极端热湿气候区建筑外壁面总换热系数研究

RESEARCH ON TOTAL HEAT TRANSFER COEFFICIENT AT EXTERIOR BUILDING SURFACE IN EXTREME HOT-HUMID CLIMATE ZONE

统计中国不同气候区主要代表城市冬、夏季室外平均风速及逐时降雨情况,采用理论研究和数据统计相结合的方法,分析对流、辐射和蒸发换热系数的理论计算方法,进而计算各城市外壁面总换热系数。结果表明:极端热湿气候区风速远大于内陆地区且壁面潮湿概率可达0.042;中国北方地区及南方部分风速特别小、壁面潮湿概率相对较小的城市,总换热系数可按规范忽略蒸发换热,但南方风速大、降雨多或风速相对较小、降雨特别频繁的城市,则需要计算蒸发换热部分。极端热湿气候区建筑夏季潮湿外壁面总换热系数经计算可达39.0 W/(m^2·K),远高于规范值。

Based on the statistical work on outdoor average wind speeds in winter or summer and hourly rainfall condition of representative cities in different climate zones,the method to combine theoretical research and data statistics is adopted. Firstly the theoretical calculation methods of convection,radiation and vaporizing heat transfer coefficients at exterior building surface are analyzed respectively,and then the total heat transfer coefficient is calculated. It shows that the wind speed of extreme hot-humid climate zone is much higher than that of inland areas and the surface moisture probability of extreme hot-humid climate zone is up to 0.042. The total heat transfer coefficient for the cities located in northern area or southern area with climatic features of very low wind speed and relatively small surface moisture probability,can be in accordance with design code,ignoring vaporizing heat transfer. However,vaporizing heat transfer must not be ignored for cities with high wind speed and great rainfall or relatively low wind speed and especially frequent rainfall in southern area. Finally,this paper takes building in extreme hot-humid climate zone as research object to calculate the total heat transfer coefficient at moisture and exterior building surface in summer,it turns out that the calculated value is up to 39.0 W/(m^2·K)and much higher than recommended value.