Abstract Radiative cooling (RC) of solar cells has received growing attention in recent years primarily due to its passive nature as compared to the other active cooling techniques. By using novel high emittance materials, the RC technique can also be integrated with a photovoltaic-thermal (PVT) system, to eventually improve the system's total efficiency (electrical and thermal output) during the day and provide additional cooling power at night. To quantify the effect of enhanced RC in a PVT system, this study investigated the performance of a regular glass encapsulated PVT module, and a spectrally modified module by using a polydimethylsiloxane coating on top of the glass layer to simulate enhanced RC. An experimentally validated simulation model was developed for performance comparison. Furthermore, a sensitivity analysis was conducted to investigate the influence of varying input parameters on system output performance. Results show that during the day, solar cell operating temperature reduced by most 1.7 °C, and electrical efficiency and total exergy efficiency increased by 0.76% and 0.5%, respectively. As for nighttime, an additional 4–7 W/m2 cooling power can be obtained. Although some improvements, the potential gains achieved by integrating enhanced RC in PVT systems are not substantially large as compared to the regular glass encapsulation in commercial PVT modules, since glass naturally has a fairly high emittance in the atmospheric window.

中文翻译：

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具有辐射冷却的光伏热系统的比较性能评估和灵敏度分析

摘要 近年来，太阳能电池的辐射冷却 (RC) 受到越来越多的关注，这主要是由于与其他主动冷却技术相比其被动性质。通过使用新型高发射材料，RC 技术还可以与光伏热 (PVT) 系统集成，最终提高系统在白天的总效率（电力和热输出），并在夜间提供额外的冷却能力。为了量化增强型 RC 在 PVT 系统中的影响，本研究通过在玻璃层顶部使用聚二甲基硅氧烷涂层来模拟增强型 RC，研究了常规玻璃封装 PVT 模块和光谱改性模块的性能。开发了经过实验验证的仿真模型以进行性能比较。此外，进行了敏感性分析以研究不同输入参数对系统输出性能的影响。结果表明，白天太阳能电池工作温度最多降低1.7℃，电效率和总火用效率分别提高0.76%和0.5%。至于夜间，可以获得额外的 4-7 W/m2 冷却功率。尽管有一些改进，但与商用 PVT 模块中的常规玻璃封装相比，通过在 PVT 系统中集成增强型 RC 所获得的潜在收益并不大，因为玻璃在大气窗口中自然具有相当高的发射率。电效率和总火用效率分别提高了 0.76% 和 0.5%。至于夜间，可以获得额外的 4-7 W/m2 冷却功率。尽管有一些改进，但与商用 PVT 模块中的常规玻璃封装相比，通过在 PVT 系统中集成增强型 RC 所获得的潜在收益并不大，因为玻璃在大气窗口中自然具有相当高的发射率。电效率和总火用效率分别提高了 0.76% 和 0.5%。至于夜间，可以获得额外的 4-7 W/m2 冷却功率。尽管有一些改进，但与商用 PVT 模块中的常规玻璃封装相比，通过在 PVT 系统中集成增强型 RC 所获得的潜在收益并不大，因为玻璃在大气窗口中自然具有相当高的发射率。