World News : As heatwaves become more frequent and intense across the world, a new cooling technology being used in China is drawing attention. Several residential and commercial buildings are installing rooftop mist cooling systems, which are designed to reduce outdoor temperatures.
Viral videos on social media claim the system can lower the surrounding temperature by 5–8°C within minutes. However, these claims have not been independently verified. The technology is intended to cool open spaces while consuming relatively little electricity.
Why Is This Technology Needed?
Climate change has led to longer and more severe heatwaves worldwide. In urban areas, concrete buildings, asphalt roads, and limited green spaces absorb and retain heat throughout the day, causing cities to remain hot even at night—a phenomenon known as the urban heat island effect.
To address this challenge, scientists and engineers are developing energy-efficient cooling solutions for outdoor environments.
How Does the Rooftop Mist Cooling System Work?
The system is based on the principle of evaporative cooling.
High-pressure nozzles spray an ultra-fine mist of water into the air. The droplets are so small that they evaporate before reaching the ground.
As water evaporates, it absorbs heat from the surrounding air. This process lowers the air temperature, making the environment feel cooler.
The same principle works in the human body—when sweat evaporates, it removes heat from the skin, creating a cooling effect.
Is It the Same as an Air Conditioner?
No.
Unlike a traditional air conditioner, which cools enclosed spaces using compressors and refrigerant gases, a mist cooling system is designed specifically for open or semi-open areas.
It does not cool an entire room but instead reduces the ambient temperature outdoors by a few degrees.
Does It Always Reduce Temperature by 5–8°C?
Not necessarily.
Although viral videos claim a temperature drop of 5–8°C, the actual cooling effect depends on weather conditions, particularly humidity.
- Dry air: Water evaporates quickly, producing greater cooling.
- Humid air: Evaporation occurs more slowly, reducing the cooling effect.
Therefore, performance varies depending on local climate conditions.
Where Is It Being Used?
In China, rooftop mist cooling systems are being installed at locations such as:
- Cafés and restaurants
- Rooftop terraces
- Gardens
- Warehouses
- Bus stops
- Outdoor event venues
The aim is to make these spaces more comfortable during extreme summer temperatures.
Why Could It Be Useful?
Experts say the technology offers several advantages:
- Lower electricity consumption than conventional air conditioning.
- Effective cooling for outdoor and semi-open spaces.
- Helps reduce the impact of the urban heat island effect.
- Can improve comfort during heatwaves.
A Promising Outdoor Cooling Solution
While rooftop mist cooling systems are not a replacement for air conditioners, they offer a scientifically proven way to lower temperatures in outdoor environments through evaporative cooling.
As cities continue to face rising temperatures due to climate change, such technologies could become an important tool for improving outdoor comfort and reducing heat stress, especially when adapted to local weather conditions.
