A study on the thermal performance of pipes embedded in concrete pavement for snow removal using latent heat thermal energy storage

Traffic accidents caused by road freezing in winter exhibit a 1.5 times higher mortality rate than under normal conditions. To address this issue, this study developed a snow removal system that combines a latent heat thermal energy storage (LHTES) unit with a concrete pavement embedded with heat transfer pipes. A numerical study was conducted using a volume of fluid (VOF) model to simulate the transient phase change process, investigating the effects of various design parameters on thermal performance. Based on these results, a specially designed double helical coil was developed to enhance heat transfer efficiency within the LHTES unit. This study analyzed 88 numerical cases to investigate the effects of average coil diameter and the coil compactness ratio (CCR) on heat transfer performance in LHTES systems. When the CCR increased from 1.5 to 5.9, the heat transfer augmentation factor increased by 3.35 times, indicating enhanced thermal performance. The dimensionless Stefan-Fourier (SteFo) number and j-f factors were introduced to quantitatively analyze the heat storage and release characteristics of LHTES across different pipe configurations embedded in the concrete. Based on the optimized design, a prototype system was fabricated and experimentally tested in a climate-controlled chamber. Infrared thermography and thermocouple sensors were used to collect thermal performance data under controlled winter conditions. During a 50-h charging process, the temperature of the phase change material (PCM) increased from 30 °C to 75 °C, storing a total of 390 MJ of thermal energy. As a result, to raise the surface temperature of the concrete pavement from –5 °C to 15 °C, the system consumed 62.1 MJ of thermal energy, with a total construction cost of $7434, demonstrating its effectiveness in snow removal under simulated winter conditions.