Optical and Thermal Emission Benefits of Differently Textured Glass for Photovoltaic Modules

Textured glass is a possible means for reflection reduction of a photovoltaic module. Texturing not only increases the energy yield of the system through reduced reflection losses, but also can play a role in dissipating waste heat through enhancing convective and radiative heat loss. In this work, we describe three textured glass surfaces analytically and model them numerically at optical (400-1050 nm) and mid-infrared (MIR, 5-30 μm) wavelengths. Spectral and directional results are processed with a series of weight functions to evaluate the total transmission to determine the optical performance and the total MIR hemispherical emissivity for the thermal performance. It is found that the proposed textured surfaces could improve the total optical transmission by 3.3%-4.6% relative to planar glass for direct solar radiance and 4.9%-6.7% for diffuse component, whereas the total MIR hemispherical emissivity is boosted by 6.6%-9.3% relative. The current most commercially favored inverted pyramid pattern may not be the most effective glass surface texturing scheme based on optical and radiative enhancement or self-cleaning properties.