Thermal oscillator

Patent metadata

Field	Value
Publication number	US-9640748-B2
Application number	US-201414894824-A
Country	US
Kind code	B2
Filing date	May 13, 2014
Priority date	May 31, 2013
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

A thermal oscillator ( 10 ) for creating an oscillating heat flux from a stationary spatial thermal gradient between a warm reservoir ( 20 ) and a cold reservoir ( 30 ) is provided. The thermal oscillator ( 10 ) includes a thermal conductor ( 11 ) which is connectable to the warm reservoir ( 20 ) or to the cold reservoir ( 30 ) and configured to conduct a heat flux from the warm reservoir ( 20 ) towards the cold reservoir ( 30 ), and a thermal switch ( 12 ) coupled to the thermal conductor ( 11 ) for receiving the heat flux and having a certain difference between two states (S 1 , S 2 ) of thermal conductance for providing thermal relaxation oscillations such that the oscillating heat flux is created from the received heat flux.

First claim

The invention claimed is:

1. A thermal oscillator ( 10 ) for creating an oscillating heat flux from a stationary spatial thermal gradient between a warm reservoir ( 20 ) and a cold reservoir ( 30 ), the thermal oscillator ( 10 ) comprising:
a thermal conductor ( 11 ) which is connectable to the warm reservoir ( 20 ) or to the cold reservoir ( 30 ) and configured to conduct a heat flux from the warm reservoir ( 20 ) towards the cold reservoir ( 30 ), and
a thermal switch ( 12 ) coupled to the thermal conductor ( 11 ) for receiving the heat flux and having two different states (S 1 , S 2 ) of thermal conductance for providing thermal relaxation oscillations such that the oscillating heat flux is created from the received heat flux, wherein the thermal oscillator ( 10 ) is embodied as a solid-state thermal oscillator ( 10 ).

2. The thermal oscillator of claim 1 , wherein the thermal switch ( 12 ) is sandwiched between the thermal conductor ( 11 ) and a further thermal conductor ( 13 ) which is connectable to the cold reservoir ( 30 ).

3. The thermal oscillator of claim 1 , wherein a vacuum gap ( 14 ) is arranged between the thermal conductor ( 11 ) and the thermal switch ( 12 ).

4. The thermal oscillator of claim 3 , wherein the vacuum gap ( 14 ) has a width between 1 nm and 200 nm.

5. The thermal oscillator of claim 1 , wherein the thermal switch ( 12 ) is configured to switch at a first switching temperature (T 1 ) from a first state (S 1 ) of the two states (S 1 , S 2 ) in which the thermal switch ( 12 ) has a first thermal conductance (k 1 ) to a second state (S 2 ) of the two states (S 1 , S 2 ) in which the thermal switch ( 12 ) has a second thermal conductance (k 2 ), and wherein the thermal switch ( 12 ) is configured to switch at a second switching temperature (T 2 ) from the second state (S 2 ) to the first state (S 1 ).

6. The thermal oscillator of claim 1 , wherein the thermal switch ( 12 ) is configured such that its two different states (S 1 , S 2 ) of thermal conductivity are adapted to provide periodic metal-insulator phase transitions leading to the thermal relaxation oscillations such that the oscillating heat flux is created from the received heat flux.

7. The thermal oscillator of claim 5 , wherein the first and the second switching temperatures (T 1 , T 2 ) of the thermal switch ( 12 ) lie between a temperature of the warm reservoir ( 20 ) and a temperature of the cold reservoir ( 30 ).

8. The thermal oscillator of claim 6 , wherein the thermal switch ( 12 ) is configured to undergo the periodic metal-insulator phase transitions in time intervals which are smaller than a thermal equilibration time or thermal time constant of the thermal conductor ( 11 ).

9. The thermal oscillator of claim 6 , wherein a switching material of the thermal switch ( 12 ) is configured to have single domain behaviour during the phase transitions.

