Watch: China’s ‘OutdoorAC’ uses rooftop misting systems to beat extreme heat

A city in China's Shanxi Province is using rooftop misting systems to combat extreme heat and urban heat island effects. The innovative evaporative cooling technology has gone viral online and is being seen as a sustainable alternative to conventional air-conditioning.

By Panyala Sukumari

Hyderabad: You must have heard of air-conditioned rooms, buses and offices, but have you ever heard of China’s ‘OutdoorAC’? Yes, you heard that right. In Yuncheng, a city in northern China’s Shanxi Province, skyscrapers and high-rise buildings are being fitted with rooftop misting systems that spray a fine mist of water into the air.

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The absorption and retention of heat by buildings, roads and concrete structures have turned the city into an urban heat island. To battle the extreme heat, residents of the Chinese city have adopted this innovative method as they were unable to withstand the soaring temperatures.

Several videos of the rooftop misting system have now gone viral on social media, showing thick clouds of mist drifting down from rooftops and cooling the streets and walkways below.

The science behind this cooling system is called evaporative cooling, and here is how it works: High-pressure nozzles are installed on rooftops to spray extremely fine droplets of water into the air. As the droplets evaporate, they absorb heat from the surrounding air, cooling it in the same way sweat cools the human body.

The interesting fact about this system is that it is far more sustainable than conventional air-conditioning, consuming very little electricity, as all it needs is water, pumps and high-pressure nozzles.

Meanwhile, some experts have raised concerns about water consumption in areas facing shortages, while others argue that the systems use relatively small amounts of water as the mist evaporates almost immediately.

As heat waves have become more common across the world, innovations such as rooftop misting systems can be adapted by various countries to help bring down temperatures during summer.