United States. Engineers at the University of California, San Diego have developed a portable patch that could provide custom cooling and heating at home, work or while traveling.
The soft, elastic patch cools or warms a wearer's skin to a comfortable temperature and keeps it there as the ambient temperature changes. It is powered by a flexible and elastic battery and can be integrated into clothing. Researchers say using it could help save energy in air conditioning and heating.
"This type of device can improve your personal thermal comfort, whether you're traveling on a hot day or you're too cold in your office," said Renkun Chen, a professor of mechanical and aerospace engineering at UC San Diego who led the study.
The device, which is in the proof-of-concept stage, could also save energy. "If using this device can make you feel comfortable within a wider temperature range, you won't need to lower the thermostat as much in summer or increase heat in winter," Chen said. For example, keeping a building's set temperature 12 degrees higher during the summer could reduce cooling costs by about 70 percent.
There are a variety of personal cooling and heating devices on the market, but they are not the most convenient to use or transport. Some use a fan, and others need to be soaked or filled with liquid like water.
Chen and a team of researchers from UC San Diego's Jacobs School of Engineering designed their device to be comfortable and easy to carry. It is flexible, lightweight and can be easily integrated into clothing.
The patch is made of thermoelectric alloys, materials that use electricity to create a temperature difference and vice versa, sandwiched between sheets of elastic elastomer. The device physically cools or heats the skin to a temperature that the user chooses.
"You could place this in places that tend to heat up or cool down faster than the rest of the body, such as your back, neck, feet or arms, to stay comfortable when it's too hot or cold," said first author Sahngki Hong, a UC San Diego mechanical engineering alumnus who worked on the project as PhD student in Chen's lab.
The researchers embedded a prototype of the patch into a mesh bracelet and tested it on a male subject. The tests were performed in a temperature-controlled environment. Within two minutes, the patch cooled the tester's skin to a set temperature of 89.6 degrees Fahrenheit. It kept the tester's skin at that temperature as the ambient temperature varied between 71.6 and 96.8 degrees Fahrenheit.
The ultimate goal is to combine several patches to create smart clothing that can be used for custom cooling and heating. So, engineers designed "soft" electronic devices that can be stretched, bent, and twisted without compromising their electronic functions.
Data Source Provider: University of California, San Diego.
