喷雾冷却下高倍聚光光伏光热“光-电-热”的耦合特性及机理研究

In recent years, concentrating photovoltaic technology developed rapidly, but the system is still not efficient because of the dual effects of concentrating energy flow density distribution and temperature field distribution. Considering the characteristics of "light-electric-heat" coupling in high-concentration photovoltaic, the temperature characteristics and illumination characteristics of photovoltaics under the influence of concentrating irradiation and temperature should be studied on the photoelectric conversion. The nonlinear coupling effect of photoelectric conversion is obtained, and the corresponding IV curve correction model is obtained. With the characteristics of small temperature difference and no contact thermal resistance of spray cooling in thermal conversion, the heat transfer mechanism of spray cooling in single-phase zone and two-phase zone is explored, and the temperature field corresponding to flow heat transfer is studied. Finally, a thermoelectric composite model of high concentration concentrating system based on spray cooling is established.. Furthermore, this project will investigate the following aspects by both numerical simulation and experimental method: the characteristics of different spray cooling parameters, the heat transfer characteristics of the photovoltaic system and the uniformity of temperature field under external environmental conditions, and a single or two phase zone performance evaluation of thermoelectric matching in the phase region will be given which provides guiding suggestions on the future application of the high concentrating photovoltaic/thermal system.

近年来高倍聚光光伏技术发展迅猛，但由于聚光能流密度分布及温度场分布的双重影响，其系统效率仍然不高。本项目针对高倍聚光光伏中“光-电-热”三者耦合影响的特点，在光电转换上，研究聚光辐照及温度耦合影响下光伏的温度特性及光照特性，揭示两者对光伏光电转换的非线性耦合影响规律，获得相应的I-V曲线修正模型；在光热转换上，结合喷雾冷却换热温差小、无接触热阻的特点，探索高热流密度下喷雾冷却在单相区及两相区的换热机理，研究对应流动换热下温度场的均匀性，获得喷雾冷却式高倍聚光光电光热转换复合模型。此外，本项目采用理论模拟与实验测试相结合的方法，对不同喷雾冷却参数特性及外部环境条件下高倍聚光光伏的换热特性及温度场均匀性等进行研究，给出喷雾冷却在单相区和两相区内热电匹配的性能评价，为高倍聚光光伏光电光热综合利用技术的发展提供指导性建议。

高效冷却散热技术是保证高倍聚光光伏安全、稳定运行的关键，本项目采用的喷雾冷却方式不仅解决了传统水冷散热存在接触热阻的问题，还能获得更为均匀的电池表面温度场分布。项目开展了喷雾冷却下高倍聚光光伏光电光热综合利用系统的理论与实验研究，获得了聚光辐照与温度场对聚光光伏光电光热转化性能的影响机理，构建了高倍聚光光伏光-电-热多场耦合的理论模型，从光、电、热多角度揭示了聚光光伏光电光热综合利用过程中能量转换的协同机理；搭建了基于喷雾冷却的聚光太阳能实验测试平台，研究了不同聚光倍数、不同进口温度、不同喷雾特性（喷嘴高度、工质参数、喷雾角度、流量、压力等）、不同环境工况下液膜特性、光电转换特性、光热转换特性和系统综合性能。一方面通过太阳能模拟器进行室内稳态实验测试，另一方面通过搭建室外聚光光伏实验测试平台进行不同室外环境下的动态实验测试，全面分析不同工况下辐照强度、温度等参数对光伏电池电效率和热效率的影响。研究表明，通过改善喷雾后电池表面的液膜分布能极大提升光伏界面的热电输出特性；喷雾冷却的电效率比传统射流提高6.5%，出口温度提高18%。出口温度与热界面温度的温差可控制在5℃左右，能够实现60℃以上高温热水的供应。在此基础上，提出了基于喷雾冷却的高倍聚光光伏光热系统㶲分析方法，获得了系统的热电匹配优化方案，为高倍聚光光伏光热综合利用系统的推广应用提供了理论依据和指导性方法。