How Ancient 'Skywells' Are Keeping Chinese Homes Cool
Many researchers are fascinated on how ancient 'skywells' are keeping Chinese dwellings cool. Southern China's skywells were important in keeping people's houses cool in the days before air conditioning.
40 year old Ru Ling enjoys hanging out in skywells. These courtyards of old Chinese residences are wonderful for her on a hot and humid day.
They are airy, cool and well-shaded.- Ru Ling
Ru resided in a century-old timber-framed house in the town of Guanlu in eastern China's Anhui province from 2014 until 2021. She relocated there for a change of scenery after spending many years living and working in air-conditioned facilities.
The natural cool feeling of my home in summer was so refreshing, and a rare find in the modern world. It also gave the house a calming and zen vibe.- Ru Ling
COPYRIGHT_CAM: Published on https://www.commercialarchitecturemagazine.com/how-ancient-skywells-are-keeping-chinese-homes-cool/ by George Evans on 2023-08-08T13:54:20.610Z
Ru claims that the house's skywell contributed to the cooling impact. And she's not alone in her praise for skywells in hot weather. According to research, the temperatures within certain skywells in southern China are up to 4.3 degrees Celsius cooler than the outdoors.
Skywell residences are becoming increasingly rare in today's rapidly urbanizing China, with air-conditioned apartments in multi-story structures and tower blocks serving as the primary form of housing.
However, a renewed interest in traditional Chinese design is prompting the restoration of certain old structures with skywells for modern use. Meanwhile, as the government pushes low-carbon construction ideas, some architects are borrowing inspiration from skywells and other ancient Chinese architectural elements to help keep new buildings cooler.
A skywell, also known as a "tian jing" (天井) in Mandarin, is a common feature of traditional homes in southern and eastern China. A skywell is smaller and less exposed to the outside environment than a northern Chinese courtyard, or "yuan zi" (院子).
According to a 2010 research published in the Journal of Nanchang University in China, they are widely encountered in residences from the Ming (1368-1644) and Qing (1644-1911) dynasties that were meant to host several generations of family.
Although the size and style of a skywell varies by location, it is usually always rectangular and positioned in the center of a house. It is surrounded on four sides by rooms or three sides plus a wall. Some big mansions feature many skywells.
They are rather frequent in traditional homes throughout most of southern and eastern China, including Sichuan, Jiangsu, Anhui, and Jiangxi. Huizhou (徽州), a historical area that spans modern-day Anhui and Jiangxi, has some of the best maintained.
Skywells were used to keep buildings cool in an age before air conditioning. Wind can enter the internal space through the aperture when it blows above a skywell home. Because outside air is frequently colder than indoor air, the entering wind travels down the walls to the lower levels, creating airflows by replacing warmer inside air that rises and exits through the aperture.
Yu Youhong, 55, has spent more than 30 years renovating skywell dwellings in Jiangxi province's Wuyuan county, which is part of the historic Huizhou. He has a plethora of information about skywells because he is the inheritor of intangible cultural assets recognized by China's Ministry of Culture and Tourism.
He claims that the primary functions of a skywell are to allow in light, increase ventilation, and collect rainwater. A skywell in Huizhou is modest but tall, and the rooms around it may block off sunlight on hot days, keeping the bottom of the skywell cool, he says.
Meanwhile, heated air from within the home can rise and leave via the hole above the skywell, which "works like a chimney."
The ground floor of old Huizhou houses normally have very high ceilings and face towards the skywell directly, which is good for ventilation. Some wealthy families had two or even three skywells, enabling them to have even better ventilation.- Yu Youhong
Although skywell structures have been there for hundreds of years in China, they have frequently been overlooked by those who prefer contemporary amenities. Skywell structures have made a comeback in the last two decades, thanks to a renaissance of traditional Chinese architecture as part of a larger rebirth of traditional Chinese culture.
Yu renovated one of the skywell residences in the village of Yan, Wuyuan county. Edward Gawne, a former marketing director from the United Kingdom, and his Chinese wife, Liao Minxin, purchased the decaying 300-year-old property in 2015.
With Yu's assistance, the couple converted the three-story mansion into a 14-room boutique hotel. Despite installing air conditioning in all of their bedrooms, Gawne and Liao left the social spaces surrounding the skywells in their original state: open and with natural airflow. According to Gawne, even without air conditioning, the skywell regions are quite pleasant in the summer.
Everyone notes when they step into the house how naturally cool it is.- Edward Gawne
Yu predicts that skywells, as an architectural feature, will become "more and more popular" among younger generations due to their ventilation and lighting capabilities, particularly as sustainability becomes a major factor in new building design.
Even when there is no natural wind, the "chimney effect" causes air circulation within a skywell residence. Because of the temperature differential between the top and bottom of the skywell, warm air inside the skywell rises, pulling colder air from the rooms to the bottom.
