Dear Phebe,

Based on climatic condition ventilated façade play major role in ensuring comfort in built environment. I will suggest you to read papers on vernacular/traditional architecture. If you are interested you can read my publications on vernacular architecture.

Regards,

Manoj

Dear Phebe

One of the aspects that must be studied in depth in the design of the performances of infills, is the behavior in dynamic conditions.

In summer the infills must ensure a good thermal shift. When the mass of the infills is approaching to a critical threshold, variable in function of the adopted code (in Italy is 230 kg/square meter), the dynamic performances go down and the use of natural ventilation can be a valid solution to improve the dynamic behavior of the facade. The periodic thermal transmittance or the thermal wave shift are two of most important factors that permit to check the performance change in relation of the technological choice done (read as "natural ventilation)

I studied in depth this problem for a patent of new technology of innovative infill panels, I think that you will find some useful informations in the attached file.

Have a good work.

Marco 

There are thermal performance duties as well as other functions.

There are different type with different roles in different comfort zone. Sometime air coming from outdoor to indoor some time from indoor to outdoor as a part of adaptive comfort system ( that sets by adaptive comfort theory). Sometime is not connecting outdoor to indoor and works as part of thermal conditioner( that sets by thermal comfort theory). Sometime time duty is to reduce heat load of the sun.

Sometime playing as exhaust role in specific to industrial building. Some time duty is to reduce heat load of sun. Some time duty is to reduce wind-load to building. 

Dear Phebe,

In general, natural ventilation of buildings through their façade is quite important to achieve a sustainable thermal design. That is achieved though openings: windows and/or air inlets, depending on the design of the façade are related to the air introduced/extracted into/from the rooms near it, and generated airflow that affect the thermal conditions of buildings. Size and position of these openings change according to weather conditions, as you can easily see in vernacular architecture, as Manoj Kumar Singh indicates. Vernacular architecture will give you important clues about how buildings adapt to weather conditions to be sustainable.

But in some countries, what we refer to as “ventilated facade systems” are modern double skin facades, with air inlets to improve their thermal design. The orientation of the façade, as well as the size of the cavity between the double skin (related with “stack effect”), the size and position of the air inlets, related with “stack effect”, will affect the thermal performance (and the energy demand of the building), but also its condensation conditions, quite important if the material of the façade is glass. That is why the design of the performance of infills is so important as Marco Vailati explains.

But improving thermal performance is not the only reason for the modern “ventilated facade systems”. As Ali Keyvanfar indicates, there are other functions which are also important for the design of these facades, for different types of buildings and in different comfort zones. If you have not yet studied psychrometric charts, you may understand better if you read the following presentation on “Comfort and Climate” (Christoph Reinhart, from Harvard Design School): http://isites.harvard.edu/fs/docs/icb.topic256758.files/L03.Thermal.II.ComfortAndClimate.pdf

Also:

• You may have a look of these facades with different materials at: http://www.archiexpo.com/cat/facades-curtain-walls/double-skin-facades-ventilated-facade-systems-L-1021-_5.html

• And you can read about the effects of this type of modern design in: “Effects of double glazed facade on energy consumption, thermal comfort and condensation for a typical office building in Singapore”. Wong Nyuk Hien, ;Wang Liping; Aida Noplie Chandra; Anupama Rana Pandey; Wei Xiaolin. In Energy and Buildings, Volume 37, Issue 6, June 2005, Pages 563–572 (I think you may be able to read the full text if you look for it in internet)

• You may also read this article comparing a double skin façade, with and without ventilation, in Spain: “Energy performance of an open-joint ventilated façade compared with a conventional sealed cavity façade”. Cristina Sanjuan; María José Suárez; Marcos González; Jorge Pistono; Eduardo Blanco. In Solar Energy, Volume 85, Issue 9, September 2011, Pages 1851–1863.

Reading all that, I think you will be able to establish "the positive and negative effects" of a ventilated facade in buildings.

Regards,

M.A. Flórez de la Colina

Hello Phebe

The reason for ventilating the façade will be different for different climate zones.

In the Scandinavian, and probably also the British climate, the relatively warm and humid indoor climate in the heating season, results in humidity diffusing into the façade, as the VCL will never be 100% tight. Thus the façade is ventilated to evacuate any moisture in the façade.

I think the previous answers covers buildings in a hot climate, where the ventilation will have other functions.