定型相变通风屋面隔热性能影响因素分析

Analysis of Factors Affecting Thermal Insulation Performance of Shaped Phase Change Ventilation Roof

本文提出一种新型屋面结构,在屋面结构内部设置相变材料层和通风层,以提高屋面隔热性能。以定型相变通风屋面作为研究对象,采用CFD数值模拟软件建立中间层定型相变通风屋面的三维传热模型,模拟分析相变温度,相变材料厚度,空腔通风策略和空腔大小等因素分别对屋面热工性能和相变材料潜热利用率的影响。模拟结果表明,对于中间层定型相变通风屋面,相变材料厚度为25 mm、相变温度为33~35℃,通风速度为2.5 m/s,空腔半径为40 mm,是最为优化的屋面结构。该工况下中间层定型相变通风屋面内表面的最高温度相比于非相变通风屋面降低了3.38℃,内表面平均温度降低了1.68℃,衰减系数降低了0.167,延迟时间增长了4小时。

This paper proposes a new roof structure, in which a phase change material layer and a ventilation layer are arranged inside the roof structure to enhance the roof insulation performance. Taking the shaped phase change ventilation roof as the research object, the three-dimensional heat transfer model of the middle layer shaped phase change ventilation roof is established by CFD numerical simulation software. The effects of phase change temperature, phase change material thickness, cavity ventilation strategy and cavity size on the thermal performance of the roof and latent heat utilization of the phase change material are simulated and analyzed. The simulation results show that for the middle layer shaped phase change ventilation roof, the phase change material thickness is 25 mm, the phase transition temperature is 33~35 ℃, the ventilation speed is 2.5 m/s, and the cavity radius is 40 mm, which is the most optimized roof structure. Under this condition, compared with the non-phase-change and non-ventilation roof, the maximum temperature of the inner surface of the middle layer shaped phase change ventilation roof is reduced by 3.38 ℃, the average temperature of the inner surface is reduced by 1.68 ℃, the attenuation coefficient is reduced by 0.167, and the delay time is increased by 4 hours.