紫禁城古建筑的避暑方法

HEAT INSULATION FOR ANCIENT BUILDINGS IN THE FORBIDDEN CITY IN SUMMER

北京夏季高温时间较长,对建筑隔热提出了较高的要求。位于北京市中心的紫禁城是明清皇家宫殿建筑群,在历史上有着较多的建筑隔热做法,主要表现为:主体建筑坐北朝南,南面大量开设门窗以利于通风;建筑群背山面水,以利于水的蒸发来降温;建筑墙体采取“填馅”做法,建筑屋顶厚重,并采取架空梁架形式,以阻碍室外热量向室内的传递;屋檐采取起翘做法,避免烈日在正午时间照入室内;在庭院内搭设体量巨大的凉棚,以遮日通风;建造地下式的冰窖建筑,以利于藏冰纳凉;采用导热系数小的木、砖作为建筑材料等。

Beijing usually has a long period of high temperature in summer,which demands that the buildings have good heat insulation performance.The Forbidden City in the center of Beijing has been the power site for emperors during Ming and Qing dynasty,which owns sorts of heat insulation methods.Its main buildings located parallel to east-west direction,with lots of windows and doors opening towards south direction,which is beneficial to ventilation.There is a river in south part of the Forbidden City,whose steam can make the buildings cool.The thick wall and roof,the beam system can all hold up the heat transfer from outdoor.Turn-up roof eave avoids indoor sunshine at midday of summer.The huge pergola is erected in courtyard for shading and ventilation.The underground structure of ice cellar produces a cool site.Besides,the building materials such as wood,brick and so on have small thermal conductivity.