Advanced parametric optimization of a nanofluid augmented PCM-based latent heat thermal energy storage system

With the increase in energy crises and consequently the rapid depletion of fossil fuels, harnessing solar energy is imperative and on the rise. However, the storage of solar energy for retention and later use demands the need for optimized and efficient storage systems. This study is concerned with the evaluation of various parameters affecting the performance of a packed bed latent heat storage system. Additionally, this work proposes utilizing four different types of paraffin PCMs as encapsulation fillings and five different types of novel heat transfer fluids (HTFs). Furthermore, an improved optimization was carried out to arrive at the best charging time. This analysis was carried out by discretizing the governing equations using a finite element scheme under suitable boundary conditions.The results suggest that the charging time depicts a distinct U-shaped curve between the considered porosity values of 0.15 and 0.7. The results show a maximum reduction of 9.37% in charging time when the bed porosity is 0.35. Additionally, increasing the water flow rate to 25 l/min causes the charging to complete in 10.125 h. Similarly, the reduction in encapsulation size shows maximum decrease at both 15 and 20 mm to be 6.10%. Cumulatively, at the optimized individual parameters, the charging time drops to just 9.25 h, thus showing the maximum decrement in charging time of 14.54% for the PCM storage medium RT56-58 in conjunction with the nanofluid designated as slurry(S).