Properly designed ventilation provides intensive air exchange, which gives its advantages both in summer and in winter. Supply and exhaust communications today are mainly based on power equipment, but the channel network of traffic flows is of great importance. The directions in which air circulation is carried out are thought out taking into account the technical conditions for the creation of mines, as well as the requirements for sanitary background and microclimate.
The concept of air exchange
During the operation of apartments and houses, the enclosed environment of the premises inevitably creates the conditions for the development of negative biological processes. To eliminate this factor, timely air renewal is necessary. Removing contaminated or exhausted air masses and the influx of fresh air is the key to the optimal sanitary and hygienic condition of the room. Also , the air circulation system can serve as a means of temperature and humidity indicators, but these are secondary tasks.
So, air exchange is a process that characterizes the operation of a ventilation system in a closed room. It can be imagined both as an expanded infrastructure with an extensive network of channels through which air flows circulate, and as a limited system that provides direct access of flows from the premises to the street.
Natural airflow
To create a duct network is one thing, and another is to make air masses circulate through them. And not just to move, but to move in the right direction and with sufficient speed. By default, the principle of natural movement of air through vertical channels is used. Such systems work on the principle of movement of warm air, which rises in conditions of a sufficient temperature difference on the street and in the house. Wind can also have an effect on air exchange by regulating traction.
But, the possibilities of such networks do not end there. For example, the natural air circulation in an apartment would rather focus on the operation of the supply openings in the walls or windows, since vertical ventilation ducts in apartment buildings are rarely provided. If there is no direct exit through the side openings due to increased sealing of the openings, a system of transition from horizontal channels to common vertical shafts is organized.
According to the standards, efficient natural ventilation is possible at 12 ° C in conditions where there is no wind. Of course, in practice, it is impossible to expect constant support of a given temperature regime, therefore one or another means of regulating traction is used. It can be adjusted through windows, fans and supply and exhaust systems.
Forced airflow
As the number of mechanical devices in the duct system increases, the movement of air will more and more comply with the principles of forced ventilation. The circulation in this case is stimulated by equipment (mainly fans), which can be dispersed in a variety of configurations. There are three models of forced air circulation:
- Exhaust - involves the removal of exhaust air from the room.
- Supply - directs street air currents into the room.
- Supply and exhaust - at least, it works through two channels that perform two-way circulation.
In domestic conditions, when operating residential premises, it is possible to dispense with supply and exhaust systems. Unless kitchens, bathrooms and technical rooms will require the creation of a complete recycling infrastructure.
Which is better - natural or forced air movement?
The choice of the concept of the air exchange device is determined by the specific operating conditions of the room. At the same time, the advantages of each system should be taken into account. In particular, the advantages of natural ventilation include:
- Inexpensive infrastructure available in construction for private homeowners.
- The lack of mechanics eliminates the need for regular maintenance and installation of power lines.
- There are no maintenance costs. It is enough to periodically clean the channels, which requires minimal investment and effort.
- No noise due to a running fan.
It turns out a simple system that is easy to use, but at the same time it gives a modest effect in terms of ventilation.
Now you can consider the advantages of a forced air circulation system:
- Regardless of external conditions, it can provide a sufficient amount of ventilation.
- In addition to circulation as such, it allows you to perform the functions of cooling, heating and filtering air masses.
- The possibility of organizing a heat exchange system involves almost free heating of incoming masses.
The disadvantages of forced air exchange are due to difficulties in the installation and maintenance of ventilation equipment, which also will require additional space for installation.
Why air exchange may not work?
In most cases, for small private houses, natural ventilation with draft is designed, which is formed when moving vertically through ventilation ducts. The problems of the operation of such systems are related to the thermal modernization of the premises. It is carried out in order to save energy in the winter, when the issue of heat saving arises. In practice, this can be expressed in the installation of plastic double-glazed windows, sealing gaps and chimneys. As a result, the paths of natural ventilation are blocked. The principle of recuperation will help solve the problem of air circulation in rooms without increasing heating costs. It is implemented by installing ventilation units with metal plates that transfer heat from the leaving masses to the incoming air.
Airing principle
This is a type of microventilation system, which involves the removal of air through the shortest paths. For example, it can be a direct air outlet from the kitchen or bathroom. Moreover, unlike windows or other points of natural circulation, the modern principle of ventilation suggests the possibility of regulating flows. These manipulations can be carried out both manually and through automation. The second option is more preferable, as it contributes to the formation of a microclimate close to natural. For example, in an apartment, air circulation according to the principle of automatic ventilation can be based on a change in the pressure indicator. The system takes into account wind speed, directing the optimal air flow into the room. Due to this, overcooling is eliminated and, in general, a comfortable temperature-humidity balance is established.
Air circulation modes - inflow and exhaust
Both the natural and forced air exchange system can work both in two modes separately, and as a supply and exhaust system. Both circulation directions must be calculated separately. For example, in assessing the optimal volumes of inflow, the rule is taken into account, according to which a complete air renewal must be carried out in 1 hour. That is, in a room with a volume of 50 m3 for 1 hour, the ventilation system must supply at least 50 m3. There is another approach to calculating the inflow volumes, which is based on the number of people in the room. So, the air circulation mode in the house will be calculated on the basis of the fact that for every person living in it there must be at least 20 m3 of street air supplied every hour. As for the tap, this mode is especially important for technical and sanitary-hygienic premises. To prevent excess pressure or vacuum from occurring in the house, the output volume must correspond to the number of injected masses.
Technical organization of the air exchange system
There are different concepts and principles for the arrangement of ventilation and ventilation systems. In the most optimized version, this will be a complex of grilles with direct air ducts, providing the supply of street air. Standard home air circulation systems involve the organization of horizontal and vertical shafts. This infrastructure is carried out using metal or plastic ducts of different sections. These can be rectangular and round, flexible and rigid structures, which are usually mounted according to the principles of hidden installation.
Conclusion
As practice shows, the design of ventilation systems in the early stages of developing a common house project in the future provides greater opportunities for solving the problem of updating air in rooms. The fact is that the efficiency of air circulation is determined not only by the ventilation infrastructure, but also by the layout of the housing, as well as insulation materials used at the construction stage. For example, integrated insulation of walls and ceilings reduces air exchange, thereby deteriorating air quality. Microventilation facilities allow locally correcting the situation, but they will also need a carefully thought-out arrangement of the points of inflow and discharge.