For those in the northern hemisphere, the warmer weather has nearly arrived. Hotter days are on the ticket, and with the World Meteorological Organisation forecasting record-setting temperatures over the next few years any relief from the blistering heat will surely be welcomed. Unfortunately, that usually means blasting air conditioners, which require vast amounts of electricity and pump out tons of environmentally hazardous greenhouse gas emissions (in turn making reinforcing the warmer weather thanks to climate change).

Researchers at the University of Cambridge may have found a solution, in the form of a new plant-based film that could render buildings and vehicles cooler, without requiring any additional energy. It works by “hacking” the natural process of heat absorption, in a process known as passive daytime radiative cooling (PDRC).

To make materials that remain cooler than the air around them during the day, you need something that reflects a lot of solar light and doesn’t absorb it.

Silvia Vignolini, Ph.D

Most human-made materials that can reflect light are treated with some form of white or mirror-finish. Unfortunately, adding those types of pigments to materials can also create undesirable effects (such as concentrated, reflective warming). Cellulose is one of the rare materials that can utilise PDRC without those issues. The researchers were able to demonstrate this in the lab with a custom, fabricated cellulose film that actively generated over 120 Watts of cooling power. It’s easy to imagine a world where this type of material was applied to the exterior of buildings and vehicles, helping to reduce the need for powerful air conditioner systems to help regulate soaring temperatures.

Read more about this interesting research at the link:

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