Abstract: An illustrative example system for managing hydrogen utilization in a fuel cell power plant includes a first hydrogen concentration sensor that provides an indication of a first concentration of hydrogen in a fluid flowing into an anode inlet of the power plant. A second hydrogen concentration sensor provides an indication of a second concentration of hydrogen in a fluid flowing out of an anode exit of the power plant. A processor determines a utilization of hydrogen by the power plant based on the first and second concentrations.

Abstract: An illustrative example system for managing hydrogen utilization in a fuel cell power plant includes a first hydrogen concentration sensor that provides an indication of a first concentration of hydrogen in a fluid flowing into an anode inlet of the power plant. A second hydrogen concentration sensor provides an indication of a second concentration of hydrogen in a fluid flowing out of an anode exit of the power plant. A processor determines a utilization of hydrogen by the power plant based on the first and second concentrations.

Abstract: An illustrative example reformer includes a housing having an inlet plenum, a reforming section, and an outlet. The inlet plenum includes a catalyst situated where a source fluid passing through the inlet plenum will be exposed to the catalyst prior to entering the reforming section.

Abstract: An illustrative example reformer includes a housing having an inlet plenum, a reforming section, and an outlet. The inlet plenum includes a catalyst situated where a source fluid passing through the inlet plenum will be exposed to the catalyst prior to entering the reforming section.

Abstract: An illustrative example electrical power generating system includes a fuel cell power plant that is configured to generate electrical power. The fuel cell power plant includes a cell stack assembly including a plurality of fuel cells that are configured to generate electrical power based on a chemical reaction. A coolant network is configured to carry fluid toward the cell stack assembly where fluid in the coolant network can become heated by absorbing heat from the fuel cell power plant. The coolant network includes a thermal hydraulic engine that is configured to generate electrical power. The coolant network is configured to carry the heated fluid to the thermal hydraulic engine where the heated fluid can be used for generating electrical power. The coolant network is configured to carry a reduced temperature fluid from the thermal hydraulic engine back toward the cell stack assembly.

Abstract: An illustrative example electrical power generating system includes a fuel cell power plant that is configured to generate electrical power. The fuel cell power plant includes a cell stack assembly including a plurality of fuel cells that are configured to generate electrical power based on a chemical reaction. A coolant network is configured to carry fluid toward the cell stack assembly where fluid in the coolant network can become heated by absorbing heat from the fuel cell power plant. The coolant network includes a thermal hydraulic engine that is configured to generate electrical power. The coolant network is configured to carry the heated fluid to the thermal hydraulic engine where the heated fluid can be used for generating electrical power. The coolant network is configured to carry a reduced temperature fluid from the thermal hydraulic engine back toward the cell stack assembly.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10). An anode flow path (24) is in fluid communication with an anode catalyst (14) for directing hydrogen fuel to flow adjacent to the anode catalyst (14), and a cathode flow path (38) is in fluid communication with a cathode catalyst (16) for directing an oxidant to flow adjacent to the cathode catalyst (16) of a fuel cell (12). Hydrogen fuel is permitted to transfer between the anode flow path (24) and the cathode flow path (38). A hydrogen reservoir (66) is secured in fluid communication with the anode flow path (24) for receiving and storing hydrogen during fuel cell (12) operation, and for releasing the hydrogen into the fuel cell (12) whenever the fuel cell (12) is shut down.

Abstract: A method for operating a fuel cell power plant to supply power to an internal load and an external load, includes the steps of evaluating power needs of the internal and external loads to determine a fixed IDC value sufficient to supply the needs; providing auxiliary power to the internal load and output power to the external load so as to maintain operation of the fuel cell power plant at the fixed IDC value; and adjusting at least one of the auxiliary power to the internal load and output power to the external load so as to maintain operation of the fuel cell power plant at the fixed IDC value. Operation within a preselected voltage range is also provided.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10). An anode flow path (24) is in fluid communication with an anode catalyst (14) for directing hydrogen fuel to flow adjacent to the anode catalyst (14), and a cathode flow path (38) is in fluid communication with a cathode catalyst (16) for directing an oxidant to flow adjacent to the cathode catalyst (16) of a fuel cell (12). Hydrogen fuel is permitted to transfer between the anode flow path (24) and the cathode flow path (38). A hydrogen reservoir (66) is secured in fluid communication with the anode flow path (24) for receiving and storing hydrogen during fuel cell (12) operation, and for releasing the hydrogen into fuel cell (12) whenever the fuel cell (12) is shut down.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10). An anode flow path (24) is in fluid communication with an anode catalyst (14) for directing hydrogen fuel to flow adjacent to the anode catalyst (14), and a cathode flow path (38) is in fluid communication with a cathode catalyst (16) for directing an oxidant to flow adjacent to the cathode catalyst (16) of a fuel cell (12). Hydrogen fuel is permitted to transfer between the anode flow path (24) and the cathode flow path (38). A hydrogen reservoir (66) is secured in fluid communication with the anode flow path (24) for receiving and storing hydrogen during fuel cell (12) operation, and for releasing the hydrogen into fuel cell (12) whenever the fuel cell (12) is shut down.

