It has been well known that using localized cooling and heating can help people regulate their body temperature, reduce muscle fatigue during exercise, and generally make feel better.  Heating and cooling pads are quite bulky, heavy, and don’t provide much control of their temperature, making them difficult to use in practice.

Engineers at the University of California San Diego have now announced the development of an electronic armband that can cool or warm the skin, doing so while considering the ambient temperature around the user. The device can run for a long time and not cause issues such as freezing of the skin or being unpleasantly hot.

The device is made possible thanks to a flexible and stretchable battery pack. It is so compliant that it can be integrated into clothing, such as shirts and pants, potentially cooling areas, such as the armpits, that may result in the greatest effect.

The new armband was tried on a group of male volunteers and it was able to cool the skin below itself to a preset 89.6° F (32 C) within two minutes, and keeping it steady thereafter as the ambient temperature in the room was modulated between 71.6° F and 96.8° F.

While there’s great benefit to such technology for regulating people’s body temperature, the researchers believe that such devices may even reduce our reliance on heating and air conditioning.

An announcement from UC San Diego explains the workings of the new device:

The researchers built the patch by taking small pillars of thermoelectric materials (made of bismuth telluride alloys), soldering them to thin copper electrode strips, and sandwiching them between two elastomer sheets.

The sheets are specially engineered to conduct heat while being soft and stretchy. Researchers created the sheets by mixing a rubber material called Ecoflex with aluminum nitride powder, a material with high thermal conductivity.

The patch uses an electric current to move heat from one elastomer sheet to the other. As the current flows across the bismuth telluride pillars, it drives heat along with it, causing one side of the patch to heat up and the other to cool down.

Study in journal Science Advances: Wearable thermoelectrics for personalized thermoregulation…

Via: UC San Diego…

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