Dongkuk CM of Dongkuk Steel said on the 1st that it developed the world's first ultra-high-reflective Solarcell 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 deliver more of the sunlight reflected from the roof to the rear of the bifacial panels.
While the total solar reflectance (TSR) of existing materials remains around 50–60, the Solarcell color steel sheet increases TSR to about 80–85. TSR indicates the ratio of total energy reflected when sunlight hits a surface. It is expressed on a 0–1 (%) scale, and a higher value means it reflects more solar energy.
A Dongkuk CM official said, "The 'Solarcell color steel sheet' is at a level unattainable with currently available roofing construction materials," adding, "When applied, it improves power generation efficiency by 30% based on bifacial solar modules."
In particular, it improves corrosion resistance, the most vulnerable part of roofing materials. Roofs are directly exposed to harsh environments such as high temperatures, high humidity, ultraviolet rays, condensation, and acid rain, and while 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), it is vulnerable to moisture, so if rain or snow seeps between the steel sheets, corrosion can progress quickly.
Dongkuk CM applied 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 was also improved more than twofold, so even after bending processes, there is no material damage.
Dongkuk CM added that by applying a double-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 Dongkuk CM Technology Research Center, said, "As a next-generation premium material boasting 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."