Types and types of heating devices. Devices and equipment for water heating system

The types of heating devices are determined by their design, which determines the method of heat transfer (convective or radiative heat transfer may prevail) from the outer surface of the devices to the room.

There are six main types of heating appliances, radiators, panels, convectors, finned tubes, smooth tube appliances and heaters.

According to the nature of the outer surface, heating devices can be with a smooth (radiators, panels, smooth-tube devices) and ribbed surface (convectors, finned pipes, heaters).

According to the material from which heating devices are made, metal, combined and non-metallic devices are distinguished.

Schemes of heating devices

a - a radiator, b - a panel, c - a convector, e - a finned tube, e - a smooth-tube device.

Metal appliances are made of cast iron (from gray cast iron) and steel (from sheet steel and steel pipes).

Combined appliances use a concrete or ceramic array in which steel or cast iron heating elements (heating panels) are embedded, or ribbed steel pipes placed in a non-metallic (for example, asbestos-cement) casing (convectors).

Non-metallic appliances are concrete panels with embedded glass or plastic pipes or with voids without pipes at all, as well as porcelain and ceramic radiators.

By height, all heaters can be divided into high (more than 600 mm high), medium (400-600 mm) and low (<400 мм). Низкие приборы высотой менее 200 мм называются плинтусными.

Schemes of heaters of five types are shown in the figure. Heater used primarily for heating air in ventilation systems.

It is customary to call a radiator a device of a convective-radiation type, consisting of separate columnar elements - sections with channels of a round or elliptical shape. The radiator emits about 25% of the total amount of heat transferred from the coolant into the room with radiation, and is called a radiator only by tradition.

The panel is a device of a convective-radiation type of relatively shallow depth, which does not have gaps along the front. The panel transmits radiation somewhat larger than the radiator part heat flow, however, only the ceiling panel can be classified as a radiation-type device (radiating more than 50% of the total amount of heat).

The heating panel can have a smooth, slightly ribbed or wavy surface, columnar or serpentine channels for the coolant.

The convector is a convective type device consisting of two elements - a finned heater and a casing. The convector transfers at least 75% of the total amount of heat into the room by convection. The casing decorates the heater and increases the rate of natural air convection at the outer surface of the heater. The convectors also include baseboard heaters without casing.

A finned tube is called an open-mounted heater convective type, in which the area of ​​​​the external heat-releasing surface is at least 9 times greater than the area of ​​\u200b\u200bthe internal heat-receiving surface.

Section of a two-column radiator

hp - total height, hm - assembly (construction) height, l - depth; b - width.

A smooth-tube device is called a device consisting of several steel pipes connected together, forming channels of a columnar (register) or serpentine (coil) shape for the coolant.

Consider how the requirements for heating devices are met.

1. Ceramic and porcelain radiators are usually made in the form of blocks, they are distinguished by a pleasant appearance, have a smooth surface that is easy to clean from dust. They have sufficiently high thermal performance: kp p \u003d 9.5-10.5 W / (m 2 K); f e /f f >1 and lower surface temperature in comparison with metal devices. When using them, the consumption of metal in the heating system is reduced.

Ceramic and porcelain radiators are not widely used due to insufficient strength, unreliable connection with pipes, difficulties in manufacturing and installation, and the possibility of water vapor penetrating through ceramic walls. They are applied in low-rise construction are used as non-pressure heating devices.

2. Cast iron radiators - widely used heating devices - are cast from gray cast iron in the form of separate sections and can be assembled into devices of various sizes by connecting sections on nipples with heat-resistant rubber gaskets. Various designs of one-, two- and multi-column radiators of various heights are known, but two-column medium and low radiators are most common.

Radiators are designed for maximum operational (the term is usually used - working) coolant pressure of 0.6 MPa (6 kgf / cm 2) and have relatively high thermal performance: k pr \u003d 9.1-10.6 W / (m 2 K) and f e /f f ≤1.35.

However, the significant metal consumption of radiators [(M = 0.29-0.36 W / (kg K) or 0.25-0.31 kcal / (h kg ° C)] and other disadvantages cause their replacement with lighter and less metal-intensive devices It should be noted their unattractive appearance when installed outdoors in modern buildings.In sanitary and hygienic terms, radiators, except for single-column ones, cannot be considered to meet the requirements, since cleaning the intersection space from dust is quite difficult.

The production of radiators is laborious, installation is difficult due to the bulkiness and significant mass of the assembled devices.

Resistance to corrosion, durability, layout advantages with good thermal performance, well-established production contribute to a high level of production of radiators in our country. At present, a two-column cast-iron radiator of the M-140-AO type with a section depth of 140 mm and inclined inter-column finning is being produced, as well as of the S-90 type with a section depth of 90 mm.

3. Steel panels differ from cast-iron radiators in their lower weight and cost. Steel panels are designed for operating pressures up to 0.6 MPa (6 kgf / cm2) and have high thermal performance: k pr \u003d 10.5-11.5 W / (m 2 K) and f e / f f ≤1.7 .

The panels are made in two designs: with horizontal manifolds connected by vertical columns (columnar shape), and with horizontal channels connected in series (serpentine shape). The coil is sometimes made of steel pipe and welded to the panel; the device in this case is called sheet-tube.

