JAILCD2025-034: Effect of Phase Change Temperature on the Performance of Encased PCM Radiant Floor Heating Systems

Abstract

To address the issues of slow heating and low efficiency in traditional encased phase change material (PCM) radiant floor heating systems (RFHS), this paper innovatively employs CFD numerical simulations to enhance system performance by adjusting the phase change temperature range of the PCM. Three temperature ranges, 298-303K, 303-308K, and 308-313K, were analyzed for their PCM thermal states, dynamic temperature trends, spatial temperature distribution, and heat flux. The results indicate that under a water temperature condition of 323K, the 303-308K range is the optimal phase change temperature for the encased PCM radiant floor heating system. This range achieves the highest PCM utilization rate, with the liquid fraction reaching 1 before the end of the heating phase, 9.89% higher than the 0.91 in the 308-313K range, and decreasing to 0.102 by the end of the cooling phase, 71.02% lower than the 0.352 in the 298-303K range. Furthermore, the temperature fluctuation on the floor surface within this range is the most stable, with a temperature difference of 5.75K, 10.58% lower than the 6.43K in the 298-303K range and 3.85% lower than the 5.98K in the 308-313K range. These findings provide theoretical support for optimizing and applying encased PCM thermal storage floor heating systems.