Experimental and numerical investigations of water–ice phase change under non-uniform cold source configurations

Phase change cold storage technology has attracted significant interest due to its high energy density and stable temperature regulation, offering promising prospects for renewable energy utilization and thermal management. However, under practical conditions, cold sources are often distributed unevenly, and the influence of this non-uniformity on freezing behavior and system performance remains insufficiently understood. This study integrates experimental measurements and numerical simulations to investigate the effect of non-uniform cold source configurations on the water–ice phase change process. A phase change heat transfer model is developed using ANSYS to examine the phase interface evolution, temperature distribution, solidification behavior, and cold energy storage performance under five representative cold source arrangements. Experimental measurements demonstrate good agreement with the numerical simulations, thereby validating the model. The results indicate that the configuration of the cold source significantly affects temperature uniformity, freezing dynamics, and energy storage efficiency. The fully covered uniform cold source configuration (Case 1) achieved the fastest freezing and highest storage rate. In contrast, a concentrated and uneven layout (Case 2) causes a 33.12% reduction in storage rate and a 52.80% increase in freeing time, showing the least effective performance. A moderately spaced, dispersed configuration (Case 3) improved heat transfer and enhanced storage efficiency when cold source resources were limited. This work emphasizes that the uniformity, continuity, spacing, and positioning of cold sources to the storage volume are critical factors affecting the system performance. These insights provide practical guidance for the development of more efficient thermal storage devices.