Due to the longer and hotter summers, traditional skywell residences further south in Lingnan (岭南), a historical region comprising of the modern-day Chinese provinces of Guangxi, Guangdong, and Hainan, as well as what is now northern and central Vietnam, had smaller and deeper skywells than other places.
A skywell, as a transition place between indoor and outdoor activity, serves as an excellent heat buffer, shielding occupants from the hot air outside. However, the majority of the cooling impact of the skywell occurs when there are bodies of water in the enclosure.
Evaporated water cools heated air, a process that is clearly reflected in Huizhou skywells. Huizhou households used to collect rainwater in their skywells because they felt it would protect and increase their riches.
Skywells in this area so have canals surrounding them to drain rainwater from the roofs. Some wealthier households, according to Yu, had a drainage system excavated under the skywell to guarantee that rainfall only left the home after circumnavigating the front hall beneath the earth.
Huizhou skywells also have a big stone vat in the center to keep water and put out flames. A study of skywell homes in two traditional Huizhou villages in 2021 discovered that evaporative cooling was most likely the key reason that average temperatures within the skywells were 2.6-4.3 degrees Celsius lower than average outdoor temperatures.
Today, government guidelines are beginning to play an important role in the reintroduction of skywells in new structures. Since 2013, the Chinese central government has advocated for green buildings that conserve resources and generate less pollution throughout their lifecycles.
A 2019 government directive mandated that 70% of structures constructed by 2022 fulfill its "green" standard, which includes a number of precise criteria such as how well insulated a building is and how ecologically friendly the building materials are.
Architects are now considering the ideas of skywells when constructing new structures in order to conserve energy. The National Heavy Vehicle Engineering Technology Research Centre in Jinan, China, is one example.
The 18-story glass-walled tower block, which was finished last year, features a massive inner skywell in the centre that extends from the fifth to the top level. The elevators, restrooms, and conference rooms are all located around this shaft, which helps enhance the lighting and ventilation of the center while also lowering total energy usage, according to the architects from Shanghai-based CCDI Group.
The former town hall site in the county of Jixi in Xuancheng, a section of ancient Huizhou, was transformed into a museum in 2013. The complex pays respect to its surroundings of Huizhou-style structures by including multiple skywells, which it claims deliver airflow to the inside and aid in the preservation of several historic trees on the property.
Meanwhile, in Sichuan, a region known for its hot and humid summers, a famous tourist town boasts a series of circular buildings with skywells and wide eaves. Because of practical issues, several buildings employ the ventilation idea of skywells to increase airflows without establishing a courtyard.
The 68-story Dongguan TBA Tower in Guandong province, for example, has internal "windpipes" that act similarly to skywells to offer natural airflows to every floor. According to the general manager of the tower, the goal is to keep the building's temperature acceptable in spring and fall by using solely natural ventilation.
According to Wang Zhengfeng, a postdoctoral researcher in environmental humanities at the Institute for Area Studies at Leiden University in the Netherlands who previously trained as an architect, ancient "green wisdom" such as skywells continue to inspire today's climate adaptive design and innovations in passive cooling.
Passive cooling is a technique that uses design and technology to cool a building without using electricity. However, Wang brings out several difficulties in incorporating skywells into modern architecture.
The processes of courtyards that allow for natural lighting, ventilation, and rain collection are widely understood, but she believes that adopting these concepts must be site-specific.
Because traditional skywells had varying shapes, sizes, and features that were highly dependent on their natural surroundings - for example, how much sunlight or rainfall was present in the region - incorporating skywells into modern buildings necessitates designers being sensitive to their project's context and situation, making them difficult to apply as a universal solution, she explains.
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. It won't be easy to be sustainable by learning from the past without reflecting on our current behaviours.- Wang Zhengfeng
Chinese skywells are built by integrating an open courtyard within a building complex, and they require regular cleaning and upkeep of the courtyard area. Maintenance also includes inspecting the surrounding rooms and ensuring the structural integrity of the building.
The layout around Chinese skywells provides privacy, security, and easy access to natural light and ventilation. It creates a buffer zone between the courtyard and the outside, optimizing functionality and livability of the building.
Yes, the Temple of Heaven in Beijing and traditional courtyard houses known as "siheyuan" in Beijing's hutongs are famous landmarks that incorporate skywells. They bring natural light into sacred spaces and living areas, respectively.
How ancient 'skywells' are keeping Chinese dwellings cool is really fascinating. When asked why skywells have gained popularity among modern Chinese people, Wang explains that the courtyard is also intended to serve as a meeting spot for families or communities, and it has ceremonial significance.
Perhaps changes in the way of life could also trigger vernacular nostalgia among people living in concrete and glass forests.- Wang Zhengfeng