Phase change materials, better known as PCMs, have become an effective energy-efficient building retrofitting technology. The selection of PCM is one of the main aspects that affect the energy consumption of PCM integrated building. In the present study, a new parameter is proposed i.e. Measure of Key Response index for selection of PCM and for stating the effect of PCM thermophysical properties on the thermal performance of PCM integrated roof for different climatic zones of India. This parameter depends on ceiling temperature, time lag, decrement factor, and heat gain of a PCM integrated roof. With the design of the experiment method and range numerical simulations of PCM integrated roof in three climatic zones of India are carried out. Experimental design using Response Surface Methodology is used to produce the set of experiments to determine the optimum PCM.The effect of different PCM properties on the thermal performance of the building is demonstrated using range analysis. The results of this study show that the proposed index is useful for identifying optimum PCM and effect of different PCM properties for different climatic zone. It is also observed the order of thermophysical properties and optimum PCM varies for each climatic zone.

相变材料（更称为PCM）已成为一种有效的节能建筑翻新技术。PCM的选择是影响PCM集成建筑能耗的主要方面之一。在本研究中，提出了一个新的参数，即用于选择PCM的关键响应指数的测量值，以及用于说明PCM热物理特性对印度不同气候区的PCM集成屋顶热性能的影响。此参数取决于PCM集成屋顶的天花板温度，时间滞后，递减系数和热增益。通过试验方法的设计，对印度三个气候带的PCM集成屋面进行了数值模拟。使用响应曲面方法学进行实验设计来确定最佳PCM的一组实验，并通过范围分析证明了不同PCM特性对建筑物热性能的影响。这项研究的结果表明，所提出的指标对于识别最佳PCM和针对不同气候带的不同PCM特性的影响是有用的。还观察到热物理性质的顺序和最佳PCM在每个气候区都不同。