Novel Silica-Based PV Glass Cover Providing Higher Radiative Cooling and Power Production Compared With State-of-the-Art Glass Covers

In this article, a novel silica-based photovoltaic (PV) glass cover with nanopyramidal coating prepared and fabricated using ultraviolet-nanoimprint lithography is proposed to maximize radiative cooling of a PV panel to decrease the PV panel temperature. The spectral profile of the coating, experimentally measured using spectroscopy, shows a flat emissivity curve close to one in a part of the mid-infrared band ranging from 8 to 14 μm (atmospheric window), and an appropriate transmittance close to one inside the solar band. A novel theoretical basis is first discussed and formulated, and experimental data are then given as verification. To provide a comprehensive comparison, experimental measurements were conducted by using four identical PV panels. The first PV panel used the proposed glass cover, while the other three PV panels utilized ordinary glass cover and state-of-the-art glass covers, i.e., self-assembled silica glass cover and glass cover with antireflective coating. Experimental measurements verify that with reference to the ordinary glass cover, the proposed glass decreases the PV panel temperature by 9.2 °C at the peak of solar radiation by intensifying radiative cooling, while it is only 2.7 °C for the self-assembled silica glass cover and the glass cover with antireflective coating even increases the PV panel temperature by 0.9 °C. Correspondingly, measurements demonstrate an increase of 4.6% in PV power generation due to temperature drop caused by the proposed glass, while it is only 1.1% and 0.5% for the self-assembled silica glass cover and the glass cover with antireflective coating, respectively.