Stanford engineers have developed low-cost textiles that cools the body more efficiently than other existing materials.
An ideal application of this garment would be for hot climates, especially where there is no air conditioning available. However, where there is air conditioning available, wearing these cool textiles will save energy costs as there will be no need for air conditioning.
Detailing their work in Science, the researchers explain:
“If you can cool the person rather than the building where they work or live, that will save energy,” said Yi Cui, an associate professor of materials science and engineering at Stanford and of photon science at SLAC National Accelerator Laboratory.
There are two mechanisms in the material. One is an existing function found in some textiles; the fabric lets perspiration to evaporate through the material, second, the innovative feature that allows body heat to pass through the plastic textile as infrared radiation.
It can be described as the anti-blanket. When you put a blanket on, it doesn’t heat you itself, rather it traps the heat you radiate to keep you warm. The new textile however does the opposite, allowing most of the warmth to be released.
“Forty to 60 percent of our body heat is dissipated as infrared radiation when we are sitting in an office,” said Shanhui Fan, a professor of electrical engineering who specialises in photonics, which is the study of visible and invisible light.
“But until now there has been little or no research on designing the thermal radiation characteristics of textiles.”
To make this textile a reality, the team implemented nanotechnology, photonics, and chemistry to give polyethylene a number of desirable characteristics. They made it to allow thermal radiation, air and water vapour to pass right through. The material is also made opaque, and to make it more fabric-like, the researchers created a three-ply version: two sheets of treated polyethylene separated by a cotton mesh for strength and thickness.
The great achievement of this project is to have clothes that keep you cooler than your own skin. When they compared it with regular cotton, it made the skin surface 3.6 F colder. This may not seem like much, but it propels the decision to have the air conditioner on or off.
The team is now working on different colours and textures, making it suitable for mass production.
“If you want to make a textile, you have to be able to make huge volumes inexpensively,” Cui concluded.
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