SMEA S.r.l. designs, engineers and manufactures double skin curtain walls that differently from the traditional type of façade consisting of a single glazing unit and an external shield to intercept the incident solar radiation, presents a further glass screen, commonly called "external skin".
These, superimposed on the single internal façade, called reflexively "internal skin", creates a cavity in which the air is recirculated, evacuating part of the heat accumulated on the exterior.
The presence of external skin allows to reduce the thermal transmittance of the façade because the internal double-glazing is no longer in contact with the external environment, but with the interspace of façades that presents a higher temperature.
The movement of the air inside the ventilated cavity allows to cool both the glazed surfaces and the (Venetian blind) shielding, considerably reducing the thermal load that flows into the interior rooms. The movement originates by natural convention (chimney effect) obtaining a flow of ascending air whose intensity grows with increasing temperatures of the glass.
In the summer period this recirculation will be much more pronounced compared to the winter period in which the façade is kept at lower temperatures.
If, due to architectural requirements, the air gap and the air inlet / outlet sections are small, it is still possible to guarantee correct recirculation by means of ventilation fans which force air flow into the air space.
The double skin façade, acting on the movement of the shielding, makes it possible to vary the solar factor g of the façade during the day, obtaining, in the central hours, or in the maximum irradiation peak, a low solar factor, similar to what is offered by a selective glass.
Unlike the traditional single-skin façade, the performance of the double-skin façade can not be described only through the solar factor g and the average thermal transmittance of the façade U [W / m2K], but must be considered the dynamic behavior of the system , which adapts to the external thermal load.
With regard to the wellbeing of the users of the building, the double skin technology considerably reduces the surface temperature of the inner façade glass, as the windows themselves are cooled by the flow of air that circulates in the ventilated cavity, this reduction in temperature, combined with the presence of the shielding that intercepts part of the external solar radiation, makes it possible to reduce the thermal load in the internal rooms, with a consequent reduction in air conditioning costs.