High efficiency thermoelectric generation

1. A thermoelectric power generating system comprising:

at least one thermoelectric assembly comprising:

at least one first heat exchanger in thermal communication with at least a first portion of a first working fluid, the first portion of the first working fluid flowing through the at least one thermoelectric assembly;

a plurality of thermoelectric elements in thermal communication with the at least one first heat exchanger; and

at least one second heat exchanger in thermal communication with the plurality of thermoelectric elements and with a second working fluid flowing through the at least one thermoelectric assembly, the second working fluid cooler than the first working fluid;

at least one heat exchanger portion configured to have at least some of the first portion of the first working fluid flow through the at least one heat exchanger portion after having flowed through the at least one thermoelectric assembly, the at least one heat exchanger portion configured to recover heat from the at least some of the first portion of the first working fluid;

at least one bypass conduit; and

at least one valve configured to selectively allow at least the first portion of the first working fluid to flow through the at least one first heat exchanger and to selectively allow at least a second portion of the first working fluid to flow through the bypass conduit, wherein the at least one heat exchanger portion is configured to receive at least some of the second portion of the first working fluid after having flowed through the at least one bypass conduit and to recover heat from the at least some of the second portion of the first working fluid.

2. The system of claim 1 , wherein the at least one heat exchanger portion comprises a first conduit through which the at least some of the first portion of the first working fluid flows and a second conduit through which at least a portion of the second working fluid flows, wherein the second conduit is in thermal communication with the first conduit such that the portion of the second working fluid receives heat from the at least some of the first portion of the first working fluid.

3. The system of claim 1 , wherein the at least one thermoelectric assembly is configured to convert high-temperature heat of the first working fluid to electricity such that low-temperature heat of the first working fluid is received by the at least one heat exchanger portion.

4. The system of claim 1 , wherein the at least one valve comprises a proportional valve.

5. The system of claim 1 , wherein the at least one valve comprises at least one component that is sensitive to high temperatures, and the at least one component is in thermal communication with the second working fluid.

6. The system of claim 1 , wherein the first working fluid comprises exhaust gas from an engine, and the at least one heat exchanger portion is further configured to use the recovered heat from the at least some of the second portion of the first working fluid to warm an engine block of the engine.

7. The system of claim 1 , further comprising at least one second heat exchanger portion configured to have at least the first portion of the first working fluid flow through the at least one second heat exchanger portion prior to flowing through the at least one thermoelectric assembly, wherein the at least one second heat exchanger portion is configured to reduce a temperature of the first portion of the first working fluid.

8. The system of claim 1 , wherein the first working fluid comprises exhaust gas from an engine, and the at least one thermoelectric assembly is integrated into at least one muffler of the engine.

9. The system of claim 1 , wherein the first working fluid comprises exhaust gas from an engine, and the at least one heat exchanger portion is further configured to use the recovered heat from the at least some of the second portion of the first working fluid to warm a passenger compartment of a vehicle comprising the engine.

10. The system of claim 1 , wherein the first working fluid comprises exhaust gas from an engine, and the at least one heat exchanger portion is further configured to use the recovered heat from the at least some of the second portion of the first working fluid to warm a catalytic converter of the engine.

11. The system of claim 1 , further comprising:

a first flow path with a first flow resistance, the first flow path through the at least one thermoelectric assembly;

at least one conduit comprising at least one wall portion having a plurality of perforations, wherein the first flow path extends through the plurality of perforations into the at least one thermoelectric assembly; and

a second flow path with a second flow resistance lower than the first flow resistance, the second flow path bypassing the at least one thermoelectric assembly.

12. The system of claim 11 , wherein the at least one conduit further comprises an inlet and an outlet, and the at least one valve is between the inlet and the outlet.

13. The system of claim 11 , wherein the at least one wall portion comprises a first wall portion with a first plurality of perforations and a second wall portion with a second plurality of perforations, the at least one valve between the first wall portion and the second wall portion, the first flow path extending through the first plurality of perforations outwardly from the at least one conduit and through the second plurality of perforations inwardly to the at least one conduit, the second flow path not extending through the first plurality of perforations and not through the second plurality of perforations.