Abstract The performances of parabolic dish collector systems depend on the losses encountered during converting solar energy into thermal energy. It encompasses optical losses from the reflector and heat losses through the solar receiver. The geometry and surface properties of the receiver were seen considerably influencing the system performance. Thermally conductive copper fins (conical shaped, tip/cone angle 30°) have been fixed inside the cavity surface for three different pitch values e.g. 12.5 mm, 22 mm and 44 mm. During brazing operation, a selective Copper Oxide (CuO) surface was formed inside of the cavity, on account of heating. The system collection efficiency values obtained using finned cavities were compared with that of smooth (conventional) one. Performance improvement of about 23.56% and 31.35% (on average) over a smooth cavity was noticed after providing conical protrusions on the radiative surface of the modified cavity receiver, with medium and higher heat boundary conditions. The percentage contributions of heat losses by conduction, convection, and radiation modes, from the examined cavities, were obtained as 1.4–3.2%, 70–75%, and 22–28% of the total losses, respectively, in case of medium irradiation concentration. The energy concentration was seen influencing these contributions of heat losses from the receivers. Mathematical analysis is also presented for comparing one of the experimental test situations outcomes.

中文翻译：

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中高热集中抛物面聚光器改进型腔体接收器的性能改进

摘要 抛物面盘式集热器系统的性能取决于将太阳能转化为热能过程中遇到的损失。它包括来自反射器的光损失和通过太阳能接收器的热损失。接收器的几何形状和表面特性明显影响系统性能。导热铜翅片（锥形，尖端/锥角 30°）已固定在腔体表面内，用于三种不同的节距值，例如 12.5 毫米、22 毫米和 44 毫米。在钎焊操作期间，由于加热，在空腔内部形成了选择性氧化铜 (CuO) 表面。将使用翅片腔获得的系统收集效率值与光滑（传统）腔的收集效率值进行比较。性能提升约 23.56% 和 31。在改进的腔体接收器的辐射表面上提供锥形突起后，注意到光滑腔体上有 35%（平均），具有中等和较高的热边界条件。在中等辐照的情况下，通过传导、对流和辐射模式从检查的空腔中获得的热损失百分比分别占总损失的 1.4-3.2%、70-75% 和 22-28%专注。能量集中被视为影响这些来自接收器的热损失的贡献。还提出了数学分析来比较实验测试情况的​​结果之一。在中等辐照浓度的情况下，来自检查腔的对流和辐射模式分别占总损失的 1.4-3.2%、70-75% 和 22-28%。能量集中被视为影响这些来自接收器的热损失的贡献。还提出了数学分析来比较实验测试情况的​​结果之一。在中等辐照浓度的情况下，来自检查腔的对流和辐射模式分别占总损失的 1.4-3.2%、70-75% 和 22-28%。能量集中被视为影响这些来自接收器的热损失的贡献。还提出了数学分析来比较实验测试情况的​​结果之一。