The Design of Near-Perfect Spectrum-Selective Mirror Based on Photonic Structures for Passive Cooling of Silicon Solar Cells

Abstract

When exposed to sunlight, crystalline silicon solar cells (CSSC) will not only generate electric energy but are also heated by solar radiation. Such a self-heating effect makes the working temperature of CSSC 20–40 °C higher than that of the ambient temperature, which degrades their efficiency and reliability. The elevated operating temperatures of CSSC are mainly derived from absorbing photons that cannot be converted to electrons. Therefore, it is important to prevent CSSC from absorbing useless solar light to have a better cooling effect. In this paper, photonic structures based spectrum-selective mirror is designed to cool the operating temperatures of CSSC passively. The mirror could make CSSC absorb about 93% of the sunlight in the wavelength range of 0.3 to 1.1 µm and only absorb about 4% of the sunlight in the wavelength range of 1.1 to 2.5 µm. Meanwhile, the design has good compatibility with the radiative cooling strategy. By applying selective-absorptive and radiative cooling strategies, the operating temperature of CSSC could be decreased about 23.2 K and 68.1 K under different meteorological conditions. Moreover, unlike the single radiative cooling strategy, the spectrum-selective mirror also has effective cooling effects in high wind speed meteorological conditions.

Maximizing Electric Power through Spectral‐Splitting Photovoltaic‐Thermoelectric Hybrid System Integrated with Radiative Cooling

“…Zhu et al [20] integrated RC with a bare crystalline Si PV panel, demonstrating that the PV panel's temperature could be reduced by 18.3 °C at 1 sun. Also, based on a crystalline Si cell, a PV system integrated with SS and RC was proposed by Gao et al, [21] and the experimental results indicated that the panel's temperature could be reduced by 23.2 °C when the wind speed was 3 m s −1 and by 68.1 °C when there was no wind. Wang et al [22] conducted multiple simulations and experiments to investigate the impact of radiative cooling on solar cells, they found RC performance varied significantly with changes in wind speed, heat load, and design, the temperature drop of 36 °C was observed in a sealed chamber relative to a system without RC.…”

“…Zhu et al [ 20 ] integrated RC with a bare crystalline Si PV panel, demonstrating that the PV panel's temperature could be reduced by 18.3 °C at 1 sun. Also, based on a crystalline Si cell, a PV system integrated with SS and RC was proposed by Gao et al, [ 21 ] and the experimental results indicated that the panel's temperature could be reduced by 23.2 °C when the wind speed was 3 m s −1 and by 68.1 °C when there was no wind. Wang et al.…”

Passive Radiative Cooling of Silicon Solar Modules with Photonic Silica Microcylinders

“…Over the past years, several different materials and methods have been explored to cool solar cells with PRC: multilayers, , 2D structures, − a combination of a multilayer and 2D structures, , or an effective medium approach. − Table lists the calculated (italic) or fabricated (bold) material systems of a few notable works, and their reported temperature reduction: calculated values are in italic, measured values in bold font. To enable comparison of the achieved temperature reductions, it is important to specify the reference material system.…”

“…A solar cell absorbs light with photon energy larger than the bandgap energy, including visible wavelengths. Over the past years, several different materials and methods have been explored to cool solar cells with PRC: multilayers, 15,16 2D structures, 17−23 a combination of a multilayer and 2D structures, 24,25 or an effective medium approach. 26−28 Table 1 lists the calculated (italic) or fabricated (bold) material systems of a few notable works, and their reported temperature reduction: calculated values are in italic, measured values in bold font.…”