Thermoelectric-based power generation systems and methods

• US 8,656,710 B2
• Filed: 07/26/2010
• Issued: 02/25/2014
• Est. Priority Date: 07/24/2009
• Status: Expired due to Fees

• Current Assignee: Gentherm Incorporated
• Original Assignee: BSST LLC (Gentherm Incorporated)
• Inventors: Bell, Lon E., Crane, Douglas T., LaGrandeur, John, van Heerden, David
• Primary Examiner(s): Tran, Binh Q
• Application Number:
  US12/843,804
• Publication Number:
  US 20110067742A1
• Time in Patent Office: 1,310 Days
• Field of Search: 602/74, 602/75, 602/92, 602/98, 603/00, 603/20, 603/21, 603/24, 165/51, 165/52
• US Class Current: 60/320
• CPC Class Codes: F01N 2240/14 a fuel burner
• CPC Class Codes: F01N 2240/36 an exhaust flap
• CPC Class Codes: F01N 2410/02 in case of high temperature, e.g. overheating of catalytic reactor
• CPC Class Codes: F01N 2410/10 for reducing flow resistance, e.g. to obtain more engine power
• CPC Class Codes: F01N 3/043 without contact between liquid and exhaust gases
• CPC Class Codes: F01N 3/2013 using electric or magnetic heating means
• CPC Class Codes: F01N 3/2053 By-passing catalytic reactors, e.g. to prevent overheating
• CPC Class Codes: F01N 5/025 the device being thermoelectric generators
• CPC Class Codes: F28D 21/0003 the heat being recuperated from exhaust gases F28D21/0014 takes precedence
• CPC Class Codes: F28D 7/106 consisting of two coaxial conduits or modules of two coaxial conduits
• 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: H10N 10/13 characterised by the heat-exchanging means at the junction
• CPC Class Codes: H10N 10/17 characterised by the structure or configuration of the cell or thermocouple forming the device
• CPC Class Codes: Y02E 20/14 Combined heat and power generation [CHP]
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Some embodiments provide a waste heat recovery apparatus including an exhaust tube having a cylindrical outer shell configured to contain a flow of exhaust fluid; a first heat exchanger extending through a first region of the exhaust tube, the first heat exchanger in thermal communication with the cylindrical outer shell; a second region of the exhaust tube extending through the exhaust tube, the second region having a low exhaust fluid pressure drop; an exhaust valve operatively disposed within the second region and configured to allow exhaust fluid to flow through the second region only when a flow rate of the exhaust fluid becomes great enough to result in back pressure beyond an allowable limit; and a plurality of thermoelectric elements in thermal communication with an outer surface of the outer shell.

Claims

1. A power generation apparatus comprising:

at least one exhaust tube having a curved outer shell configured to contain a flow of exhaust fluid;

at least one heat exchanger extending through a first region of the at least one exhaust tube, the at least one heat exchanger in thermal communication with the curved outer shell;

a second region of the at least one exhaust tube extending through the at least one exhaust tube, the second region having a low exhaust fluid pressure drop;

at least one exhaust valve configured to allow exhaust fluid to flow through the second region only when a flow rate of the exhaust fluid becomes great enough to result in back pressure beyond an allowable limit; and

at least one thermoelectric element in thermal communication with an outer surface of the curved outer shell, the at least one thermoelectric element configured to accommodate thermal expansion of the at least one exhaust tube during operation of the power generation apparatus.

2. The apparatus of claim 1, further comprising at least one coolant conduit in thermal communication with the at least one thermoelectric element, the at least one coolant conduit comprising an inner tube and an outer tube in thermal communication with one another, wherein the outer tube has a greater diameter than the inner tube and comprises expansion joints configured to accommodate dimensional changes due to thermal expansion between the curved outer shell and the coolant conduit.

3. The apparatus of claim 1, wherein the at least one exhaust tube accommodates dimensional changes due to thermal expansion without expansion joints.

4. The apparatus of claim 1, further comprising at least one hot side shunt in substantial thermal contact with the curved outer shell and with the at least one thermoelectric element, the at least one hot side shunt comprising at least one portion that connects with the at least one thermoelectric element at a surface that is not parallel to the curved outer shell.

18. The power generation system of claim 1, wherein the at least one thermoelectric element comprises a plurality of thermoelectric elements surrounding a portion of the outer shell, wherein the plurality of thermoelectric elements comprises a first array of thermoelectric elements at a first end portion of the at least one exhaust tube and a second array of thermoelectric elements at a second end portion of the at least one exhaust tube, wherein during operation, the first end portion is at a higher temperature than is the second end portion, wherein the thermoelectric elements of the first array of thermoelectric elements are longer than the thermoelectric elements of the second array of thermoelectric elements.

