Innovations in solar energy: Synthesis and evaluation of diffuse booster reflector ceramic coating for enhancing thermal and photovoltaic systems performance

Our research focused on developing a ceramic coating to optimize the performance of thermal solar systems (T), photovoltaic systems (PV), and their combined photovoltaic-thermal systems (PVT). After assessing various metals, we selected enameled low-carbon steel SAE 1008 as the best-suited substrate. Potential precursor powders, namely celestite, titanium dioxide, and alpha alumina, emerged as the top choice due to their impressive attributes. The ceramic coating was synthesized using the sol-gel process and applied through spraying and dip-coating. Coating characterization was carried out using UV–VIS, X-ray diffraction, and mechanical property assessments. Initial substrate cleaning significantly increased diffuse relative reflectance. Alpha alumina exhibited a reflectance of 93.71 %, titanium dioxide 98 %, and celestite 79.81 %. Dip-coating showed a reflectance of 76.07 % in the 400–800 nm range, decreasing to 74.70 % after the 24-h salt corrosion test. This method resulted in a coating with a 2H hardness rating, 4B adhesion, 95 % coverage, a thickness of 0.043 mm, and surface roughness metrics of 3.22 μm (Ra). In contrast, the spraying technique yielded coatings with a slightly better reflectance of 78.31 %, which diminished to 77.34 % after a 24-hour spray salt test. These coatings displayed a 4H hardness, 5B adhesion, full 100 % adhesion coverage, a thickness of 0.053 mm, and a roughness of 6.44 μm (Ra). Conclusively, our data suggests that the tailored ceramic coatings, especially the sprayable variant, have a significant potential for large-scale applications, thereby playing a pivotal role in amplifying solar system performance.