Abstract: A method of determining a distribution of electrolytes in a flow battery includes providing a flow battery with a fixed amount of fluid electrolyte having a common electrochemically active specie, a portion of the fluid electrolyte serving as an anolyte and a remainder of the fluid electrolyte serving as a catholyte. An average oxidation state of the common electrochemically active specie is determined in the anolyte and the catholyte and, responsive to the determined average oxidation state, a molar ratio of the common electrochemically active specie between the anolyte and the catholyte is adjusted to increase an energy discharge capacity of the flow battery for the determined average oxidation state.

Abstract: A solar power system includes a solar energy collector that has at least one solar receiver that is operable to carry a working fluid and at least one solar reflector that is operable to direct solar energy towards the at least one solar receiver to heat the working fluid. The working fluid has a maximum predefined operational temperature up to which it can be heated. A first storage unit is connected to receive the working fluid from the at least one solar receiver, and a second storage unit is connected to provide the working fluid to the at least one solar receiver. A power block generates electricity using heat from the heated working fluid. A heater is operable to heat the working fluid to approximately the maximum predefined operational temperature.

Abstract: A flow battery includes an electrochemical cell that has a first electrode, a second electrode spaced apart from the first electrode, and a separator layer arranged between the first electrode and the second electrode. The separator layer is formed of a polymer that has a polymer backbone with cyclic groups that are free of unsaturated nitrogen and one or more polar groups bonded between the cyclic groups.

Abstract: A cost estimator may estimate execution costs for execution of at least one query against a database, using at least one existing index, if any, and based on estimation criteria determined from analyzing the query execution. A candidate index provider may provide candidate indexes, based on the estimation criteria, and re-estimate the execution costs to obtain updated execution costs, using the candidate indexes. An index recommender may recommend a recommended index, based on the updated execution costs.

Abstract: A membrane electrode assembly includes a membrane, an anode catalyst layer and a cathode catalyst layer. The anode catalyst layer is on a first side of the membrane and the cathode catalyst layer is on a second side of the membrane, wherein the second side of the membrane is opposite the first side of the membrane along a first axis. The cathode catalyst layer includes agglomerates formed of a catalyst support supporting catalyst particles, an agglomerate ionomer and an inter-agglomerate ionomer. The agglomerate ionomer surrounds the agglomerates and the inter-agglomerate ionomer is in regions between the agglomerates surrounded by the agglomerate ionomer. The agglomerate ionomer is different than the inter-agglomerate. Methods to produce the catalyst layer are also provided.

Abstract: A flow battery stack includes a plurality of flow battery cells, a manifold and a heat exchanger. Each flow battery cell includes an electrode layer that is wet by an electrolyte solution having a reversible redox couple reactant. The manifold includes a solution passage that exchanges the electrolyte solution with the flow battery cells. The heat exchanger includes a heat exchange fluid passage. The heat exchanger exchanges heat between the electrolyte solution in the solution passage and a heat exchange fluid directed through the heat exchange fluid passage. The flow battery cells, the manifold and the heat exchanger are arranged between first and second ends of the flow battery stack.

Abstract: A gas sensor for detecting one or more contaminants in a refrigerant includes a housing having disposed therein a membrane electrode assembly comprising a sensing electrode, a counter electrode, and a solid polymer electrolyte disposed between the sensing electrode and the counter electrode. The sensing electrode comprises nanoparticles of a first catalyst comprising noble metal. The counter electrode comprises nanoparticles of a second catalyst comprising noble metal. The sensing electrode in the sensor has been preconditioned by exposure under a positive voltage bias to a preconditioning gas comprising the contaminant(s) or their precursors or derivatives.

Abstract: A device (10) for use in a fuel cell includes a fuel-cell flow-field channel (18) having a channel-inlet section (42) and a channel-outlet section (44). At least one of the channel-inlet section (42) or the channel-outlet section (44) includes an obstruction member (46) that partially blocks flow through the fuel-cell flow-field channel (18).

Abstract: Fuel cell systems and related methods involving accumulators with multiple regions of differing water fill rates are provided. At least one accumulator region with a relatively more-rapid fill rate than another accumulator region is drained of water at shutdown under freezing conditions to allow at least that region to be free of water and ice. That region is then available to receive water from and supply water to, a fuel cell nominally upon start-up. The region having the relatively more-rapid fill rate may typically be of relatively lesser volume, and may be positioned either relatively below or relatively above the other region(s).

Abstract: A method is disclosed for regenerating an electrode of a flow battery. The method can be executed during shutdown of the flow battery from an active charge/discharge mode to an inactive, shut-down mode in which neither a negative electrolyte nor a positive electrolyte are circulated through at least one cell of the flow battery. The method includes driving voltage of the least one cell of the flow battery toward zero by converting, in-situ, the negative electrolyte in the at least one cell to a higher oxidation state. The negative electrolyte is in contact with an electrode of the at least one cell. The higher oxidation state negative electrolyte is used to regenerate, in-situ, catalytically active surfaces of the electrode of the at least one cell.

Abstract: A gas detection device including a vessel, wherein the vessel contains an aqueous solution, and a sensing element operably coupled to the vessel, wherein the sensing element is not in direct contact with the aqueous solution.

