The solar irradiance received by the solar cell is partially lost as heat, which carries negative effect on its voltage and in turn, its generated power. This trapped heat within the photovoltaic module is considered waste energy. Hence, techniques to extract this heat to utilize it for thermal loads, such as water heating or drying, are presented throughout the literature. Most prominent technique is the hybrid photovoltaic thermal collector. This device will serve in cooling the solar cell and hence improving its efficiency during operation. Meanwhile, it will absorb the heat and transfer it into a working fluid. The fluid could be utilized directly or indirectly for thermal loads in moderate and low temperature range applications. The type of working fluid highly affects the photovoltaic thermal performance and its physical design. This paper tracks the development of working fluids and analyzes highly efficient photovoltaic thermals from the literature. Moreover, a lengthy discussion on state-of-the-art photovoltaic thermal systems is presented and recommendations for future works are listed as well.

中文翻译：

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先进的光伏集热器

太阳能电池接收到的太阳辐照度部分以热量的形式散失，从而对其电压产生负面影响，进而对其产生的功率产生负面影响。光伏模块内的这种滞留热量被认为是浪费能源。因此，在整个文献中都介绍了提取这种热量以将其用于热负荷（例如水加热或干燥）的技术。最突出的技术是混合光伏集热器。该设备将用于冷却太阳能电池，从而提高其运行效率。同时，它会吸收热量并将其转化为工作流体。该流体可直接或间接用于中低温范围应用中的热负荷。工作流体的类型高度影响光伏热性能及其物理设计。本文跟踪了工作流体的发展，并分析了文献中的高效光伏热学。此外，还对最先进的光伏热系统进行了长时间的讨论，并列出了对未来工作的建议。