Reduced work efficiency, a constant feeling of weakness in the body, increased nervousness, a regular desire to take a nap are often the result of insufficient air exchange. However, these problems will help prevent proper ventilation and air conditioning.
And it will not be possible to restrict ourselves to the natural system only - it has a number of drawbacks. It is necessary to choose the optimal mechanical type of air exchange and mixing by analyzing the pros and cons of each of the methods.
Let's try together to understand how the various ventilation systems work and in what cases a particular variety is used.
The content of the article:
- Why is ventilation necessary?
- Air conditioning process
- Mechanical method of air evacuation
Description of the supply system
- The principle of operation and structure of the structure
- Where does this method apply?
Characteristics of exhaust ventilation
- Structure and principle of operation
- Nuances of using the system
- The essence of the exhaust ventilation
- How does local ventilation work?
- Conclusions and useful video on the topic
Why is ventilation necessary?
Air renewal helps to prevent diseases of the cardiovascular and central nervous system, increased level of sweating, deterioration of attention, chronic diseases in people with weak immunity.
Standard ventilation system allows:
- reduce the concentration of dust and other small particles in the air;
- choose a comfortable temperature for work;
- remove the exhaust gases and aggressive components that cause allergies.
Of course, you can open the vents, but then dust and dirty air will enter the room. And in the cold time of day, heating costs will increase. Also, drafts have a negative impact on human health.
Natural ventilation system can not fully ensure the ventilation of the room
Air conditioning process
Even in the warm season it is problematic to carry out a simple exchange of air without the use of special devices. Therefore, it is advisable to use additional equipment.
In the summer the air is humid and warm. Air conditioning will provide him with a cleaner and lower temperature setting. For example, split-systems, industrial air conditioners and chiller-fan coil.
But in the cold season the air is frosty and less humid. Naturally, do not forget about filtering. However, it is still necessary to warm and humidify the air, which is successfully coped with. heater, ensuring the temperature rises to a comfortable level.
This process is often provided by mixing: cold flows are combined with warm ones. The air is cooled in special chambers due to the ingress of small drops of water.
There are also rooms that require a special approach to the organization of ventilation. For example, in gymnasiums with pools, water evaporates constantly, increasing the level of humidity.
Water evaporates from the pools, which condenses on the walls and ceiling of the room. Proper ventilation can prevent excessive moisture.
Solve such problems intended dehumidifiers. The lack of the latter is the lack of ventilation. The air stays indoors but the moisture level decreases. Therefore, the concentration of oxygen falls, which adversely affects the well-being of people.
Mechanical method of air evacuation
Natural ventilation often does not perform its direct functions. Therefore, the need to use an artificial system becomes urgent. Her main difference is that she works with coercion.
Mechanical type of ventilation is used not only in industrial production, but also in residential premises. Its action is based on the work of electric motors, air heaters, fans and filters.
Key advantages of an artificial system over a natural one:
- Efficiency. Transferring virtually any air volume over considerable distances in the room.
- Weather independence. Perfect execution of direct functions by the system at any time of the year.
- Additional features. Adjusting the temperature and humidity levels, cleaning the air from dust and other small particles.
Mechanical ventilation is divided into channel and channelless. When the first air passes through a special elongated paths.
Effectively use a combination of mechanical and natural ventilation systems
In ductless systems, fans are placed in a special design. They provide an influx of fresh air masses.
Depending on the type of mechanical ventilation systems are divided into supply, exhaust and supply and exhaust.
Description of the supply system
The main objective of this type of ventilation is to provide fresh air to the room. So that the equipment can perform its functions optimally, complex models are equipped with additional elements that are responsible for cleaning and moisturizing.
The main disadvantage is the lack of air intake. Therefore, the room can not be 100% filled with updated air masses.
The principle of operation and structure of the structure
The standard system includes a fan that is mounted in the transom window. It provides fresh air in the room. In the latter increases the concentration of gases. Therefore, there is no room for exhaust air and it leaves the room through special exhaust vents.
The key component of the system is the intake fan. Its main parameters are power, air supply efficiency and pressure in the working area. The length and complexity of the channels directly depend on the requirements for the technical characteristics of the fan.
In addition to this device, the system consists of the following elements:
- air ducts;
Filters are responsible for removing mechanical particles such as dust, insects, debris, etc. from the air that arrives. Can provide coarse, fine and very fine cleaning. Depending on the features of the work, they are divided into electrostatic, dry and wet.
