Heat Heat extracted from the subcells and condensation process is circulated through the fuels cell coolant loop to a heat exchanger. Heat from the fuel cell heat exchanger is transferred to the Freon-21 coolant loop in the Orbiter midfuselage. Reactant consumption is directly related to the current produced. Purging Due to contaminant and inert gas buildup during the fuel cell operation, purging is necessary several times per day in each cell. This is normally accomplished with reactant gas pressurized flow through the purge lines and vents.
Electrical power is available during the purge cycle.