Ventilation systems

Water vapour and carbon dioxide are examples of air pollution. Excessive concentration of some substances in rooms can cause discomfort and malaise of their users. Combinations of various pollutants cause for example headache, respiratory diseases, fatigue, allergies or cancer. That is why proper ventilation in buildings is so important. Ventilation is responsible for maintaining proper air quality. Its purpose is to remove contaminated air from rooms and to bring fresh air into the inside. It can also alternatively dilute airborne pollutants up to admissible values. Taking into account the fact that the air in rooms is constantly being polluted, ventilation is even necessary. It is also extremely important because its absence causes a side effect in the form of moisture. Steamed-up windows, moisture and fungus on walls - they are the effects of poorly selected ventilation.

Properly functioning ventilation in residential buildings is therefore:

• Preventing development of mould,
• Providing proper air quality,
• Increasing or decreasing air exchange - depending on demand,
• Removal of carbon dioxide, water vapour, carbon monoxide, tobacco smoke and other harmful "smells".

Ventilation systems - natural and mechanical

The primary criterion for distribution of ventilation systems is the source of air movement. Room ventilation can occur, for example, in a natural way (gravity). Then, air movement is caused by natural factors such as temperature difference (air density inside and outside the building) and wind. The advantages of such ventilation are certainly low operating and investment costs (it does not require electricity), as well as space saving. Natural ventilation systems will work in rooms with a fireplace. The disadvantages, however, are that their effectiveness depends on atmospheric conditions and it is impossible to filter air in this case. In addition, this type of ventilation does not allow to recover heat from the exhausted air.

Ventilation systems can also operate mechanically (in a forced way). Then any air exchange is independent of any atmospheric factors. The air flow is forced by operating fans. The main advantage of mechanical ventilation is that it fulfils its role in every room, regardless of weather conditions.

Mechanical ventilation methods

Mechanical ventilation is mainly divided into supply (where air supply is carried out mechanically and the removal is natural), exhaust and supply/exhaust ones.

• Exhaust (extract) ventilation:

  • The simplest solution in which air gets into a building naturally under vacuum and is removed mechanically,
  • It comprises of a duct fun, exhaust ducts in rooms that require ventilation: in the kitchen, bathroom and rooms without windows and exhaust of air, which is installed on the outer wall of the building or in the roof (inner tile)
  • Fan speed controls the intensity of air exchange;

• Supply and exhaust ventilation:

  • Air exchange takes place with the use of fans,
  • It comprises of a network of exhaust air ducts that draw in air through a fan from the room and blow it out, and from air supply networks - the air is drawn in to the outside and pressed inward,
  • Its advantage is creating the possibility of heating the supplied air by a recuperator,
  • The air can also be cooled by a ground heat exchanger,
  • Thanks to such a system, it is possible to draw in the air from one source and additionally purge it from any harmful substances, thus avoiding the inflow of contaminated air into the interior;

Hybrid ventilation (bipolar):

• This is a combination of natural and exhaust ventilation,
• External conditions decide whether hybrid ventilation operates like a gravity or mechanical one,
• It consists of exhaust ducts and air inlet vents, hybrid tops (which are equipped with low power motors and are installed at the outlet of ventilation ducts over the roof of the house);

Ventilation with heat recovery - recuperation:

One of the advantages of a mechanical ventilation system is the possibility to recover heat. This allows to save heat consumption used for heating and to improve the quality of air and comfort of users. Recuperation, or ventilation system with heat recovery, the main part of which is a device - a recuperator, which heats cool air from the outside with warm air that is removed from the interior. In the winter, cool air is heated and in the summer - cooled. The exhausted and contaminated air is removed through extract air grates and directed to the air handling unit, where, through the exhaust fan, the air is transported through the filter to the recuperator. In addition, the advantage of this type of ventilation system is the fact that recuperation reduces noise, drafts, prevents moisture in the rooms and effectively removes unpleasant odours as well as dust, carbon dioxide, water vapour and any other harmful substances.

