Staying Cool Without Air Conditioner


In warmer months, it’s tempting to crank the AC or plant yourself in front of the nearest fan. There are other natural ways that help to keep cool in the warmer season. But that’s not enough. So, scientists have developed a scalable metamaterial with ultimate properties that are not found in nature. This metamaterial acts as a kind of air conditioner for structures. It can cool the object with the power of 90W/m2 in direct, noon-time sunlight.

This newly devised material has the ability to cool objects even under direct sunlight with zero energy and water consumption. It works very efficiently by reflecting incoming solar energy back into space. In addition, it allows the surface to cast off its own heat in the form of infrared thermal radiation.

Professor Xiaobo Yin said, “We feel that this low-cost manufacturing process will be transformative for real-world applications of this radiative cooling technology. It could supply an eco-friendly way of supplementary cooling.

Staying Cool Without Air Conditioner

Scientists developed this material through a glass polymer that is just 50 micrometers thick. It cools the object without requiring an air conditioner or air conditioning system. Passive radiative cooling is the process by which objects naturally shed heat in the form of infrared radiation without consuming energy.

The thermal radiation allows the material to provide some natural nighttime cooling. So, a small amount of solar energy revokes passive radiation whenever the material is directly exposed to sunlight.

While developing, the main challenge was creating a material that could revert solar rays to the atmosphere. Thus, scientists covered the glass polymer with a silver coating for maximum spectral reflectance.

In testing, this metamaterial shows its average radiative cooling power larger than 110W/m2 for a continuous 72 hours. This power is roughly equivalent to the electricity generated using solar cells for a similar area.

Professor Ronggui Yang said, “Both the glass-polymer metamaterial formation and the silver coating are manufactured at scale on roll-to-roll processes.

According to scientists, it can be used for thermoelectric power plants, which currently require large amounts of water and electricity to maintain the operating temperatures of their machinery. It also has the potential to be used for both residential and commercial applications.


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