, a water immiscible fluid circulating means for circulating the water immiscible fluid from the accumulator means to the coolant loop, and a coolant loop drain line secured between the coolant loop and the accumulator means for draining the water coolant from the coolant loop into the accumulator means;
• b. circulating the water immiscible fluid from the accumulator means to the coolant loop to displace the water coolant from the coolant loop and draining the water coolant from the coolant loop into the accumulator means through the coolant loop drain line;
• and,
• c. draining the water immiscible fluid from the coolant loop back into the accumulator means.

A freeze tolerant fuel cell power plant for producing electrical current from reducing fluid and process oxidant reactant streams, the power plant comprising:

• a. at least one fuel cell;
• b. a coolant loop having a water transport plate secured within the fuel cell that directs a water coolant through the fuel cell, and a coolant circulating means secured to a coolant passage for circulating the water coolant through the coolant loop;
• and,
• c. a water displacement system including;
• i. an open tube accumulator that contains a water immiscible fluid and coolant water;
• ii. a water immiscible fluid feed line secured between a water immiscible fluid discharge of the accumulator and the coolant loop that directs the water immiscible fluid from the accumulator into the coolant loop;
• iii. a water immiscible fluid re-cycle line secured between the water immiscible fluid feed line and the accumulator that directs the water immiscible fluid from adjacent the water immiscible fluid discharge of the accumulator to a water immiscible fluid inlet of the accumulator in fluid communication with open tubes of the accumulator;
• iv. a heater means for heating the water immiscible fluid secured in heat exchange relationship with the water immiscible fluid adjacent the water immiscible fluid discharge of the accumulator;
• v. a water immiscible fluid circulating means secured in fluid communication with the water immiscible fluid feed line for circulating the water immiscible fluid from the accumulator;
• vi. a coolant loop drain line secured between the coolant loop and a water coolant drain inlet of the accumulator;
• and,
• vii. fluid displacement control valve means for selectively directing the water immiscible fluid to flow from the accumulator into the coolant loop, for selectively directing the water coolant within the coolant loop to flow into the accumulator, for selectively directing heated water immiscible fluid to flow from the accumulator into the coolant loop and back into the accumulator, and for selectively directing heated water immiscible fluid to flow from adjacent the discharge of the accumulator through the water immiscible fluid re-cycle line and through the open tubes of the accumulator.