Ventilation systems are categorized by the principle of operation into natural, mechanical and hybrid. Let’s talk about each of them in detail.

Natural ventilation

The work of gravity ventilation is based on the natural movement of air caused by the difference in pressure and temperature inside and outside the building. Fresh air enters the building through gaps in windows and doors or special air intakes. Exhaust air goes outside through exhaust openings connected to ducts. Ventilation grilles are placed under the ceiling in the kitchen, bathroom and toilet.

In a building with designed natural ventilation, the airflow directions are arranged in two ways:

  • From bottom to top (effect of temperature and air density differences);
  • From upwind to downwind (effect of wind).

In rooms such as pantry or utility cellar without ventilation ducts in the outer wall is installed inlet valve, equipped with a ventilation grille or mesh from the outside

The following factors influence the efficiency of gravity ventilation:

  • external atmospheric pressure (wind force);
  • temperature difference: external and internal;
  • the height at which air exchange takes place;
  • resistance inside the ducts.

Gravity ventilation depends on weather conditions, is not regulated, is associated with the need to build ventilation ducts, is inefficient.

Mechanical ventilation

Mechanical ventilation systems can be realized in different ways.

The most popular solutions:

  • exhaust fans are mounted in ducts and provide more efficient removal of exhaust air than in natural ventilation;
  • supply and exhaust air can be supplied and removed using a central fan in a supply and exhaust unit;
  • mechanical ventilation with recovery – heat exchangers allow heat to be recovered (returned) and save energy for heating the house.

Mechanical ventilation does not depend on conditions outside the building and works more efficiently than natural ventilation. It allows you to control and regulate the amount of supply and exhaust air. It is more efficient.

Hybrid ventilation

Hybrid ventilation is a combination of natural and mechanical ventilation. It works alternately, adjusting to weather conditions. Utilizes temperature differences and wind. When necessary, it starts a fan that is located in the ventilation duct.

Classification of air conditioners

Depending on the place of installation of the internal unit, the following types of air conditioners can be distinguished:

  • duct;
  • cassette;
  • column;
  • wall-mounted;
  • floor-ceiling (aka console).

The principle of their operation is identical. The difference lies in the configuration and method of installation. In floor air conditioners, the internal unit is placed on the floor next to the outer wall. In ceiling air conditioners it is suspended from the ceiling. In wall-mounted – it is fixed on the wall under the ceiling. In cassette air conditioners, the indoor unit is mounted in the stretch ceiling (only the ventilation grille remains in sight). In multi-split systems, one outdoor unit serves several indoor units installed in different rooms. The air is distributed through a system of ducts. The outdoor unit can be installed on the roof or outside the wall.

Industrial air conditioning often uses chiller-fancoil units, an environmentally friendly alternative to traditional air conditioning. In them, the role of refrigerant, instead of Freon, is played by water or ethylene glycol solution. This allows unlimited scalability of the system, economical air conditioning and heating of large buildings. VRV/VRF systems, or multi-zone air conditioning, are gaining popularity. How does it work? The system analyzes the outside air temperature and the desired room temperature (which is set by the user). The unit then automatically adjusts the system’s operation to efficiently accomplish the task at hand.

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