Abstract: A flow battery includes an electrode operable to be wet by a solution having a reversible redox couple reactant. In one embodiment, the electrode can have plurality of micro and macro pores, wherein the macro pores have a size at least one order of magnitude greater than a size of the micro pores. In another embodiment, the electrode includes a plurality of layers, wherein one of the plurality of layers has a plurality of macro pores, and wherein another one of the plurality of layers has a plurality of micro pores. In another embodiment, the electrode has a thickness less than approximately 2 mm. In still another embodiment, the electrode has a porous carbon layer, wherein the layer is formed of a plurality of particles bound together.

Abstract: Cathode exhaust of an evaporatively cooled fuel cell stack (50) is condensed in a heat exchanger (12a, 23, 23a) having extended fins (14, 25a) or tubes (24, 24a) to prevent pooling of condensate, and/or having the entire exit surface of the condenser rendered hydrophilic with wicking (32) to conduct water away. The cathode exhaust flow paths may be vertical or horizontal, they may be partly or totally rendered hydrophilic, and if so, in liquid communication with hydrophilic end surfaces of the condenser, and the condensers (49) may be tilted away from a normal orientation with respect to earth's gravity.

Abstract: An aircraft fuel tank ullage gas management system is disclosed. The system includes an electrochemical cell having a membrane electrode assembly that includes a cathode and anode separated by an electrolyte separator. A cathode fluid flow path is in fluid communication with the cathode, and receives the flow of cabin air from the cabin air fluid flow path and discharges nitrogen-enriched air. An anode fluid flow path is in fluid communication with the anode, and discharges oxygen or oxygen-enriched air. The electrochemical cell also includes water in fluid communication with the anode. The system includes an electrical power source and electrical connections to the anode and cathode for providing an electric potential difference between the anode and cathode. An ullage flow path receives nitrogen-enriched air from the cathode fluid flow path and delivers it to the fuel tank. An optional flow path delivers humidified oxygen-enriched air back to the cabin.

Abstract: A fuel cell power plant (36) has vertical fuel cells (102) each sharing a half of a hybrid separator plate (100) which includes a solid fuel flow plate (105) having horizontal fuel flow channels (106) on one surface and coolant channels (108) on an upper portion of the opposite surface, bonded to a plain rear side of a porous, hydrophilic oxidant flow field plate (115) having vertical oxidant flow channels (118). Coolant permeates through the upper portion of the porous, hydrophilic oxidant flow field plates and enters the oxidant flow channels, where it evaporates as the water trickles downward through the oxidant flow field channels, thereby cooling the fuel cell.

Abstract: A flow battery that includes an electrochemical cell having first and second half-cells and an ion-selective separator there between wherein a fluid pressure differential across the ion-selective separator for a controlled amount of time is selectively utilized to urge a concentration imbalance of the electrochemically active species between the first and second electrolytes toward a concentration balance.

Abstract: A method of determining a distribution of electrolytes in a flow battery includes providing a flow battery with a fixed amount of fluid electrolyte having a common electrochemically active specie, a portion of the fluid electrolyte serving as an anolyte and a remainder of the fluid electrolyte serving as a catholyte. An average oxidation state of the common electrochemically active specie is determined in the anolyte and the catholyte and, responsive to the determined average oxidation state, a molar ratio of the common electrochemically active specie between the anolyte and the catholyte is adjusted to increase an energy discharge capacity of the flow battery for the determined average oxidation state.

Abstract: A membrane electrode assembly includes a membrane, an anode catalyst layer and a cathode catalyst layer. The anode catalyst layer is on a first side of the membrane and the cathode catalyst layer is on a second side of the membrane, wherein the second side of the membrane is opposite the first side of the membrane along a first axis. The cathode catalyst layer includes agglomerates formed of a catalyst support supporting catalyst particles, an agglomerate ionomer and an inter-agglomerate ionomer. The agglomerate ionomer surrounds the agglomerates and the inter-agglomerate ionomer is in regions between the agglomerates surrounded by the agglomerate ionomer. The agglomerate ionomer is different than the inter-agglomerate. Methods to produce the catalyst layer are also provided.

Abstract: A membrane electrode assembly includes an anode including a hydrogen oxidation catalyst; a cathode; a membrane disposed between the anode and the cathode; and a peroxide decomposition catalyst positioned in at least one position selected from the group consisting of a layer between the anode and the membrane and a layer between the cathode and the membrane wherein the peroxide decomposition catalyst has selectivity when exposed to hydrogen peroxide toward reactions which form benign products from the hydrogen peroxide. The peroxide decomposition catalyst can also be positioned within the membrane. Also disclosed is a power-generating fuel cell system including such a membrane electrode assembly, and a process for operating such a fuel cell system. The assembly components contain ionomer material which can be perfluorinated or non-perfluorinated, high temperature, hydrocarbon, and the like.

Abstract: A method of processing a porous article includes distributing a blended material that includes an electrically conductive material and a binder into a cavity of a mold that is at a temperature below a curing temperature of the binder. The electrically conductive material is formed from particles of the electrically conductive material that have a size distribution such that 10 vol % of the particles are less than 12 micrometers in diameter, 50 vol % of the particles are less than 27 micrometers in diameter, and 90 vol % of the particles are less than 53 micrometers. The blended material is compressed within the cavity under a molding pressure, and the mold is heated to a curing temperature of the binder to form a molded article.