摘要 |
Water passageways (67; 78, 85; 78a, 85a) that provide water through reactant gas flow field plates (74, 81) to cool the fuel cells (38) may be grooves (76, 77; 83, 84) or may comprise a plane of porous hydrophilic material (78a, 85a), may be vented to atmosphere (99) by a porous plug (69), or pumped (89, 146) with or without removing any water from the passageways. A condenser (59, 124) receives exhaust of reactant air that evaporatively cools the stack (37), and may have a contiguous reservoir (64, 128), be vertical (a vehicle radiator, FIG. 2), be horizontal across the top of the stack (37, FIG. 5), or below (124) the stack (120). Condenser air flow may be controlled by shutters (155), or by a controlled, freeze-proof heat exchanger (59a). A deionizer (175) may be used. Sensible heat transferred into the water is removed by a heat exchanger 182; a controller (185) controls water flow (180) and temperature as well as air flow to provide predetermined allocation of cooling between evaporative and sensible.
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