Systems supply and exhaust ventilation, providing air exchange in the building, during winter operation pump cold air into the room, which must be somehow heated. The easiest to install and most affordable, but at the same time effective heating element is the air heater, which we will talk about in this article.

The publication discusses the types of heaters, provides an algorithm for their calculation and installation instructions, as well as presents the most popular equipment models and gives recommendations on their choice.

Types of air heaters for ventilation

Air heater is a heating device installed inside the ventilation duct. Its main function is to heat the air entering the room during the cold season. Depending on the principle of operation, two types of heaters are distinguished:

• water;
• electrical.

In small buildings with an area of ​​up to 100 squares, it makes sense to use electrical equipment, since it does not require regular maintenance during operation and differs more simple installation... Premises with an area of ​​150 m 2 - offices, cottages, public buildings, it is rational to equip with water heaters, since the cost of electricity for heating a large amount of air will be excessively high

Hot water heaters consist of a series of tubes in a metal frame through which heated water circulates (in rare cases, oil or ethylene glycol). Such units are connected to the system district heating or to the boiler through the inlet pipes located on the end of the body. The body itself, as a rule, has rectangular section, however, there are models for round ventilation ducts.

Depending on the shape of the tubes, water heaters are divided into smooth-tube, plate and bimetallic. The most common smooth-tube designs, however, they have a drawback in the form of low heat transfer. In products where the tubes are replaced by plates, this is better, the bimetallic water heater, in which the tubes are made of copper, a material with the highest heat transfer coefficient, has the highest efficiency.

An electric heater is a device in which the air is heated by heating elements, onto which aluminum or copper fins are pressed (necessary to increase the heat exchange area). The power of electrical units can reach hundreds of kilowatts, while all equipment with a capacity of over 3.5 kW must be powered directly from the panel, and heaters with a power of 7 kW or more require power from a three-phase 380 V.

Heating air heaters electric type outperform the water ones in terms of ease of installation - it is much easier to bring to the installed in ventilation duct equipment with a power cable than a pipe from a central heating system. An additional factor affecting the labor intensity of the installation is the absence of the need for thermal insulation, which must be performed when piping in order to avoid cooling the water circulating through them.

The electric heater is easier to operate - the supply air temperature is controlled by means of a remote temperature sensor that regulates the heating temperature of the heating elements. While the water unit does not have direct adjustment mechanisms, in order to change the air temperature, it will be necessary to regulate the power of the heat exchanger and the amount of water supplied to the heater.

However, water equipment is more affordable, for comparison - an electric heater of 40 kW will cost you 12-13 thousand, while a water one can be bought for 7-8 thousand rubles. The saving factor is also important, the operating costs of a water heater are much less than an electric one.

1.1 The place of the air heater in the ventilation of a private house (video)

1.2 Features of the calculation of equipment

Selecting a heater for the system supply ventilation must be carried out on the basis of calculations, during which the required power and equipment performance are determined. To perform such a calculation, you need to have the following initial data:

• system performance (volume of air circulating through ventilation per hour of operation) - V;
• initial air temperature outside the window - t1;
• required indoor air temperature - t2;
• tabular information on the density and heat capacity of air.

Initially, you need to calculate the air by mass, this is done according to the formula M = R * D, in which:

• R is the volumetric air flow;
• D - average air density

To find out the density of air, you need to determine it average temperature and see its specific gravity in the table below. For example, if air comes from the street with a temperature of -8 degrees, and the room temperature should be raised to 21 degrees, then the average value will be 14.5 0, which, according to the table, corresponds to a density of 1.23.

We can now calculate the air mass flow rate. Its volume flow rate must be indicated in technical documentation to specific ventilation system... As an example, let's take a productivity of 1500 m 3 / h, the total consumption will be 1500 * 1.23 = 1845 kg / h.

• M - air consumption by mass per second
• WITH - specific heat supply air (taken from the table);
• t1 and t2 are the outside and inside air temperatures, respectively.

