Corrugated heat storage structures: An optimized solution for latent heat storage efficiency in fluctuating flows

Phase change material (PCM) plays a vital role in thermal energy storage across a wide range of applications, thanks to their distinctive properties and benefits. To address the pressing need for improved thermal energy storage efficiency in waste heat recovery systems exposed to fluctuating heat sources, such as exhaust gas and hot water, this study investigates the charging performance of Gas-PCM latent heat storage units under variable flow conditions. Using the enthalpy-porous medium model, the phase change dynamics of PCM under different heat transfer fluid inlet conditions are examined, with experimental validation integrated into the simulations to ensure the robustness of the model and methodology. The findings reveal that flat heat storage designs perform optimally under prominent temperature variations, while corrugated designs excel when large flow fluctuations dominate. Notably, under fluctuating flow conditions, the PCM melting time was reduced by up to 11.7 % compared to constant flow conditions, while the heat storage capacity, over a fixed duration, was enhanced by as much as 11.0 % relative to constant flow conditions, highlighting the critical role of flow rate dynamics over temperature variations in improving heat transfer efficiency and storage performance. These results provide valuable insights into the optimization of thermal energy storage systems for renewable energy applications, contributing to advancements in energy utilization efficiency. • This study optimizes Gas-PCM storage under fluctuating flow and temperature conditions. • Corrugated units reduce PCM melting time by 11.7 % and increase storage capacity by 11.0 %. • Flat units perform better with temperature changes, while corrugated units excel with flow fluctuations. • Flow rate dynamics are crucial for optimizing thermal energy storage efficiency in these systems.