Abstract: A thermal priority fuel cell power plant includes a cell stack assembly for generating an electrical power output. The cell stack assembly includes an anode, a cathode, and a waste heat recovery loop. The waste heat recovery loop is configured to remove waste heat generated from the electrochemical reaction and is thermally coupled to the cell stack assembly for managing the waste heat of the cell stack assembly and for supplying thermal power to a thermal load demand. The waste heat recovery loop includes a heat exchanger in heat exchange relationship with the coolant outlet conduit and the thermal load demand. A controller is operatively associated with the cell stack assembly and the waste heat recovery loop. The controller controls the operation of the cell stack assembly by adjusting a fuel cell power plant parameter responsive to the thermal load demand.

Abstract: A thermal priority fuel cell power plant includes a cell stack assembly for generating an electrical power output. The cell stack assembly includes an anode, a cathode, and a waste heat recovery loop. The anode is configured to receive a fuel, the cathode is configured to receive an oxidizer, and the cell stack assembly is configured to generate the electrical power output by electrochemically reacting the anode fuel and the cathode oxidizer in the presence of a catalyst. The waste heat recovery loop includes a coolant inlet conduit and a coolant outlet conduit, and is configured to remove waste heat generated from the electrochemical reaction. A waste heat recovery loop is thermally coupled to the cell stack assembly for managing the waste heat of the cell stack assembly and for supplying thermal power to a thermal load demand. The waste heat recovery loop includes a heat exchanger in heat exchange relationship with the coolant outlet conduit and the thermal load demand.

Abstract: An Organic Rankine Cycle system is combined with a fuel cell system, with the working fluid of the Organic Rankine Cycle system being integrated directly into the cooling system for the fuel cell. The waste heat from the fuel cell is therefore applied directly to preheat and evaporate the working fluid in the Organic Rankine Cycle system to thereby provide improved efficiencies in the system.

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: A method of operating a system for combined heat and power (CHP) includes generating electricity using a prime mover having a mechanical drive system. The method further includes distributing a variable amount of electricity from the prime mover to an electrical load and distributing a variable amount of electricity from the prime mover to a dummy load.

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: 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: An Organic Rankine Cycle system is combined with a fuel cell system, with the working fluid of the Organic Rankine Cycle system being integrated directly into the cooling system for the fuel cell. The waste heat from the fuel cell is therefore applied directly to preheat and evaporate the working fluid in the Organic Rankine Cycle system to thereby provide improved efficiencies in the system.

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: 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: 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), 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: 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 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.

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: 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: 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 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: Method and apparatus for changing the state of operation of a fuel cell, such as starting the fuel cell up or shutting the fuel cell down, are disclosed. An idle load is applied to the fuel cell when the cell temperature is between about normal operating temperature and a transition temperature, and fuel and oxidizer are supplied to the fuel cell commensurate with the power delivered to the idle load. Below the transition temperature, purging/passivation procedures known in the art can be followed, and an open or dummy load applied to the fuel cell. At normal operating temperature or above a service load is applied to the fuel cell.

Abstract: Fuel mixing control arrangements are provided for fuel cell power plants (10) operating on multiple fuels (22, 24, 26). A fuel delivery system (16) supplies hydrogen-rich fuel (20) to the cell stack assembly (CSA) (12) after controlled mixing of a primary fuel (22) and at least a secondary fuel (24), each having a respective “equivalent hydrogen (H2) content”. The relative amounts of the primary fuel (22) and secondary fuel (24) mixed are regulated (18, 34, 36) to provide at least a minimum level (LL) of hydrogen-rich fuel having an equivalent hydrogen content sufficient for normal operation of the CSA (12). The primary fuel (22) is a bio-gas or the like having a limited, possibly variable, equivalent H2 content, and the secondary fuel (22) has a greater and relatively constant equivalent H2 content and is mixed with the primary fuel in an economic, constant relationship that assures adequate performance of the CSA (12). One or more parameters (IDC, P, V, E. C.