An example of such a calculation is (1845/3600) * 1007 * (21- (-9)) = 15482.62 W. As a result, we find out that the required power of the heater in a particular case is 15.5 kW. However, it is necessary to purchase equipment taking into account the power reserve, which should be at least 10-15% of the calculated value.

2 Gas heaters - purpose, scope

There is also such equipment as gas heater, which is fundamentally different from the technique discussed above. These units in everyday life, better known as "heat guns", are mobile heaters widely used on construction sites when carrying out repair work (for drying paintwork and plaster coatings). Also, gas heaters are used to heat industrial and industrial premises - workshops, hangars, warehouse buildings... V agriculture heat guns are used for heating greenhouses and greenhouses, farms, fodder storages.

The gas heater device is shown in the image, where the following structural units are marked:

1. Metal body.
2. Burner.
3. Fan.
4. Control block.
5. Intake nozzle.
6. Thermostat.

Gas units, depending on the type of fuel consumed, are classified into two types - equipment operating on liquefied gas and on natural (main) gas. The advantages of using this equipment include a high efficiency of its operation, reaching 97% (heat guns are much more efficient than other types of heaters, especially when working on large areas). Also, a gas heater will cost significantly less than any other heater of comparable power.

A serious disadvantage of such units is the need to use auxiliary equipment for the removal of gas combustion products outside, without which it is impossible to use heat guns inside a residential building.

Heaters today are presented in several varieties. One of them is a water channel, designed for If we make comparisons with electrical analogs, then water heaters require less energy consumption. But if you want to carry out the calculation and installation yourself, then you should know that it will be somewhat more difficult to do this, in comparison with electrical appliances.

The principle of operation of supply ventilation

If a water heater is used for supply ventilation, then the air in the system and drying units will be heated. The described device should be in the role of a separate module or as part of monoblock installations. A heater is a heat exchange device where a heat source heats a passing air stream by contact with heating elements. Air coolers are also called heaters, but they are much less common. Similar devices operate on the basis cold water or freon, which are in heat exchange surfaces.

After you have become aware of the principle of operation of supply ventilation with a water heater, you can begin to make calculations and further installation of the device. Most often, such manipulations are carried out in large premises, which can be large stores, industrial enterprises, and warehouses... If you use such devices, then you can save on electricity, because a minimum of electrical energy is required to work. The connection is made to the heating mains, and the air that enters the room is heated by warm water. A water heater for supply ventilation, the section of which is presented in the article, has one more important advantage, which is expressed in the fact that such devices are compact in size. Calculating and installing the device yourself, you will not face the problem of the need to allocate a large space.

Main advantages

The equipment described in the article is very productive, it is capable of creating strong temperature drops. By outward appearance heaters are a case that looks very aesthetically pleasing. If there is a desire to extend the life of the device, so as not to run into monetary costs, it is necessary to monitor correct work... For a similar thermal equipment it is not recommended to use water from heating mains, the temperature of which is more than 180 degrees. You must also take into account the standards that prescribe the degree of contamination of the air masses. chemical elements and dust. If a wall-mounted water heater for supply ventilation of a house is used under improper conditions, then it is doomed to breakdown and failure.

Working conditions

Hot water heaters should be installed in ventilation systems, as well as connected to central heating in cool rooms or rooms with a temperate climate. When it comes to production and industrial premises where the temperature is high enough, this technique is not used. It is important to take into account the parameters of the operating mode of the device, which are described in the passport, only then the device will delight long term exploitation.

The control of supply ventilation with a water heater is quite simple, however, in order for this condition to be fulfilled, it is important to carry out the installation according to the rules prescribed by the manufacturer. Diagonal dimensions will determine the pitch to the damper, channel bend and other elements. It is important to ensure that the device is operated under conditions not lower than 0 degrees, otherwise the heater may freeze. It is important to analyze the integrity of the tubes, plates and other system components prior to installation.

Conclusion

The connection by means of flanges, which must be installed butt, is the maximum simple solution to connect the device to the piping system.

Providing optimal access to fresh and clean air in living quarters, especially in warm weather, is a fairly simple task. To do this, it is only necessary that the supply ventilation is equipped with a fan with sufficient power.

