In a private house, amenities and comfort are important. A comfortable microclimate will provide heating and ventilation of the cottage, civilized conditions will create water and electricity, sewerage and gas supply. Ideally, all systems are designed simultaneously, taking into account their further interaction.
We will tell you how to organize a stable, full-fledged air exchange. We will show you which scheme is better to prefer and how to choose equipment that will work perfectly for the benefit of the owners. You will learn all about the intricacies of designing an autonomous ventilation system.
The content of the article:
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Ventilation options
- The principle and operation of the gravitational system
- Mechanical ventilation and its types
- Supply and exhaust system with a recuperator
- Technical points in the development of ventilation
- Conclusions and useful video on the topic
Ventilation options
The impeccably functioning ventilation of the building is not only cool, but also clean air that meets all sanitary standards. It is a serious mistake to believe that a conventional range hood or air conditioner will solve this problem, since the added the climate system simply combines fresh air with exhaust air, diluting it, and bacteria and odors remain.
Due to the widespread ubiquitous sealing, the rules of air infiltration, which were widely used in construction during the Soviet era, no longer work. Then, for ventilation of apartment buildings built from environmentally friendly building materials, there were enough gaps in the wooden frames and exhaust ventilation ducts.
Each room in the cottage should be regularly ventilated and completely “washed” with a stream of fresh air. Effective ventilation ensures an optimal microclimate
Now, for the sake of sealing, effective seals are installed in window and door frames to prevent natural inflow. Impervious films and insulation materials are used in building structures, preventing not only thermal energy leaks and moisture penetration, but also air flow.
All this saves energy resources, but leads to difficulty in natural air exchange between the street and the interior of houses. In order to ensure a regular supply of fresh air to confined spaces and arrange ventilation. It can be natural, mechanical and mixed.
The principle and operation of the gravitational system
The natural system that ensures regular air exchange in the cottages is due to the forces of gravity. The movement of air flows in it is justified by the difference in pressure, temperature and air density outside the windows and inside the building.
Cool outside air is drawn in through the supply valves, open vents, and plastic transoms ajar for micro-ventilation. A new fresh portion pushes the spent air mass towards the hood, which in private buildings can be in the ventilation shaft, in the ceiling with access to the attic, and then to the street, or through the wall directly to the street.
The draft force in the chimney is largely influenced by the wind and the cross-section, length and other parameters of the ventilation ducts. However, it works only at a street temperature of no more than 12-15 degrees Celsius, with an increase in values, the efficiency of the hood is significantly reduced.
The gravitational type is the cheapest and easiest to implement version of the air exchange system. There is practically nothing to break in it, but there can be malfunctions. They happen due to the equalization of pressure inside the room and outside the cottage.
In winter, on the contrary, the upward air flows intensify, and the heat “flies out into the chimney”. There are methods to improve performance natural ventilation system - installation of a deflector or check valves on the channel, but this does not radically change the situation.
According to sanitary standards, the volume of incoming clean air is:
- 3 cubic meters / hour per 1 sq. meter of rooms;
- 25 cubic meters / hour for bathrooms;
- 35 cubic meters per adult.
For convenience, another standard is often used - the frequency of air exchange, which reflects how much once the air in the room must be replaced within an hour (in Russia, this indicator is at least 0.35 times / hour).
In order to ensure the movement of air in cottages with sealed windows, exhaust and supply valves are used. If the valves are equipped with fans, the natural system becomes a mixed
In practice, the inconsistency of the quality and composition of the air mass with sanitary and epidemiological standards is manifested in the following negative factors:
- in violation of the temperature regime;
- in the appearance of dampness, mold;
- in the manifestation of tobacco smoke and kitchen odors;
- in increasing the level of carbon dioxide.
The main advantage of the gravitational type of ventilation is only simplicity and minimal costs. After all, the natural circuit does not fully fulfill the functions assigned to it of updating the air in a hot the period when, for the same gravitational reasons, the air can move in the opposite direction: from the house to window.
Mechanical ventilation and its types
In order to prevent such phenomena and balance the flow of fresh and polluted air, in cottages install equipment for mechanical (or as it is called forced) regulation of air exchange. Mechanical ventilation systems include: not only the supply and exhaust devices, but also the supply and exhaust complex.
Installation of systems involves the installation of units and blocks for the supply and exhaust of air into air duct system (their simplest representatives are kitchen hoods and duct air conditioners).
An air handling unit is a grouping of supply and removal into one monoblock. This class also includes circuits with fans installed simultaneously in both the exhaust and the supply. Note that in supply and exhaust circuits only the hood or only the inflow always works, and the owner has a choice which is preferable to use.
When planning the supply and exhaust ventilation of a cottage, an important condition for the normal operation of the system should be taken into account - clean air must be supplied to all residential, utility and household premises. The hood is suitable for areas with unstable humidity and temperature: in bathrooms, kitchens, showers, etc.
In addition to the main rooms, in which it is necessary to provide a healthy comfortable furnishings, in most country houses there is a large number of technical, household and special premises.
Depending on the purpose, they require an individual approach to the organization of their service:
- Baths, saunas and swimming pools require ventilation with humidity control.
- In a fireplace and boiler room with an atmospheric gas boiler, it is necessary to maintain combustion with an oxygen supply.
- In dressing rooms and pantries, simple ventilation is sufficient.
If clean air enters living rooms, children's rooms and bedrooms, but is removed from toilets, bathrooms and kitchens, this is a typical example of correct arranged ventilation of the cottage and competently designed organization of a system of any type, regardless of the factor of motivation, gravitational or mechanical.
