New clothing tech to cool like air-conditioning
An effective & scalable textile for personal thermal management, the new material lets heat body gives off as infrared radiation to pass through.
An effective & scalable textile for personal thermal management, the new material lets heat body gives off as infrared radiation to pass through.
CLOTHING, HOT COUNTRIES & TECHNOLOGY
New clothing tech to cool like air-conditioning
2/09/2016
AFP News agency
American researchers at Stanford University have created a low-cost textile made of a plastic base that could cool the body when woven into clothing.
This new material could cool the body and keep people in hot climates cool without using air conditioning.
COULD REDUCE AIR-CONDITIONER USE IN HOT CLIMATES LIKE THAILAND
The engineers suggested in the US journal Science that the textile could become a way to keep people living in hot climates cool without using air conditioning.
"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 and of photon science at Stanford.
Scientists blended nanotechnology, photonics and chemistry to develop the material, which cools the wearer in two ways.
(Source: Carla Schaffer @carlaschaffer)
HOW DOES IT WORK?
Like cotton, the textile allows sweat to evaporate through the material, but the new development allows it to also let through heat the body gives off as infrared radiation.
The latter is a characteristic of polyethylene, the clear, clingy plastic already used as kitchen wrap.
All objects -- including our bodies -- discharge heat as infrared radiation in the form of invisible light wavelengths.
Clothing traps those wavelengths close to the body, but the new plastic textile lets them through.
40-60% OF BODY HEAT DISSIPATED AS INFRARED RADIATION WHEN SITTING IN OFFICE
"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.
"But until now there has been little or no research on designing the thermal radiation characteristics of textiles."
To test the cooling capabilities of the experimental material, researchers put swatches of the plastic material and cotton fabric on bare skin and compared skin surface temperature.
IF DISSIPATING THERMAL RADIATION ONLY CONCERN, WEAR NOTHING
"Wearing anything traps some heat and makes the skin warmer," Fan said.
"If dissipating thermal radiation were our only concern, then it would be best to wear nothing."
The cotton fabric made the skin 3.6 degrees Fahrenheit (2 degrees Celsius) warmer than the new material, suggesting that wearing the "cooling textile" might make people less likely to resort to turning on fans or air conditioners.
The scientists said they will continue working to add more colors, textures and cloth-like traits to their product.
"If you want to make a textile, you have to be able to make huge volumes inexpensively," Cui said.
Shows how Nanoporous PE (polyethylene) textiles allows human body radiation to pass through clothing unlike normal textile (Source: Science)
EFFECTIVE & SCALABLE TEXTILE FOR PERSONAL THERMAL MANAGEMENT
To understand the new technology from a scientist's perspective, here is the abstract of the article published in the academic journal Science:
"Thermal management through personal heating and cooling is a strategy by which to expand indoor temperature setpoint range for large energy saving. We show that nanoporous polyethylene (nanoPE) is transparent to mid-infrared human body radiation but opaque to visible light because of the pore size distribution (50 to 1000 nanometers). We processed the material to develop a textile that promotes effective radiative cooling while still having sufficient air permeability, water-wicking rate, and mechanical strength for wearability. We developed a device to simulate skin temperature that shows temperatures 2.7° and 2.0°C lower when covered with nanoPE cloth and with processed nanoPE cloth, respectively, than when covered with cotton. Our processed nanoPE is an effective and scalable textile for personal thermal management" (Source: Science here).
Actual sample of Nanoporous PE (polyethylene) textile as used in the laboratory for testing (Source: Yi Cui Group at Stanford)
http://www.bangkokpost.com/news/asia/1076664/new-plastic-clothing-textile-could-keep-people-cool
http://news.stanford.edu/2016/09/01/plastic-clothing-material-cools-skin/
http://web.stanford.edu/group/cui_group/
http://www.theverge.com/2016/9/1/12726336/plastic-wrap-cooler-than-cotton-new-fabric-nanoporous-polyethylene
http://www.popsci.com/new-plastic-fabric-keeps-its-cool-better-than-cotton
http://science.sciencemag.org/content/353/6303/1019.full
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