Method of optimizing operating efficiency of fuel cells

• US 7,575,822 B2
• Filed: 06/14/2004
• Issued: 08/18/2009
• Est. Priority Date: 04/09/2003
• Status: Active Grant

• Current Assignee: Bloom Energy Corporation
• Original Assignee: Bloom Energy Corporation
• Inventors: Gottman, Matthias, Sridhar, K. R., Venkataraman, Swaminathan, Mitlitsky, Fred
• Primary Examiner(s): Maples; John S
• Application Number:
  US10/866,238
• Publication Number:
  US 20040224193A1
• Time in Patent Office: 1,891 Days
• Field of Search: None
• US Class Current: 429/444
• CPC Class Codes: H01M 2008/1293 Fuel cells with solid oxide electrolytes
• CPC Class Codes: H01M 2008/147 Fuel cells with molten carbonates
• CPC Class Codes: H01M 2250/40 Combination of fuel cells with other energy production systems
• CPC Class Codes: H01M 2250/405 Cogeneration of heat or hot water
• CPC Class Codes: H01M 8/04007 related to heat exchange
• CPC Class Codes: H01M 8/04052 Storage of heat in the fuel cell system
• CPC Class Codes: H01M 8/04925 Power, energy, capacity or load
• CPC Class Codes: H01M 8/0494 of fuel cell stacks
• CPC Class Codes: H01M 8/04992 characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence
• CPC Class Codes: H01M 8/0656 by electrochemical means H01M8/065 takes precedence
• CPC Class Codes: H01M 8/1011 Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
• CPC Class Codes: H01M 8/184 Regeneration by electrochemical means
• CPC Class Codes: Y02B 90/10 Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A method of operating a fuel cell electrochemical system includes receiving at least one of a cost of electricity and a cost of fuel and adjusting at least one of an operating efficiency and throughput of the fuel cell based on the at least one of the received cost of electricity and the received cost of fuel.

Claims

1. A method of operating a fuel cell electrochemical system, comprising:

operating a fuel cell in a fuel cell mode to generate electricity;

receiving at least one of a cost of electricity and a cost of fuel;

adjusting an operating efficiency and throughput of the fuel cell based on the at least one of the received cost of electricity and the received cost of fuel; and

storing heat generated by the fuel cell operating in the fuel cell mode;

wherein the at least one of operating efficiency and throughput of the fuel cell is adjusted for operation in the fuel cell mode; and

wherein the step of adjusting comprises adjusting the operating efficiency in the fuel cell mode below an optimum efficiency and adjusting the throughput of the fuel cell to be about equal to an optimum throughput when the cost of electricity is higher than a predetermined cost or the cost of fuel is lower than a predetermined cost.

2. A method of operating a fuel cell electrochemical system, comprising:

operating a fuel cell in a fuel cell mode to generate electricity;

receiving at least one of a cost of electricity and a cost of fuel;

adjusting an operating efficiency and throughput of the fuel cell based on the at least one of the received cost of electricity and the received cost of fuel; and

providing additional heat to the fuel cell operating in the fuel cell mode;

wherein the at least one of operating efficiency and throughput of the fuel cell is adjusted for operation in the fuel cell mode; and

wherein the step of adjusting comprises adjusting the operating efficiency in the fuel cell mode to be about equal to an optimum efficiency and adjusting the throughput of the fuel cell to be below an optimum throughput when the cost of electricity is lower than a predetermined cost or the cost of fuel is higher than a predetermined cost.

3. The method of claim 2, wherein the additional heat is provided to the fuel cell from heat stored during fuel cell operation in the fuel cell mode at an efficiency below the optimum efficiency.

4. The method of claim 2, wherein the additional heat is provided to the fuel cell from at least one of an external renewable heat source, an external non-renewable heat source, and heat from balance of plant components of the electrochemical system.

5. A method of operating a fuel cell electrochemical system, comprising:

receiving at least one of a cost of electricity and a cost of fuel;

adjusting at least one of an operating efficiency and throughput of a fuel cell based on the at least one of the received cost of electricity and the received cost of fuel;

storing heat generated by the fuel cell when the fuel cell operates at an efficiency lower than an optimum efficiency; and

providing the stored heat to the fuel cell when the fuel cell operates at an efficiency that is about equal to the optimum efficiency.

6. The method of claim 5, wherein:

the heat is stored when the fuel cell operates at an efficiency lower than an optimum efficiency in at least one of fuel cell and electrolysis modes; and

the heat is provided when the fuel cell operates at an efficiency that is about equal to the optimum efficiency in at least one of fuel cell and electrolysis modes.

7. The method of claim 6, wherein:

the heat is provided when the fuel cell operates in the fuel cell mode to increase a thermally sustainable voltage of the fuel cell;

or

the heat is provided when the fuel cell operates in the electrolysis mode to decrease a thermally sustainable voltage of the fuel cell.

8. The method of claim 5, wherein the step of adjusting at least one of an operating efficiency and throughput comprises adjusting the operating efficiency.

9. The method of claim 5, wherein the step of adjusting at least one of an operating efficiency and throughput comprises adjusting the throughput.

10. The method of claim 5, wherein the step of adjusting at least one of an operating efficiency and throughput comprises adjusting the operating efficiency and the throughput.

11. A fuel cell electrochemical system, comprising:

a fuel cell; and

a first means for adjusting at least one of operating efficiency and throughput of the fuel cell based on at least one of a received cost of electricity and a received cost of fuel; and

a second means for storing heat generated by the fuel cell operating in the fuel cell mode;

wherein the first means is a means for adjusting the operating efficiency of the fuel cell in the fuel cell mode below an optimum efficiency to increase an electricity generation rate of the fuel cell when the cost of electricity is higher than a predetermined cost or the cost of fuel is lower than a predetermined cost.

12. A fuel cell electrochemical system, comprising:

a fuel cell; and

a first means for adjusting at least one of operating efficiency and throughput of the fuel cell based on at least one of a received cost of electricity and a received cost of fuel; and

a second means for providing additional heat to the fuel cell operating in the fuel cell mode;

wherein the first means is a means for adjusting the operating efficiency of the fuel cell in the fuel cell mode to be about equal to an optimum efficiency to decrease an electricity generation rate of the fuel cell when the cost of electricity is lower than a predetermined cost or the cost of fuel is higher than a predetermined cost.