Exhaust hoods are required to remove the air flow. ventilation pipes. In cross-sectional shape, they are round and rectangular, in degree of rigidity - rigid and flexible. Aluminum and polymer corrugated air ducts are flexible.
Due to the corrugation, flexible ones have the greatest resistance, however, there are situations when you cannot do without them. Turns are easier and faster to perform with corrugation. It is also placed in areas that compensate for the linear thermal expansion of plastic ventilation pipes and ducts.
Ventilation ducts in cottages are laid hidden and open. In the first case, they are laid during the construction of walls, in the second, they are laid on top of structures. Most often, open air ducts are masked under stretch ceilings.
Pipes for ventilation devices are rigid and flexible. Rigid ones are produced from aluminum, welded and spiral wound steel, plastic. Materials combine lightness and durability
When installing a standard supply ventilation system, two difficulties appear over time:
- a large amount of thermal energy spent on heating the incoming air and going into the exhaust pipe;
- insufficient level of humidity inside the room during a cold period.
Installing a recuperator quickly and efficiently solves these difficulties.
Supply and exhaust system with a recuperator
Now they are increasingly used air handling units with a recuperation function, the process of heat exchange between the waste warm stream leaving the room and the incoming cold air.
Depending on the coolant that heats the air, recuperators are water and glycol. Depending on the type of heat exchanger regenerative devices are divided into plate and rotary. A feature of the rotary is the rotating drum-heat exchanger and the absence of freezing.
In systems with heat recovery, the exhaust air flow is used to increase the temperature of the fresh portion drawn by the device from the street.
Recuperators are manufactured for installation on the roofs of service houses. There are models located in the attic space, there are also apartment options that handle separate housing in high-rise buildings.
The characteristics of the plate model depend on the material of the heat exchanger cassette (plastic, aluminum, cellulose and stainless steel). Both types of recuperators are considered the most popular due to their simplicity, reliability and high efficiency; they are effectively used in ventilation systems of cottages.
Recuperators are divided into plate and rotary recuperators according to the principle of recycling exhaust air. In the former, fresh air is only heated by the waste stream passing behind the adjacent plate, without mixing. In the second, a drum rotating in the body partially mixes the fresh stream with the waste stream.
Application supply and exhaust devices with recuperation function maintains comfortable conditions and provides:
- relative humidity, by dehumidification or humidification;
- balance between supply and extract air volumes;
- comfortable air temperature, by cooling it with air conditioners or heating it with heating devices.
Ventilation units with a recuperator are an energy-saving system that allows you to save heat in winter. energy up to 50%, while usually, with the onset of cold weather, a large amount of energy is spent on heating clean supply air number.
In the arrangement of ventilation systems for apartments and private cottages, plate recuperators are mainly used. They are smaller, quieter and easier to maintain. Rotary equip networks of industrial and commercial facilities, put them on roofs
The systems partially warm up the incoming flow, and the built-in heater brings the temperature to the desired value.
Technical points in the development of ventilation
When choosing equipment for a ventilation system, it is necessary to use several basic design indicators in operation. For example, multiplying the values of the volume of the room and the rate of air exchange, you can get the value of the production capacity of the fan required for the full service of the cottage.
Those who are thinking about how to correctly make ventilation in a cottage, naturally, should take into account possible losses and choose a fan with a margin. One important point should be taken into account - the equipment of the exhaust system should be 10-15% more powerful than the supply one, so that the used air does not accumulate in the room.
For the competent organization of ventilation in the cottage, a number of important factors must be taken into account:
- Location of the exhaust duct route. Pipes should be placed mainly vertically and in a straight line, preferably without turns (since each turn reduces traction by 10%) and of the same diameter along the entire length of the route.
- Chimney height. The mouth of the chimney should be at least half a meter above the roof of the cottage (the air should be removed above the roof). The installation of a deflector also significantly increases the circulation of the air flow (up to 20%).
- Section and dimensions of ventilation ducts. The most cost-effective is considered to be a circular cross-section, and in practice, rigid circular ventilation systems are often used. channels, due to the ease of installation, the lowest resistance and, as a result, the high intensity of the air flow.
He will acquaint you with the rules for calculating the area of air ducts next article, which is worth reading to all owners of suburban property.
Also, to increase traction, the maximum diameter and length of the pipe to be laid should be used whenever possible.
To form a normal draft in the chimney, adhere to the standards for its height. If between it and the ridge is less than 1.5 m, it should rise 0.5 m above the ridge ridge.
When developing a supply and exhaust system, it is necessary to remember some technical points:
- the amount of incoming and outgoing air must be balanced;
- clean air is delivered to all rooms, and dirty air is outflowed from areas with unstable humidity and temperature conditions;
- ventilation from the bathroom and the kitchen hood cannot be combined into one channel;
- the speed of the circulating flows in the exhaust pipes and air ducts should not be more than 6, and at the outlet 3 meters per second.
The mechanical ventilation system is certainly more productive than the natural “sister”. Its operation is completely unaffected by weather data; its activation and deactivation can be automated. However, it is much more complicated and more expensive in the device.
Conclusions and useful video on the topic
The following video will acquaint you with the steps of installing the air ducts:
The principle of operation of the gravitational ventilation system is presented in the video:
Ventilation hood design guide:
So, in a cottage, regardless of what building material and in what area it is built, a full-fledged air exchange is required. Supply and exhaust ventilation, the development of which must be included in the project, is a reasonable choice.
Knowing the principles of organization, the device of the gravitational system can be easily dealt with without the involvement of builders. It is more correct to entrust the design and installation of mechanical ventilation to heating engineers.
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