旋转门Revolving door这东西，说起来是人类文明发展的重要一环，但你要说它没什么屁用也是对的。为什么有这种差异，就要从旋转门的起源说起。
在欧美地区室外较冷因此室內大多是开着暖气，在大楼中的热空气会延着大楼內部往上升，而在大楼的低楼层形成一个吸力将外面的空气吸进去 (所以在有烟囱的金炉烧金纸的时候, 金纸放在旁边就会自己被吸进去)。
这种现象在越高的大楼变得越明显，当楼高到一定程度之后一般的门在开关时会伴随有一股强大的气流而造成开关门及人员进出的危险。而旋转门的发明就是为了解决这个问题。在人进出的过程中旋转门可以完完全全隔绝室內外的空间，因此室內外的空气不会有对流，就不会有上述的问题。
另一个解决的方式就是设立双层门，內外门不同时开就也可以达成隔绝內外空气的效果。但是当人员进人出频繁的时候內外门就常会同时被打开而失去作用。所以说起来，旋转门是盖摩天大楼的关键技术之一，甚至可以說，没有旋转门的话，或许现在也不会有摩天大楼了。
但是在不开暖气的大楼，其实是没有‘烟囱效应’这个问题的。安装旋转门纯粹是崇洋媚外的表现，是多余无用的装饰品。
Skyscraper design requires some sort of draft block, such as revolving doors, to prevent the chimney effect of the tall structure from sucking in air at high speed at the base and ejecting it through vents in the roof while the building is being heated, or sucking in air through the vents and ejecting it through the doors while being cooled, both effects due to convection. Modern revolving doors permit the individual doors of the assembly to be unlocked from the central shaft to permit free flowing traffic in both directions, but this feature is typically used only during emergencies, or to admit oversize objects. Normally, the revolving door is always closed so that wind and drafts cannot blow into the building, to efficiently minimize heating and air conditioning loads.－－From Wikipedia
Skyscraper design requires some sort of draft block, such as revolving doors, to prevent the chimney effect of the tall structure from sucking in air at high speed at the base and ejecting it through vents in the roof while the building is being heated, or sucking in air through the vents and ejecting it through the doors while being cooled, both effects due to convection. Modern revolving doors permit the individual doors of the assembly to be unlocked from the central shaft to permit free flowing traffic in both directions, but this feature is typically used only during emergencies, or to admit oversize objects. Normally, the revolving door is always closed so that wind and drafts cannot blow into the building, to efficiently minimize heating and air conditioning loads.－－From Wikipedia
活到老学到老。上面仅仅是旋转门作用之一，想要知道更多‘旋转门到底是干嘛用的’，拜托自己上网查询。。。
来源网络
来源网络
