Cycle cut-off criterion effect on the performance of cascaded, sensible, combined sensible-latent heat storage tank for concentrating solar power plants

Thermocline thermal energy storage (TES) technology that uses the molten salt as heat transfer fluid is cheaper than a traditional two-tank structure, owing to its composite design and use of inexpensive filler materials. Nevertheless, this TES type suffers from the significant disadvantage of low capacity and utilization ratio when it is integrated with concentrating solar power plants due to moderate charge/discharge cut-off values. The primary purpose of the current research is to investigate and evaluate the impact of the change charge/discharge cut-off values on the thermal performance of six different TES tank configurations. First, the equations for the dispersion-concentric model were approached through the MATLAB program, and then the present research results are authenticated. The results show that the thermocline zones shrink when the charge cut-off value rises, and the discharge cut-off value reduces because a higher charge cut-off value and a smaller discharge cut-off value permit a longer charge/discharge time. Moreover, when the cut-off value of the charge/discharge changes simultaneously, the combined sensible-latent heat storage configuration has the highest capacity ratio, utilization ratio, recovered energy, and overall efficiency, which equals 90.55%, 83.3%, 147.2 MWh, 91.3%, respectively, at low charge cut-off value.