The theoretical efficiency of solar thermophotovoltaic (STPV) systems is much greater than their efficiencies achieved in practice. Optical cavities can improve the performance of STPV systems by increasing the emitter-to-PV cell view factor and by facilitating photon recycling, whereby photons are reflected back to the emitter. Photon recycling reduces losses and increases the temperature of the emitter, thereby increasing efficiency. Our study presents STPV systems comprising optical cavities in the form of oblate and prolate spheroids. The geometry of the optical cavity can be tuned to control the degree of photon recycling, emitter temperature, emission losses, and the emitter-to-PV cell effective view factor and separation distance without using complex nano- or microstructured materials or optical filters. Numerical analysis shows an optical cavity in the form of a prolate spheroid, prolate spheroid with a middle annular aperture specular reflector, and integrated oblate- and prolate-spheroid can be used to achieve efficiencies of 17.7%, 18.9%, and 22%, respectively, under solar irradiation at a concentration factor of 1500X. These robust spheroid-based optical cavities can be used to design improved STPV systems with increased durability and higher performance.

中文翻译：

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基于球体的光学腔，用于稳健的太阳能热光伏系统中的可调谐光子回收和发射器温度控制

太阳能热光伏 (STPV) 系统的理论效率远高于其实际实现的效率。光学腔可以通过增加发射器到 PV 电池的视角系数和促进光子回收来提高 STPV 系统的性能，从而将光子反射回发射器。光子循环减少了损耗并增加了发射器的温度，从而提高了效率。我们的研究提出了 STPV 系统，其中包含扁球体和长球体形式的光腔。无需使用复杂的纳米或微结构材料或滤光片，即可调整光腔的几何形状以控制光子循环程度、发射器温度、发射损耗以及发射器到 PV 电池的有效视角系数和分离距离。数值分析表明，长球体、具有中间环形孔径镜面反射器的长球体以及集成扁球体和长球体形式的光学腔可分别实现 17.7%、18.9% 和 22% 的效率，在 1500X 的聚光因子的太阳照射下。这些坚固的基于球体的光学腔可用于设计改进的 STPV 系统，具有更高的耐用性和更高的性能。