Assessment of the Thermal Efficiency of a Solar Storage Tank Employing Cascaded Phase Change Materials (CPCM)

This study assesses the thermal energy storage capabilities of a solar thermal storage system comprising multiple triplex-tube units. These triplex-tube systems incorporate three distinct phase change materials (PCMs), specifically RT44HC, RT54HC, and RT62HC. The heat transfer fluid employed here, namely water, captures solar thermal energy and subsequently conveys it to the cascaded PCM materials, where it is stored as latent heat. A numerical model is developed to combine the phase change and heat transfer processes using the enthalpy method. To validate the numerical model, a comparison is made with existing published data. The thermal efficiency of the triplex-tube storage system is examined in two scenarios: one involving a single PCM and the other utilizing cascaded PCMs. The analysis is conducted considering the meteorological data for Marrakesh city, Morocco.