It is necessary to prevent the contact of air channels with foreign objects and moisture. Therefore, we cannot do without a special covering.
Heaters or heaters are responsible for increasing the temperature of the incoming air. They are water and electric type. The first work on the basis of the heating system at home. The power source of the second is the electrical network.
As for the additional elements, they can be:
- noise reduction elements;
- means of automation of the system;
- and others.
The air receiver must be in a clean place that is protected from dust. Near this structural element should be placed inlet chamber.
Where does this method apply?
The mechanical type of flow organization is used for both residential and industrial facilities. Responsible for the whole room or only for a separate part of it, for example, a workplace in production. Provides air with optimal temperature.
It also creates special clean zones, even if in other rooms there is an increased level of toxic substances. Can be combined with exhaust and natural ventilation systems.
Read more about how to properly equip the ventilation system read in this material.
The intake system is quite compact and virtually silent in operation. Differs in ease of installation and maintenance.
Characteristics of exhaust ventilation
Exhaust system - the opposite of the intake. Its task is to remove the polluted air from the room. There are holistic and collective types.
Structure and principle of operation
Evacuation type ventilation is popular for arranging apartments. Provides a conclusion of the fulfilled or warmed air. Exhaust Grilles or ventilation valves usually placed at the top of the room. Fresh air enters through special connectors directly from the external environment or through neighboring rooms.
The system can be placed at a certain distance or completely block the source of pollution. If it is possible to limit the point of release of toxic substances, then local ventilation will be effective, and if not, it will be common.
Here the key is the fan. It is his power that determines the efficiency of the entire system. There are low-pressure exhaust devices (air flow rate up to 50 m / s), medium air up to 80 m / s, and high pressure (up to 200 m / s).
The main elements of this type of ventilation are as follows:
- Fume hoods. They are the most effective. Remove excessively humid and warm air, heavy gases and dust.
- Suction. Eliminate the maximum amount of harmful substances, taking away a minimum of air. Do not interfere with the employee to perform duties.
- Exhaust umbrellas. Designed for the withdrawal of substances that rise up. There are types whose work is based on natural or forced burden.
- Exhaust panels. Effective for removing dust and hot harmful gases. Relevant for workplaces where welding parts.
- Onboard pumps. It is used when working with large or dimensional objects that are held vertically with metal cords or other means. They have a small diameter (less than 100 mm) and are located away from the object of work.
The exhaust system is designed primarily for the evacuation of exhaust air. Given the above structural elements, they are effective for local ventilation.
Nuances of using the system
This type of exhaust ventilation is suitable for rooms with a low level of concentration of harmful substances. At the same time, the latter can come at different levels, in a holistic and separate streams.
Holistic type is less noisy in operation due to the design features, in particular, the body
This system is relevant for warehouses, supermarkets, sports facilities, recreational facilities and residential premises. It is used in industrial premises where the release of toxic substances cannot be avoided. It is optimally combined with natural and forced ventilation. It can act both locally and provide a general conclusion of the waste mass.
When choosing, it is necessary to analyze the characteristics of the exhaust air. If the latter contains a lot of aggressive substances, then it is advisable to stop on the variant with anti-corrosion coating.
The essence of the exhaust ventilation
This type of renovation of air masses in the room is considered one of the most optimal. It allows you to combine the advantages of supply and exhaust systems.
The key task in the design is to balance the volumes of incoming and outgoing air. If the first one prevails, then the pressure in the room increases due to the high concentration of gases, with an increase in the amount of evacuated air - decreases.
Supply and exhaust system is used in both residential and industrial premises
Supply and exhaust ventilation has two varieties. The first is mixing, when clean air through special structural elements enters the room, mixes with the existing gases and exits through special valves.
The other type is embossed ventilation. Installation of the system takes place at the floor level. The elementary laws of physics work here - exhaust air has a high temperature, therefore it is displaced by gases that flow. It leaves through the gratings located on the ceiling of the room.
But fresh air enters the lower part of the room, where it slowly moves. Therefore, in the working area, in the part of the room where the tenants are directly located, comfortable conditions are created for work and leisure.
For efficient displacement ventilation, it is necessary that the fresh air has a lower temperature than that already in the building. For residential premises the difference is 1-3 ° С, for plants, factories and other objects with special requirements - 1-5 ° С.
It is necessary to monitor the temperature of incoming air and available in the room. If the above ranges are not observed, convection will occur.
