Dongkuk CM develops ultra-high-reflective color steel to boost solar panel output - CHOSUNBIZ

Dongkuk CM of Dongkuk Steel said on the 1st that it developed the world’s first ultra-high-reflective “solar cell color steel sheet” dedicated to solar power, based on its independently developed ternary high-corrosion-resistant coating technology.

Dongkuk CM determined that increasing the surface reflectance of color steel sheets used as roofing materials could improve the power generation efficiency of bifacial solar modules, and developed a product that maximizes reflectance compared with existing materials. The principle is to transmit more of the sunlight reflected from the roof to the rear side of the bifacial panel.

While the total solar reflectance (TSR) of existing materials remains at the 50–60 range, the solar cell color steel sheet raises total solar reflectance to the 80–85 range. Dongkuk CM said this is a level unattainable with existing roofing construction materials, and when applied, it improves power generation efficiency by 30% based on bifacial solar modules.

In particular, it improved corrosion, the most vulnerable point of roofing materials. Roofs are directly exposed to harsh environments such as high temperatures, high humidity, ultraviolet rays, condensation, and acid rain, and glass wool—which is mainly used on the inner side of steel sheets in sandwich panels—is strong in insulation (temperature retention) and noncombustibility (fire prevention) but vulnerable to moisture, so if rain or snow seeps between the steel sheets, corrosion can progress quickly.

Dongkuk CM integrated its exclusively held ternary SLX (Soft-GLX) coating technology, securing more than double the corrosion resistance compared with ordinary galvalume steel sheets through precise adjustment of the zinc-aluminum-magnesium ratio and special processes. Workability has also been improved more than twofold, so even after bending processes, there is no material damage.

Dongkuk CM added that by applying a “two-layer structural design,” it enhanced corrosion-blocking performance by designing the front side of the steel sheet that receives sunlight and the rear side that contacts glass wool differently.

Choi Woo-chan, head of the technology research institute at Dongkuk CM, said, “As a next-generation premium material that boasts overwhelming reflectance and corrosion resistance even in extreme environments, it can also deliver energy-saving effects such as cool roofing, where roof temperatures drop as reflectance increases.”