An airflow window is composed of at least two panes of glass and a cavity between them that allows the flow of
ventilation
Ventilation may refer to:
* Ventilation (physiology), the movement of air between the environment and the lungs via inhalation and exhalation
** Mechanical ventilation, in medicine, using artificial methods to assist breathing
*** Ventilator, a m ...
air. They operate on similar principles to a
double-skin facade
The double-skin façade is a system of building consisting of two skins, or façades, placed in such a way that air flows in the intermediate cavity. The ventilation of the cavity can be natural, fan supported or mechanical. Apart from the type o ...
, but on a smaller scale. The general idea is to improve the
energy efficiency
Energy efficiency may refer to:
* Energy efficiency (physics), the ratio between the useful output and input of an energy conversion process
** Electrical efficiency, useful power output per electrical power consumed
** Mechanical efficiency, a ra ...
of a cavity window by heating or cooling the cavity with ventilation air.
Benefit
In warm climates the window is used for exhausting ventilation air. Cooler air enters the cavity at the bottom, from the interior space, is heated during transfer upwards through the cavity and is exhausted at the top of the cavity to the exterior. In cold climates the window is used for intake of ventilation air. Cold air enters the bottom of the cavity, from the outside, is heated during transfer upwards though the cavity, and enters the interior space at the top of the cavity. More complex designs exist, which for example do not transfer ventilated air between the interior and exterior, or which have multiple ventilation channels.
The movement of air through the cavity can be forced (by means of mechanical devices such as
fans
Fan commonly refers to:
* Fan (machine), a machine for producing airflow, often used for cooling
** Hand fan, an implement held and waved by hand to move air for cooling
* Fan (person), short for fanatic; an enthusiast or supporter, especially wit ...
), or occur freely, by means of
convection
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...
. Whether the air flow is free or forced can affect energy efficiency of the window.
References
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External links
Aluminum Windows
Windows
Heating, ventilation, and air conditioning