Chinese scientists have developed a new type of cement that can cool buildings naturally, without using any electricity. This cooling cement reflects sunlight and releases heat into space, helping buildings stay significantly cooler even under strong sunlight. The innovation could reduce indoor temperatures by more than 5°C and lower carbon emissions linked to construction by around 25%.
Buildings consume nearly 40% of global energy and generate about 36% of carbon emissions, largely because air conditioning demand rises sharply during hot weather. Traditional cement absorbs heat during the day and releases it slowly, which makes homes and offices warmer and forces greater reliance on cooling systems. However, the new cooling cement reverses this process by reflecting most sunlight and releasing heat away from buildings, thereby keeping structures cooler and reducing the need for air conditioners or fans.
How cooling cement works without electricity
The science behind this cement is based on a natural process called radiative cooling. Radiative cooling allows a surface to reflect sunlight while also sending heat away as invisible infrared radiation. This heat travels through the atmosphere and escapes into space. Because of this dual action, the material stays cool even in direct sunlight.
Traditional cement absorbs sunlight and stores it as heat. The new cement reverses this behavior. It reflects a large portion of incoming solar radiation and releases internal heat instead of holding onto it. This creates a cooling effect that works all day without any power source.
To achieve this, researchers redesigned the internal structure of cement at a very small scale. They used common raw materials rich in calcium, silica, alumina, and sulfur. When these materials combine in a specific way, they form large amounts of a mineral called ettringite.
Ettringite usually exists in small quantities in ordinary cement. In this new technology, it becomes the main feature. The cement contains ettringite crystals of different sizes. These crystals scatter sunlight in many directions, which increases reflectivity. At the same time, the material emits heat in the mid-infrared range, allowing energy to escape into space instead of warming the building.
Special rubber molds and controlled pressure help form this unique crystal structure. The process does not require rare materials or complex machinery. This makes the technology suitable for large-scale manufacturing using existing cement production systems.
Real-world performance and durability of the material
Tests under real outdoor conditions showed strong cooling results. When placed in direct sunlight, the surface of the cooling cement stayed up to 26°C cooler than regular cement. It also remained about 5.4°C cooler than the surrounding air temperature. These differences are large enough to noticeably lower indoor temperatures.
Lower surface temperatures mean less heat enters buildings through roofs and walls. This reduces the need for air conditioning, especially during peak heat hours. As a result, energy use drops, and electricity grids face less pressure during heatwaves.
Laboratory tests confirmed that the cooling cement is not fragile or short-lived. It maintained high mechanical strength similar to traditional cement. The material resisted wear from abrasion, damage from ultraviolet light, and exposure to corrosive liquids. It also survived repeated freeze-thaw cycles, which often weaken building materials over time.
Because of this durability, the cement can be used in many construction settings. It works for roofs, exterior walls, coatings, and other structural elements. Builders can apply it in different climates and designs without sacrificing safety or strength.
Environmental impact and large-scale construction benefits
The environmental advantages of cooling cement go beyond lower energy use. Cement production alone causes about 8% of global carbon dioxide emissions. This new production method reduces the carbon footprint of cement manufacturing by around 25%.
By cutting emissions during both production and building operation, the material addresses two major climate challenges at once. Less air conditioning means fewer emissions from power plants. Cleaner production reduces pollution at the source.
India and China move away from US treasuries as gold becomes strategic anchor
This technology is especially valuable for hot urban areas. Cities often suffer from the urban heat island effect, where concrete and asphalt absorb heat and raise local temperatures. Widespread use of cooling cement could help cities stay cooler and more comfortable.
The benefits are also significant for developing regions. Many areas lack reliable electricity for air conditioning. Cooling buildings through materials instead of machines offers a practical solution without expensive infrastructure upgrades. The manufacturing process supports quick adoption. Existing cement plants can adjust their operations with minor changes.
Cooling cement can be used as a surface coating or as part of structural components. This flexibility allows builders to integrate it into new projects or apply it to existing buildings. Its performance under sunlight and harsh conditions makes it suitable for residential, commercial, and public infrastructure.
By turning cement from a heat-trapping material into a cooling surface, this technology changes how buildings interact with their environment. It shows how smart material design can reduce energy demand, cut emissions, and improve comfort without adding complexity or cost. This development highlights the role of materials science in addressing climate and energy challenges through simple, passive solutions that work every day without consuming power.
