Boston, Nov 14 (PTI) Stanford researchers have developeda reversible fabric that can keep the wearer either warm orcool, depending on which side faces out.
The material could keep people more comfortable in arange of temperatures, and hence help save energy on airconditioning and central heating in homes.
Scientists from Stanford University in the US created adouble-sided fabric based on the same material as everydaykitchen wrap.
For every one degree Celsius that a thermostat is turneddown, a building can save a whopping 10 per cent of itsheating energy, and the reverse is true for cooling.
Adjusting temperature controls by just a few degrees hasmajor effects on energy consumption.
Our bodies have many ways of controlling our temperature.
When it is cold, the hairs in our skin stand out to trap warmair. Eventually, we may start shivering to produce moreradiant heat in our muscles.
When it is hot, we release heat as infrared radiationfrom our skin, and if we are still warm we start to sweat.
Water evaporating away from our bodies carries a largeamount of heat with it.
However, these mechanisms only help within a few degrees.
When we get outside the temperature range to which our bodiescan adapt, and we reach for the dial on the heating or airconditioning.
Although they were inspired by transparent, water-impermeable kitchen wrap, their new material was opaque,breathable and retained its ability to shuttle infraredradiation away from the body.
Compared to a cotton sample, their fabric kept artificialskin two degree Celsius cooler in a laboratory test – possiblyenough to stop a person from ever reaching for a fan or thebuilding thermostat.
The team is first textile could save a building full ofworkers 20 to 30 per cent of their total energy budget.
Researchers realised that controlling radiation couldwork both ways. He stacked two layers of material withdifferent abilities to release heat energy, and thensandwiched them between layers of their cooling polyethylene.
On one side, a copper coating traps heat between apolyethylene layer and the skin; on the other, a carboncoating releases heat under another layer of polyethylene.
Worn with the copper layer facing out, the material trapsheat and warms the skin on cool days. With the carbon layerfacing out, it releases heat, keeping the wearer cool.
Combined, the sandwiched material can increase a person'srange of comfortable temperatures. With inhabitants wearing atextile like that, buildings in some climates might never needair conditioning or central heating at all.
The white-coloured fabric is not quite wearable yet,researchers said.
"Ideally, when we get to the stuff you want to wear onskin, we'll need to make it into a fiber woven structure,"said Yi Cui from Stanford.
Woven textiles are stronger, more elastic, morecomfortable, and look much more like typical clothing.
The team aims to create an easily manufactured, practicaltextile that people could use to save huge amounts of energyaround the world. PTI MHN SARMHN.
This is unedited, unformatted feed from the Press Trust of India wire.