【作者】 黄春勇；

【导师】 王厚华；

【作者基本信息】 重庆大学 ， 供热、供燃气、通风及空调工程， 2008， 硕士

【摘要】 长江流域地区的建筑气候特征十分复杂,夏季气候炎热,冬季阴冷,突出表现在夏季时间长,太阳辐射强度大。该地区的窗户节能应侧重在夏季隔热上,兼顾冬季保温。由于《夏热冬冷地区居住建筑节能设计标准》(JGJ134-2001)对住宅建筑窗户的传热系数提出了更严格的标准,因此要求新建住宅建筑上推广使用节能玻璃窗。中空玻璃具有良好的保温隔热、降低冷辐射和不结露等性能,将替代双玻窗成为住宅上首先考虑选用的节能产品。论文主要研究中空玻璃的热工性能,着重通过传热系数这一节能指标来研究中空玻璃的最佳空气夹层厚度。论文首先分析了中空玻璃的节能原理,提出了影响中空玻璃节能性能的主要因素,包括原片玻璃、空气夹层的厚度与气体种类,室内外的环境条件等。对中空玻璃的热工计算进行分析,尤其是对空气夹层的传热热阻进行计算。在理论分析的基础上,论文采用数值模拟方法对中空玻璃空气夹层内的自然对流换热进行分析。采用常壁温边界条件对不同的中空玻璃结构和壁面温度条件进行模拟。模拟结果表明,空气夹层内自然对流换热的主要影响因素包括夹层内的气体种类、夹层的相对厚度δ/ H和夹层冷热壁面温差ΔT ,其中夹层厚度对对流换热的影响最大。辐射换热是中空玻璃主要的传热形式,导热和对流所占比例较小。对空气夹层来说,辐射换热量是一常数,空气夹层的最佳厚度即是是对流换热量达到最小的厚度。并对空气夹层内的温度场、速度场和压力场进行了分析,发现空气夹层内的对流微弱,可以把传热过程近似看成纯导热。由模拟结果计算中空玻璃的传热系数K,与玻璃热工计算的成熟软件的计算数据比较吻合。然后以长江流域地区的七个主要城市为代表,模拟计算了各城市的中空玻璃最佳空气夹层厚度。为了验证模拟结果的可靠性,论文采用了正交试验。对空气夹层厚度、高度以及冷热壁面温度3大因素进行正交试验设计。实验采用热水箱法,通过实验测量空气夹层的热流量Q、热壁面温度t H和冷壁面温度t C以及空气夹层壁面积A,以公式Q = h_s (t_H - t_C )A计算空气夹层的当量换热系数。由于实验装置的散热损失较大,实验结果与模拟结果在空气夹层传热系数值上相差较大,但是对空气夹层最佳厚度的确定仍具有指导意义。论文最后分析了中空玻璃在建筑上的适用性,对住宅建筑使用中空玻璃和其他玻璃的能耗进行对比分析,中空玻璃对减少建筑能耗具有明显的作用。更多还原

【Abstract】 In Yangtze River zone, it is very complex in the construction climate characteristics, hot in summer and cold wet in winter, especially long time in summer and huge of solar radiation intensity. Energy saving in window should focus on thermal insulation in summer and heat preservation in winter. Owing to the norm,“Design standard for energy efficiency of Residential Buildings in hot summer and cold winter zone”(JGJ134-2001), held out more strict standard for the heat transfer coefficient of window in the residential construction ,it is required to amply to use energy saving glazing in new buildings. It keeps good performances of insulating against heat, reducing cold radiation and non-moisture condensation. Therefore it will substitute for double-pain window and become the energy saving products that considered being to use at first in residential buildings. The thermal technology performance of the insulating glass will be mostly researched in the paper, especially the optical air-layer thickness of the insulating glass will be researched by the energy saving index of heat transfer coefficient.The energy saving principle of the insulating glass in the paper has been analyzed at first. And then the main factors has put forward for the energy saving index of the insulating glass, including original block of glass, the air-layer thickness, kinds of gas and the environmental condition inside and outside the room, etc. The paper analyses to calculate the thermal resistance of the insulating glass, especially of the air-layer.On the basis of the analysis of theory, the natural convection in the air-layer of the insulating glass is adopted a law of numerical simulation. In the numerical simulation, it is adopted to use the condition of ordinary wall temperature for the different structure of insulating glass and the different wall temperature. The simulation results show that the main factors include kinds of gas in the layer, the relative layer thickness and the temperature difference between cold and hot wall for the nature convection in air-layer. Among the factors, the relative layer thickness is the most influential. The main heat transfer is the radiation heat transfer while the heat conduction and convection are relatively small in proportion. The radiation heat transfer assumes constant in the air-layer. So the optical air-layer thickness is assumed the thickness to make the convection heat transfer reach the minimum. The temperature field, the velocity field and the pressure field in the air-layer have been analyzed and the convection heat transfer in the air-layer is found faint and could approximation be regarded as the pure conduction heat transfer. The heat transfer coefficient is calculated by the results of simulation, compared correctly with the calculated data by the maturate software. Then, the optical air-layer thickness has been simulated in the main cities in the Yangtze River zone.To verify the simulation results, the orthogonal test is adopted in the paper. It designs for the three factors of the air-layer thickness and height and the temperature difference between cold and hot wall. The hot wall tank method is used in the experiment and the heat transfer throng the air-layer, the temperatures in cold and hot wall and the air-layer area was measured to calculate the heat transfer coefficient by the forma Q = K (t_H - t_C)A. Because the losses of heat were big in the experimental apparatus, there were great difference in calculating the heat transfer coefficient between the simulation and experiment. However, it is still directive significant to determine the optical air-layer thickness.The paper analyzes the applicability of the insulating glass in buildings finally. And the energy consumption through the insulating glass and else glasses were proceeded contrastive analysis. The results show that it is obvious to reduce the energy consumption in buildings.更多还原