Thermoelectric generator and fuel cell for electric power co-generation

• US 8,568,938 B2
• Filed: 08/28/2009
• Issued: 10/29/2013
• Est. Priority Date: 08/28/2009
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Gao, Lijun, Liu, Shengyi, Chien, Chin-Hsi, Roe, George M.
• Primary Examiner(s): Crepeau, Jonathan
• Application Number:
  US12/550,131
• Publication Number:
  US 20110048484A1
• Time in Patent Office: 1,523 Days
• Field of Search: None
• US Class Current: 429/436
• CPC Class Codes: H01M 8/04007 related to heat exchange
• CPC Class Codes: H01M 8/0432 Temperature; Ambient temperature
• CPC Class Codes: H01M 8/12 operating at high temperature, e.g. with stabilised ZrO2 electrolyte
• CPC Class Codes: H01M 8/1246 the electrolyte consisting of oxides
• CPC Class Codes: H10N 10/00 Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects integrated devices or assemblies of multiple devices H10N19/00
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

Systems and methods of electric power generation are disclosed. A particular method includes generating electric power using a fuel cell. The method also includes generating additional electric power using a thermoelectric generator (TE) by routing exhaust from the fuel cell to a hot side of the TE and routing fuel cell intake gases to a cold side of the TE. The method also includes preheating the fuel cell intake gases by routing the fuel cell intake gases from the TE through a heat exchanger (HX).

Claims

1. A system, comprising:

a fuel cell having a fuel cell inlet to receive preheated intake gas and a fuel cell outlet to release hot fuel cell exhaust;

a heat exchanger (HX) having a HX cold-side inlet, a HX cold-side outlet, a HX hot-side inlet and a HX hot-side outlet; and

a thermoelectric generator (TE) to generate electric energy based on a temperature differential between a TE cold-side and a TE hot-side, the TE comprising;

a TE cold-side inlet to receive intake gases;

a TE cold-side outlet coupled to the HX cold-side inlet;

a TE hot-side inlet coupled to the fuel cell outlet to receive the hot fuel cell exhaust;

a TE hot-side outlet coupled to the HX hot-side inlet to provide the hot fuel cell exhaust received at the TE hot-side inlet to the HX hot-side inlet; and

a bypass control valve between the fuel cell outlet and the HX hot-side inlet, wherein the bypass control valve is adjustable to control an inlet temperature of the preheated intake gas received at the fuel cell inlet.

2. The system of claim 1, wherein the bypass control valve adjusts the inlet temperature of the preheated intake gas by enabling a portion of the hot fuel cell exhaust to bypass the TE hot-side inlet, wherein the portion of the hot fuel cell exhaust that bypasses the TE hot-side inlet is mixed with an output of the TE hot-side outlet and provided to the HX hot-side inlet.

3. The system of claim 2, further comprising a controller coupled to the bypass control valve, wherein, during operation, the controller adjusts an open angle of the bypass control valve to change the inlet temperature of the preheated intake gas, wherein the portion of the hot fuel cell exhaust that bypasses the TE hot-side inlet is controlled based on the open angle of the bypass control valve.

4. The system of claim 1, wherein the intake gases include an oxidizer.

5. The system of claim 1, wherein the fuel cell comprises a high temperature fuel cell.

6. The system of claim 1, wherein the fuel cell comprises a solid oxide fuel cell (SOFC).

7. The system of claim 1, wherein the TE comprises a radial element in which the hot fuel cell exhaust flows from the TE hot-side inlet to the TE hot-side outlet in parallel with the intake gases flowing from the TE cold-side inlet to the TE cold-side outlet.

8. The system of claim 1, wherein the HX comprises a counter-flow heat exchanger.

9. The system of claim 3, wherein the controller adjusts power output generated by the TE by adjusting the bypass control valve.

10. A platform, comprising:

a fuel cell to generate electric power;

a thermoelectric generator (TE) to generate additional electric power using a temperature differential between fuel cell exhaust from the fuel cell and fuel cell intake gases;

a heat exchanger (HX) to preheat the fuel cell intake gases before the fuel cell intake gases are provided to the fuel cell by recovering heat from the fuel cell exhaust after the fuel cell exhaust has passed through the TE; and

a controller to control a sum of the electric power and the additional electric power by controlling a bypass valve, wherein the bypass valve enables a portion of the fuel cell exhaust to bypass the TE, wherein the portion of the fuel cell exhaust that bypasses the TE is determined by the bypass valve, and wherein the portion of the fuel cell exhaust that bypasses the TE is provided to the HX along with the fuel cell exhaust received at the HX after passing through the TE.