This type of ventilation has both advantages and disadvantages. The advantages include the possibility of use in industrial buildings, which are characterized by the release of toxic substances and elevated temperatures, and high efficiency.
But the disadvantages include the following:
- the need for relatively large areas for inlet diffusers;
- increase of the adjacent territory;
- reduction of the effectiveness of the system as a result of the ingress of excess items into the supply diffusers;
- increase vertical temperature gradient.
The latter is the difference between the temperatures of the gas in the working area and under the ceiling.
If you want to stop the choice on the system of ventilation and air conditioning by displacement, then analyze the placement and power of the heating equipment. These characteristics affect the combination of air flow in the room.
For example, the incoming air, which must enter the work area directly, may be blocked by warm gases from batteries or heaters. As a result, ventilation is obtained not by displacement, but by mixing.
The mixing process involves the entry of air into the room in one or several ways. But the exhaust gases come in one stream.
In the working area, the velocity of exhaust air is one third less than that of the inlet air.
The key parameter for blending ventilation is ejection. This is a combination of any kind of medium, when one of them influences and guides the other. In a particular case, this is the possibility of diffusers to harmoniously combine air jets.
Ejection determines the characteristics of the ventilation system. For example, mixing is provided by jet-type diffusers with a large index value. A displacement characteristic device with a small rate of injection.
To minimize the number of drafts in case of deviation of the difference between the temperatures of the incoming and indoor air from the norm, diffusers should have a large figure.
Also important are the speed of movement of air masses and air temperature. To ensure maximum comfort, it is necessary that gases move no faster than 0.18 m / s and have a temperature of from 20 to 22 ° C.
The speed of air movement depends on the geometry and purpose of the room, the temperature in the working area and the interior.
Especially dangerous to human health and well-being is the excess of the first and a decrease in the second indicator. Then it is difficult to simply be indoors, not to mention any productive activity.
When designing ventilation, the effect of physical obstacles must be considered. The latter include lamps, tiers, ceilings, columns, etc., placed on the ceiling.
In most cases, the flow of incoming air can bypass an obstacle whose width is 1/50 of the ceiling height.
Audiences - non-standard rooms, which are distinguished by a significant working area, a large number of listeners and a high ceiling. Accordingly, the approach to ventilation is quite specific.
A popular way is to supply fresh air directly under the seats of the listeners. It is believed that the incoming gases will be heated, rise to the ceiling and out of the room.
However, practice shows that this approach is wrong - gases behave in the same way as liquids. At first air gathers in the lower part of an audience and only after that rises.
Rational placement of the diffuser - in the front of the classroom or classroom
Even reasoned calculations and computer modeling do not guarantee the most accurate prediction of the direction of air movement. However, it is necessary to consider the number and location of diffusers relative to each other, the placement of heating elements, obstacles and other factors.
Most studies regarding the location of diffusers prove that mixing ventilation deserves an arbitrary assessment. For example, it is effective to place the air outlets at the entrance to the room from the rear desks.
But if you place taps in other parts of the audience, then in most cases you will not be able to get the desired effect. A proper exchange can prevent the formation of a strip of warm and exhaust air.
We also recommend that you read another article where we described in more detail the principle of operation of supply and exhaust ventilation. Read more - go to reference.
How does local ventilation work?
If the air purposefully gets into certain areas of the room or is removed from there, then such ventilation is qualified as local. The latter is divided into supply and exhaust.
Local ventilation is much less expensive if used than the general one. It is popular in industrial premises that require rapid updating of gases. Allows to reduce moisture and temperature.
In most cases, a combination of local and general ventilation occurs, with one type being complemented by another.
Local exhaust design is also used in industry. Relevant for removing toxic substances, reducing the temperature in a certain small part of the room. In more detail about the ventilation of industrial premises we told in this article.
Allows you to prevent the consequences of these and other negative factors. It has a positive effect on the comfort of the work of employees, since harmful substances leave the room almost immediately after formation.
If work associated with the release of toxic substances is carried out throughout the whole or greater area of the premises, then local ventilation will not be effective. However, it is still advisable to use it in front of the places with the highest emissions.
Conclusions and useful video on the topic
Video about local ventilation in the room with technological equipment:
The video explains the features and relevance of the design of the ventilation system, its equipment options and installation details:
Features of the standard ventilation system demonstrates the video:
Each of the ventilation systems has its own characteristics. When choosing you need to take into account many factors: from the specifics of the use of the premises to the presence of obstacles to the air flow. However, a careful approach will allow to stay at the optimum ventilation system.
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