19. The power generation system of claim 18, wherein the plurality of thermoelectric elements further comprises a third array of thermoelectric elements at a middle section of the at least one exhaust tube, wherein the third array of thermoelectric elements are shorter than the first array of thermoelectric elements and are longer than the second array of thermoelectric elements.

20. The power generation system of claim 18, wherein the length of the thermoelectric elements of the first array of thermoelectric elements is greater than or equal to about twice the length of the thermoelectric elements of the second array of thermoelectric elements.

21. The power generation system of claim 18, further comprising a plurality of hot side shunts attached to the outer shell and forming rings that surround the outer shell, in thermal contact with the outer shell, and in thermal contact with the plurality of thermoelectric elements.

22. The power generation system of claim 18, further comprising a plurality of cold side shunts in thermal contact with the plurality of thermoelectric elements, wherein a thermal gradient across each thermoelectric element of the plurality of thermoelectric elements is in a direction that is parallel to the outer shell.

23. The power generation system of claim 1, further comprising an inner sleeve which lines an inside surface of the at least one heat exchanger and separates gas flow between the at least one heat exchanger and the second portion.

5. A power generation apparatus comprising:

at least one exhaust tube configured to contain a flow of exhaust fluid, the exhaust tube having a high temperature end, a low temperature end opposite the high temperature end, and a middle section between the high temperature end and the low temperature end during operation of the waste heat recovery apparatus;

a first plurality of thermoelectric elements connected to the high temperature end, each thermoelectric element of the first plurality of thermoelectric elements having a first temperature differential along a first length of the thermoelectric element during operation;

a second plurality of thermoelectric elements connected to the middle section, each thermoelectric element of the second plurality of thermoelectric elements having a second temperature differential along a second length of the thermoelectric element during operation; and

a third plurality of thermoelectric elements connected to the low temperature end, each thermoelectric element of the third plurality of thermoelectric elements having a third temperature differential along a third length of the thermoelectric element during operation;

wherein the second length is longer than the third length; and

wherein the first length is longer than the second length.

6. The apparatus of claim 5, wherein the first length is greater than or equal to about twice the third length.

7. A power generation apparatus comprising:

at least one exhaust tube configured to contain a flow of exhaust fluid;

at least one bypass region extending through the at least one exhaust tube, the at least one bypass region having a low exhaust fluid pressure drop;

at least one coolant conduit configured to contain a flow of coolant within a first tube, the at least one coolant conduit comprising a second tube enclosing at least a portion of the first tube and a thermally conductive material disposed between the first tube and the second tube;

at least a first shunt extending from the at least one exhaust tube;

at least a second shunt extending from the at least one coolant conduit and in thermal communication with the second tube; and

at least one thermoelectric element thermally connected between the first shunt and the second shunt.

8. The apparatus of claim 7, wherein the first shunt is held tightly against the at least one exhaust tube by at least one band extending circumferentially around the perimeter of the at least one exhaust tube.

9. The apparatus of claim 8, wherein a shell of the exhaust tube comprises a conductive material, and wherein an electrical insulator is disposed between the at least one band and the shell of the exhaust tube.

10. A thermoelectric system comprising:

a plurality of thermoelectric elements;

at least one cooler side shunt and at least one hotter side shunt in thermal communication with at least one of the plurality of thermoelectric elements;

at least one heat exchanger in thermal communication and physically integrated with the at least one hotter side shunt; and

wherein the at least one heat exchanger is substantially electrically isolated from the at least one thermoelectric element.

11. The thermoelectric system of claim 10, wherein the at least one hotter side shunt is physically coupled with the at least one heat exchanger.

12. The thermoelectric system of claim 10, wherein the at least one heat exchanger is in close physical proximity to the plurality of thermoelectric elements, such that cooling power, heating power, or power generation from the thermoelectric elements that is lost from ducting and other components that slow warm up or light off is reduced.

13. The thermoelectric system of claim 10, wherein the at least one hotter side shunt extends into the heat exchanger.

14. The thermoelectric system of claim 10, wherein the at least one heat exchanger has a honeycomb structure.

15. The thermoelectric system of claim 10, further comprising at least one alternative flow path configured to reduce heat transfer between at least one working media and the at least one heat exchanger.

16. A catalytic converter comprising:

a plurality of thermoelectric systems of claim 10;

at least one controller configured to individually control each of the plurality of thermoelectric systems;

at least one sensor in communication with the at least one controller and configured to measure at least one operating parameter of the catalytic converter; and

wherein the at least one controller adjusts electrical power sent to the plurality of thermoelectric systems in response to the at least one operating parameter.

17. The thermoelectric system of claim 10, further comprising at least one combustor physically integrated into the at least one heat exchanger, wherein the at least one thermoelectric element is sandwiched between the at least one hotter side shunt and the at least one cooler side shunt.