11. The platform of claim 10, further comprising a fuel storage system to store fuel to be used by the fuel cell.

12. The platform of claim 10, further comprising an oxidizer storage system to store oxidizer to be used by the fuel cell.

13. The platform of claim 10, wherein the platform includes a mobile platform including at least one of a watercraft, an aircraft, a space craft, and a land-based vehicle.

14. The platform of claim 10, wherein the portion of the fuel cell exhaust that bypasses the TE is determined by an open angle of the bypass valve.

15. A method, comprising:

generating electric power using a fuel cell, wherein the fuel cell comprises an anode and a cathode, wherein the anode generates a first exhaust, and wherein the cathode generates a second exhaust;

generating additional electric power using a thermoelectric generator (TE) by;

routing the first exhaust from the anode of the fuel cell to a hot-side inlet of the TE, wherein the second exhaust is not routed to the hot-side inlet of the TE; and

routing fuel cell intake gases to a cold-side inlet of the TE;

preheating the fuel cell intake gases at the TE; and

controlling a temperature of the fuel cell intake gases by adjusting a bypass valve, wherein the fuel cell intake gases are further preheated by enabling a portion of the first exhaust to bypass the hot-side inlet of the TE via the bypass valve and mixing the portion of the first exhaust with the fuel cell intake gases.

16. The method of claim 15, the method further comprising:

routing the first exhaust from a hot-side outlet of the TE to a hot-side inlet of a heat exchanger (HX);

routing the fuel cell intake gases from a cold-side outlet of the TE to a cold-side inlet of the HX to recover additional heat from the first exhaust received from the hot-side outlet of the TE; and

preheating the fuel cell intake gases at the HX prior to mixing the fuel cell intake gases with the portion of the first exhaust.

17. The method of claim 15, wherein the portion of the first exhaust that is mixed with the fuel cell intake gases is controlled by adjusting an open angle of the bypass valve.

18. The method of claim 15, wherein a temperature of the first exhaust before entering the hot side inlet of the TE is between about 600 degrees C. and about 800 degrees C.

19. The method of claim 15, wherein a temperature of the fuel cell intake gases before entering the TE is less than about 50 degrees C.

20. The method of claim 15, further comprising:

generating additional electric power using a second TE by;

routing the second exhaust from the cathode of the fuel cell to a hot-side inlet of the second TE, wherein the first exhaust is not routed to the hot-side inlet of the second TE; and

routing second fuel cell intake gases to a cold-side inlet of the second TE;

preheating the second fuel cell intake gases at the second TE; and

controlling a temperature of the second fuel cell intake gases by adjusting a second bypass valve, wherein the second fuel cell intake gases are further preheated by enabling a portion of the second exhaust to bypass the hot-side inlet of the second TE via the bypass valve and mixing the portion of the second exhaust with the second fuel cell intake gases.

21. A method comprising:

generating electric power using a fuel cell, wherein the fuel cell comprises an anode and a cathode, wherein the anode generates a first exhaust, and wherein the cathode generates a second exhaust;

generating additional electric power using a thermoelectric generator (TE) by;

routing the second exhaust from the cathode of the fuel cell to a hot-side inlet of the TE, wherein the first exhaust is not routed to the hot-side inlet of the TE; and

routing fuel cell intake gases to a cold-side inlet of the TE;

preheating the fuel cell intake gases at the TE; and

controlling a temperature of the fuel cell intake gases by adjusting a bypass valve, wherein the fuel cell intake gases are further preheated by enabling a portion of the second exhaust to bypass the hot-side inlet of the TE via the bypass valve and mixing the portion of the second exhaust with the fuel cell intake gases.

22. The method of claim 21, the method further comprising:

routing the first exhaust from a hot-side outlet of the TE to a hot-side inlet of a heat exchanger (HX);

routing the fuel cell intake gases from a cold-side outlet of the TE to a cold-side inlet of the HX to recover additional heat from the second exhaust received from the hot-side outlet of the TE; and

preheating the fuel cell intake gases at the HX prior to mixing the fuel cell intake gases with the portion of the second exhaust.