Abstract:
An improved performance and cost-effective control for an automatic motor vehicle HVAC system in which the system variables are controlled without regard to a measured in-car temperature during steady-state conditions, and in which the steady-state control is modified during transient conditions by a time-dependent open-loop compensation term, INCAR. The initial value of INCAR, a target value and a time rate of change are initialized as a function of environmental and system conditions at the onset of the transient condition. At ignition key-on, INCAR is initialized in accordance with an estimate of the in-car temperature, and exponentially adjusted toward a predetermined reference temperature (target), such as 75°, at a rate determined by the initial temperature, preferably with adjustments being made for door opening and closing. At ignition key-off, INCAR is initialized at its current value, and exponentially adjusted toward a target temperature based on ambient air temperature and solar loading, to form a basis for in-car temperature initialization at the next ignition key-on. For extended key-off periods, system temperature sensors may be used to initialize INCAR.
Abstract:
A fuel cell assembly (50) having manifold means for providing fuel and air to, and removing spent fuel and air from, flow passageways across the anodes (16) and cathodes (18) in a fuel cell stack. The sizes and proportions of the supply (23',33') and return (27',41') manifolds are optimized, and the total cross-sectional area of the return manifold is about twice the cross-sectional area of the supply manifold. The pressure drop in the manifolds is less than about one-quarter of the total pressure drop across the anode and cathode passageways in the stack, which ratio may be attained by adjusting the thickness of the anode and cathode spacers (38') and/or the size of the chimneys. Widthwise uniformity of flow across the anodes and cathodes is improved by forming each of the manifolds as a plurality of smaller, parallel flow conduits.
Abstract:
An emergency shutdown apparatus for a solid-oxide fuel cell system, including a fuel cell stack, comprises a reservoir containing a reducing fluid, a valve enabling or preventing flow of the reducing fluid from the reservoir to the fuel cell stack, a timing circuit operating and controlling the valve, and a battery powering the timing circuit. The apparatus for an emergency system shutdown is able to operate independently of the main power plant and does not require any active control from the solid-oxide fuel cell system. The disclosed apparatus is entirely a stand-alone component that may be added to any conventional solid-oxide fuel cell system. The apparatus in accordance with the invention can be recharged, allowing the same hardware to be used over and over, however, a disposable unit could be used if found to be desirable.
Abstract:
An SOFC stack system including a reformer and fuel flow arrangement permitting optimized fuel reforming at all power load levels between 0% and 100%. A portion of the anode tail gas is combined with fresh air and fuel. The mixture is sent to a main reformer configured for endothermic reforming. Reformate is sent through a hydrocarbon cracker that breaks any hydrocarbons in the reformate into methane before the reformate enters the stack. At 100% load, there is no reforming in the main reformer; all of the fuel is internally reformed within the stack. At 0% load, all of the fuel is reformed in the main reformer. At loads between 0% and 100%, reforming is a mixture of endothermic reforming in the main reformer and internal reforming of methane within the stack. This strategy allows highest fuel processing efficiencies available through the full range of stack operation.
Abstract:
A fuel cell assembly (50) having manifold means for providing fuel and air to, and removing spent fuel and air from, flow passageways across the anodes (16) and cathodes (18) in a fuel cell stack. The sizes and proportions of the supply (23',33') and return (27',41') manifolds are optimized, and the total cross-sectional area of the return manifold is about twice the cross-sectional area of the supply manifold. The pressure drop in the manifolds is less than about one-quarter of the total pressure drop across the anode and cathode passageways in the stack, which ratio may be attained by adjusting the thickness of the anode and cathode spacers (38') and/or the size of the chimneys. Widthwise uniformity of flow across the anodes and cathodes is improved by forming each of the manifolds as a plurality of smaller, parallel flow conduits.
Abstract:
A Combined Heat and Power System ("CHPS") includes a solid oxide fuel cell system and a vapor compression cycle heat pump. The CHPS improves the overall efficiency of a CHP system with respect to conversion of fuel energy to usable heat and electrical energy without need for an accessory burner-heat exchanger system. The compressor motor of the heat pump is powered by a portion of the electricity generated by the SOFC, and the thermal output of the heat pump is increased by abstraction of heat from the SOFC exhaust. This integration allows for novel and complementary operation of each type of system, with the benefits of improved overall fuel efficiency for the improved CHP system.
Abstract:
A Combined Heat and Power System ("CHPS") includes a solid oxide fuel cell system and a vapor compression cycle heat pump. The CHPS improves the overall efficiency of a CHP system with respect to conversion of fuel energy to usable heat and electrical energy without need for an accessory burner-heat exchanger system. The compressor motor of the heat pump is powered by a portion of the electricity generated by the SOFC, and the thermal output of the heat pump is increased by abstraction of heat from the SOFC exhaust. This integration allows for novel and complementary operation of each type of system, with the benefits of improved overall fuel efficiency for the improved CHP system.