Access to electricity isn't a given at all times and in every location. This becomes an issue when you are storing products that need to be cooled or otherwise will get spoiled. Taking inspiration from a desert-dwelling animal, scientists claim to have found a solution to this problem with an innovative new power-free cooling system.

Scientists developed a dual-layer passive, power-free cooling system - Image Credit: Jeffrey Grossman, et. al

There are issues with the continuous availability of electricity around the globe. Power outages can happen at any place at any time. On top of that, there are problems with the availably of power in developing countries, complicating the distribution of critical food and medical supplies. A group of MIT engineers took inspiration from nature in developing a solution to this problem and published their findings in a paper published in the science journal: joule.

The team took a closer look at the camel, an animal that manages to stay cool in scorchingly hot deserts, seemingly without issue. They developed a double-layered, passive cooling system consisting of hydrogel and aerogel mimicking sweat glands, reducing the temperature by evaporating water. The upper aerogel layer, in its turn, performs like fur, insulating against external heat while allowing water vapor to go through. The rather impressive end result is a system capable of keeping items cool five times longer than current-gen power-free technology!

Once again, nature proves to be a great source of inspiration for scientists - Image Credit: Dmitry Rukhlenko via Shutterstock / HDR tune by Universal-Sci

Jeffrey Grossman, one of the authors of the beforementioned paper, explained in a press release that the team took the traditional approach of passive cooling (which focuses mainly on mimicking the evaporation from sweat glands in mammals) and augmented it with the beneficial characteristics of insulation. The key here is that they identified the critical role of fur isolation as it appears in nature. An evaporation-insulation bilayer allows for prolonged passive evaporative cooling time with the same amount of water consumption.

An efficient power-free cooling solution becomes increasingly useful in light of the warming climate. There is a growing need to cool buildings, pharmaceuticals, food, and more. Consequently, researchers around the globe are in hot pursuit of passive cooling systems that do not need external energy sources. Contemporary methods that are solely based on evaporation from hydrogels need a substantial amount of water to operate correctly, making them less useful as a long-lasting cooling agent.

The difference insulation makes when it comes to water consumption has also been observed in nature by zoologists. According to Grossman, it turns out that a shorn camel has to increase the water expenditure for sweating by half during the day compared to a camel with a woolly coat. In order to emulate this coat, the team synthesized highly porous, hydrophobic silica aerogels with approximately half the thermal conductivity of air and then mixed those with sweat gland-mimicking hydrogels.

The transparent hydrogel-aerogel cooling bilayer in proprtion - Image Credit: Zhengmao Lu and Ningxin Chen via EurekAlert

A sample of the new combination was tested with controlled ambient temperature and relative humidity, showing that the test sample could hold a temperature of 7 degrees Celcius lower than its environment. A conventional passive cooling solution was capable of keeping temperatures a little further below ambient than the new system for 40 hours. However, the new system lasted much longer. It kept its below ambient temperature for a whopping 200 hours before it exhausted its water reserve.

All things considered, this new innovation promises a giant leap forward in passive cooling capabilities. It will help millions of people worldwide combat the difficulties that go along with a warming climate, and it once again goes to show that we can still learn from nature; all we need is a keen observing eye and the relentless passion of scientists.

If you are interested in a more detailed explanation of what the science team actually did to bring their new cooling method to fruition, be sure to check out the paper listed below.

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