Sarah Kubitschek Hospital Salvador / João Filgueiras Lima. Image © Nelson Kon

交叉通风、烟囱效应等自然通风的其他概念
Cross Ventilation, the Chimney Effect and Other Concepts of Natural Ventilation

由专筑网李韧，蒋晖编译

自然风是一种免费、健康的、可再生资源，能够提高项目的舒适性。资源的健康意识和减少能源消耗的需求使得许多项目对于空调的运用逐渐减少。建筑师与工程师开始应用被动式系统来提升项目的热舒适性能。有证据表明，在一些极端气候亦或是人工系统之中，通风需求可能无法满足，但在大多数情况下，都能做到自然通风，从而通过被动式系统使得空气得以流通，尤其是在项目初始阶段，这些设计便尤为重要。

这是较为复杂的概念，但是我们可以通过一些方法将其简化。诸如自然交叉通风、自然烟囱效应、自然冷却体系等一系列的通风系统，以及良好的施工，能改善项目的热舒适性，减少能源消耗。

自然交叉通风是指在某种确定的环境或建筑之中设置开口，这些开口布置在相对或者相邻的墙体之上，便于空气的进入与排出。这种系统专为高温气候区的建筑而设，可以改变建筑内部的空气流通，并且有效降低室内温度。

MK27工作室设计的LEE住宅便应用了能够完全打开的窗扇，当窗扇放置在墙体之中时，体块能够在两个相对的墙体之间形成大型开口，从而保证充足的自然通风，同时通过稳定的空气变化而形成热平衡。

Nothing is more rational than using the wind, a natural, free, renewable and healthy resource, to improve the thermal comfort of our projects. The awareness of the finiteness of the resources and the demand for the reduction in the energy consumption has removed air-conditioning systems as the protagonist of any project. Architects and engineers are turning to this more passive system to improve thermal comfort. It is evident that there are extreme climates in which there is no escape, or else the use of artificial systems, but in a large part of the terrestrial surface it is possible to provide a pleasant flow of air through the environments by means of passive systems, especially if the actions are considered during the project stage.
This is a highly complex theme, but we have approached some of the concepts exemplifying them with built projects. A series of ventilation systems can help in the projects: natural cross ventilation, natural induced ventilation, chimney effect and evaporative cooling, which combined with the correct use of constructive elements allows improvement in thermal comfort and decrease in energy consumption.
Natural cross ventilation is when openings in a certain environment or construction are arranged on opposite or adjacent walls, allowing air to enter and exit. Indicated for buildings in climatic zones with higher temperatures, the system allows constant changes of the air inside the building, renewing it and still, considerably reducing the internal temperature.
Taking the Lee House by Studio MK27 uses window frames that allow full opening, when embedded inside the walls, the design solution allowed the volume to have large openings in two walls positioned opposite each other, providing abundant ventilation and causing thermal equilibrium by constant air changes.


Casa Lee / Studio MK27. Image © Fernando Guerra | FG+SG

诱导通风是指利用热压系统来冷却空气，热空气比冷空气轻，那么在这种情况下，在外部或者内部环境之中，热空气会上升，冷空气会下降。在这样的通风系统之中，开口位置会更靠近地面，那么冷空气便能通过热空气的上升而进入空间内部，在这样的空间之中，在上方天花板通常会设置有诸如天窗等通风口。

Induced natural ventilation refers to thermal induction systems are used to conduct air cooling. The warm air is lighter than the cold air, in this case, in an external or internal environment the warm air goes up and the cold air goes down. In this ventilation system, openings are positioned close to the ground so the cold air enters the space by pushing the mass of warm air above, where air outlets are positioned in the ceiling such as sheds and clerestory.


