© ArchDaily

How Do Double-Skin Façades Work?

由专筑网邢子，小R编译

双层表皮立面是指一个由两层表皮（通常是玻璃）组成的立面系统，空气通过中间的空腔流动。这个空间（从20厘米到几米不等）可以作为极端温度、风沙和声音的隔离层，改善了建筑在高温和低温等极端条件下的热效率。运用双层表皮立面最著名的例子之一就是由Foster+Partners设计的绰号为“小黄瓜”的圣玛丽阿克斯30号大楼。

中间空腔流动的气流可以通过自然产生，也可以通过机械驱动，双层玻璃也可以包含防晒装置。

Double skin façades. Almost a self-explanatory name for façade systems consisting of two layers, usually glass, where in air flows through the intermediate cavity. This space (which can vary from 20 cm to a few meters) acts as insulation against extreme temperatures, winds, and sound, improving the building's thermal efficiency for both high and low temperatures. Perhaps one of the most famous examples of double-skin facades is Foster+Partners' 30 St Mary Ax Building, "The Gherkin."
The airflow through the intermediate cavity can occur naturally or be mechanically driven, and the two glass layers may include sun protection devices.


Cortesia de Renzo Piano Building Workshop

虽然这种概念并不新鲜，但建筑师和工程师运用双层表皮立面的趋势却越来越明显。特别是在摩天大楼的设计中，因其透明的外观、热舒适性以及较少的噪音，可以降低空调的运行成本，消除对窗户专用技术的需求而备受青睐。

While the concept of double-skin façades is not new, there is a growing tendency for architects and engineers to use them. Particularly in skyscraper design, they are favored for their transparent façade, thermal and auditory comfort, reduced air conditioning costs, and elimination of the need for window-specific technologies.


Cortesia de Renzo Piano Building Workshop

此外，双层表皮立面不论在凉爽或是温暖的气候中，都具有很强的适应性。正是这种多功能性使得双层表皮立面变得多样有趣，可以通过一些微小的变化，例如随着打开或关闭进出气口的翼片或着启动空气循环器，立面就会发生相应的变化。

在寒冷的气候条件下，空气缓冲层可以作为阻止热量损失的屏障。空腔内被阳光加热的空气可以间接加热玻璃内的空间，减少了室内对供暖系统的需求。

Additionally, double-skin façades are adaptable to cooler and warmer weather. It is this versatility that makes them so interesting: through minor modifications, such as opening or closing inlet or outlet fins or activating air circulators, the behavior of the façade is changed.
In cold climates, the air buffer works as a barrier to heat loss. Sun-heated air contained in the cavity can heat spaces outside the glass, reducing the demand for indoor heating systems.


Cold climate. Image © ArchDaily

而在炎热的气候条件下，表皮可以利用空腔将热空气排出建筑，以减少太阳辐射并降低制冷负荷。多余的热量可以通过烟囱效应排出，因为空气密度的差异会产生循环运动，导致热空气逸出。当空腔内的空气温度上升时，空气被推到室外，在隔绝热量的同时还能给周围环境带来了一丝微风。

In hot climates, the cavity can be vented outside the building to mitigate solar gain and decrease the cooling load. Excess heat is drained through a process known as the chimney effect, where differences in air density create a circular motion that causes warmer air to escape. As the air temperature in the cavity rises, it is pushed out, bringing a slight breeze to the surroundings while isolating against heat gain.


Hot climate. Image © ArchDaily


Hot climate. Image © ArchDaily

总的来说，双层表皮立面非常依赖于能直接影响内部舒适度和用户生活质量的外部条件，例如太阳辐射、外部温度等。因此，精心的设计对于每一个案例都必不可少，需要详细了解包括太阳方位、环境、局部辐射、温度条件、建筑占用率等因素。下面我们将总结一些双层表皮的优点和缺点：

Overall, double-skin façades depend heavily on external conditions (solar radiation, external temperature, etc.) that directly influence internal comfort and user quality of life. Therefore, careful design is essential for each case, requiring detailed knowledge of solar orientation, context, local radiation, temperature conditions, building occupancy, and much more. We highlight, below, some of their benefits and disadvantages:


© Martin Van der Wal

优点

• 减少制冷和加热负荷；
• 带来清晰的视野和自然光；
• 改善隔离条件，无论是对于温度还是噪音；
• 带来自然通风和空气更新，创造健康的环境。
  

Benefits

• Reduce cooling and heating demand;
• Allow clear views and natural light;
• Improve insulation, whether thermal and acoustic;
• Allow natural ventilation and air renewal, creating a healthier enivronment.
  

© Martin Van der Wal

缺点

• 建设初期成本高；
• 空间消耗；
• 维护需求；
• 如果环境发生重大变化（例如，其他建筑物的阴影遮挡），表皮可能无法正常工作。
  

Disadvantages

• Much higher initial cost of construction;
• Space consumption;
• Maintenance demand;
• It may fail to function properly if the context changes significantly (shading by other buildings, for example).
  

© Sergio Grazia


© Cemal Emden


© Cemal Emden