Supply and exhaust ventilation: operating principle, device, calculation of system power

Residents of large cities want to breathe clean air. And outside the window there is dust and stench of automobile exhausts, evaporation of asphalt and industrial giants. The stove cooks in the apartment, the machine erases and the floors are covered with long-pile synthetic carpets. All these are sources of harmful emissions that we breathe. There is a simple, albeit not cheap, means to solve the problem - supply and exhaust ventilation for an apartment and a private house.

Operating principle

The principle of operation of supply and exhaust ventilation is simple and efficient. Exhausted air is drawn from the apartment, saturated with fumes, dust, carcinogens, unpleasant odors and allergens. At the same time, street air is supplied, cleared of all possible hazards and brought to a pleasant temperature.

The advantages of supply and exhaust ventilation at home are obvious:

• The apartment has clean air. By the way, the owners of such equipment are practically devoid of the need to wipe the dust! The installation removes up to 97% of all particles deposited on the surfaces of tables and cupboards;
• The equipment is environmentally friendly, it does not emit any harmful substances into the atmosphere;
• Apartment ventilation complies with fire safety standards;
• Installation allows you to create the perfect microclimate in your home, does not require constant attention and is controlled automatically.

A simple and understandable operating principle made the supply and exhaust ventilation systems the most popular among existing types of climatic equipment.

Supply and exhaust ventilation device

All systems of supply and exhaust ventilation for an apartment or house are divided into two types:

• monoblock;
• typesetting.

Monoblocks are released from the conveyor fully ready for use. Just connect the air ducts with your own hands and the ventilation system is ready. Compact monoblocks take up very little space and are specially designed for installation in apartments.

Stacked units are assembled from individual components directly in the house. The characteristics of the components for supply and exhaust ventilation are calculated, as usual, taking into account individual requirements. The typesetting system provides more functionality and automation. However, monoblocks win due to their small size. Any installation is equipped with a timer that sets the parameters of the microclimate. For large offices and large country houses, a prefabricated ventilation system is preferable.

What does the system consist of? We arranged the elements in a logical order: from the air intake to its supply to the room:

• Intake grille. Mounted externally at the inlet to the duct. They are supplied with a net or grill from rodents, debris;
• Check Valve. It blocks the duct from the penetration of cold air. It can be electric or mechanical. Sometimes, instead of a valve, a gate is installed on manual or mechanical control;
• Filters Located in the ducts. In the supply and exhaust ventilation systems of apartments, coarse filters with coal filler are usually used;
• Air heater or air heater. Heats the supply air before entering the room. Home systems typically use electric heaters.Water heat carriers take up more space, more expensive and more complicated;
• Evaporator. Serves for cooling the air in summer. Work on freon or water, using a chiller system;
• Fan. Stimulates air to move. The correct calculation of supply and exhaust ventilation largely depends on the characteristics of the fan;
• Sound absorber. When the fan is operating, a noticeable hum is formed, which is drowned out by a muffler;
• Ducts. Pipes for transporting air can be round or rectangular, of various thicknesses and from different materials, rigid or flexible;
• Distribution grilles and shades. They are installed at the exit to the room. Thanks to them, air enters the room not in a single stream, but in pleasant thin streams;
• Automation controlling all this equipment. It contains at least controllers for heating and fan speeds;
• Sensors They collect and submit data on the indoor microclimate: air temperature, humidity. Another group of sensors monitors the operation of the equipment;
• Recuperator. An important component of supply and exhaust ventilation, although not required. Allows you to save up to a third of the energy spent on heating the supply air.

Specifications

When choosing a ventilation system, it is necessary to pay attention to the following technical characteristics:

• Dimensions of the device. Very important for owners of apartments with a limited area and low ceiling height;
• Power Information. Most installations are powered by a standard 220 V / 50 Hz power supply;
• The weight of the device. Fasteners must be foreseen in advance;
• Nominal fan power. The power of supply and exhaust ventilation is one of the defining characteristics, measured in watts;
• Fan performance in cubic meters per hour;
• Decibel output noise level. Although modern equipment is quite quiet, it’s worth asking about these parameters. After all, a home supply and exhaust ventilation installation is located right in the apartment. Good performance 24 - 38 dB;
• The degree of air filtration. Depends on the type of filters, G is enough for an apartment;
• Availability and type of heat exchanger;
• Duct diameter;
• Availability and power of heating and cooling air. Not all ventilation systems are equipped with heating and cooling;
• Type of control system.

