中国“天井”好神奇！外媒关注：建筑竟然自带避暑功效？
中国古代建筑还会自己降温？没错！在没有空调的古代，天井不得不说是古建筑的一项伟大发明。
什么是天井？在中国传统建筑中，房屋和房屋、房屋和墙壁之间围成的空间是天井。天井可以追溯到明清时期，在解决采光的同时，让室外风进入室内并从天井排出，形成自然的“空调系统”，改善通风、收集雨水。
Skywells are smaller, less exposed spaces within a building and were a typical feature of homes in southern and eastern China, dating back to the Ming and Qing dynasties. Skywells were originally designed to cool buildings before air-conditioning and to allow in light, improve ventilation, and harvest rainwater.
近日，英国广播公司（BBC）也发现了中国“天井”中蕴含的智慧，并对“天井”中避暑、绿色的理念做了详细的报道。
BBC: 中国古代“天井”如何给房屋降温
“天井”是如何给建筑降温的
中国天井瓦檐精巧，环境幽雅，不仅具有地方民俗特色，还是历史文化的重要表征。梁思成先生说：“建筑之始，产生于实际需要，受限于自然物理，非着意于创新形式。”中国传统建筑中，没有哪种构思是纯粹为了装饰的，都有其实用价值。
图源：视觉中国
英国广播公司（BBC）采访了一位在江西省婺源县花了30多年时间修复天井住宅的中国老人俞友鸿。俞友鸿表示，在空调出现之前，人们设计天井是为了给建筑物降温。当有风吹过时，风可以通过天井的开口进入室内空间。由于室外空气通常比室内空气更冷，吹进来的微风沿着墙壁吹到较低的楼层，取代室内温暖的空气，形成气流，使室内温暖的空气上升并通过开口离开。
Skywells were designed to cool buildings in an era well before air-conditioning existed. When wind blows above a skywell house, it can enter the indoor space through the opening. Because outdoor air is often cooler than indoor air, the incoming breeze travels down the walls to the lower stories and create airflows by replacing warmer indoor air, which rises and leaves through the opening.
同时，文章还分析了影响“天井”降温效果的两种因素。首先，在没有自然风的情况下，由于“烟囱效应”，空气循环仍然在天井住宅内进行。天井顶部和底部之间的温差使天井内的热空气上升，将房间里的冷空气吸引到天井底部，从而实现降温的效果。
Even when there is no natural wind, air circulation still takes place inside a skywell home due to the "chimney effect". The temperature difference between the top and bottom of the skywell means warm air inside the skywell rises, drawing cooler air from the rooms to the bottom of the skywell.
图源：视觉中国
其次，作为室内生活和室外环境之间的过渡空间，天井起到了有效的热缓冲作用，保护居民免受室外热空气的影响。但是，天井冷却效果的最大部分实际上是在外壳内有水体时产生的。蒸发的水冷却热空气，这一过程被称为蒸发冷却。
As a transition space between indoor life and the outdoor environment, a skywell acts as an effective heat buffer to shield residents from the hot air outside. But the largest part of skywell's cooling effect actually comes when there are bodies of water in the enclosure.
在2021年，对两个传统村落天井民居进行的一项研究发现，蒸发冷却可能是天井内平均温度比外部平均温度低2.6-4.3摄氏度的主要原因。
A 2021 study of skywell dwellings in two traditional Huizhou villages found that evaporative cooling was likely the main reason that average temperatures inside the skywells were 2.6-4.3 C lower than the average external temperatures.
“天井”的现代妙用
天井，是中国古人追求“天人合一”的范例。通过天井，住宅与自然互动，人与天地对话。如今，古建筑中的“天井”也和现代建筑设计理念相结合，焕发新的生机。
目前，建筑师在设计新建筑时正在借鉴“天井”的节能原理。例如，位于济南的国家重型汽车工程技术研究中心。这座去年竣工的18层玻璃幕墙塔楼中间有一个巨大的室内天井，从5层一直延伸到顶层。
Architects are now looking towards the principles behind skywells while designing new buildings to save energy. One example is the National Heavy Vehicle Engineering Technology Research Center in the eastern Chinese city of Jinan. The 18-storey glass-walled tower block, completed last year, has a giant interior skywell in the middle, which stretches from the fifth to the top floor.
位于济南的国家重型车辆工程技术研究中心的巨大天井。图源：悉地国际
来自上海CCDI悉地国际集团的建筑师说，电梯、卫生间和会议室都位于井道周围，这样有助于改善建筑的采光和通风，降低整体能耗。
The elevators, toilets and meeting rooms are all situated around this shaft, which helps improve the lighting and ventilation of the center and reduces the overall energy consumption, the architects, from the Shanghai-based CCDI Group say.
文章还指出，一些摩天大楼出于实用性考虑，利用天井的通风原理改善空气流通。例如，位于广东省的68层高的东莞TBA大厦通过内部“风管”将自然气流引入每一层，其功能与天井类似。该大厦的总经理表示，这样做的目的是利用自然通风来保持大厦春秋两季的舒适温度。
Some skyscrapers use the ventilation principle of skywells to improve airflows without building a courtyard out of concerns of practicality. The 68-storey Dongguan TBA Tower in Guandong province, for example, brings natural airflows to every floor with internal "windpipes" that function in a similar way to skywells. The tower's general manager said that the aim is to keep the building’s temperature comfortable in spring and autumn, using only natural ventilation.
在以夏季炎热潮湿而闻名四川，一些旅游村也拥有一系列带天井和大屋檐的圆形房屋，从而达到给房屋降温的目的。
Meanwhile, a popular tourist village in Sichuan – a province known for its hot and humid summer – has a series of round houses with skywells and large eaves.
“天井”中蕴含的绿色理念
文章还肯定了“天井”在绿色发展领域的作用。荷兰莱顿大学区域研究所环境人文博士后研究员王正峰（音译）表示，天井等古代 “绿色智慧”不断启发着当今的气候适应性设计和被动降温创新。被动降温是一种结合设计和技术的方法，可以在不使用电力的情况下为建筑物降温。
Ancient "green wisdom" such as skywells continue to inspire today's climate adaptive design and innovations in passive cooling, according to Wang Zhengfeng, a postdoctoral researcher in environmental humanities at the Institute for Area Studies at Leiden University in the Netherlands. Passive cooling is a method that incorporates design and technology to cool a building without the use of power.
图源：视觉中国
王正峰也指出了将天井引入现代设计的一些挑战。她说，天井促进自然采光、通风和雨水收集的机制众所周知，但这些原则的应用需要因地制宜。
However, Wang points out some challenges for bringing skywells into modern designs. The mechanisms of courtyards facilitating natural lighting, ventilation and rain collection are well known, but applying these principles needs to be site-specific, she says.
她表示，随着人工照明、空调和供水的普及，我们依赖于这些带给我们便利的技术而很少考虑环境成本，如果不反思我们当前的行为，只学习过去，要实现可持续发展并不容易。
"Meanwhile, artificial lighting, air-conditioning and water supply have become so readily available that we depend on them with little regard for the environmental cost," she adds. "It won't be easy to be sustainable by learning from the past without reflecting on our current behaviours."
“天井”是古建筑的避暑神器，你还知道建筑的其他避暑方式吗？欢迎留言分享！
编辑：朱迪齐
实习生：戴博晓
来源：BBC 古建家园 illuminem
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