Thermal performance of cascaded and combined sensible-latent heat storage tank under fluctuations in sunlight and electric demand

Abstract

Based on its composite construction and usage of low-cost filler materials, thermocline thermal energy storage technology, which uses the molten as a heat transfer fluid, is more expensive than a conventional two-tank storage system. However, when integrated with concentrated solar power plants, the thermocline tank type experiences a significant disadvantage of low capacity and utilization ratio due to fluctuations in solar energy availability or an alteration in the electrical demand. The major concern of this subject is to look into, determine, and assess the charge and release cycle systems using various storage designs and under fluctuations in solar energy availability or a change in electricity demand. To examine the tank's cyclical thermal properties, a two-phase mathematical approach is developed. The current numerical formulas have been solved using the MATLAB program, and the findings of this analysis have been verified. The findings show that the combined sensible-latent heat storage scenario has the highest capacity ratio of 52.4%, the utilization ratio of 45.5%, retrieved energy of 181.06 MWh, and comprehensive efficiency of 67.3% than the cascaded layers heat storage scenario at a charging time of 11 h.