Natural ventilation: the solution to ensure the appropriate air changes and, in some cases, refresh the environment. Natural ventilation and controlled ventilation.
In a properly designed building, thenatural ventilationplays a crucial role in securing thehome comfort and good energy efficiency.
The purpose of thenatural ventilationconsists inregularhumidity levels, temperature, avoid the formation of condensation and mold and above all ensure a change of air to eliminate domestic pollutants and cooking vapors.
To ensure goodnatural ventilation, some environments are put into "overpressure" and others into "depression". A practical example is given bynatural ventilation in residential buildingswhere the living room and bedroom are placed in overpressure while the kitchen and bathroom in depression precisely because in these last two rooms more vapors are produced (kitchen fumes and condensation from the toilets).
Therenatural ventilationis made possible thanks tonatural draft systemsspecially designed but also in a more classic way by opening doors and windows.
Natural ventilation due to infiltrations
At home we are often victims of an involuntary system ofnatural ventilation; let's talk about drafts! The drafts areair infiltrations,air flows that are generated due to gradients such as the pressure difference between the inside of the house and the external environment or the temperature difference. The cause of the drafts (air infiltration) is bad insulation of the windows. We have mentioned theair infiltrationsto emphasize that thenatural ventilationit is present in all domestic environments but not always in a functional way.
Chimney effect and natural ventilation
Is calledchimney effector stack effect and consists of a movement of air that goes from the bottom up. Therenatural ventilation induced by the chimney effectit is possible in multi-storey buildings where it is possible to create ascending air motions realized, again this time, thanks to a gradient. In this case, the gradient is given by the difference in air density between the lower and upper parts of the volume (between the lowest and highest floors of the house). The warm air is characterized by a lower density and being lighter it is always found in the upper part of the building.
Therenatural ventilationis triggered by air infiltrations in the lower floor, this air will moveof coursefrom the lower part to the upper part of the house where it can flow towards the outside of the building by implementing the so-calledchimney effect. One mechanismsimilaris the one marked by the ventilated roof. To know more:ventilated roof, how it works.
Natural wind induced ventilation
This is the form ofnatural ventilationsimpler than can take advantage ofducts made ad hocor doors and windows.
The openings (doors, windows, ventilated ducts), if they do not cover more than 20% of the facade, have no control over the internal pressure of the building. The sale produces a certain pressure on the external walls of the building, this pressure increases with the speed of the wind. If the openings of the building represent more than 20% of the facade they become of great importance in the mechanism ofnatural ventilationwhy thecross ventilationit really depends on the distribution of the pressure exerted on the different sides of the building.
Natural ventilation for cooling
With careful planning of the openings, thenatural ventilationcan be used forcooling of the building. Therenatural ventilation in residential buildingsof modern construction plays a fundamental role in maintaining the comfort temperature: thanks to natural ventilation it is possible to maintain a temperature of around 26 ° C even if external temperatures reach up to 40 ° C.
In this context, various strategies are exploited: the night air exchangemade possible by the lower external temperatures than the inside of the building or a continuous movement of the air that increases the feeling of freshness in the home environment.