Air inlet vents (passive air inlets, slot vents):

• These are small, simple devices installed in a wall or a window with a rain cover,
• Depending on their construction, they can provide constant (non-adjustable) or adjustable air exchange,
• Air supply can be adjusted manually or automatically,
• With the use of a device, fresh air is filtered to the room and outgoing air is removed through the air ducts;

Ground heat exchanger (GHE):

• This is a supportive and complementary solution of a ventilation system,
• Thanks to its simple construction, it can be installed practically anywhere and in any conditions,
• Renewable energy is obtained from the land at shallow ground depth,
• Air from the outside can be cooled in the summer and warmed in the winter using the GHE,
• It provides initial air filtration.

Air handling units - essential elements of a ventilation system

A very important element of mechanical ventilation systems are air handling units. Here is a place where number of air treatment processes, necessary to maintain the required parameters in the room, take place. There are for example fans and heaters used for heating air in air handling units. Furthermore, their important component are air filters that are used to clean the air. Their role is to stop pollutants that enter a building from the outside. Air handling units are often also called air-conditioning units. In this type of handling units a more complex air treatment takes place, i.e. its humidification or dehumidification.

The most common mistakes made in case of ventilation systems

No matter what kind of ventilation you choose, it is important to know which errors to avoid at installation.

In case of ventilation with heat recovery, it is important to remember that:

• A system should not be installed in unheated rooms such as attic therefore,
  for proper operation, it should be installed in interiors with minimum temperature of 8 degrees C. Additionally, to achieve better result, it is worth to insulate the recuperator and the channels,
• Window joinery should be tight - in this way there will be no energy losses,
• Ventilation ducts should be protected against damage during construction,
• There should be an easy access to a recuperator,
• A gap between the bottom edge of the door and the floor should be provided - this is especially important in case of so-called wet (kitchen, bathroom) and commercial (pantry, dressing room) rooms,
• A system should not compose of non-insulated flexible channels (i.e. flexy) as they generate very high flow resistance,
• A recuperator of too low power should not be used,
• Folded flexible pipes should not be used,
• Ventilation ducts should be isolated and properly assembled,
• A system should be constructed in accordance with a specially designed project,
• Calculations concerning resistance of a system should be considered,
• This type of ventilation should not be installed in a house where gravity ventilation has already been installed,
• When installing, it is also important to remember about connecting elements that provide adequate tightness such as nipples, bands, sealing tapes.

On the other hand, in case of gravity ventilation the following mistakes are made:

• There is no design of the system, which would include the appropriate amount of air removed and supplied by the ventilation system,
• There is no insulation of ventilation chimneys,
• There are no window or wall air inlet vents,
• Cross-sections of ventilation ducts are too small,
• A ventilation system is not tight,
• Chimney cowls that block free flow of air have been installed.

Industrial ventilation  - from design to implementation

Our company, based in Katowice, Poland, offers comprehensive assistance in constructing various types of ventilation including:

• Developing a concept,
• Drawing up a design,
• Fitting and supplying all necessary equipment (including air handling units),
• Assembly and activation of appliances used in industrial ventilation.

We specialize in designing and complex construction of ventilation systems for industrial, commercial and service buildings, offices, manufacturing plants and other premises with very high technical and technological requirements.
Industrial ventilation - we guarantee high quality of services.

Industrial ventilation - service and repair

Our engineers have extensive expertise in the field of industrial ventilation as well as necessary experience. Our employees compose a highly qualified team of service technicians.

Systematic servicing of ventilation equipment allows to maintain appliances fully efficient and productive, and ensures their failure-free operation. So if you live in Europe and you would like to have an efficiently operating ventilation system - you know where to find us. If you run a production company in Poland or the surrounding countries like Germany,Netherlands and whole EU - you can also rely on our industrial ventilation specialists.