10. The thermal oscillator of claim 9 , wherein the switching material has a thickness between 10 nm and 100 nm.

11. The thermal oscillator of claim 9 , wherein a lateral dimension of the switching material is restricted such that single domain behaviour during the phase transitions is ensured.

12. The thermal oscillator of claim 1 , wherein the thermal conductance of the thermal conductor ( 11 ) is between a first magnitude (k 1 ) of thermal conductance of the thermal switch ( 12 ) in its first state (S 1 ) and a second magnitude (k 2 ) of thermal conductance of the thermal switch ( 12 ) in its second state (S 2 ).

13. The thermal oscillator of claim 1 , wherein the thermal conductor ( 11 ) includes a pyroelectric material configured for energy harvesting upon cycling its temperature.

14. The thermal oscillator of claim 1 , wherein a thermal electrode ( 15 ) is attached to the thermal conductor ( 11 ) or to the thermal switch ( 12 ) such that the created oscillating heat flux is receivable at an external device.

15. The thermal oscillator of claim 1 , wherein the thermal conductor ( 11 ) has a plurality of spacers ( 17 , 18 , 19 ) for defining a certain distance (D) to the thermal switch ( 12 ).

16. The thermal oscillator of claim 1 , wherein the thermal switch ( 12 ) includes at least one of the following switching materials:
vanadium(II)-oxide, titanium-doped vanadium(III)-oxide, silicon-phosphor, silicon-arsenic, silicon-boron, silicon gallium.

17. The thermal oscillator of claim 1 , wherein the thermal conductor ( 11 ) includes silicon-dioxide.

18. A device ( 40 ) comprising at least one thermal oscillator ( 10 ), the thermal oscillator for creating an oscillating heat flux from a stationary spatial thermal gradient between a warm reservoir ( 20 ) and a cold reservoir ( 30 ), the thermal oscillator ( 10 ) comprising:
a thermal conductor ( 11 ) which is connectable to the warm reservoir ( 20 ) or to the cold reservoir ( 30 ) and configured to conduct a heat flux from the warm reservoir ( 20 ) towards the cold reservoir ( 30 ), and
a thermal switch ( 12 ) coupled to the thermal conductor ( 11 ) for receiving the heat flux and having two different states (S 1 , S 2 ) of thermal conductance for providing thermal relaxation oscillations such that the oscillating heat flux is created from the received heat flux, wherein said at least one thermal oscillator ( 10 ) is embodied as a solid-state thermal oscillator ( 10 ).

19. The device of claim 18 , wherein the device ( 40 ) is embodied as an energy harvesting device, as a sensing device, as a switching device or as a clocking device.

20. A method for creating an oscillating heat flux from a solid-state thermal oscillator ( 10 ) providing a stationary spatial thermal gradient between a warm reservoir ( 20 ) and a cold reservoir ( 30 ), the method comprising:
conducting a heat flux from the warm reservoir ( 20 ) towards the cold reservoir ( 30 ) by means of a thermal conductor ( 11 ) which is thermally connected to the warm reservoir ( 20 ) and/or to the cold reservoir ( 30 ),
receiving the heat flux by a thermal switch ( 12 ) which is coupled to the thermal conductor ( 11 ) and which has two different states (S 1 , S 2 ) of thermal conductance, and
creating an oscillating heat flux from the received heat flux by means of thermal relaxation oscillations of the thermal switch.

Assignees

• IBM

Inventors

• Gotsmann Bernd
• Menges Fabian

Classifications

• F28F13/00

  Arrangements for modifying heat-transfer, e.g. increasing, decreasing (F28F1/00 - F28F11/00 take precedence) · CPC title

• H01L37/02 Primary

  Electricity · mapped topic

• H03L1/02

  against variations of temperature only · CPC title

• H01L41/113

  Electricity · mapped topic

• F28F2013/008

  Variable conductance materials; Thermal switches · CPC title