Electricity-Free Cooling: The Ideal Approach to Climate Control?

In the context of the world "having a headache" with global warming, cooling technology that does not emit carbon and does not consume electricity is likely to be a breakthrough.

Radiant coolers provide electricity-free cooling by radiating heat that is not absorbed by the atmosphere (Photo: KAUST).

Faced with a brutally hot summer in 2022, and record high temperatures observed in many major cities in the first half of 2023, countries have gradually realized the more important need than ever for non-electric cooling solutions, as well as reducing carbon emissions.

To solve this problem, leading researchers in radiative cooling from King Abdullah University of Science & Technology (KAUST) have come up with a solution that they say could 'save' the Earth, while also bringing us back to a balanced orbit.

Accordingly, the devices will be built based on a radiative cooling mechanism, providing electricity-free cooling by radiating heat within a narrow wavelength range - also known as the "transparency window" of the atmosphere.

At this "window", heat is not absorbed by the atmosphere as it normally would be, but instead escapes directly into space.

This is an environment where atoms stop working completely, creating an equilibrium temperature of absolute zero. It will act as a giant heat sink and easily absorb all the heat emitted.

Simulation of radiation cooling, where heat is sent out into space so as not to affect the atmosphere (Photo: Bruker).

However, this method still faces some challenges in achieving cooling below ambient temperature under direct sunlight exposure conditions.

According to Qiaoqiang Gan, the research leader, we must also simultaneously minimize the thermal effect of solar energy absorption to maximize thermal emission in the "atmospheric window".

Additionally, since the radiative cooling method uses the sky as a heat sink, most experiments were conducted in a local outdoor environment.

This will lead to certain difficulties as we cannot control weather conditions and changes in measurement settings.

However, the method still promises to bring great potential when a good overall strategy is built and implemented synchronously.

'By leveraging radiative cooling, we can achieve zero, or even negative, carbon emissions ,' Qiaoqiang Gan asserted.

The method has been included in Saudi Arabia's national strategic plan Vision 2030, and could pioneer the country's local cooling needs.