The solar cooker is a vital device to attain sustainable development goals. Solar concentrating cookers (SCCs) are preferred mostly for intermediate to high-temperature cooking applications. The solar flux reflected and concentrated by the reflecting surface of the collector of a particular design of SCC are mainly responsible for the heating of the cooking pot/receiver. Hence, the quantification of the concentration-effect and subsequent assessment of effectiveness and role of reflecting surface in the opto-thermal performance analysis and rating of the SCCs is an essential and critical requirement.

This work proposes a thermal method to determine an Effective Concentration Ratio (C_eff.) for any design of SCC. Two thermal tests, with and without reflecting surface, were performed on the SCC. Results depict that determination of C_eff. allows the quantification of realistic concentration ratio and comments on the thermal and optical performance analysis of the SCC. The mean value of C_eff. is determined as 4.998 and the geometric concentration ratio computed to be ~ 12.35 for the SCC used in the present work. This result indicates the effectiveness of the concentrating surface. Thus, C_eff. is an effective tool to estimate the efficacy of/degradation in the performance analysis of reflecting surface of the different designs of the SCCs and can be effectively used for grading of SCCs. This method may be helpful for other solar concentrating collectors of several design configurations as well.

太阳能炊具是实现可持续发展目标的重要设备。太阳能聚光炊具 (SCC) 主要用于中高温烹饪应用。由 SCC 特定设计的集热器的反射面反射和聚集的太阳能通量主要负责烹饪锅/接收器的加热。因此，在 SCC 的光热性能分析和评级中，浓度效应的量化以及随后对反射表面的有效性和作用的评估是必不可少的关键要求。

这项工作提出了一种热方法来确定任何 SCC 设计的有效浓度比 ( C _eff. )。在 SCC 上进行了有和没有反射面的两个热测试。结果描述了C _{eff 的}确定_。允许对实际浓度比进行量化，并对 SCC 的热和光学性能分析进行评论。C _eff的平均值_。被确定为 4.998，并且对于当前工作中使用的 SCC，几何浓度比计算为 ~ 12.35。该结果表明聚光面的有效性。因此，C _eff。   是在不同设计的 SCC 的反射面性能分析中评估/降解效果的有效工具，可有效用于 SCC 的分级。这种方法对于具有多种设计配置的其他太阳能集热器也可能有帮助。