Sarah Kubitschek Hospital Salvador / João Filgueiras Lima. Image © Nelson Kon

这种模式的一大案例便是巴西的Sarah Kubitschek医院，该项目由巴西建筑师João Filgueiras Lima设计，建筑师通过弯曲的金属屋面，进行不同的尺度与方向的延伸与重复，然后通过上方的开口释放热空气与杂质，但仍保持室内的自然采光。需要强调的是，因为这是健康项目，因此需要适当地减少交叉通风系统的应用，因为这会引起病毒的传播。

An excellent example of this model is the Sarah Kubitschek Hospital in Salvador Brazil, designed by the Brazilian Architect João Filgueiras Lima, who through curved metallic sheds, with large and different extensions, successively repeated, ventilate the environments by the release of warm air and impurities through the upper openings, still guaranteeing natural light. It is worth emphasizing that in projects related to Health, it is avoided the use of systems that appropriate cross ventilation, since it can cause bacteria transmission by the propagation of air.


Reichstag / Norman Foster. Image© Renate Dodell via Flickr  Licença CC BY-ND 2.0

在高层建筑之中，建筑师常常应用竖向通风系统。冷空气在暖空气的压力下被迫上升，同时也引用了诱导通风系统。高层项目中心或塔楼的开口区域也使得同样的空气进行流通，然后再通过天窗等开口将气体排出室外。福斯特在德国议会大厦的穹顶项目中就应用了这种通风系统，气流会在穹顶顶部与外部封闭的倒锥形空间中流通，然后在顶部排出室外。

In vertical buildings, vertical ventilation flow through the chimney effect is constantly used. Cold air exerts pressure under the warm air forcing it to go up, as well as in induced ventilation. However, in this case, opened areas by the project center or towers allow the same air to circulate through the environment, leaving through the roof, clerestory, zenithal openings or wind exhausts. The dome of the New German Parliament, Reichstag, designed by Norman Foster is an example of this ventilation system. Through a summit with external glass closure and inverted cone with panels mirrored to the center allows air circulation in the building, which is released by the opening at the top.


Estratégias bioclimáticas do Edifício da Empresa de Desenvolvimento Urbano (EDU) em Medellin. Image Cortesia de EDU


Building of the Urban Development Company (EDU) in Medellin. Image © Alejandro Arango

在哥伦比亚麦德林全新城市发展公司（Urban Development Company——EDU）总部的施工中，工人们应用了高品质的预制外部表皮元素，这使得内部太阳能烟囱能够过滤外部冷空气。这些做法都是由简单的材料制作而成，而这些材料具有热质量控制和热力学概念效果，从而产生恒定气流的温度之中产生一定的变化，例如从冷到热，在工作空间中创造空气流动。

In the construction of the new Urban Development Company (EDU) headquarters in Medellin, an outer skin composed of high-quality prefabricated elements allows conduct to an internal solar chimney to refresh the outside cold air. This is done with simple materials that generate thermal mass control and thermodynamic concepts - convex and thermal forces - generating a change in the temperature of the constant fluid air, from the cold to the warm one, creating air currents in the workspaces.


Assembly Palace of Chandigarh / Le Corbusier. Image © Laurian Ghinitoiu

柯布西耶在昌迪加尔的设计作品，以及尼迈耶尔在巴西利亚的作品之中都应用了蒸发冷却系统，通过大型水面来形成主要的气体流向，在有开口的建筑前侧，风经过水面，形成一定比例的湿度状况，保证了空气的清新。

除了通风系统之外，建筑师们还应该考虑施工机制。

The evaporative cooling system, used in Le Corbusier's work in Chandigarh and Oscar Niemeyer's work in Brasilia, uses the availability of large water mirrors or lakes, strategically positioned towards predominant air currents, in front of buildings with openings, after floating above the water the wind follows with a certain percentage of humidity, guaranteeing freshness to arid climates.
In addition to ventilation systems, constructive mechanisms should also be considered.


