Thermo-economic evaluation of PCM layer thickness change on the performance of the hybrid heat storage tank for concentrating solar power plants

The current research examines how increasing the thickness of the phase change material (PCM) layer impacts the thermal and economic behavior of the hybrid sensible-latent heat storage reservoir utilized in solar power plants in order to prevent temperature fluctuations at the end of discharge cycles. On the basis of two-phase dispersion-concentric equations, a detailed transient numerical analysis is developed. The mathematical model equations are computed using the MATLAB program, and the present numerical findings are validated. Numerical investigations are used to compare the proposed storage system to the sensible heat storage (SHS) system in the context of cost and efficiency. The impact of various performance evaluation indexes, including axial temperature allocation, thermocline layer degradation, charging time, discharging time, and overall efficiency, are investigated. The results showed that the (35% PCM-30% SHS-35% PCM) configuration possesses the most considerable thermocline thickness of 7.94 m at the charge period of 360 min, while the SHS case has 3.2 m thermocline thickness at the charge period of 420 min. Due to its optimized efficiency, reduced thermocline area, and comparatively low cost, the (15% PCM-70% SHS-15% PCM) configuration demonstrates a more viable choice among the considered cases.