An end to arguments over the temperature of office air conditioning could be on the horizon after scientists invented a material which cools the body by 4F.
The new cloth reflects sunlight while also allowing heat radiating from a person’s body to escape.
While people have been wearing furs and cloths to keep warm for tens of thousands of years. the development of clothing which cools down the body has remained challenging.
At normal skin temperatures of 93F (34C) the human body emits mid-infrared (IR) radiation in the wavelength range that partially overlaps with that of the visible light spectrum, which means that any cloth which blocks visible light, also traps in body heat.
Now researchers at Stanford University in the US have developed a low-cost, plastic-based textile that, if woven into clothing allows body heat to escape while preventing light and heat penetrating.
Describing their work in the journal Science, the researchers suggest that the new fabric could help keep people cool in hot climates without air conditioning.
Dr Yi Cui, an associate professor of materials science and engineering and of photon science at Stanford, said: “If you can cool the person rather than the building where they work or live, that will save energy.”
The new material – dubbed nanoPE – is made of a special kind of cling film which has tiny holes, one hundred times smaller than a human hair which allow infrared light to pass through, but cause visible light – which has a different wavelength – to bounce off. The material also allows perspiration to evaporate through the material.
Currently cotton only allows 1.5 per cent of infra-red waves to pass through but the new material lets 96 per cent of waves out, making the wearer feel nearly 4 degrees Fahrenheit cooler than if they wore normal cotton clothing.
The researchers said the difference means that a person dressed in their new material might feel less inclined to turn on a fan or air conditioner.
“Forty to 60 per cent of our body heat is dissipated as infrared radiation when we are sitting in an office,” said Prof Shanhui Fan of Stanford.
“But until now there has been little or no research on designing the thermal radiation characteristics of textiles. Wearing anything traps some heat and makes the skin warmer.
“If dissipating thermal radiation were our only concern, then it would be best to wear nothing.”
The team is now experimenting with producing bright colours and testing whether it could be used in tents, buildings and vehicles.
Prof Fan added: “In hindsight, some of what we’ve done looks very simple, but it’s because few have really been looking at engineering the radiation characteristics of textiles.”
Image credit & Article via: The Telegraph