Air blowing in ventilation systems

The blowing of air inside a room is one of the procedures by which we facilitate its ventilation, that is to say the renewal of the indoor air that is loaded with humidity, CO2, and other contaminants, to replace it with clean and dry air from outside. Traditionally, natural ventilation has been used to carry out this air renewal, and to a lesser extent mechanical ventilation, which achieves the extraction of contaminated air from bathrooms, kitchens, parking lots, garages, and storage rooms located below the ground level of the building.

Natural ventilation

This type of ventilation can be obtained in three ways:

Unilateral ventilation occurs due to the difference in pressure and temperature through the openings and infiltrations of the thermal envelope of the building that connects the interior with the exterior of the house. When the air pressure is higher on one side of the enclosure, a flow is generated through which the air circulates from the area with higher pressure to the area with lower pressure. This system is activated when we open any window of the outer enclosure of a house or spontaneously through the infiltrations produced in the facade enclosures. In this type of natural ventilation, the convective flow generated in a room when the air heats up and rises is also utilized. This way, it is possible to ventilate boiler rooms and kitchens that use gas as fuel by placing ventilation grilles in the upper and lower areas of the rooms to facilitate air circulation.

Cross ventilation originates when the circulation of a flow of air is activated between an entrance and an exit located in opposite enclosures of the outer facade. It is activated by pressure difference, generating positive pressure at the entrance and negative pressure at the exit. It occurs periodically through the intervention of the user, so it is not guaranteed to occur with sufficient regularity.

Thermal ventilation is carried out through vertical ducts. It is activated by the difference in densities in the air, which results from the variation in temperature and the volume of humidity contained in the environment. The warm air weighs less than cold air, and humid air weighs less than dry air, generating an upward movement that allows air to flow towards the upper part of the rooms.

Hybrid ventilation

In this type of ventilation, natural renewal of the indoor air occurs when the pressure and temperature conditions are favorable and mechanical extraction of the air when conditions are unfavorable. To function correctly, the intake for air blowing must be installed in the exterior enclosures of the dry rooms of the house, i.e., dining rooms, living rooms, and bedrooms, and extraction in the wet rooms: toilets, bathrooms, and kitchens.

Mechanical ventilation

It occurs through the operation of electromechanical equipment placed in certain locations of the house: outer enclosures, false ceilings, roofs, etc. The admission of air occurs mechanically while the extraction can be mechanical or balanced. With double-flow mechanical ventilation, it is possible to control the flows and volumes of air admission and extraction so that ventilation occurs at a constant rate programmed by the user. This allows ventilation to be regular and enables significant savings in energy consumption.