However, in the winter period, the existing concept should be radically changed to the arrangement of the entire ventilation system. In this case Special attention recommend using air heaters for supply ventilation, which will take full care of establishing a sufficient number of free access to housing warm air and a favorable microclimate in the rooms.

A heater is a device (equipment) designed to carry out heat exchange by heating an air stream by contacting it with a certain number of heating elements.

Such a device is installed in ventilation systems, both in the form of free-standing modules, and in combination with monoblock structures.

Types of air heaters used in supply ventilation systems

The choice of such devices for is based, as a rule, on several main factors, including performance, the total area of ​​the room, the power of the equipment, as well as the climatic characteristics of a particular area. Taking into account all the listed characteristics, the following types are used:

• electric heaters for supply ventilation - the use of this type of heaters is considered the most economically justified, based on the fact that the electric heater does not require complex communications (it is enough to connect the device to the power supply) and is equipped with special heating elements for the most efficient heat exchange, which convert electrical energy into thermal energy.
• water heaters for supply ventilation - their main purpose is to heat air in ventilation systems with a round and rectangular cross-section, therefore they are successfully used for heating cottages, shops, large complexes, warehouses and premises, including livestock farms.

The use of electric heaters is effective when the area of ​​the ventilated room is within 100-150m2. The main advantages of such heaters are simplicity installation works and their general availability, and the disadvantage is the high level of energy consumption.

Water heaters are quite practical, profitable and reliable devices for efficient heating of large air volumes (over 150 m2) and do not need constant or frequent maintenance. The quality of their work depends entirely on the availability of automatic control.

When installed at the top point with a downward direction, the water-type heater is able to quickly and easily equalize the temperature of the air mass of the room, thanks to the equipment of this type of heat exchanger with a special thermostat. For better heating, such devices can be combined into a single structure.

The ventilation system based on water heaters operates according to the scheme: the external air flow entering through the air intake grids, passing through the louvered grilles, enters the filter section, where it is directly cleaned from dust and all kinds of mechanical impurities. After that, the purified air enters the heater for further heating by means of the heat given off by the main water.

Among the wide range of water heaters, heaters with the use of bimetallic and aluminum finning elements have gained particular popularity.

Strapping methods

Regulatory reinforcement cage(piping of the supply ventilation heater), depending on the source of heated water used, is often carried out in two ways:

• the use of two-way valves - in cases of using a city network, in which the flow of the reverse amount of water is not recorded, there is only a need to maintain a constant temperature;
• the use of three-way valves - in cases of consumption from a boiler or boiler room, where the flow rate of the reverse volume of water is strictly fixed, and any changes affect the normal functioning of the entire system. You will also find it helpful to read how to organize.

is an obvious necessity, since it allows you to control the performance of the equipment and protects it from excessive freezing in the winter period.

Determination of the required power value of the installation

When selecting heating equipment for arranging supply ventilation, it is imperative that the necessary indicators are:

• performance based on external air flow environment;
• pressure generated by the operation of the fans;
• the total power of the heating device;
• the area of ​​the air supply pipelines;
• permissible rate of occurrence of various kinds of noise effects;
• the speed of penetration of air currents.

Particular attention is paid to determining the power level of the heater.

The process of installing air heaters is used in supply ventilation systems in order to heat the outside air mainly in cold weather. The power indicator can be calculated based on the parameters of the ventilation performance, the minimum, as well as the set temperature of the air flows, both outside and at the outlet. For effective work the supply system is often equipped with a power regulator designed to reduce the fan speed during the cold period.

A number of essential rules and restrictions should be taken into account:

• possibility of application different types food;
• a three-phase connection is necessary when using a heater with a power of more than 5 kW. In this case, three-phase power is the most acceptable option, since the current will be much lower.

