Investigating new measures by jointly employing distinct and local heat transfer enhancement in latent heat thermal energy storage systems for buildings

To address the issue of decreasing thermal storage capacity during the enhancing of latent heat thermal energy storage (LHTES) in buildings. This study proposes a hybrid two-step method to mitigate this effect. Step one segregates LHTES into fusible and refractory zones based on Phase change material (PCM) melting behavior. Step two employs local enhancements tailored to zone heat transfer characteristics. In this paper, solar radiation intensity, metal foam porosity, and nanoparticle mass fraction effects and sensitivity analysis on locally enhanced LHTES are numerically examined. Five performance indicators were used to evaluate. The results show that employing hybrid two-step method is effective to enhance the synergistic effect on natural convection and heat conduction. When the porosity increases from 92% to 98%, the energy storage capacity can be increased by 10.25%, the energy storage rate is increased by 8.61%, while melting time increased by 4.4%. Every 1 wt% of Graphene nano-particle adds, the heat transfer rate is increased by 0.6%, while energy storage decreases by 3%. The hierarchy of parameters influencing the performance of the LHTES system is as follows: solar radiation intensity holds the highest significance (accounting for 65.31%), followed by porosity (accounting for 31.25%), and then the mass fraction of nanoparticles (accounting for 3.2%). These findings provide valuable insights for the design and optimization of building energy storage systems.