Natural ventilation not only brings benefits to thermal comfort, air renewal in buildings, and the well-being of occupants, but it is also a sign of savings. Using natural ventilation is one of the basic principles of sustainable architecture, as wind is a natural, free, and renewable resource. In addition to bringing several advantages to buildings, natural ventilation helps maintain good indoor air quality because of constant exchange, creating comfortable environments and reducing energy costs.
Air circulation in buildings varies with the type and characteristics of their structure, occupancy, openings to the outside, location, orientation, exposure to atmospheric agents (wind, temperature, and pressure), and types of ventilation devices installed. Many Brazilian properties tend to have problems with humidity, mold, the proliferation of mites, accumulation of dirt particles, and thermal insufficiency, as they are constructions without planning that do not take advantage of the wind to guarantee a healthy environment.
Mechanical ventilation is the only solution for places that do not have windows, such as bathrooms in some apartments. Exhaust fans are used when there is little ventilation and fulfill two functions: eliminating unpleasant odors from the environment and removing moisture from the bathroom, reducing its levels after someone finishes taking a shower. Air extractors for bathrooms are installed on the ceiling and activated by an electric switch.
What Ventilation Systems Are Used
There are two basic mechanisms related to the ventilation of buildings: natural ventilation and mechanical ventilation. A third ventilation mechanism is already in use, called hybrid ventilation, which combines the characteristics and advantages of natural ventilation and mechanical ventilation systems.
The Natural Ventilation
Natural ventilation takes advantage of nature to create pressure differences that cause enough air circulation to ensure air circulation throughout the tall building. These forces are the temperature variations between the outside and the inside of the building and the action of the wind on it. Several types of natural ventilation are used in the construction of tall buildings.
Cross ventilation assisted by wind towers. System with SAP calculations that uses a tower that collects the wind-driven air, directing it to the lower levels allowing cross ventilation. It is used in tall buildings as it allows using the wind from the upper floors to ventilate the entire building;
Thermal draft ventilation assisted by a solar chimney. System that uses building materials that have great solar absorption to make the evacuation duct warmer than the environment, which will favor the thermal draft effect.