The maximum permissible value of the current consumed by the heating equipment is calculated on the basis of a rather simple formula:

I = P (power) / U (supply voltage)

For a single-phase voltage, the value of U is equated to 220V, with a three-phase power supply - 660V.
An important parameter is also the temperature of the supply air flow when heating the air heater of a given power parameter, which is calculated by the formula:

T = 2.98 x P (power) / L (ventilation system performance)

The standard values ​​of the calculated power of the heating installation for apartments and houses can be 1-5 kW and 5-50 kW - at enterprises or in an office. In cases where it is impossible to use an electric type of air heater with a given power, you should resort to installing a water heater, which uses water from different systems heating, including autonomous or central.

In general, in small rooms it is more expedient to install electric air heaters for supply ventilation, since they are easy to use and do not take much time to install. For buildings with a large area the best option the installation of water heaters will become, thanks to which electricity is significantly saved and the energy consumption required for heating water is reduced.

It is a device used to increase the air temperature in an enclosed space. The design of this device is based on tubular channels through which flows warm water, heated air or vaporous substances. The heater is used for heating air in air conditioning devices, drying plants, ventilation equipment and so on. The water in this device heats up to a temperature of over 170 degrees. In fact, the air heater is a heat exchanger. The most widespread are devices of the channel type, which is a fragment of an air duct with heat-dissipating elements installed in it.

Types of heaters

Depending on the type of heat energy transfer, there are water and electric duct heaters. The water heater is a tubular heat exchanger that looks like an auto radiator. Typically, it is connected to a district heating system. The electric heater differs in that heating elements are used here as heat release elements. In addition, air heaters may differ depending on the structure and sectional shape of the ventilation system. They can be rounded or rectangular shape... Recently, heating blocks, in which heat recovery is carried out, have become more and more popular. A design feature of such devices is that the cooled air entering them is heated by heat exchange with the outgoing hot air. At the same time, there is no mixing of air flows. Such a system was developed on the basis of the well-known Ammos oven.
Fig 1. "Drawing of the air heater of the Ammosov system. 1840s."

Electric heater

Air heater with electrical structure incorporates steel glowing filaments or wire spirals. Thanks to this design, the device creates a current resistance, due to which electricity is converted into heat energy.

The main positive traits electric duct heaters:
• insignificant pressure drop compared to traditional air heaters;
• for electric heaters, you can easily calculate the power;
• availability and low price installation.

Among the disadvantages, it can be noted that a large inertia is created in the steel filaments. Due to this, electric heaters can quickly overheat, which requires the installation of additional protection against overheating. Also important point are the increased operating costs of electric duct heaters. In practice, it has been proven that the cost of electricity in this case will exceed the cost of heat in water heaters. Electric heaters are mainly recommended for use in supply systems, in which the air consumption does not exceed 10 cubic meters per hour. They are much easier to install, set up and connect. However, due to the high operating costs, water heaters are installed in most cases. In general, electric heaters cost slightly more than water heaters.

Water heater

The most common type of air heater is a water heater with a perpendicular flow. It is used in most ventilation devices... In these devices, the movement of water is carried out in a rectangular direction and in the direction opposite to the air current. Due to this, water flows from bottom to top through the channels. Due to this, air bubbles are at the top of the structure, from where they are removed without problems through special air taps. An indispensable component of any design of a water heater is a piping unit. This unit is a special part, with the help of which the supply is carried out hot water to the heat exchanger.

The water heater includes the following parts:
• circular pump;
• three-way valve;
• fittings;
• block for device control;
• a strapping knot, which is necessary to control the performance of the heater and slow down its freezing.

If the heater is supposed to be operated in climatic conditions, where the ambient temperature drops below zero degrees, then it must be equipped with an anti-freeze system. Otherwise, the water in the channels can burst the pipes when freezing.

The principle of operation of heaters

The basis of the design of any heater are elements for heat transfer, which look like metal tubes with a special outer surface... Thanks to this structure, the area of ​​the device increases and the efficiency of heat transfer increases. The cooled or heated coolant circulates through the finned pipes. WITH outside air flow passes through the pipes, which can accordingly be cooled and heated after contact with the pipes. The principle of operation is that the coolant has an increased level of heat transfer compared to air flows. The ribbed design of the air heater includes steel plates mounted on pipes or wound wire.

