Abstract:

In order to determine the effects of the phase change material filled glass window (PCMW) on building energy consumption in the hot summer and cold winter area of China, dynamic heat transfer process and heat transfer parameters of the PCM filled glass window and the hollow glass window (HW) exposed to different non-steady boundary conditions related to the climatic characteristic of the sunny and rainy days both in summer and winter were investigated. The experiments of the dynamic heat transfer process of PCMW and the hollow glass window (HW) in a representative sunny summer day were conducted, and the one dimensional numerical simulations under the same condition were conducted. The temperatures of the interior surfaces of the two kinds of window were obtained. The results of experiment and simulation were in good agreement. Then the validated numerical model was used to simulate the dynamic heat transfer processes of the two kinds of windows at more different weathers which were representative both in summer and in winter, the temperature and heat flux fluctuations on the interior surfaces of the two glass windows were analyzed based on simulation results. According to the obtained results, it was concluded that in the representative sunny summer day, the peak temperature on the interiorsurface of the PCMW (glauber's salt) reduced by 10.2℃, and the heat entered the building through the PCMW (glauber's salt) reduced by 39.5%, comparing with the hollow glass window. However, in the representative rainy summer day, the representative sunny winter day and the representative rainy winter day, the dynamic thermal performance of the PCMW (glauber's salt) was unsatisfactory as it cannot decrease the building energy consumption. Long period measurements and monitoring of the PCMW will be further researched to validate long term performance prediction based on numerical simulation.

Key words: PCM-filled glass window, numerical simulation, experimental validation, heat transfer, temperature time lag, temperature decrement factor

摘要：

为了研究含相变材料的玻璃窗对夏热冬冷地区建筑能耗的影响,建立了相变玻璃窗和中空玻璃窗的动态传热数学模型并对两者在夏季晴天时动态传热过程进行数值模拟;搭建了玻璃窗动态传热性能测试装置并在夏季晴天条件下对两者进行了对比试验。获得了玻璃窗内壁面温度随时间的变化规律,计算结果和实验结果吻合良好。利用验证过的传热模型进一步分析了含相变材料Na₂SO₄·10H₂O的玻璃窗和中空玻璃窗在夏热冬冷地区冬夏两季晴天与阴雨天的动态热调节性能,得到了相变玻璃窗与中空玻璃窗内壁面温度和热通量随时间的变化规律。结果表明:在夏季晴天时,该相变玻璃窗内壁面的峰值温度比中空玻璃窗低10.2℃,通过相变玻璃窗进入室内的热量比中空玻璃窗减少39.5%。但是在夏季阴雨天、冬季晴天和冬季阴雨天时,该相变窗的动态热调节性能较差且无节能效果。

关键词: 相变玻璃窗, 数值模拟, 实验验证, 传热, 温度延迟, 温度衰减因子