Optimization of melting and solidification processes of PCM: Application to integrated collector storage solar water heaters (ICSSWH)

This work presents a detailed analysis of an improved Integrated Collector Storage Solar Water Heater (ICSSWH). This type of device is well suited for rural areas of Morocco because of its low cost, simplicity and compact structure. The innovation targeted in this system lies in the integration of a latent storage system by using a layer of phase change materials (PCM) in its lower part. Indeed, this integration is likely to increase the thermal energy delivered to the user during the night. The overall performance of the system depends on external climate data, type of PCM used and its mass, and flow rate of water. N-eicosane is considered as PCM in this application while hourly weather data corresponding to the city ER-RACHIDIA is used for the analysis. A detailed 2-D transient simulation has been established to optimize the system performance by studying the effect of different design variables and operating conditions. A deep analysis was also made to understand the PCM melting and solidification processes for a better exploitation of this storage technique. Optimized results are obtained when a mass flow rate of 0.0015 kg/s is used with a PCM thickness of 0.01 m and a set temperature of 313 K.