The panels meet the architectural and construction requirements, especially in buildings of large building elements, are easily cleaned of dust, and allow mechanizing their production using automation. On the same production areas, it is possible to produce up to 5 million m 2 of steel radiators instead of 1.5 million m 2 enp of cast-iron radiators per year. Finally, when using steel panels, labor costs are reduced during installation due to a decrease in the mass of metal to 10 kg/m 2 enp. Reducing the mass increases the thermal stress of the metal to 0.55-0.8 W / (kg K). The spread of steel panels is limited by the need to use high quality cold-rolled steel sheet with a thickness of 1.2-1.5 mm, resistant to corrosion. When manufactured from ordinary sheet steel, the service life of the panels is reduced due to intense internal corrosion. Steel panels, except for sheet-pipe panels, are used in heating systems with deoxygenated water.

Stamped steel panels and radiators of various designs are widely used abroad (in Finland, USA, Germany, etc.). In our country, medium and low steel panels are produced with columns and serpentine channels for single and paired (in depth) installation.

4. Concrete heating panels are manufactured:

1. with concreted serpentine or columnar heating elements made of steel pipes with a diameter of 15 and 20 mm;
2. with concrete, glass or plastic channels of various configurations (metal-free panels).

These devices are located in the enclosing structures of the premises (combined panels) or attached to them (attached panels).

When using steel heating elements, concrete heating panels can be used at a working coolant pressure of up to 1 MPa (10 kgf / cm 2).

Concrete panels have thermal performance close to those of other smooth devices: k pr \u003d 7.5-11.5 W / (m 2 K) and f e / f f ≈1, as well as high thermal stress of the metal. Panels, especially combined ones, meet strict architectural, construction, sanitary and hygienic and other requirements.

However, concrete panels, despite their compliance with most of the requirements for heating devices, are not widely used due to operational shortcomings (combined panels) and installation difficulties (attached panels).

5. Convectors have relatively low thermal performance k pr \u003d 4.7-6.5 W / (m 2 K) and f e / f f<1, для отдельных типов конвекторов до 0,6. Тем не менее их производство во многих странах растет (при сокращении производства чугунных отопительных приборов) из-за простоты изготовления, возможности механизации и автоматизации производства, удобства монтажа (масса всего 5-8 кг/м 2 энп). Малая металлоемкость способствует повышению теплового напряжения металла прибора. M=0,8-1,3 Вт/(кг К) . Приборы рассчитаны на рабочее давление теплоносителя до 1 МПа (10 кгс/см 2).

Convectors can have steel or cast iron heating elements. Currently, convectors with steel heaters are produced:

• skirting convectors without casing (type 15 KP and 20 KP);
• low convectors without a casing (such as "Progress", "Accord");
• low convectors with casing (Comfort type).

Skirting convector type 20 KP (15 KP) consists of a steel pipe with a diameter of d y = 20 mm (15 mm) and closed fins 90 (80) mm high with a step of 20 mm, made of sheet steel with a thickness of 0.5 mm, tightly fitted on the pipe . Convectors 20 KP and 15 KP are produced in various lengths (every 0.25 m) and are assembled at the factory into units consisting of several convectors (in length and height), pipes connecting them and control valves.

It should be noted such an advantage of using skirting convectors as improving the thermal regime of rooms when they are placed in the lower zone along the length of windows and outer walls; in addition, they take up little space in the depth of the premises (building depth is only 70 and 60 mm). Their disadvantages are: the cost of sheet steel, which is not efficiently used for heat transfer, and the difficulty of cleaning the fins from dust. Although their dust-collecting surface is small (less than that of radiators), they are still not recommended for heating rooms with increased sanitary and hygienic requirements (in medical buildings and children's institutions).

The low convector of the "Progress" type is a modification of the 20 KP convector, based on two pipes connected by common fins of the same configuration, but of greater height.

The low convector of the Akkord type also consists of two parallel steel pipes d y = 20 mm, through which the coolant flows in series, and vertical finning elements (height 300 mm) made of sheet steel 1 mm thick, mounted on pipes with 20 mm gaps. Ribbed elements forming the so-called front surface of the device are U-shaped in plan (rib 60 mm) and open to the wall.

Convector type "Accord" is manufactured in various lengths and installed in one or two rows in height.

In a convector with a casing, air mobility increases, which contributes to an increase in the heat transfer of the device. The heat transfer of convectors increases depending on the height of the casing.

Jacketed convectors are mainly used for space heating in public buildings.

The low convector with Comfort casing consists of a steel heating element, a detachable casing made of steel panels, an air outlet grille and an air regulation valve. In the heating element, rectangular ribs are mounted on two pipes d y =15 or 20 mm in increments of 5 to 10 mm. The total mass of the heater metal is 5.5-7 kg/m 2 enp.

The convector has a depth of 60-160 mm, is installed on the floor or on the wall and can be through the movement of the heat carrier (for connecting horizontally with another convector) and end (with a coil).

The presence of a valve for air control allows you to connect the convectors in series along the coolant without installing fittings to control its amount. Convectors can also be with artificial convection when installed in a fan casing of a special design.

6. Ribbed tubes are made of gray cast iron and are used at operating pressures up to 0.6 MPa (6 kgf / cm 2). The most widespread are flanged cast-iron pipes, on the outer surface of which thin cast round ribs are placed.

Due to the high coefficient of finning, the outer surface of a finned tube is many times larger than the surface of a smooth tube of the same diameter (inner diameter of the finned tube 70 mm) and length. The compactness of the device, the reduced surface temperature of the fins when using a high-temperature coolant, the comparative ease of manufacture and not high price determine the use of this thermally inefficient device: k CR =4.7-5.8 W/(m 2 K); f e / f f \u003d 0.55-0.69. Its disadvantages also include unsatisfactory appearance, low mechanical strength of the ribs and the difficulty of cleaning from dust. Finned tubes also have a very low thermal stress of the metal: M = 0.25 W / (kg K).

