Camels have developed a seemingly illogical approach to staying cool and conserving water in a scorching desert: they have a thick layer of insulating fur. Taking essentially the same approach, MIT researchers have developed a system that keeps you cool in hot conditions without the need for a power source.
Most people would not consider wearing a camel wool coat on a hot summer day. But many of the desert dwellers tend to wear heavy outerwear. And that’s why. It turns out that a camel coat or heavy human clothing reduces moisture loss. In doing so, sweat can evaporate to provide a cooling effect.
Tests have shown that a shaved camel loses 50% more moisture than a regular camel.
The new system, developed by engineers at the Massachusetts Institute of Technology, uses a two-layer material to achieve a similar effect. The lower layer of material that replaces the sweat glands consists of a hydrogel, a gelatin-like substance. It is located on a spongy matrix from which water easily evaporates. The material is then coated with a layer of airgel that acts as a fur.
Hydrogels are already being used for some cooling systems, but field tests and detailed analysis have shown that this new two-layer material, about a centimeter thick, provides better cooling. More than 7 ° C and five times longer than one hydrogel. The two-layer material stays cool for more than 8 days instead of two with just a hydrogel.
The system can be used to package foods to keep them fresh, the researchers said. It will also allow medicines such as vaccines to be safely stored as they are transported to remote locations. A passive system that runs exclusively on heat not only provides cooling, but also reduces temperature fluctuations that can accelerate product and food spoilage.
The main raw material used in the double layer system is inexpensive. The airgel is made from silica, which is essentially beach sand. It’s cheap and affordable. However, the technological equipment for making the airgel is not cheap. This aspect will require further development in order to scale the system. But at least one start-up company is already interested in the scientists’ discovery.