Numerical simulation and performance analysis of cascaded latent heat storage systems under steady and unsteady inlet temperature conditions

Cascaded latent heat storage (CLHS) is a promising technology for enhancing heat transfer and enabling multi-level heat utilization. However, practical heat sources , such as solar thermal energy and industrial waste heat , often show significant fluctuations in their output. This study utilizes numerical simulations to investigate the performance of three LHS configurations—single-stage LHS, series CLHS, and parallel CLHS—under steady and unsteady inlet temperature conditions. Results demonstrate that CLHS significantly enhances both heat storage and discharge rates. Under steady-state conditions, series CLHS and parallel CLHS exhibit 9.35 % and 10.03 % higher heat storage rates, respectively, compared to single-stage LHS. Under non-steady-state conditions, CLHS demonstrates superior robustness, storing more heat even with significant inlet temperature fluctuations. Notably, series CLHS experiences higher heat loss compared to parallel CLHS. These findings suggest that series CLHS is suitable for applications prioritizing rapid charging where heat loss is less critical, while parallel CLHS is advantageous when balanced charge/discharge rates, stability, and minimal heat loss are of paramount importance. • Cascaded latent heat storage (CLHS) holds promise for enhanced heat transfer and multi-level heat utilization. • Numerical simulations explore LHS configurations under steady and unsteady inlet temperature. • Series and parallel CLHS show superiority under steady-state conditions. • CLHS demonstrates robustness under non-steady-state conditions. • Parallel CLHS is advantageous for balanced performance.