Abstract: A method to control the heat balance of fuel cell stacks in a fuel cell system, the fuel cell system including at least one fuel cell unit including fuel cell stacks, whose fuel cells include an anode side and a cathode side, as well as an electrolyte interposed therebetween, and a recuperator unit for heat exchange for preheating a supply flow of the cathode side. In the method, a desired portion is separated from the fuel exhaust flow coming from the anode side and adapted to be mixed with the cathode side exit flow before said recuperator unit. Also provided is a fuel cell system implementing the method.
Abstract: A fuel cell system arrangement is disclosed for controlling an Oxygen-to-Carbon (O/C) relationship by providing water to an anode side fuel recirculation, pumping the provided water to facilitate a water flow, and evaporating water from the facilitated water flow for generating pressurized steam having at least the motive pressure for a steam jet-ejector. The at least one steam jet-ejector can inject at least part of the steam to the fuel cell system, and entrain part of an essentially low pressure anode exhaust gas stream in the anode side gas recirculation and compress the gas mixture to an intermediate pressure of the fuel feed-in stream for controlling the Oxygen-to-Carbon (O/C) relationship in the fuel side of the fuel cell system.
Abstract: An exemplary cooling arrangement for high temperature fuel cell system for substantially reducing the amount of purge gas in a system shutdown situation includes a fuel cell having an anode side, a cathode side, and an electrolyte between the anode side and the cathode side. The cooling arrangement includes a coolant source capable of providing coolant to be used in a cooling process of the high temperature fuel cell system during the system shutdown situation, and a cooling structure in connection with the coolant source arranged in a thermal effect area of the fuel cell stacks. The arrangement also includes the vessel that feeds the coolant into the cooling structure from the coolant source, a heat exchanger that exhausts used coolant from the cooling structure, and an actuating device that uses a triggering force to trigger a coolant flow in the cooling structure, when the system shutdown situation has started.
Abstract: Exemplary embodiments are directed to a fuel cell system that is fed fuel and provided information on the fed fuel. The system generates information about fuel utilization in the fuel cells and oxygen to carbon ratio (O/C ratio) in the fuel cell system process and includes features for controlling a loading of the fuel cells. The fuel cell system also includes a first closed loop controller for controlling the feeding of fuel by taking into account the fuel utilization information as process feedback information, and by implementing a constraint function taking control of O/C ratio by restricting output of the first controller when said O/C ratio deviates from an allowed range, and a second controller for controlling active fuel cell loading by implementing a constraint function taking control of fuel utilization restricting output of the second controller when said fuel utilization deviates from an allowed range.
Abstract: An exemplary arrangement and method for controlling operating conditions of a fuel cell device are disclosed. The fuel cell device having plural fuel cells, each including an anode side, a cathode side, an electrolyte between the anode side and the cathode side, and being arranted in a stack. The control arrangement includes at least one controllable electrical heater configured to produce controllable heat quantities, at least two controllers that control fuel cell quantities including at least a portion of air flowing to the fuel cells and heat applied to the stack environment. The controllable heat quantities and controllable fuel cell quantities are controlled to meet a target value. The fuel cell device includes a low level high speed controller configured to control at least one controllable electrical heater to operate the heater as a buffer for excess energy of the fuel cell device.