They are applied in industrial premises where there is no significant dust emission, and in auxiliary rooms with temporary stay of people.

Currently, round finned tubes are produced in a limited range of lengths from 0.75 to 2 m for horizontal installation. Steel-iron finned tubes are being developed, which include PK-type finned tube with 70 X 130 mm rectangular fins. This pipe is easy to manufacture and relatively light in weight. The base is a steel pipe d y \u003d 20 mm, poured into cast-iron fins 3-4 mm thick. Two longitudinal plates are cast over the ribs to protect the main fin from mechanical damage. The device is designed for operating pressure up to 1 MPa (10 kgf / cm 2).

Scheme of a convector with a casing

1 - heating element, 2 - casing, 3 - air valve.

For a comparative thermal performance of the main heating devices, the table shows the heat transfer of devices 1 m long.

Heat transfer of heating devices with a length of 1 m at Δt cf = 64.5 ° and a water flow rate of 300 kg / h.

As can be seen from the table, deeper heating devices are characterized by high heat transfer per 1 m of length; The cast-iron radiator has the greatest heat transfer, the smallest - the plinth convector.

7. Smooth-tube devices are made of steel pipes in the form of coils (the pipes are connected in series according to the movement of the coolant, which increases its speed and the hydraulic resistance of the device) and columns or registers (parallel connection of pipes with reduced hydraulic resistance of the device).

Devices are welded from pipes d y =32-100 mm, located at a distance from one another of at least a selected pipe diameter to reduce mutual exposure and, accordingly, increase heat transfer to the room. Smooth-tube devices are used at operating pressures up to 1 MPa (10 kgf / cm 2). They have high thermal performance: k pr \u003d 10.5-14 W / (m 2 K) and f e / f f ≤1.8, and the largest values ​​\u200b\u200bare related to smooth steel pipes 32 mm in diameter.

Indicators of heating devices of various types

Note: The sign + indicates the fulfillment, the sign - non-fulfillment of the requirements for devices; the ++ sign marks the indicators that determine the main advantage of this type of heater.

Smooth-tube devices meet sanitary and hygienic requirements - their dust-collecting surface is small and easy to clean.

The disadvantages of smooth-tube devices include their bulkiness due to the limited area of ​​​​the outer surface, the inconvenience of placing under windows, and the increase in steel consumption in the heating system. Given these shortcomings and unfavorable appearance, these devices are used in industrial premises in which there is a significant emission of dust, as well as in cases where other types of devices cannot be used. In industrial premises, they are often used to heat skylights.

8. Heaters - compact heating devices of a large area (from 10 to 70 m2) of the outer surface formed by several rows of finned tubes; they are used for air space heating in local and central systems. Directly in the premises, heaters are used as part of air-heating units various types or for recirculating air heaters. The heaters are designed for the operating pressure of the coolant up to 0.8 MPa (8 kgf/cm 2); their heat transfer coefficient depends on the speed of movement of water and air, therefore it can vary widely from 9 to 35 or more W / (m 2 K) [from 8 to 30 or more kcal / (h m 2 ˚C)].

The table shows the indicators of heating devices of various types; conditionally noted the fulfillment or non-fulfillment of the requirements for devices.

Depending on the various features design heaters on the market, have different characteristics. The main thing when installing them is correct selection the desired model, optimally suited for a particular case.

Varieties

Most often, the classification of heating devices is carried out according to the following criteria:

• the heat carrier used, which can be heated water, gas or even air;
• material of manufacture;
• operational characteristics: dimensions, power, installation method and the ability to control the heating rate.

It is better to choose the best option, taking into account the features of the heating system of the building, operating conditions, observing all the requirements for heating devices.

In addition to the performance of devices, it is worth considering the possibility of their installation. So, for example, in the absence of gas supply and the impossibility of organizing water heating, the only option would be electrical devices.

water system

Most often used and therefore have the most wide range of heaters for water heating systems. This is due to their good efficiency and optimal level purchase, installation and maintenance costs.

Structurally, the devices are not too different from each other. Inside each there are channels for the flow of hot water, the heat from which is transferred to the surface of the device, and then, with the help of convection, to the air of the room. For this reason they are called convection.

In water heating systems, the following types of radiators can be used:

• cast iron;
• steel;
• aluminum;
• bimetallic.

All these heaters have their own characteristics, due to which they are selected for each specific case, depending on the area of ​​\u200b\u200bthe room, the nuances of installation, the quality and type of coolant (which is sometimes antifreeze).

The power of each device is regulated by the number of sections, which can be chosen by almost anyone. Although with an estimated length of one battery more than 1.5-2 m, it is recommended to install two smaller devices side by side.

Cast iron was one of the most popular materials in domestic heating systems. His choice, as a rule, was due to the relatively low cost. Later, such devices began to be used less frequently, since they have a low heat transfer coefficient (only 40%), due to which the power of one section is approximately 130 watts. Although they can still be found in old-style systems. In a modern interior, designer models of cast-iron radiators are sometimes used.

The advantages of such devices are big square surface that gives off heat to the room, and a long service life (up to 50 years). Although there are still more disadvantages - they include a relatively large volume of coolant used (up to 1.4 liters), and the difficulty of repair, and the inertia of heating, due to which the temperature increase of the device is relatively slow, and even the need for periodic (at least once every 3 year) cleaning. In addition, heavy sections are very difficult to install.

The use of aluminum radiators makes it possible to provide maximum level heat transfer - the power of the section can reach 200 W (which is enough for heating 1.5–2 sq. M).

Their cost is quite affordable, and their light weight allows you to install yourself. True, the operation of the device is possible for only 20-25 years.