Duct heater selection

On energy efficiency the heater is influenced by the coefficient of its heat transfer against the background of certain energy costs. Accordingly, the energy efficiency of the heater will be the higher, the more heat it can give off with comparable energy consumption. When choosing a heater, it is necessary to take into account not only its energy efficiency, but also other indicators. In particular, its dimensions play an important role when choosing a device so that it can function normally in a certain ventilation system. After the installation of the device, it is recommended to completely eliminate the influence of harmful chemical components and adhering components from the passing air on the device. To do this, install additional filters.

Installing a duct heater

A duct heater has the ability to significantly heat the air that passes through it. The device raises the air temperature up to 80 or even up to 120 ºС. Therefore, the device can be used to warm up the discharged air even in very low temperatures up to -30 ºС. When installing water duct heaters, remember that they need additional mounting strapping details. Installation of equipment can be carried out using two air exchange schemes - by the mechanism of air inflow and recirculation, as well as by the mechanism of closed air recirculation. The duct heater works most efficiently in systems natural ventilation installed in basements. This is the most the best option in terms of air intake. However, when installing a duct heater in systems artificial ventilation this is not important, since the air enters the heater tanks with the help of fans.

The duct heater can be connected to the ventilation system not only as a single module, but also in combination with monoblock ventilation equipment. In this case, the heater is a device that acts as a heat source. The duct heater heats up the air flow passing through it in contact with the heat transfer elements. The heater can be in the form of an air cooler, which is much less widespread than a traditional heater. The air heaters cooler operates on the basis of freon or chilled water, which circulate in the heat exchange elements of the device.

Ceiling heaters

Due to the maximally flat body, it is possible to install the heater in very low rooms. This heater can be installed directly under the ceiling. The device takes air from below, after which it passes through the filtration system, warms up and enters through special holes in different directions. Ceiling heaters of this series are distinguished by ease of installation, stylish shapes, variety colors and reduced noise pressure in the system.

Heaters are distinguished by the type of coolant:- water, - steam

By the type of surface, steam and water heaters are distinguished: -smooth tubular, - ribbed.

By the nature of the movement of the coolant, the heaters are divided into: - one-way, - multi-way.

By the number of rows of pipes, the heaters are divided into two models: -medium (C) with three rows of pipes, -large (B) with four rows of pipes.

Air heater: purpose and classification.

Heater- one of the most important elements climatic equipment providing the required temperature parameters in the premises for various purposes... It is the function of these devices that includes heating the air in heating, ventilation and air conditioning systems, and it is on their performance that the comfort of staying in the building and the premises of this building fully depends. Heater, due to its high performance, is widely used for heating rooms with significant internal volumes? office centers, retail and warehouse premises, sports and entertainment complexes, stations Maintenance, garage premises and production workshops. The mobility that many models have heaters, allow them to be used in construction for heating closed rooms that are in a state of construction or repair. The active use of these devices when carrying out construction works is also explained by the fact that the classic heater Is a device with small size and weight, easy to operate and unpretentious in operation. The high performance that heater, is explained by its ability to create a large temperature difference (70 - 110 degrees), which also makes it possible to use it in supply ventilation systems. In such cases heater successfully copes with its functions even when the air temperature outside the room reaches values ​​- 25 degrees. The versatility that heater, also lies in the fact that in the warm season it can be used as a high-performance fan to circulate air in ventilated rooms. It should be noted that heater as an element of the ventilation and heating system, it can operate at air temperatures outside the premises, the values ​​of which vary from - 25 to + 40 degrees, and the humidity ranges from 25 to 98%. The high performance that such a device possesses allows it to be used to equip drying chambers... In such cases, the most common coolants supplied to heater, are hot water or superheated steam, the temperature of which can have values ​​of 180 - 190 degrees, and the value of the working pressure reaches 1.2 MPa.

Heater Is simple enough technical device, it consists of elements that give off heat to the passing air, tube sheets, covers equipped with pipes for supplying and removing the coolant, as well as side shields that cover its body.