In addition to the technical characteristics of the supply and exhaust ventilation, the location is indicated: internal or external, operating temperature range and operating mode.

For supply and exhaust ventilation with a recuperator, the efficiency of the recuperator is specified, which on average is 90%

Manufacturers

Supply and exhaust ventilation units for apartments, cottages and medium-sized offices are very widely represented on the market in a wide variety of price ranges.

The brand	Model	Producing country	Air consumption, m3 \ h	Average price, thousand rubles
Lossney	VL-100EU5	Japan	55-100	29
Daikin	VAM 150-2000	Japan	150-2000	72
Electrolux	EPVS-200-1300	Sweden	200-1300	41
Dantex	DV 250HRE-1200HRE	China	150-1200	29
Heru	90T-1600T	Sweden	150-8000	88
Uni	4 REL EC	Norway	up to 720	148
Breezart	700 roto	Russia	up to 750	229

Table 1. Some manufacturers of air handling units

Using a recuperator

Supply and exhaust ventilation with a recuperator is the best that the market can offer today. The recuperator uses the room temperature to heat the supply air.

There are 3 types of recuperators:

• rotary;
• lamellar;
• with intermediate heat carrier.

Although a rotary device is more efficient, plate-type recuperators are more often used in small supply and exhaust ventilation devices. They are more compact and cheaper. Rotary recuperators operate at a temperature of -15 degrees and below, so they are good for outdoor installations.

Calculation of supply and exhaust equipment

For the right choice, you need to know the main technical characteristics of the supply and exhaust ventilation.

Performance definition

We calculate the volume of each served room:

V=h*S,

here h - room height, S - area of ​​the room.

We calculate the multiplicity of air exchange:

K=n*V,

here n - the table value for the living space is 2.

We increase the obtained value of K by 25-30% and the performance of the supply and exhaust ventilation is calculated.

Average performance values ​​are:

• for apartments - 100 - 500 cubic meters / hour;
• for country houses - 1000 - 2000 cubic meters / hour.

Determination of heating power

W=0,36*O*T,

here O - volume of passing air, Tz - average winter temperature.

Determination of cooling power

The previous formula is used, only the value changes T - for the summer.

Determination of steam generator power

W=h*S*u

here h - room height, S - area of ​​the room, u - the minimum humidity for the living room is 30.

Calculation of the diameter of the ducts

To calculate the cross-sectional area of ​​ventilation pipes in a residential building or apartment, you can use simple ratios:

• for an apartment or a private house on 1 square. the area of ​​the room is 5.4 square meters. cm cross-sectional area of ​​the pipe;
• for sheds and garages - 17.6 sq.cm.

Calculation of consumed electricity

You can plan ahead for the future maintenance costs of home ventilation.

Sm=(∆Td *K*c*Pd*Ld+∆Tn*K*c*Pn*Ln)*Nd/1000,

the long formula is decrypted quite simply:

ΔTd and ΔTn - the difference in day and night temperatures, calculated separately for each month, you can see the values ​​on the Internet,TO - power of installationwith - heat capacity of the air, a constant value of 0.336,Ld and Ln - the price of kilowatts / hour for day and night,Pd and Pn the length of the day and night in hours,Nd - the number of days in a month.

Electricity costs can be reduced using a recuperator or a VAV system. At the same time, the installation price increases by an average of 20%.

DIY supply and exhaust ventilation

To assemble the supply and exhaust ventilation for an apartment with your own hands, you need to have not only locksmith skills, but also theoretical knowledge. Therefore, before making the supply and exhaust ventilation in the apartment, weigh the pros and cons, consult a specialist and only after that get down to work. With your own hands in an apartment from separate compact devices you can assemble quite worthy and working supply and exhaust ventilation.

The inflow is provided by a compact air supply unit, and the exhaust fan is amplified by an exhaust fan, which is mounted in the duct in the kitchen or in the toilet. It turns out ventilation with mechanical motivation. The advantages of the proposed scheme:

• low cost;
• simple installation;
• no need to conduct ducts;
• equipment is installed without violating the decorative finish of the apartment;
• power supply and exhaust ventilation is easy to calculate;
• repair of combined ventilation system will cost quite inexpensively.

And a bit of tar: prefabricated ventilation with mechanical motivation will work noisy due to exhaust fans. Choosing the power of devices, it is important to carefully balance the inflow and blowing, otherwise drafts, low pressure and other unpleasant health effects are possible.

The use of mechanical traction on the hood can be abandoned. Establish a forced flow, then the exhaust air will be “squeezed out” through the ventilation grilles.