Their advantages include the presence in the design of convection panels that improve air circulation over the surface, ease of installation of devices for regulating the intensity of the coolant flow, as well as ease of installation. The radiator section, which has a power of up to 180 W, is capable of heating about 1.5 square meters. m area.

Despite the advantages that such heating devices have, there are problems in their use. So, for example, for bimetallic radiators, dilution of water with antifreezes is not recommended, which, although they do not allow the system to freeze, adversely affect internal surfaces heating devices.

In addition, these options are the most expensive of all that are used in a water heating system.

Electrical heating devices

All electrical appliances used when it is not possible to install a water heating system have different features and characteristics - from power to the principles of heat generation. At the same time, the main disadvantages of any such equipment are the high cost of operation and the need for an electrical network capable of withstanding heavy loads (with a total power of electric heaters of more than 9–12 kW, a network with a voltage of 380 V is required). Each variety has its own advantages.

The design that electric heating devices have of this type, allows you to quickly heat the room with the help of moving through them air currents.

Air gets inside the devices through the holes in the lower part, it is heated using a heating element, and the exit is provided by the presence of upper slots. To date, there are electric convectors power from 0.25 to 2.5 kW.

Oil devices

Oily electric heaters also use the convection method of heating. Inside the case contains a special oil, which is heated by a heating element. In this case, the heating can be regulated using a thermostat that turns off the device when the air reaches the set temperature.

The features of the heaters is their high inertia. Due to this, the heaters heat up very slowly, however, even after a power cut, their surface continues to emit heat for a long period of time.

In addition, the surface of oil equipment heats up to 110-150 degrees, which is much higher than the parameters of other devices and requires special handling - for example, installation away from objects that can ignite.

The use of such radiators makes it possible to conveniently control the intensity of heating - almost all of them have 2-4 operating modes. In addition, taking into account the performance of one section of 150–250 kW, it is quite easy to select a device for a particular room. And the range of most manufacturers includes models with a power of up to 4.5 kW.

Choosing heating devices, the principle of which is based on the radiation of thermal waves in the infrared range, the owner of a private house or premises for other purposes receives the following advantages:

• a noticeable reduction in electricity consumption compared to traditional electrical equipment(within 30%);
• no decrease in the oxygen content in the air, which saves people in the room from headaches;
• very high heating rate (even a cold room warms up within a few minutes).

Usually electric infrared heaters are used. Much less common gas appliances designed mainly for street heating, production shops and playgrounds or cottages.

Kinds

Classification of devices for infrared heating produced by the method of emitting waves. There are film devices that transmit radiation to surrounding objects from resistor conductors located on the surface of a special film. Power - within 800 W per 1 sq. m.

The second type is carbon fiber. In them, radiation comes from a spiral inside a sealed glass bulb. Appliances of this type have a power of 0.7 to 4.0 kW.

The advantage of the former is the ability to use them as electric underfloor heating. While carbon heaters are much more powerful, although they require compliance with increased fire safety measures.

gas heating

In order to reduce heating costs, gas-fired heaters are often used. One of the simplest types of such equipment is gas convector, connected either to the gas supply system or to a cylinder with liquefied propane. In this case, the burner does not come into contact with the surrounding atmosphere, and oxygen enters it through special pipe(which can be brought outside to maintain normal indoor air quality).

Such types of heating devices have high power (up to 8 kW or more), are relatively cheap to operate due to the low cost of the energy carrier.

The disadvantages include: the need to register with regulatory organizations, the arrangement good ventilation and the need for periodic cleaning of the nozzles. In addition, in the event of a malfunction of equipment in the room, the amount of hazardous to health carbon dioxide. Therefore, in apartments and other premises with a permanent stay of people, such devices are rarely used - while, for example, for a summer residence or a garage, they can be simply irreplaceable.

It is impossible to imagine heating a room without heating devices, which are presented on the market in a fairly wide range. species diversity. In order to choose the most suitable option, a number of factors must be taken into account.

What are

The classification of heating devices is carried out according to the following criteria:

• Heat carrier type. May be liquid or gaseous.
• Manufacturing material.
• Specifications. This refers to the size, power, features of the installation and the presence of adjustable heating.

When choosing the best option, it is necessary to build on the features of the heating system at home and operating conditions. In this case, the entire list of requirements and standards regarding heating devices must be observed. Along with the power of products, the specifics of their installation are of great importance. In the absence of gas supply and the possibility of arranging water heating, there is still an option with electric heaters.

Water heating system device

Water heating is the most common way to heat buildings. This explains the presence on sale of a significant variety of varieties of heating devices for water circuits. The reasons lie in the good level of efficiency of these products, as well as reasonable costs for the purchase, installation and maintenance. The designs of these heating devices are very similar to each other. The core of each of them is a cavity: hot water circulates through it, heating the surface of the battery. Next, the convection process comes into play, transmitting heat to the entire room.

Radiators for water heating systems can be made from the following materials:

1. Cast iron.
2. Become.
3. aluminum.
4. Combinations of materials (the so-called "bimetallic batteries").

Each of these types of heating devices has its own specifics. In each specific case, it is necessary to take into account the area of ​​\u200b\u200bthe heated room, installation features, the quality and type of coolant used (for example, in some cases antifreeze is used). To regulate the power of the batteries, it is possible to increase or detach the sections. It is desirable that the length of one radiator does not exceed 1.5-2 meters.

Cast iron batteries

The cast-iron type of heating appliances is one of the most common options for completing domestic centralized systems. It was preferred to other varieties mainly because of its cheapness. In the future, devices of this type began to be gradually replaced by devices with a higher heat transfer coefficient (at cast iron batteries he is only 40%. Currently, cast iron radiators are mainly equipped with old-style systems. As for modern interiors, you can find designer cast-iron models in them.

The strengths of the device of heating devices include a significant surface area through which energy is transferred from the coolant to the surrounding space. Another notable advantage is the durability of cast iron batteries: they can last 50 years or more without problems. There are also disadvantages, and there are many of them. Firstly, the coolant is used in very large volumes (up to 1.5 liters per section). Cast iron warms up slowly, so you have to wait until, after turning on the boiler, heat begins to flow into the rooms. Repairing such batteries is not easy, and in order to minimize the likelihood of breakdowns, they have to be cleaned every 2-3 years. Installation work is complicated by the large weight of the radiators.

Aluminum batteries

Aluminum devices have a very high heat dissipation, which allows you to bring the power of one section up to 200 watts. This is quite enough for full heating of 1.5–2 m 2 of living space. The advantages of aluminum batteries include their low cost and low weight, which greatly simplifies installation work. In terms of service life, aluminum appliances are almost two times inferior to their cast-iron counterparts (they can last no more than 25 years).

Bimetallic batteries

The strength of bimetallic structures are special convection panels that increase the quality of air circulation. In addition, devices of this type can be equipped with special regulators, with which you can increase or decrease the flow rate of the coolant. Installation work in its simplicity resembles the installation of aluminum radiators. Each of the sections has a power of 180 W, providing heating of 1.5 m 2 area.

In some cases, the use of water-type heating devices meets with serious difficulties. For example, bimetallic radiators cannot be installed in systems where antifreeze is used as a coolant. These anti-freeze liquids that protect pipes from freezing can have a destructive effect on the inside of batteries. You should also take into account the high cost of this heating option.

Electric types of heaters

In cases where problems arise with the organization of water heating, it is customary to use electric heaters. They are also represented by several varieties, differing from each other in power and method of heat transfer. The most significant disadvantage of household heating appliances of this kind is the high cost of consumed electricity. This often requires the laying of new wiring, designed for increased loads. If a general power of all electric heaters exceeds 12 kW, technical standards provide for the organization of a network with a voltage of 380 V.

Convection type of heaters

Convection-type electric heaters are characterized by the ability to heat rooms with high speed, which is facilitated by the circulating currents of warm air. Bottom part devices is equipped with special holes for suction of air flows, for heating of which heating elements are used (warm air exits through the upper notch). The power of modern heaters of this type ranges from 0.25-2.5 kW.

Oil coolers

Oil heaters also use the principle of convection. Inside the apparatus, special oil is poured for heating with a heating element. To regulate the heating, a thermostat is often used, which turns off the power when the desired temperature is reached. Oil powered devices are characterized by high inertia. This is manifested in the slow heating of the device and in the same slow cooling after the power supply is cut off.

The surface temperature is usually heated to 110-150 degrees, which requires compliance with safety rules. Such a device must not be installed close to flammable surfaces. Oil radiators are equipped with a convenient adjustment of the heating intensity, designed for 2-4 operating modes. Keeping in mind the power of one section (150–250 kW), choosing the optimal model for heating a particular room is not at all difficult. The maximum power of such a device is limited to 4.5 kW.

infrared heating

The choice of heating devices infrared type brings the following dividends:

• Energy saving up to 30% when compared with conventional electrical appliances.
• Oxygen in the air does not burn.
• The room heats up in minutes.

Classify infrared devices according to the method of transmitting waves. In new heaters, the transmission of radiation to the surrounding space is carried out thanks to resistor conductors installed on a special film. The power of warm mats can reach 800 W/m2. Film heaters are convenient because they can be used to organize underfloor heating.

As for carbon emitters, the waves in them are emitted by spirals from a sealed transparent flask. The power of such devices is in the range of 0.7-4.0 kW. The power of carbon heaters is an order of magnitude higher, which provides for more stringent fire safety measures.

Gas heating

In order to save money, you can use gas heaters. Their simplest variety is a gas convector, which is switched to main gas pipeline or an LPG tank. The burner of the device is completely protected from contact with the surrounding atmosphere: in this case, a special tube is used to supply oxygen, which is brought out into the street through a hole in the wall. These devices are characterized by high power (at least 8 kW) and low cost of operation. Among weaknesses gas heaters we can highlight the mandatory registration with regulatory agencies, the need for effective ventilation and the need for regular cleaning of nozzles.

Heating appliances can be safely called the crown of any heating system. Without them, any water heating loses all practical meaning. In this article we will talk about how the most common types of heating devices are classified and what advantages they have. So, let's begin!

The first type of classification is according to the method of heat transfer.

There are 3 ways to transfer heat from a heater to the environment:

• radiation (radiation),
• convection (direct air heating)
• radiation-convective (combined) method.

Heat transfer by radiation. Also called radiant heat transfer. Any heated body emits infrared (radiation) rays, which, moving perpendicular to the radiation surface, increase the temperature of the bodies on which they fall, without increasing the air temperature. Further, the bodies that receive radiation become warmer themselves and begin to produce infrared rays, heating the surrounding objects. And so it goes in a circle. At the same time, the temperature at different points in the room remains the same. An interesting fact is that radiation (infrared) radiation is perceived by our body as heat and does not harm our body at all, exerting on it, according to doctors, even positive effects. Radiation heating devices (radiators) agreed to be considered those devices that betray in environment more than 50% heat by radiant way. Such devices include various kinds of infrared heaters, "warm floors", sectional cast-iron and tubular radiators, individual models of panel radiators and wall panels.

