Abstract: The air blower (18) of a fuel cell power plant (9) is used to force water out of the coolant flow fields (27) of a fuel cell stack (10), a coolant pump (35) and a heat exchanger (40) through a valve (46) which is closed during normal operation. The water removal occurs as part of a shutdown procedure in which the fuel cell stack continues to operate so that it provides the power for the air pump and to assist in water removal (such as retaining low vapor pressure). The water flow to an accumulator (33) is blocked by a valve (29) during the shutdown procedure.

Abstract: A cell stack assembly (102) coolant system comprises a coolant exhaust conduit (110) in fluid communication with a coolant exhaust manifold (108) and a coolant pump (112). A coolant inlet conduit (120) enables transportation of the coolant to the coolant inlet manifold. The coolant system further includes a bypass conduit (132) in fluid communication with the coolant exhaust manifold and the coolant inlet manifold, while a bleed valve (130) is in fluid communication with the coolant exhaust conduit and a source of gas. Operation of the bleed valve enables venting of the coolant from the coolant channels, and through a shut down conduit (124). An increased pressure differential between the coolant and reactant gases forces water out of the pores in the electrode substrates (107,109). An ejector (250) prevents air form inhibiting the pump. Pulsed air is blown (238,239,243,245) through the coolant channels to remove more water.

Abstract: A start system for enabling rapid fuel cell power from sub-freezing initial conditions in a fuel cell power plant which comprises heating an antifreeze coolant source and melting ice in the sump of a cell stack assembly with the heated antifreeze to effect start up.

Abstract: A cell stack assembly (102) coolant system comprises a coolant exhaust conduit (110) in fluid communication with a coolant exhaust manifold (108) and a coolant pump (112). A coolant inlet conduit (120) enables transportation of the coolant to the coolant inlet manifold. The coolant system further includes a bypass conduit (132) in fluid communication with the coolant exhaust manifold and the coolant inlet manifold, while a bleed valve (130) is in fluid communication with the coolant exhaust conduit and a source of gas. Operation of the bleed valve enables venting of the coolant from the coolant channels, and through a shut down conduit (124). An increased pressure differential between the coolant and reactant gases forces water out of the pores in the electrode substrates (107, 109). An ejector (250) prevents air form inhibiting the pump. Pulsed air is blown (238, 239, 243, 245) through the coolant channels to remove more water.

Abstract: A start system for enabling rapid fuel cell power from sub-freezing initial conditions in a fuel cell power plant which comprises heating an antifreeze coolant source and melting ice in the sump of a cell stack assembly with the heated antifreeze to effect start up.

Abstract: The present invention provides water-soluble, extended-release chemical formulations, in tablet form, for urine pretreatment, that require minimal, if any, use of a binder component, yet are non-dusting, pliable, structurally strong, and not weakened by exposure to aqueous streams. The present invention also provides a simple and reliable method for controlled dispensing of such tableted formulations into a liquid stream that is particularly advantageous for use in micro-gravity environments, such as spacecraft urinal systems.

Abstract: The present invention provides water-soluble, extended-release chemical formulations, in tablet form, for urine pretreatment, that require minimal, if any, use of a binder component, yet are non-dusting, pliable, structurally strong, and not weakened by exposure to aqueous streams. The present invention also provides a simple and reliable method for controlled dispensing of such tableted formulations into a liquid stream that is particularly advantageous for use in micro-gravity environments, such as spacecraft urinal systems.

Abstract: A chemical pump system that utilizes a self-driven compressor to increase the system pressure while obviating the need for a one-way valve and liquid head to provide the driving force for the reactants, thus enhancing long distance transport. The system comprises a chemical heat pipe employing reversible endothermic/exothermic chemical reactions to transfer thermal energy between a heat source and a heat sink. At least one reactant is self-driven substantially unidirectionally through the heat pipe by compressing the reactant(s) with a compressor and heating the reactant(s) to a predetermined pressure and temperature sufficient to form a reaction product having at least a 150% molar increase. The reaction product is expanded with an expander that is linked mechanically to the compressor. The expansion energy is sufficient to compress the reactants to the predetermined pressure while maintaining the self-driven unidirectional flow.

Abstract: A first gas produced or supplied at a first location is reacted (combined) with a selected reactant in a reversible chemical reaction to produce a gaseous reaction product which is converted to liquid-form and conveyed, as a liquid, to a second location remote from the first location, whereupon it is converted back to its original gaseous constituents in a chemical reaction the reverse of the initial reaction. The regenerated first gas, now at the second location, is separated from the regenerated reactant which is returned to the first location to be used again.