Ventilation by Brise Soleil Diagram. Image © Matheus Pereira

一些设备是保证良好的自然通风，除了光线与太阳能控制之外，如果设计能够结合太阳能和当地的风力状况，那么就可以保证极佳的室内空间热舒适。它们还能够通过开口尺寸，以及各种材质来进行通风的计算。

Brises Soleil or sun breakers are excellent mechanisms to guarantee natural ventilation, which in addition to light and solar control if properly designed and positioned in conjunction with solar and local wind conditions, can guarantee excellent internal thermal quality. They also allow control, if furniture, or even in case of leaked elements (cobogos, perforated plates, mashrabiyas, among others) causes direct ventilation with the possibility of calculation in percentage according to the size of the openings.


Windows Openings Diagram. Image © Matheus Pereira

建筑师应当考虑开口的形式，在实际状况中，我们需要思考环境，即如果选择滑动玻璃的窗户，那么真正的通风率只有50%。跨度相同，如果我们选择一扇或者两扇窗户面板，那么整个通风状况则更加整体一些。根据窗户、门扇的选择，这也会直接或间接地影响风向，其中这氛围水平、竖直、倾斜三个方向，另外还会影响室内空气质量的百分比。

The consideration of the types of openings is indispensable. In a practical way, let us think of an environment that, if a window with two sheets of sliding glass is chosen, it is understood that when opening, only 50% of the opening will allow the wind to enter. With the same size of the span, if we opt for a window with one or two open sheets, the ventilation will be integral. Depending on the type of window, seal or door chosen, it will directly influence the direction of the winds (vertical, horizontal or inclined) and percentage of the inward air mass.


Ventilation diagram. Image © Matheus Pereira

另外还需要考虑的是通风障碍，例如在通高的空间之中，下部区域的开放入口和两扇位于对面中央墙体中部和最高点的窗户。那么在这里，中央墙体就扮演着障碍的角色，同时引导了风向。其他的元素也能够解决这些问题，例如通过多孔砖来替代砖石砌体。

墙体、窗台、面板、家具等开口与通风障碍的不同高度也直接或间接地影响了室内通风速度与程度。在每个项目之中，建筑师都应该注意结合考虑通风系统的类型与程度。

Barriers should also be considered. Think of an environment with a double ceiling height, an opening (door) in the lower area and two other openings (windows) positioned on the opposite wall in the middle and highest point, and in the center, a half-height wall. Of course, the central wall will act as a barrier and mandate the direction of the winds. Other constructive elements may help in solving the problem, such as the replacement of masonry with perforated bricks - cobogos.
The different heights of the openings and barriers (walls, sill, panels or furniture) arranged by the space also directly influence the level and speed of ventilation levels. In each project, attention should be paid to their arrangement according to the type and level of ventilation required.


Casa Lee / Studio MK27. Image © Fernando Guerra |  FG+SG


Planta_Casa Lee / Studio MK27. Image Cortesia de Studio MK27

参考：
ABNT 15.575. Guia para arquitetos na aplicação da Norma de Desempenho. Disponível em: <http://www.caubr.gov.br/wp-content/uploads/2015/09/2_guia_normas_final.pdf>. Acesso em 2017年12月31日.
GIVONI, Baruch. 建筑与城市设计的气候因素.  纽约: Van Nostrand Reinhold, 1998.
ROMERO, Marta Adriana Bustos. Princípios bioclimáticos para o desenho urbano.  2a ed. São Paulo: Pro E, 2000.
VAN LENGEN, Johan. Manual do arquiteto descalço. 1a ed. 圣保罗: B4 Editores, 2014. p.46-53.

References:
ABNT 15.575. Guia para arquitetos na aplicação da Norma de Desempenho. Disponível em: <http://www.caubr.gov.br/wp-content/uploads/2015/09/2_guia_normas_final.pdf>. Acesso em 31 Dez 2017.
GIVONI, Baruch. Climate Considerations in Building and Urban Design.  New York: Van Nostrand Reinhold, 1998.
ROMERO, Marta Adriana Bustos. Princípios bioclimáticos para o desenho urbano.  2a ed. São Paulo: Pro E, 2000.
VAN LENGEN, Johan. Manual do arquiteto descalço. 1a ed. São Paulo: B4 Editores, 2014. p.46-53.