Heat transfer by convection. The convective method of heat transfer looks completely different. The air warms up from contact with the hotter surfaces of convection heaters (convectors). The heated volume of air rises to the ceiling of the room due to the fact that it becomes lighter than colder air masses. The next volume of air rises to the ceiling after the first, and so on. Thus, we have a constant circular circulation of air masses "from the radiator to the ceiling" and "from the floor to the radiator". As a result, there is a feeling familiar to the inhabitants of rooms heated by a convector - at the level of the head, the air can be warm, and a feeling of cold is felt in the legs. Convective devices are commonly called heating devices that carry out convection of at least 75% of the heat of the total volume. Convectors include tubular and lamellar convectors, ribbed tubes and steel panel heaters. Radiation-convective method of heat transfer.

The radiative-convective or combined heat transfer method includes both types of heat transfer described above. They are possessed by devices that give off heat to the environment in a convective way by 50-75% of the total amount of heat transfer carried out. Radiation-convective heating devices include panel and sectional radiators, floor panels, smooth-tube devices.

The second type of classification is according to the material from which the heaters are made.

Here we are dealing with 3 groups of materials:

• metals,
• nonmetals,
• combined.

Metal heaters include heaters made of steel, cast iron, aluminum or copper, as well as possible combinations of two of the listed metals (bimetallic heating devices).

Non-metallic heaters are rare in the domestic heating market. In the manufacture of such devices, glass is almost always used.

To the class combined instrumentation heating standardly include panel radiators (consist of an external concrete or ceramic insulating layer and an internal metal - steel or cast-iron heating elements) and convectors (metal pipes with ribs located in an additional metal casing).

The third way to separate heating devices is according to the degree of thermal inertia.

In this case, thermal inertia is the residual heat transfer to the room after the heater is turned off. Thermal inertia can be small or large (depending on the diameter of the pipes and specific types of heaters).

The last way to classify thermal appliances is according to its linear dimensions(meaning height and depth).

Because dimensions often vary by model and local space heating requirements, describe this method classification is meaningless.

Conclusion

This article has covered some of the concepts that describe how heat transfer works. In addition, standard methods for classifying the main types of heating appliances present on the domestic market were given. heating equipment. We hope you found something interesting in this article. Happy to be of service!

If you want to learn more about the characteristics of the main types of heating devices, we strongly recommend that you read the series of articles “The main thing about heating devices” on our website!

How to choose the best radiators

Russia is in such climate zone, where heating systems used for a long time. Sometimes housing is heated even for six months. Therefore, experts recommend a more careful approach to the choice of heating devices.

The modern market offers a huge number of models designed for different operating conditions. Often technical features become the fundamental criteria to be guided by when buying. But there are still a lot of additional nuances, which we will talk about.

Existing Requirements

All heating systems have one purpose - they are designed to create comfortable living conditions in the winter season. The temperature in the room should be at least 18–20 degrees, but this is not the only condition that a heating device must meet. Let us designate other criteria and requirements, on the basis of which one can judge the efficiency of the heating device and the degree of its perfection.

Criteria classification

All criteria are conditionally divided into several groups:

1. Sanitary and hygienic. There are standards that limit the maximum surface temperature. Appliances should have the smallest horizontal area, which does not allow a large amount of dust to accumulate. The shape of the installation must allow for easy cleaning, removal of dust and other contaminants, and cleaning of nearby surfaces.
2. Economic. Any installation must guarantee an optimal ratio of price and efficiency, minimizing the cost of production, metal use and maintenance during operation.
3. Architectural and construction. Recently, much attention has been paid to the ergonomics and versatility of devices. They should fit well into existing stylistic concepts and occupy a small amount of space.
4. Assembly and production. Any unit must have sufficient strength and reliability. And its installation should not require the involvement of a super-professional workforce.
5. Operational. Modern heating installations should allow to regulate heat transfer, provide sufficient heat and water resistance when operating in the maximum allowable technical parameters.
6. Thermotechnical. It is important to maximize the heat flow, which gives the coolant per unit area of ​​the room.

It is almost impossible to find a heating device that would meet all these requirements, since there are no ideal designs. Therefore, manufacturers are still experimenting in this direction, offering modified installations to potential buyers. This explains a large assortment similar products. Each species meets one of the above requirements. Therefore, when choosing a unit, it is necessary to focus on priority criteria.

For example, for medical institutions sanitary and hygienic component is important, for designer interiors- architectural and construction. And in the domestic sphere, most often they pay attention to assembly and production and operational requirements, so other indicators may be slightly worse. To understand the priorities in more detail, it is necessary to study the classification of modern heating appliances.

Types of heat transfer

All heaters, taking into account the method of transferring heat flow, can be divided into two large groups:

1. convective systems.
2. Radiant modes.

Convective appliances transfer heat by moving air masses. It is known from the school course of physics that air, when heated, rises, there it cools down and falls down. Convection systems consist of units that heat the air in a room and create natural processes convection in it.

Radiant systems transfer heat using infrared radiation. They act similarly natural source heat - the sun, which heats not the air, but objects. Accumulating heat, they then give it to the surrounding space.

Technical features of the convective system

Types of electric convectors

The most striking example of a convective heating method is autonomous and central heating systems. They use various radiators as heating devices.

According to the material of manufacture and the form of construction, they are divided into:

1. For sectional batteries.
2. Tubular.
3. Panel.
4. plate models.

What are the advantages and disadvantages of each type?

Sectional

Sectional batteries are separate heating units, consisting of a different number of sections, which determines the power of the heater. Sectional radiators can be made from different materials. The most common- these are cast-iron models, but relatively recently analog products made of steel, aluminum or bimetal have appeared. For higher efficiency, they are made in the form of ribs and channels, have different height and the width of the ribs, as well as the manufacturing design.