It turns out combined ventilation with heating, quiet operation and fully automated. And now, detailed instructions on how such ventilation is done in the apartment.

Selection of equipment for air flow

There are two types of air handling units:

• compact;
• universal.

Compact serve only one room, installed on a door or wall. The compact air handling unit works without air ducts. Air enters through a hole in the wall or door, is filtered, warmed up and fed into the room with the desired intensity. All parameters are set manually.

Universal are located under a false ceiling or on a closed balcony. The installation will serve the entire apartment, but it is necessary to conduct a network of ducts. This is the main difference from the compact. Such equipment is more cumbersome, its installation is more complicated. Nevertheless, it is entirely possible to independently make ventilation in the apartment on the basis of a universal air supply.

Plan the placement of the universal air handling unit before the start of cosmetic repairs. Then the air ducts easily hide behind decorative elements.

Supply air installation

If the choice fell on a universal air supply unit, the first stage of work is the choice of a place for it and the laying of air ducts. Flexible ventilation pipes are convenient, if a number of rules are taken into account during their installation, they will serve very effectively.

Avoid turns, if this is not possible, do them at an obtuse angle. Duct length should be as short as possible.

The supply unit is mounted near the outer wall, the smallest compacts can even be hung on the bottom of the balcony door.

Progress:

1. A hole with a diameter of about 10 cm is drilled in the wall (door) (see the instructions for the device for sure).
2. We insert a supply pipe, previously wrapped with thermal insulation, into the hole.
3. From the side of the street we fix the grate.
4. We hang the ventilation unit from the inside, fasten it to the wall with screws or dowels.
5. We stretch the air ducts, if a universal air supply is selected, we connect the power supply.

The first part of the supply and exhaust ventilation for the apartment is already assembled. Now we will deal with the conclusion of the exhaust air.

Selection of equipment for air exhaust

We will remove air from the most “polluted” rooms: the bathroom and the kitchen, using a time-tested exhaust fan.

Choose exhaust fans equipped with humidity and motion sensors. Such devices do their job better, using less electricity.

A fan is installed instead of an exhaust grill. It is advisable to equip the hood with a check valve. This low-cost device is a plastic shutter on a horizontal axis offset upward. The valve blocks the air flow from the ventilation system, preventing reverse draft.

If the fan is equipped with sensors, electric current is supplied to it continuously. Simpler models are powered from the light switch or run with a separate button. The second option for the kitchen is preferable.

We cannot but mention the device that is universally used for exhaust air - cooker hood. The effectiveness of the hood is explained by the fact that it captures vapors and odors directly in the zone of their appearance. When choosing, you should pay attention to the following parameters:

• view (flat, island, dome, built-in);
• dimensions;
• operating principle (recirculation or air exhaust);
• performance;
• noise level;
• control method (touch or mechanical).

Model	A type	Operating modes	Productivity (m3 \ h)	Power (Watts)	Type of control
Hansa OKS 653 SWN	dome	Retraction \ circulation	620	160	Sensor
Hotpiont HLB 6.7	recessed	Retraction \ circulation			Buttons
Elikor 60 IX	dome	challenge	430	185	Buttons
Cata cn-600	dome	Retraction \ circulation	583	80	Buttons
Snindo Avior 60 SS \ BG	dome	Retraction \ circulation	800	238	Sensor
Krona Kamilla 2M	recessed	Retraction \ circulation	550	200	Buttons
Gorenie wht961	dome	Retraction \ circulation	755	288	Sensor
Samsung HDC9A90	dome	challenge	861		Sensor

Table 2. Characteristics of some models of cooker hoods

By installing exhaust devices, you get supply and exhaust ventilation with mechanical motivation and heating.

Supply and exhaust system maintenance and repair

Mechanical supply and exhaust ventilation installation is a rather complicated equipment, which consists of many components. All of them must work in concert, if this does not happen, repair of the supply and exhaust ventilation is necessary. Additionally, the home system needs service, which includes:

• debugging of the main parameters;
• cleaning filters and ducts;
• fire safety compliance control.

If the equipment breaks down, we strongly advise against undertaking repairs yourself. Monoblocks have a guarantee. But even if the system is typesetting, the supplier (usually he and the installer) gives a guarantee for equipment and installation work. Only repair the supply and exhaust ventilation system if you are very well versed in the issue, took part in the installation and own the diagnostic equipment.

Video about a homemade recuperator for supply and exhaust ventilation: