HZ Info, the IECOC°C radiative cooling coatings (hereinafter (cooling coating),jointly developed by China Construction Zhonghuan Construction Development Group Co., Ltd. (CSCEC Zhonghuan) and Harbin Institute of Technology, has completed field validation across multiple scenarios including petrochemical storage tanks, cold-chain warehousing, and industrial plants, adding a new achievement to the field of industrial energy-saving coatings.
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The key to this technological breakthrough lies in solving the long-standing industry challenge of "optical crowding." Conventional radiative cooling materials require extremely thick coatings to simultaneously achieve high reflectivity and high emissivity, but increasing coating thickness leads to mutual interference in optical performance. Drawing inspiration from the biomimetic structure of human skin folds, the research team innovatively adopted a multi-bandgap particle complementary coupling mechanism, enabling different functional fillers to divide tasks within a thin-layer system. This design reduced coating thickness from 500 microns to 100 microns, cut costs by 60%, and achieved 97% for both solar reflectance and atmospheric window emissivity, with overall performance representing the highest value reported internationally.
Founded in 2021 and headquartered in Suzhou, CSCEC Zhonghuan is a wholly owned subsidiary of China Construction Second Engineering Bureau Co., Ltd. and serves as the lead unit for the bureau's investment, R&D, design, construction, and operation in municipal environmental protection, water conservancy and hydropower, and new energy sectors. Professor Wang Fuqiang's team at Harbin Institute of Technology has long been engaged in research on radiative heat transfer and solar spectral regulation. Their foundational research was initially oriented toward building energy efficiency, and after publishing papers, the results remained at the laboratory prototype stage for some time. Following a technical exchange, the two parties reached a cooperation agreement, with CSCEC Zhonghuan leveraging its central state-owned enterprise platform's market resources and engineering capabilities to drive the technology toward industrialization.
Petrochemical storage tanks are one of the key application scenarios for radiative cooling technology. After successful pilot-scale testing, this technology was also among the first to undergo validation in tank scenarios. Open-air storage tanks exposed to prolonged sunlight often see surface temperatures exceeding 70°C. Traditional spray cooling not only consumes enormous amounts of water but also carries safety risks associated with oil vapor accumulation.
This pain point is particularly evident in the 136 tank farm of the Hainan Danzhou refining and chemical complex. Five 3,000-cubic-meter spherical tanks stand side by side. The tank marked 136-T-05 has a bright white exterior, standing out conspicuously. The other tanks, which rely on spray cooling, are mottled with rust and dark yellow in appearance. Li Xiang, head of CSCEC Zhonghuan's R&D Center, explained that the pilot tank barely requires water spraying for cooling, and its surface shows no scale or metal corrosion. On a sunny day at 30°C, the surface temperature of the tank coated with the cooling coating can drop by approximately 25°C, and the temperature of the medium inside the tank decreases by about 6.8°C. To achieve the same cooling effect through spraying would consume 35 tons of water per day.
Beyond cooling performance, whether the coating can maintain its properties over the long term is equally critical. The cooling coating has completed a 180-day field condition test at Hainan Refining & Chemical, with a scrub resistance of 40,000 cycles. A 2,000-hour artificial accelerated aging test report issued by a third-party testing institution shows that the coating's solar reflectance decay rate is less than 2%, with no blistering or peeling of the paint film. Based on the coating's aging rate, its effective protection period can reach 15 years.