Almost all of them require a large number coolant. Some have significant limitations for use, but they all have one thing in common - the convection way of functioning. To understand where and how a particular device can be used, you should pay attention to the technical features of each.

Cast iron sections

Cast iron heating appliance

Pig-iron radiators - the most ancient heating device which lives the second life today. The design familiar from childhood is outdated, so cast-iron radiators began to fit poorly into modern interiors. Manufacturers have not yet been able to find a better alternative, so they made certain concessions. O They did not change the shape of the front panel, rounded the corners, reduced the size of the sections, added automation and made a convex three-dimensional ornament for each section. As a result, the devices have changed outwardly, so buyers again turned their attention to them.

Cast iron is the only metal that today is ideally suited to the conditions and features of operation. It is resistant to corrosion and unpretentious to the quality of the coolant. Cast iron, although it heats up slowly, gives off most of the heat by radiation, heating the room more evenly over its entire height.

Almost all products are designed for an internal system pressure of 9 atmospheres. But they have a large margin of safety, and long-term use of devices has shown that they are able to function effectively even at an operating pressure of 15 atmospheres. The hydraulic resistance of cast iron is minimal, so batteries from it can be used where natural circulation is provided.

Despite extensive modernization, manufacturers have not yet succeeded in eliminating another drawback. Cast iron products are still heavy, with each section weighing an average of 8 kg. Therefore, it is difficult to transport cast-iron radiators and install them alone. Cast iron appliances are still difficult to clean and many people don't like their rough surface.

aluminum sections

The very first receiver of cast iron products was aluminum sectional radiators. New devices are devoid of the disadvantages of cast iron products, but they have completely different disadvantages that are also worth mentioning. But first about the good.

aluminum radiator

Aluminum installations have improved technical indicators:

1. High level of heat transfer and ideal surface plane.
2. Improved convection transfer method.
3. The small weight of each section - up to one and a half kilograms against eight.
4. Reduced volume of used coolant - 0.25 liters of water is consumed to fill one section.
5. Rapid heating of the room.
6. Possibility of installation automatic knots, regulating the mode of operation of each section.
7. Wide operating pressure range.

Given such technical features, aluminum batteries could be called ideal heating devices, if not for one BUT. Brittle metal is very sensitive to the pH of the coolant. If it is even slightly higher than allowable norms, aluminum begins to break down from the inside and becomes porous, like a sponge. Therefore, any water hammer will provoke a leak.

When using parts made from other metals, electrochemical corrosion occurs, which can also lead to utility accidents. Therefore, the use of the described products is permissible only in autonomous systems, where it is possible to control the quality of the supplied water and use cleaning filters.

Bimetal sections

Bimetallic heating radiators

An alloy of two metals was supposed to be a compromise between reliability, ease of operation and efficiency. Manufacturers managed to create a good alternative to cast iron products. Externally, bimetallic sections are similar to aluminum radiators. They have all their advantages and at the same time are devoid of many disadvantages.

Technologists have figured out how to eliminate the contact of the coolant with fragile and capricious aluminum. In bimetallic radiators, water moves through steel pipes that are installed inside an aluminum casing. Steel - durable material, capable of withstanding operating pressures up to 30-45 atmospheres. At the same time, the entire product weighs not much more than aluminum models.

There are no restrictions on the use of bimetallic products today. From the inside, steel parts are coated with special polymer compounds that prevent the development of corrosion phenomena. The only drawback of such radiators is the high price compared to other products. And it is this circumstance that is hindering the growth of bimetal popularity.

Tubular appliances

Radiators in the interior

Tubular batteries are different from sectional design. They are made in the form of vertical curved tubes connected to each other from below and from above using collectors. The efficiency of heat transfer is influenced by various factors - the size of the model, its height, width and diameter of the tubes.

Three types of tubular batteries can be found on sale:

1. Steel products.
2. Tubular convectors.
3. Towel dryers.

All of them differ from each other in mass design features which are also worth mentioning.

Steel tubular radiators

The technical features of steel tubular instruments are well known. The height of the products can be both 0.3 and 3 meters. The wall thickness of the pipes also varies. For example, at Russian manufacturers it is equal to 2mm. The device is designed for a pressure of 10–12 atmospheres, but domestic manufacturers produce models that can withstand a working pressure of 15–22 atmospheres. The method of heat transfer is dominated by the radiative rather than the converter mechanism.

The smoothness of the curves and the absence of corners make it easy to wash the device, so the tubular steel radiator- the most hygienic model of all existing. She has one drawback - low corrosion resistance. The fact is that steel is subject to oxygen oxidation, so it is necessary that the radiator be filled with water all the time. It is extremely difficult to ensure this condition where the central heating system operates. Indeed, in the summer, public utilities drain water from the common system. Therefore, tubular models cannot be used in apartment buildings.

Note! There are no tubular steel batteries absolutely resistant to corrosion. But Russian products are made taking into account domestic operating conditions, and European models do not differ in the large thickness of the pipe walls. Also, European manufacturers do not process the internal parts of the parts, while Russian tubular devices are coated from the inside with special polymer compounds that increase their service life.

Tubular convectors

Steel tubular convectors

Radiator convectors are a new generation of heating devices. AT cross section in such models, the tubes look like a donut. The pipe has double walls, between which the coolant flows. This design made it possible to double the heat transfer of the devices. At the same time, the efficiency of the process increases due to heat transfer by the device walls, as well as due to the creation of a converter flow, which is formed between the inner walls of the pipes.

