How does radiative cooling coating become a scientific mechanism and a significant energy-saving practice for electricity-free cooling?
Publish Time: 2026-02-25
Against the backdrop of global warming and energy shortages, a new type of electricity-free energy-saving cooling coating—radiative cooling coating—is quietly changing traditional cooling methods. It does not rely on electricity, yet it can significantly reduce the surface and internal temperature of objects, and is widely used in high-heat-load scenarios such as photovoltaic energy storage power stations, energy storage containers, bulk storage tanks, and outdoor battery cabinets. Its core secret lies in the synergistic effect of high reflectivity and high emissivity, constructing a highly efficient, green, and sustainable passive cooling system.1. High Reflectivity: Blocking Heat Absorption at the SourceThe first line of defense for radiative cooling coating is its extremely high solar reflectivity. This coating is typically composed of nano-scale inorganic fillers and polymer resins, possessing excellent broadband reflectivity, especially in the visible and near-infrared bands, where reflectivity can reach over 95%. This means that when sunlight shines on the coated surface, most of the energy is directly reflected back to the atmosphere, rather than being absorbed by the material and converted into heat energy. This mechanism effectively curbs the temperature rise of the object's surface, avoiding the "heat island effect" and achieving cooling at its source.2. High Emissivity: Actively Dissipating Heat into SpaceSimply reflecting heat is insufficient for sustained cooling. Another core advantage of the radiative cooling coating lies in its high infrared emissivity. The coating has an emissivity exceeding 90% in the 8-13 micrometer "atmospheric transparency window" band, efficiently releasing heat generated by the object itself due to environmental conduction or residual heat absorption into outer space in the form of thermal radiation. This process requires no external energy drive; it is a purely physical phenomenon known as "passive radiative cooling." Even during the day when sunlight is intense, this mechanism continues to operate, achieving all-weather cooling.3. Synergistic Effect: Constructing a "Reflection + Radiation" Dual-Effect Cooling ModeThe combination of high reflectivity and high emissivity allows the coating to form a "one-in, one-out" thermal management closed loop: minimizing heat input on one hand and accelerating heat output on the other. This synergistic effect of the dual mechanism allows the coated surface temperature to be 10°C to 25°C lower than the ambient temperature, significantly suppressing internal temperature rise. For example, in outdoor battery cabinet applications, the internal temperature can be reduced by more than 15°C, greatly alleviating the operational pressure on the temperature control system.4. Significant Energy Savings and Outstanding Economic BenefitsIn practical applications, the energy-saving effect of the radiative cooling coating is remarkable. Taking photovoltaic energy storage power stations as an example, battery cabinets exposed to high temperatures for extended periods accelerate battery degradation and increase the cooling load on air conditioning. After applying this coating, air conditioning operating time is reduced by more than 30%, with some projects showing energy savings approaching 40%, resulting in annual electricity cost savings of tens of thousands of yuan. In a storage base in Hubei, the surface temperature difference of the walls reached as high as 27°C after applying the coating, significantly reducing internal air conditioning energy consumption. Application on bulk storage tanks can also effectively reduce oil evaporation, improving safety and storage and transportation efficiency.5. Self-Cleaning Performance Extends Service LifeThis coating also possesses excellent self-cleaning properties. After special surface treatment, it exhibits superhydrophobic and anti-fouling characteristics, effectively repelling dust, rainwater, and oil stains. It automatically cleans itself under natural rainfall, maintaining high reflectivity over the long term and preventing performance degradation due to dust accumulation. This characteristic significantly reduces maintenance costs, making it particularly suitable for scenarios where frequent cleaning is difficult, such as high-altitude or outdoor environments.6. Green and Low-Carbon, Contributing to Sustainable DevelopmentRadiative cooling coating produces no carbon emissions throughout its entire lifecycle. It is easy to apply, non-toxic, and harmless, aligning with green building and carbon neutrality goals. It not only reduces energy consumption but also decreases reliance on traditional refrigeration equipment, representing a crucial technological path for promoting industrial energy conservation and eco-friendliness.In summary, radiative cooling coating achieves true electricity-free cooling through the scientific synergy of high reflectivity and high emissivity, demonstrating outstanding energy-saving performance in practical applications. As the technology matures, it will inject new momentum into the green and low-carbon transformation across a wider range of fields.
