Methods and systems for efficient operation of integrated fuel cell-fuel reformer systems
AssigneeNuvera Fuel Cells, LLC
InventorJames C. Cross, III
Life of this patent
Estimating the term…
Abstract
Methods and related systems for determining an efficient operating state for an integrated fuel cell/fuel reformer power system have been developed. Such a method forms the basis of a control strategy for an integrated system. The method describes optimization of the efficiency of operation of a power system comprising a fuel processor and a fuel cell operating in an integrated way. Maps of the operating properties of the system components are determined by experiment. For any desired power level, a unique vector of control setpoints can be calculated from these known properties of the subcomponents and the system, which vector of values can be used to set the values of system controls to a state that optimizes the system efficiency at the specified power output.
Claims18
A method of operating an integrated power system comprising a fuel cell and a fuel processor at a required power output, comprising:
- determining a plurality of operating points for the fuel cell for providing the required power output, each operating point comprising operational values for fuel cell voltage, fuel cell current, input hydrogen, and bypass hydrogen;
- determining a plurality of operating points for the fuel processor for providing the input hydrogen to the fuel cell at the required power output, each operating point for the fuel processor corresponding to an operating point for the fuel cell and comprising operational values for the fuel input, hydrogen output, and input of bypass hydrogen from the fuel cell;
- calculating the total system efficiency for each operating point for the fuel cell and corresponding operating point for the fuel processor, wherein total system efficiency is calculated as power level divided by the fuel input;
- based upon the total system efficiency calculation, selecting an operating point for operation of the integrated power system;
- and
- operating the integrated system at the selected fuel cell operating point and fuel processor operating point.
A method of operating an integrated power system comprising a fuel cell and a fuel processor, the method comprising the steps of:
- a. constructing an operating map of the fuel cell, wherein said map contains one or both of:
- i. values of hydrogen supply required for production of a desired level of power, and
- ii. calculation procedures for determining such values of hydrogen supply using stored data;
- b. constructing an operating map of the fuel processor, wherein said map contains one or both of:
- i. values of fuel supply required for production of the level of hydrogen production required, given a level of anode bypass gas, and
- ii. calculation procedures for determining such values of fuel supply, using stored data;
- c. specifying a required level of power output, (P);
- d. determining from the operating map of the fuel cell a set of values of current (I) and voltage (V) that will produce the specified level of power output;
- e. calculating the required rate of hydrogen supply (H), and the associated values of anode gas bypass (A), for each of these sets of values of I and V;
- f. determining from the operating map of the fuel processor, given the rate of hydrogen supply (H) required by the power output and the associated rate of anode gas return (A), the rate of fuel to feed to the processor;
- g. determining the overall system efficiency for each of the set of values of F, H, and A, by one method selected from calculating the efficiency using the formula:
- efficiency=P/F, and of noting the value of F;
- h. finding by calculation the highest efficiency available along the curve described by the set of points, or equivalently finding the lowest value of fuel consumption (F);
- and
- i. selecting the values of I, V and F associated with that point to set the operating parameters of the integrated system.
A method of operating an integrated power system comprising a fuel cell and a fuel processor, the method comprising the steps of:
- a. specifying a desired level of power output (P);
- b. determining a set of values for current (I) and voltage (V) that will produce the specified level of power output for the fuel cell;
- c. calculating the rate of hydrogen supply (H), and the associated rate of anode gas return (A), for each of the paired values if I and V;
- d. determining, given the required rate of hydrogen supply (H) and the associated rate of anode gas return (A), a rate of fuel feed (F) to the fuel processor;
- e. determining overall system efficiency for each set of values of I, V, and the associated values A, H and F, for a particular desired power level P;
- f. determining an optimal efficiency point among the system efficiency values at the same desired power level P;
- and
- g. selecting the values of I, V, and F associated with the optimal efficiency point to set the operating parameters of the integrated system.
Dependencies are inferred from the claim text.