Low power thermoelectric systems
A device for manipulating the temperature of a surface may include a heat transfer surface including active portions and a passive portion. The passive portion may include an inner passive portion disposed between each of the active portions and/or may include an outer passive portion that may surround each of the active portions. The active portions may form 40-90% of a total surface area of the heat transfer surface, where total surface area includes active portions and an inner passive portion. The passive portion(s) may have a thermal conductivity less than the active portion. A processor may be in electrical communication with thermoelectric modules defining or forming the active portions to generate a heat flux through the heat transfer surface. The heat flux through the active portions may be between 500 and 15,000 W/m 2 during nominal operation of the device.
1. A wearable device for manipulating a temperature of a surface, comprising:
a heat transfer surface configured to be placed in contact with the surface, wherein the surface is a user's skin, and the heat transfer surface comprising:
an active portion defined by a single thermoelectric module, wherein the active portion has a first thermal conductivity, and
an inner passive portion wherein a perimeter of the inner passive portion is fully surrounded by the active portion and wherein the inner passive portion has a second thermal conductivity less than the first thermal conductivity
wherein the perimeter of the active portion is fully surrounded by an outer passive portion.
2. The device of claim 1 , further comprising a heat sink thermally coupled to the inner passive portion, and wherein a heat flux through the active portion is in an opposite direction relative to a heat flux through the inner passive portion during operation of the device.
3. The device of claim 1 , wherein the active portion forms 40-60% of a total surface area of the heat transfer surface.
4. The device of claim 1 , wherein the heat transfer surface has a power consumption between 0.1 and 2 W during operation of the device.
5. The device of claim 1 , wherein a heat flux through the active portion is between 8,000 and 11,000 W/m 2 during operation of the device.
6. The device of claim 1 , wherein a total surface area of the heat transfer surface is between 200 and 1000 mm 2 during operation of the device.
7. The device of claim 1 , wherein the thermoelectric module is rectangular.
8. The device of claim 1 , wherein the thermoelectric module is annular.
9. The device of claim 1 , wherein a heat flux through the active portion is between 500 and 15,000 W/m 2 during operation of the device.
10. The device of claim 1 , wherein the heat transfer surface has a plurality of active portions.
11. The device of claim 1 , further comprising a spreader configured to transfer heat and thermally coupled with the thermoelectric module.
12. The device of claim 11 , wherein the inner passive portion is thermally isolated from the spreader.
13. The device of claim 1 , wherein the thermoelectric module includes a plurality of thermoelectric piles.
14. The device of claim 1 , wherein a boundary of a total surface area is defined by a region sharing a boundary with outer edges of the thermoelectric module.
15. The device of claim 1 , wherein the active portion is raised relative to the inner passive portion.
16. The device of claim 1 , further comprising a processor in electrical communication with the thermoelectric module, the processor configured to cause the thermoelectric module to generate heat flux through the heat transfer surface, wherein a heat flux through the active portion is between 500 and 15,000 W/m 2 .
17. The device of claim 1 , further comprising a power source coupled to the thermoelectric module, and wherein the thermoelectric module is configured to actively heat and/or cool the surface.