| "Dual-layered glass façades … allow natural ventilation in high wind environments such as at the upper stories of high-rise buildings. This type, the most popular in Europe, enables users to control their working environment while helping to eliminate "sick-building syndrome," which can result from an over-reliance on air-conditioning... According to some estimates by environmental engineers, certain types of ventilated façades show energy savings of 30 to 50 percent." Lang and Herzog, Architectural Record, August 2000. |
Solar control façades | Daylighting façades | Double skin façades and natural ventilation | Active façade systems
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Double-skin façades and natural ventilation
performance | building roster
Double-skin façades and natural ventilation
Heat extraction double skin façades | Night-time ventilation | Mixed-mode and natural ventilation
The double-skin façade is a European Union (EU)
architectural phenomenon driven by the aesthetic desire for an all-glass
façade and the practical desire to have natural ventilation for improved
indoor air quality without the acoustic and security constraints of
naturally-ventilated single-skin façades.
The foremost benefit cited by design engineers of EU double-skin façades is acoustics. A second layer of glass placed in front of a conventional façade reduces sound levels at particularly loud locations, such as airports or high-traffic urban areas. Operable windows behind this all-glass layer compromise this acoustic benefit, particularly if openings in the exterior layer are sufficiently large to enable sufficient natural ventilation. Another cited benefit is that double-skin façades allow renovation of historical buildings or the renovation of buildings where new zoning ordinances would not allow a new building to replace the old with the same size due to more stringent height or volume restrictions.
The second layer of glass provides opportunities for heat recovery during the cold EU winters and heat extraction during the summer. Shading systems placed within the interstitial cavity are protected from the weather. Thermal comfort is purported to be improved with this buffer space compared to conventional window systems.
The complexities and design variations of double-skin façades are large, requiring significant engineering expertise to design well. For California, we discuss two particular energy-efficiency strategies for double-skin façades: solar control and night-time ventilation. EU engineers caution their clients that energy-efficiency is not the foremost benefit of double-skin façades and that such benefit derived may well be small, depending upon circumstances. The architectural press counters with claims of significant energy savings.
Question/Information: eslee@lbl.gov