A novel spectrally selective crystalline silicon cell for reducing the radiation heat loss of photovoltaic/thermal collector

Photovoltaic/thermal (PV/T) hybrid systems are an advanced solar technology that simultaneously produces electricity and heat, enhancing solar energy efficiency and supporting carbon neutrality goals. Nevertheless, the high mid-infrared emissivity (∼0.9) of crystalline silicon cells, results in significant radiative heat loss, thus limiting the thermal performance. The textured structure of C-Si cells further amplifies mid-infrared emissivity, and applying a low-emissivity coating directly onto the textured surface fails to achieve the desired spectral selectivity. To address this issue, we propose a spectrally selective coating structure for C-Si solar cells, wherein the textured surface is filled with PDMS and a low-emissivity coating is applied to the resultant flat surface. Taking the IBC cell as an example, achieve a high solar absorptivity (α = 0.9) and a reduced mid-infrared emissivity (ε = 0.34). We simulated the performance of the Low-e PV/T system using TEC fins and conducted indoor experimental tests. Experimental results demonstrate that the electrical efficiency of the low-emissivity cell decreases by 1.74 % compared to the conventional cell, while the thermal efficiency of the low-emissivity glazed PV/T collector is relatively increased by 16.24%–51.73 % in the operating temperature range of 60–80 °C. Furthermore, annual simulations using TRNSYS modeling reveal that the low-emissivity glazed PV/T collector exhibits a higher heat yield and superior overall solar utilization efficiency, outperforming conventional glazed PV/T collectors in terms of energy conservation.