Abstract: A method for operating a fuel cell power plant to provide end-use electricity, end-use heat and end-use reformate includes the steps of providing a fuel cell power plant that consumes reformate to provide electricity and heat, said fuel cell power plant having a nominal reformate flow rate and including a fuel processor system for generating reformate from a hydrocarbon fuel; operating the fuel processor system so as to provide a reformate flow at a rate greater than the nominal reformate flow rate; operating the fuel cell power plant using a first portion of the reformate flow to generate the electricity and the heat, the first portion being less than or equal to the nominal reformate flow rate; and providing a second portion of the reformate flow as the end-use reformate.

Abstract: Fuel cell power plants (19, 47, 60, 86, 102, 112, 121) include recycle fuel from a fuel exit (29) of the last fuel flow field (23, 52, 64, 89) of a series of flow fields (20-23; 49-52; 61-64; 87-89) labeled M?N through M, applied either to the Mth flow fields or both the Mth and the (M?1)th flow fields. The fuel recycle impeller is a blower (30), a turbocompressor (30a) driven by an air exhaust, an ejector (30b) or an electrochemical hydrogen pump (30c). Fuel from a source (77) may be applied both to the first fuel flow field (87) and an additional fuel flow field (88, 74, 75, 89) of a series of flow fields to reduce pressure drop and flow rate requirements in the first of the series of flow fields and assure more fuel in the additional fuel flow field. Flow to the additional fuel flow field may be controlled by voltage (126) in such field or fuel content (128) of its exhaust. Transient fuel volume is provided by a tank (125).

Abstract: A vane (31) at the juncture of orthogonal conduits (25-28) allows flow of air to and from the air inlet/outlet manifold (12) of a fuel cell stack (11) when it is disposed in a first position, and totally blocks the conduits (25, 26) so as to isolate the air flow fields of the fuel cells (17, 18) when in a position normal to the first position. A vane (41) can comprise the divider of the air inlet/outlet manifold when in a vertical position, and totally block off the manifold when in a horizontal position. A vane (59) can align with the divider (24) of an air inlet/out manifold when in a vertical position, and block the passage between the manifold and conduits (44, 46) when in a horizontal position. Similar vanes may be used for single-valve selection of flow or containment of fuel reactant gas.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10). An anode flow path (24) is in fluid communication with an anode catalyst (14) for directing hydrogen fuel to flow adjacent to the anode catalyst (14), and a cathode flow path (38) is in fluid communication with a cathode catalyst (16) for directing an oxidant to flow adjacent to the cathode catalyst (16) of a fuel cell (12). Hydrogen fuel is permitted to transfer between the anode flow path (24) and the cathode flow path (38). A hydrogen reservoir (66) is secured in fluid communication with the anode flow path (24) for receiving and storing hydrogen during fuel cell (12) operation, and for releasing the hydrogen into fuel cell (12) whenever the fuel cell (12) is shut down.

Abstract: A fuel cell power plant system includes the ability to operate an enthalpy recovery device even under cold conditions. A bypass arrangement allows for selectively bypassing one or more portions of the enthalpy recovery device under selected conditions. In one example, the enthalpy recovery device is completely bypassed under selected temperature conditions to allow the device to freeze and then later to be used under more favorable temperature conditions. In another example, the enthalpy recovery device is selectively bypassed during a system startup operation. One example includes a heater associated with the enthalpy recovery device. Another example includes preheating oxidant supplied to one portion of the enthalpy recovery device.

Abstract: A cell stack assembly includes a plurality of plates defining a primary cell stack portion having a primary air flow path, a fuel flow path and a primary coolant flow path; and an auxiliary coolant stack portion defining an auxiliary air flow path and an auxiliary coolant flow path, the auxiliary air flow path being communicated with the primary air flow path, whereby water is condensed from air in the auxiliary air flow path.