Device for recovering and converting heat energy into electrical energy

Patent metadata

Field	Value
Publication number	US-9444371-B2
Application number	US-201314378267-A
Country	US
Kind code	B2
Filing date	Feb 13, 2013
Priority date	Feb 14, 2012
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A device for converting heat energy into electrical energy including cells, the cells including: a first cavity with one wall for contacting a heat source; a second cavity with one wall for contacting a cold source; a primary channel between the first cavity and the second cavity transporting a fluid as liquid drops, the primary channel providing transport of liquid fluid drops from the second cavity to the first cavity; at least one secondary channel between the first cavity and the second cavity transporting the fluid as a gas; a piezoelectric material provided in one of the cavities; and a fluid as a liquid and gas contained within the cell.

First claim

The invention claimed is:

1. A device for recovering and converting heat energy into electrical energy comprising at least one cell comprising:
a first cavity, at least one part of at least one wall of which is configured to contact a heat source;
a second cavity, at least one part of at least one wall of which is configured to contact a cold source;
a primary channel connecting the first cavity and the second cavity and configured to transport a fluid as liquid drops, the primary channel comprising means providing transport of liquid fluid drops from the second cavity to the first cavity;
at least one secondary channel connecting the first cavity and the second cavity and configured to transport the fluid as a gas;
at least one piezoelectric material provided in at least one of the first and second cavities;
a fluid as a liquid and gas contained within the cell;
at least one connector to connect the piezoelectric material to a device for recovering electrical energy generated by the piezoelectric material.

2. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein the means providing transport of liquid fluid drops includes an inner surface of the primary channel having a surface energy gradient oriented such that the liquid drops move from the second cavity to the first cavity.

3. The device for recovering and converting heat energy into electrical energy according to claim 2 , wherein the surface energy gradient is obtained by at least a first and a second surface portion successively arranged in this order between the second cavity and the first cavity, each of the portions having fluid-wettability properties, the wettability of the second portion being higher than that of the first portion.

4. The device for recovering and converting heat energy into electrical energy according to claim 3 , wherein the wettability properties are obtained by a layer of a material having the wettability properties and/or by structuring at least one portion of the inner surface.

5. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein the means providing transport of liquid fluid drops is of electrostatic type, or implement an electro-wetting phenomenon.

6. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein the primary channel has a flow cross section raising from the second cavity to the first cavity.

7. The device for recovering and converting heat energy into electrical energy according to claim 6 , wherein at least one part of an inner surface of the primary channel on a side of the second cavity has low fluid-wettability properties.

8. The device for recovering and converting heat energy into electrical energy according to claim 6 , wherein the primary channel has a flared shape.

9. The device for recovering and converting heat energy into electrical energy according to claim 6 , wherein the primary channel includes at least two successive segments having different flow cross sections, the flow cross sections increasing from the second cavity to the first cavity.

10. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein the flow cross section of the secondary channel prevents liquid drops from flowing through.

11. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein the secondary channel opens into the second cavity in proximity of one end of the primary channel opening into the second cavity.

12. The device for recovering and converting heat energy into electrical energy according to claim 1 , comprising at least a first cell and a second cell, and a transfer channel connecting the first cavity of the first cell to the second cavity of the second cell and the second cavity of the first cell to the first cavity of the second cell.

13. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein the walls of the first and second cavities are made of a heat conducting material, and wherein the device comprises an external element connecting the walls of the first and second cavities, the external element being of a heat insulating material.

14. The device for recovering and converting heat energy into electrical energy according to claim 1 , comprising a piezoelectric material in the first and second cavities.

15. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein the piezoelectric material contacts the wall configured to contact the heat source and/or the cold source.

16. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein the piezoelectric material includes a suspended membrane.

17. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein a diameter of the primary channel is lower than or equal to that of the liquid drops.

18. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein a volume of the first and/or second cavity is between 1 and 10 times a volume of a liquid drop.

19. The device for recovering and converting heat energy into electrical energy according to claim 1 , wherein the fluid is water or a solvent, or is a hydrofluoroether.

20. The device for recovering and converting heat energy into electrical energy according to claim 1 , comprising a plurality of adjacent cells, the cells being distributed with a variable density as a function of a local density of a heat flux emitted by the heat source.

21. A system for recovering and converting heat energy into electrical energy comprising a device for recovering and converting heat energy into electrical energy according to claim 1 , wherein a temperature of the heat source is such that a temperature of the wall of the first cavity contacting the same is at least equal to a boiling temperature of the fluid.

22. The system for recovering and converting energy into electrical energy according to claim 21 , wherein the heat source includes a portable electronic device.

Assignees

• Commissariat A L'Energie Atomique Et Aux Ene Alt
• St Microelectronics Crolles 2 Sas
• Commisariat A L'Energie Atomique Et Aux Energies Alternatives

Inventors

• Ollier Emmanuel
• Monfray Stephane
• Skotnicki Thomas
• Soupremanien Ulrich

Classifications

• H02N2/18 Primary

  producing electrical output from mechanical input, e.g. generators (for measurement devices G01) · CPC title

• H01L41/08

  Electricity · mapped topic

• H01L41/047

  Electricity · mapped topic

• H02N2/185 Primary

  using fluid streams · CPC title

• H10N30/87

  Electrodes or interconnections, e.g. leads or terminals · CPC title