The main classifying parameter heaters is the type of coolant that it uses. So, depending on this criterion , air heater it can be water - KSk, which uses hot water as a heat carrier, or steam - KSk, which uses superheated dry steam.

Heater, in addition, it can have a different type of heat-transfer surface, depending on which it can be smooth-tubular and ribbed. Designs in which special fins are applied to the pipes, due to the larger area of ​​the heat-transfer surface, are more efficient than devices with smooth surfaces.

Another parameter by which they are classified heaters, is their design. So, there are spiral-rolling structures, bimetallic, connected to the coolant system by welding or special flanges and bolted joints.

Classification of air heaters depending on their internal design.

The movement of the heat carrier inside air heater can be organized according to two basic principles, which is ensured by the design of this device. Aquatic heaters KSK are multi-pass devices. The movement of hot water in such devices passes through special headers with partitions. The baffles are installed in the transverse plane, which makes it possible to impart a consistent character to the movement of hot water in the collectors. The use of such constructive solutions allows you to impart a high speed to the movement of the coolant, which most directly affects the increase in the intensity of heat transfer. Multi-pass devices, due to their properties, are more efficient than single-pass designs. As a rule, multi-port devices are installed in systems with a horizontal arrangement of heat transfer elements.

Steam heater KPSK is a one-way device installed in systems with vertical arrangement of heat-transfer elements. Devices with such a principle of the passage of the coolant have pipes on both sides, which provide its supply and discharge. The coolant from the junction box enters simultaneously all the tubes of the one-way device and passes through them only once, giving off its heat to the passing air stream along the way.

Heater, depending on the capacity, may contain different number rows of pipes in their design. So, there are medium devices containing three rows of pipes, and large heaters, the structure of which contains four rows of pipes.

A separate category is made up of the so-called electrical heaters, the design of which is equipped with a special electric ten. Such devices with small overall dimensions and mass, are completely autonomous, they do not require a centralized network of hot water or steam and only need an electric power supply. The biggest drawback of such devices, which significantly limits their use, is their low power, which allows them to be used only for rooms with small dimensions. In addition, such devices consume enough a large number of electrical energy, which in some cases can be very critical.

Advantages of using water heaters.

Water heater, using hot water as a heat carrier, is one of the most effective devices of this kind, allowing you to heat rooms big size in a relatively short period of time. Importantly, a small amount of electricity is consumed, which makes such a device also very economical. Such heater, depending on its structural performance, can work on the principle of closed air circulation or take it from the outside. Usually, closed systems are used in cases where people are constantly in the heated room. The second type of such devices can be used to heat any premises: warehouses, hangars for various purposes, basements, etc.

Water heater, besides its efficiency, it also has high safety. Today, such devices, with various capacities, are successfully used to heat warehouse and shopping centers, industrial premises, sports halls, service stations, garages, greenhouses and livestock farms. Even having a small power and overall dimensions, such a device, due to its high performance, is capable of heating large rooms. So, for example, setting this heater at the top of the room and directing the flow of warm air downward, you can effectively eliminate the temperature gradient and ensure uniform heating of the air throughout the volume. If necessary, you can create whole heating systems composed of several such devices, each of which is equipped with a thermostat that is responsible for turning them on and off. The creation of such systems, composed of several water devices connected in series, can significantly reduce the cost of heating rooms with a large volume.

Importantly, water heater connects to the existing heating system of buildings, which does not require the creation special conditions and additional financial costs for its installation and launch. Electricity, which such a device necessarily needs, is not consumed for heating, but only for ensuring the operation of the fan, which consumes it in very small quantities.

High efficiency of water heaters, their ability to provide rapid heating of air in heated rooms is achieved due to the following factors:

Use of hot water from the central heating system of the building as a heat carrier, which, as a rule, has a fairly high temperature;

The use in the design of such devices of tubular finned heat exchangers, which allow for an effective exchange of heat between hot water and passing air;

The presence in the design of such devices of fans that effectively mix the air, making it as homogeneous as possible in its temperature parameters;

The use of such heaters special blinds with adjustable flaps, with the help of which it is possible to direct heated air to that part of the room where it is most needed at a given time.