Experimental investigations on a sensible heat thermal energy storage system towards the design of cascaded latent heat storage system

In the present work, a system comprising cylindrical vertical type sensible-based thermal energy storage (TES) tanks integrated with external type compound parabolic concentrating (XCPC) solar collectors and heat loading device was designed, fabricated, constructed, experimented, and analyzed. The XCPC solar collector system transfers the solar energy to charge the insulated TES tanks through heat transfer fluid circulation and discharge the energy to the selected application. The primary objective of the present research is to study the performance and stratification effects during the charging and discharging cycles through various parameters to select the suitable phase change materials (PCMs) for the proposed cascaded latent heat storage (CLHS) system. Further, experiments were conducted under simultaneous and sequential modes of charging and discharging processes. The performance analysis of the overall system on a time-average basis (0.125 hr) was carried out. The results revealed that simultaneous mode would help to collect more energy from the solar collector, and it increases the cumulative energy stored in the tank and the average charging efficiency of the tank. The same was also ensured from the stratification performance parameters, such as stratification number, Richardson number, and mix number. The higher stratification achieved in both modes revealed that the CLHS system with three different PCMs of phase change temperatures of 70 degrees C, 63 degrees C, and 53 degrees C, located at three different zones, will enhance the performance of the storage system. The results are highly beneficial for practicing engineers toward designing the CLHS system integrated with solar collector for any application.

Automated summary

In this study, a system combining thermal energy storage tanks with solar collectors and heat loading devices were designed and analyzed. The performance and stratification effects of the system were studied through experiments. The results showed that charging and discharging simultaneously could collect more solar energy and increase the efficiency of the tanks. The use of phase change materials with different phase change temperatures in the system improved its performance.