Abstract In this work, a comparative experimental analysis of a conventional flat plate solar collector (FPSC) and an identical prototype with thermal storage system by PCM is presented. Thermal performance of the devices was studied from experimental and mathematical approaches. For experimental approach, both collectors were operated and analyzed simultaneously under the same real outdoor conditions. An experimental set-up monitored solar radiation, water inlet and outlet temperature, ambient temperature, wind speed, and temperatures of main components as glass cover, absorber plate and PCM. Heat transfer rates losses, internal PCM behavior as liquid fraction of PCM and accumulated energy were estimated and discussed using a mathematical approach. In this method, experimental results were evaluated to assess the performance of both collectors under the same operating conditions. In addition, different experimental cases were considered in order to improve the thermal performance of the prototype. Two different PCMs, a contact thermal conduction enhancement, and inclination of the collectors were analyzed. Experimental and analytical results indicate that the contact conduction between the absorber and PCM, and the selection of the PCM itself are key factors to increase the collector performance respect to conventional FPSC, while tilting the collector presented no significant improvement in latitude of the experimental tests. The prototype with PCM increased the night outlet temperature in 2 °C and maximum accumulated energy increased 630 Wh respect to the collector without PCM. The proposed improvements for collector with PCM rose the maximum liquid fraction of PCM from 0.3 to 0.9.

中文翻译：

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带和不带PCM的平板太阳能集热器的实验对比分析

摘要 在这项工作中，介绍了传统平板太阳能集热器 (FPSC) 和具有 PCM 蓄热系统的相同原型的对比实验分析。从实验和数学方法研究了器件的热性能。对于实验方法，在相同的真实室外条件下同时操作和分析两个收集器。一个实验装置监测太阳辐射、进水和出水温度、环境温度、风速以及玻璃盖、吸收板和 PCM 等主要部件的温度。使用数学方法估计和讨论了传热率损失、作为 PCM 液体部分的内部 PCM 行为和累积能量。在这种方法中，评估实验结果以评估两种收集器在相同操作条件下的性能。此外，还考虑了不同的实验案例，以提高原型的热性能。分析了两种不同的 PCM、接触热传导增强和收集器的倾斜度。实验和分析结果表明，吸收器和 PCM 之间的接触传导以及 PCM 本身的选择是提高集热器性能相对于传统 FPSC 的关键因素，而倾斜集热器对实验测试的宽容度没有显着改善。具有 PCM 的原型将夜间出口温度提高了 2 °C，并且最大累积能量相对于没有 PCM 的集热器增加了 630 Wh。