空心砌块通风墙体热工性能实验研究

Experimental Study on Thermal Performance of Hollow Block Ventilation Wall

利用混凝土空心砌块中心孔洞上下贯通的特点,建立空心砌块通风墙体的实验模型,对武汉地区南向空心砌块通风墙体夏季设计日工况进行实验研究。通过实测墙体内外表面温度和热流,研究不同的空腔气流温度和速度对其隔热性能的影响,并与非通风墙体进行对比,探讨空心砌块通风墙体的隔热性能。结果表明:空心砌块通风墙体能够有效的提高墙体当量热阻,降低从室外传入室内的热量,有较大的节能潜力,空腔内风速对墙体热工性能影响较大。与不通风墙体相比,空腔内风速越大,其隔热性能越好,空腔内风速分别为0.3 m/s,0.9 m/s,1.5 m/s,1.9 m/s时,当量热阻由0.64 m^2·K/W增加为1.61 m^2·K/W,3.06 m^2·K/W,3.86 m^2·K/W和4.12 m^2·K/W,全天内表面热流分别降低40.5%,73.3%,79.4%和82.6%,墙体内表面平均温度分别降低1.8℃,2.8℃,3.0℃和3.1℃;气流温度对当量热阻和内表面热流影响较小。

The experimental model of hollow block ventilation wall is established by using the characteristics of the hole from up to down in the center of the concrete hollow block. The experimental study is carried out for the south hollow block ventilation wall on the design day of Wuhan. By measuring the wall surface internal and external temperatures and heat fluxes, the effects of different airflow temperatures and speeds in cavity on thermal insulation performance were compared with that of non-ventilation wall, and the thermal insulation performance of hollow block ventilation wall was discussed. The results show that： The hollow block ventilation wall can effectively improve the equivalent thermal resistance of the wall, reduce the heat transfer from the outside into the room, and has a great potential for energy saving, air velocity in the cavity has a great influence on the thermal performance of the ventilated wall. Compared with the non-ventilated wall, when the air velocity in the cavity is 0.3, 0.9, 1.5 and 1.9m/s, the thermal resistances increase from 0.637 m^2·KAV to 1.61, 3.06, 3.86 and 4.12 m^2.KAV, respectively; the heat fluxes of the internal surface are decreased by 40.5%, 73.3%, 79.4% and 82.6%, respectively, the average temperatures of internal surface can be cut by 1.8, 2.8, 3.0 and 3.1℃, respectively. The airflow temperature has little effect on the equivalent heat resistance and the heat flux of the internal surface.