Abstract: A technique that is usable with a fuel cell system includes using a stored energy source to supply power to a load, placing a fuel cell stack in an inactive state during the using, returning the fuel cell stack to an active state to recharge the stored energy source and returning the fuel cell stack to the inactive state in response to the completion of the charging. Another technique may include determining a system power demand in the fuel cell system and may include determining whether a fuel cell stack is exhibiting unstable behavior during an interval of low power demand from the fuel cell stack. In response to these determinations, the fuel cell stack is isolated from the fuel cell system. Another technique includes pulsing a fuel processor of the fuel cell system with an input reactant flow to minimize at least one of a power loss and a startup time of the fuel processor.

Abstract: A cogeneration fuel cell system and associated methods of operation are provided that accommodate a demand for heat as well as a demand for electric power. The system is operated among various modes to balance heat and power demand signals. In general, a fuel cell system is coupled to a power sink and a heat sink, and a controller is adapted to respond to data signals from the power sink and the heat sink. As examples, such data signals from the heat sink may include a temperature indication or a heat demand signal (such as from a thermostat), and such data signals from the power sink may include a voltage or current measurement, an electrical power demand signal, or an electrical load.

Abstract: The present invention provides a method for enabling qualification of at least a portion of a fuel cell system. The method includes electronically obtaining at least one result of a test of the at least a portion of a fuel cell system and electronically comparing the at least one result to at least one qualifying criteria.

Abstract: The present invention provides a method for enabling qualification of at least a portion of a fuel cell system. The method includes electronically obtaining at least one result of a test of the at least a portion of a fuel cell system and electronically comparing the at least one result to at least one qualifying criteria.

Abstract: A technique that is usable with a fuel cell stack includes providing a fuel flow to the stack, changing the fuel flow and observing a response of at least one cell voltage of the stack to the change in the fuel flow. An efficiency of the stack is regulated based on the observation.

Abstract: A cogeneration fuel cell system and associated methods of operation are provided that accommodate a demand for heat as well as a demand for electric power. The system is operated among various modes to balance heat and power demand signals. In general, a fuel cell system is coupled to a power sink and a heat sink, and a controller is adapted to respond to data signals from the power sink and the heat sink. As examples, such data signals from the heat sink may include a temperature indication or a heat demand signal (such as from a thermostat), and such data signals from the power sink may include a voltage or current measurement, an electrical power demand signal, or an electrical load.

Abstract: A cogeneration fuel cell system and associated methods of operation are provided that accommodate a demand for heat as well as a demand for electric power. The system is operated among various modes to balance heat and power demand signals. In general, a fuel cell system is coupled to a power sink and a heat sink, and a controller is adapted to respond to data signals from the power sink and the heat sink. As examples, such data signals from the heat sink may include a temperature indication or a heat demand signal (such as from a thermostat), and such data signals from the power sink may include a voltage or current measurement, an electrical power demand signal, or an electrical load.

Abstract: A technique that is usable with a fuel cell stack includes providing a fuel flow to the stack, changing the fuel flow and observing a response of at least one cell voltage of the stack to the change in the fuel flow. An efficiency of the stack is regulated based on the observation.

Abstract: A technique that is usable with a fuel cell stack includes providing a fuel flow to the stack, changing the fuel flow and observing a response of at least one cell voltage of the stack to the change in the fuel flow. An efficiency of the stack is regulated based on the observation.

Abstract: A preconditioning technique is disclosed to reduce the time that is needed to incubate membranes of a fuel cell stack. In this manner, the technique includes providing gas flows to an anode region and a cathode region of the fuel cell during a preconditioning time interval without causing electrochemical reactions to occur in the fuel cell. Subsequently, during an incubation time interval, electrochemical reactions occur in the fuel cell to incubate the membranes.

Abstract: A cogeneration fuel cell system and associated methods of operation are provided that accommodate a demand for heat as well as a demand for electric power. The system is operated among various modes to balance heat and power demand signals. In general, a fuel cell system is coupled to a power sink and a heat sink, and a controller is adapted to respond to data signals from the power sink and the heat sink. As examples, such data signals from the heat sink may include a temperature indication or a heat demand signal (such as from a thermostat), and such data signals from the power sink may include a voltage or current measurement, an electrical power demand signal, or an electrical load.

Abstract: The invention provides a fuel cell incorporating a thermal management scheme and associated methods of operation. In one aspect, a fuel cell system includes a frame enclosing a fuel cell, a coolant flow circuit and a heat exchanger. The frame has at least one external panel mounted thereon to enclose the fuel cell, a coolant circuit and heat exchanger. The coolant flow circuit is adapted to circulate a coolant through the heat exchanger and across a surface of the fuel cell to provide heat transfer between the fuel cell and the heat exchanger. An inlet orifice and an outlet orifice are coupled to the frame and to the heat exchanger, and are adapted to provide an export flow circuit from the inlet orifice through the heat exchanger to the outlet orifice. An insulating material is fixed to a surface of the external panel.

Abstract: A cogeneration fuel cell system and associated methods of operation are provided that accommodate a demand for heat as well as a demand for electric power. The system is operated among various modes to balance heat and power demand signals. In general, a fuel cell system is coupled to a power sink and a heat sink, and a controller is adapted to respond to data signals from the power sink and the heat sink. As examples, such data signals from the heat sink may include a temperature indication or a heat demand signal (such as from a thermostat), and such data signals from the power sink may include a voltage or current measurement, an electrical power demand signal, or an electrical load.

Abstract: A cogeneration fuel cell system and associated methods of operation are provided that accommodate a demand for heat as well as a demand for electric power. The system is operated among various modes to balance heat and power demand signals. In general, a fuel cell system is coupled to a power sink and a heat sink, and a controller is adapted to respond to data signals from the power sink and the heat sink. As examples, such data signals from the heat sink may include a temperature indication or a heat demand signal (such as from a thermostat), and such data signals from the power sink may include a voltage or current measurement, an electrical power demand signal, or an electrical load.

Abstract: A cogeneration fuel cell system and associated methods of operation are provided that accommodate a demand for heat as well as a demand for electric power. The system is operated among various modes to balance heat and power demand signals. In general, a fuel cell system is coupled to a power sink and a heat sink, and a controller is adapted to respond to data signals from the power sink and the heat sink. As examples, such data signals from the heat sink may include a temperature indication or a heat demand signal (such as from a thermostat), and such data signals from the power sink may include a voltage or current measurement, an electrical power demand signal, or an electrical load.

Abstract: A technique that is usable with a fuel cell stack includes providing a fuel flow to the stack, changing the fuel flow and observing a response of at least one cell voltage of the stack to the change in the fuel flow. An efficiency of the stack is regulated based on the observation.

Abstract: The present invention provides a method for enabling qualification of at least a portion of a fuel cell system. The method includes electronically obtaining at least one result of a test of the at least a portion of a fuel cell system and electronically comparing the at least one result to at least one qualifying criteria.