Blowing Air Into Ventilation Systems
Blowing air into a room is one of the procedures by which we manage to facilitate its ventilation, that is, the renewal of the interior air that is loaded with moisture, CO2 and other pollutants, to replace it with clean and dry air from outside. Traditionally, to carry out this renewal of air, natural ventilation has been used and to a lesser extent mechanical ventilation with which we achieve the extraction of contaminated air from bathrooms, kitchens, parking lots, garages and storage rooms located on the first floor of the building.
Natural Ventilation. This type of ventilation can be obtained in three ways:
One-sided ventilation is produced by the difference in pressure and temperature through the gaps and infiltrations of the building’s thermal envelope that bring the interior into contact with the exterior of the dwelling.
When the air pressure is higher on either side of the enclosure, a flow is generated through which air circulates from the area with higher pressure to the area with less pressure. This system is activated when we open any window of the exterior enclosure of a house or spontaneously through the leaks that occur in the facade enclosures. This type of natural ventilation also takes advantage of the convective flow that is generated in a room when the air is heated and rises. In this way, it is possible to ventilate the boiler rooms and the kitchens that use gas as fuel, placing ventilation grilles in the upper and lower areas of the rooms to facilitate air circulation.
Cross ventilation is created when the circulation of an air flow is activated between an entrance and an exit located on opposite sides of the exterior facade enclosure. It is activated by pressure difference, generating a positive pressure at the inlet and a negative pressure at the outlet. It is produced in a timely manner through the intervention of the user, so there is no guarantee that it will be carried out with sufficient regularity.
The ventilation by thermal drought is done through vertical ducts. It is triggered by the difference in air density, which causes the variation in temperature and volume of moisture contained in the environment. The hot air weighs less than the cold, and the humid air less than the dry, generating an upward movement that allows the air to move to the top of the premises.
In this type of ventilation, the natural renewal of the indoor air is carried out when the pressure and temperature conditions are favourable and the mechanical extraction of the air when the conditions are unfavourable. In order for it to work properly, the air intake must be installed in the external enclosures of the dry premises of the dwelling, i.e., dining rooms, living rooms and bedrooms, and the extraction in the wet premises: toilets, bathrooms and kitchens.
It is produced through the operation of electromechanical equipment arranged in certain places in the house: exterior enclosures, false ceilings, roof, etc. The air intake is produced mechanically while the extraction can be mechanical or balanced.
With the mechanical ventilation of double flow is achieved to control the flows and volumes of admission and extraction of air, so that the ventilation is done in a constant regime programmed by the user. This allows the ventilation to be regular and a remarkable saving in energy consumption can be obtained.