Properly designed ventilation ensures intensive air exchange, which has its advantages both in summer and in winter. Supply and exhaust communications today are mainly based on power equipment, but the channel flow network is also of great importance. The directions in which air is circulated are thought out taking into account the technical conditions for the creation of mines, as well as the requirements for a sanitary background and microclimate.
The concept of air exchange
During the operation of apartments and houses, the closed environment of the premises inevitably creates conditions for the development of negative biological processes. To eliminate this factor, timely air renewal is necessary. The removal of polluted or waste air masses and the inflow of fresh air is the key to an optimal sanitary and hygienic condition of the premises. Also, the air circulation system can serve asas a means of temperature and humidity indicators, but these are tasks of a secondary order.
So, air exchange is a process that characterizes the operation of the ventilation system in an enclosed space. It can be imagined both as an extended infrastructure with an extensive network of channels through which air flows circulate, and as a limited system that provides a direct exit of air flows from the premises to the street.
Natural air circulation
Creating a network of air ducts is one thing, and another is to make air masses circulate through them. And not just move, but move in the right direction and with sufficient speed. By default, the principle of natural air movement through vertical channels is used. Such systems work on the principle of the movement of warm air, which rises under conditions of a sufficient temperature difference in the street and in the house. The wind can also influence air exchange by adjusting the thrust force.
But, the possibilities of such networks do not end there. For example, natural air circulation in an apartment is more likely to focus on the operation of air inlets in 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 openings, a system of transition from horizontal channels to common vertical shafts is organized.
According to standards, efficient operation of naturalventilation is possible at 12 °C in conditions when there is no wind. Of course, in practice, it is impossible to expect constant maintenance of a given temperature regime, therefore, one or another means of regulating the thrust force is used. It can be adjusted through windows, fans and air handling units.
Forced air circulation
As the number of mechanical devices in the duct system increases, the air movement will more and more conform to 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.
- Inlet - directs street air flows 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, supply and exhaust systems can be dispensed with. Unless kitchens, bathrooms and utility rooms require a complete recycling infrastructure.
Which is better - natural or forced air movement?
The choice of the concept of an air exchange device is determined by the specific operating conditions of the room. In this case, the advantages of each system should be taken into account. In particular, the benefitsnatural ventilation include:
- Inexpensive infrastructure available to build for private homeowners.
- The absence of mechanics eliminates the need for regular maintenance and laying power lines.
- No maintenance costs. It is enough to periodically clean the channels, which requires minimal investment and effort.
- No noise due to running fan.
The result is a simple system that is easy to operate, but at the same time it has a modest effect in terms of ventilation.
Now you can consider the benefits of a forced air circulation system:
- Regardless of external conditions, it can provide sufficient 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 implies almost free heating of the incoming masses.
The disadvantages of forced air exchange are due to the difficulties in installing and maintaining ventilation equipment, which also requires additional installation space.
Why might the air exchange not work?
In most cases, for small private houses, natural ventilation is designed with draft, which is formed when moving through the ventilation ducts vertically. The problems of operation of such systems are associated with the thermal modernization of premises. It is carried out for the purposeenergy saving for the winter, when the question of saving heat arises. In practice, this can be expressed in the installation of plastic double-glazed windows, sealing cracks and chimneys. As a result, natural ventilation paths are blocked. The principle of recuperation will help to solve the problem of air circulation in the premises without increasing the cost of heating. It is implemented by installing ventilation units with metal plates that transfer heat from the outgoing masses to the newly incoming air.
Ventilation principle
This is a kind of micro-ventilation systems, which involves the removal of air along the shortest paths. For example, it can be a direct air outlet from the kitchen or bathroom. At the same time, unlike windows or other points of natural circulation, the modern principle of ventilation implies 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 the wind speed, directing the optimal air flow into the room. Thanks to this, hypothermia is excluded and, in general, a comfortable temperature-humidity balance is established.
Air circulation modes - intake and exhaust
Both natural and forced systemsair exchange can work both in two modes separately, and as a supply and exhaust. Both directions of circulation must be calculated separately. For example, in assessing the optimal volumes of inflow, the rule is taken into account, according to which a complete renewal of air should 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 volume of inflow, which is based on the number of people in the room. Thus, the air circulation regime in the house will be calculated based on the fact that for each person living in it there should be at least 20 m3 of street air entering every hour. As for the withdrawal, this mode is especially important for technical and sanitary-hygienic premises. In order to avoid excessive pressure or vacuum in the house, the output volume must correspond to the amount of pumped masses.
Technical organization of the air exchange system
There are different concepts and principles for arranging ventilation and ventilation systems. In the most optimized version, this will be a set of grilles with straight air outlet channels that ensure the supply of outdoor air. Standard home air circulation systems involve the organization of horizontal and vertical shafts. This infrastructure is carried out using metal or plastic air ducts of different sections. It can be rectangular and round, flexible and rigid structures, which are usually mounted according to the principles of concealed installation.
Conclusion
As practice shows, the design of ventilation systems in the early stages of the development of the overall design of the house in the future provides more opportunities for solving the problem of updating indoor air. 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 by the insulating materials used during the construction phase. For example, complex insulation of walls and ceilings reduces air exchange, thereby worsening air quality. Locally, microventilation means can correct the situation, but they will also need a carefully thought-out layout of the inflow and outlet points.
