Fabric that works like heater & AC too!

Scientists have developed a smart reversible material that can keep the wearer warm or cool depending on which side it faces out

Stanford researchers have developed a reversible fabric that can keep the wearer either warm or cool, depending on which side faces out. The material could keep people more comfortable in a range of temperatures, and hence help save energy on air conditioning and central heating in homes. Scientists from Stanford University in the US created a double-sided fabric based on the same material as everyday kitchen wrap.

For everyone degree Celsius that a thermostat is turned down, a building can save a whopping 10 per cent of its heating energy, and the reverse is true for cooling. Adjusting temperature controls by just a few degrees has major 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 warm air. Eventually, we may start shivering to produce more radiant heat in our muscles.

When it is hot, we release heat as infrared radiation from our skin, and if we are still warm we start to sweat. Water evaporating away from our bodies carries a large amount of heat with it. However, these mechanisms only help within a few degrees. When we get outside the temperature range to which our bodies can adapt, and we reach for the dial on the heating or air conditioning.

Although they were inspired by transparent, waterimpermeable kitchen wrap, their new material was opaque, breathable and retained its ability to shuttle infrared radiation away from the body.

The team is first textile could save a building full of workers 20 to 30 per cent of their total energy budget. Researchers realised that controlling radiation could work both ways. He stacked two layers of material with different abilities to release heat energy, and then sandwiched them between layers of their cooling polyethylene.

On one side, a copper coating traps heat between a polyethylene layer and the skin; on the other, a carbon coating releases heat under another layer of polyethylene. Worn with the copper layer facing out, the material traps heat and warms the skin on cool days. With the carbon layer facing out, it releases heat, keeping the wearer cool.