Ease of maintenance, beautiful appearance, a completely new design - these are the main advantages of the described device.

Towel dryers

It is worth mentioning separately another type of tubular heaters - heated towel rails. They perform two functions at once - they heat the bathroom and dry towels.

Towel warmers can be connected to central heating by mounting them in the heating cycle. In our country, this element is connected to the DHW system, so the device often fails. And all because the steel from which these devices are made is afraid of oxidation processes. When connected to a hot water supply, water enriched with calcium, iron and other impurities enters the radiator, which gradually leads to the “overgrowth” of pipes. As a result, heated towel rails quickly become unusable.

Note! When connected to a heating cycle, this does not happen. Therefore, when choosing a model, you should pay attention to the features of its connection. On sale there are models made of different materials. More than others, heated towel rails made of black or stainless steel, stranded, aluminum or brass are common. Experts recommend purchasing stainless steel models.

Often, non-ferrous metals require compatibility with the materials from which other elements of the system are made. For example, in order for copper heated towel rails to function well and for a long time, it is necessary to connect to them copper pipes and fittings, and this is a very expensive pleasure. If you do not follow this rule, it will not be possible to prevent abrasive wear.

If the model is connected to the DHW system, it is worth choosing double-circuit products. They have a longer service life. Hot water flows in one circuit and heats the other. In this case, the dryer tubes do not come into contact with the aggressive medium of the coolant, do not overheat and do not experience system pressure.

Panel batteries

The name itself speaks of the design of such devices. rectangular shape acts as a heating source. In this case, the coolant circulates between steel sheets with vertical channels, which increases the usable area of ​​the installation.

In finished form, such a unit may contain several panels welded together. They are placed parallel to each other and covered with a special powder enamel, and the upper and side parts are closed with decorative inserts.

The technical features of this model are as follows:

• The installation is light in weight.
• The products on sale are different sizes and different from each other in width and height.
• The device has a slight inertia.
• 75% of the heat is transferred using the converter method.
• The working pressure for each model is different, so it is necessary to choose a device, taking into account precisely this value.

All of the above can be attributed to positive moments. But such a choice also has disadvantages. The first is a little water pressure. Maximum rate- 10 atmospheres, so panel radiators are very sensitive to water hammer. But this is not the main thing.

The inner surface of the panels is not protected by anything, therefore, when interacting with oxygen, the steel quickly becomes rusty and “loses weight”. This means that panel devices for heating can only be used in autonomous systems that are constantly filled with water.

Plate batteries

steel radiator

Lamellar radiators are convectors in their purest form, the main advantage of which is reliability. The design is always closed on top with an aluminum case, so you can’t get burned on such batteries. Their heat transfer is 95%. Thermal inertia is negligible.

But the plate device has more disadvantages than advantages. This is an unpresentable appearance, and low heat transfer, and the need to maintain high temperature coolant. In addition, due to the low intensity of heat convection, the room warms up inefficiently.

But modern manufacturers are trying to improve such models, struggling with their negative aspects. The experts have achieved good luck in this direction. Firstly, now copper tubes are used to make the base, on which copper and aluminum plates are mounted. Secondly, modern models have original design, which fits perfectly into popular stylistic concepts. And this circumstance is very popular with those who dream of exclusive interiors.

Such a disadvantage as uneven heating of the room easily turns into a virtue where the height of the ceilings exceeds the standard dimensions. Large front halls, lobbies, exhibition stained-glass windows, indoor pools, loggias and winter gardens - wall-mounted models, linear varieties, as well as appliances built into the floor are used here today.

The operating pressure in plate batteries is 16 atmospheres. There are exclusive copies in which the working pressure reaches 37 atmospheres.

So far, manufacturers have not been able to eliminate another drawback of the described option - poor compatibility with the current system, as well as difficulties in caring for the device.

Technical features of the radiant system

Movement of heat in a radiant system

A radiant system differs radically from a convective one. It makes no sense to describe the technical features, since their study is the lot of specialists. But let's take a closer look at the advantages of this heating method and outline the main types of devices.

Positive points

1. Radiant heaters have an efficiency of 95%, which is explained by the direct conversion of electricity into heat. For comparison, this figure is 50% for converter systems. It is impossible to believe the claims of manufacturers that they were able to achieve 100% of indicators in this regard. This is against the laws of physics. The efficiency of any device mounted on the wall will drop by 30%. In addition, he "eats" usable space and warms the air that is under the ceiling. And a person “uses” the already cooled air, which tends to the battery.
2. A radiant device heats up a room much faster. Even when it is turned off, the room cools down for a long time. And all this happens due to the fact that it is not the air that is heated, but objects, which then themselves give off heat.
3. The absence of convection eliminates the movement of air masses, as well as temperature differences. As a result, no
4. Heating modes in radiant heaters can be controlled by adjusting the temperature and creating more comfortable conditions.
5. The described installations always work silently. In addition, any unit is easy to mount, move to a convenient place, and also dismantle.
6. Modern models consume 30% less electricity.

Types of devices

There are two types of radiant devices:

1. long wave models.
2. Infrared heaters.

They differ from each other in different intensity of heating of the heating element. For infrared heaters, the heater heats up to 800 degrees, and for long-wave heaters - only up to 250 degrees. But the second variety is fireproof, does not burn oxygen, heats the room evenly and creates very soft comfortable heat.

Other varieties

Which underfloor heating is better

There are several more types of heating devices that cannot be attributed to either converter models or radiant devices. This is a "warm floor" system and radiant films.

Warm floor

In terms of efficiency, warm floors occupy an intermediate step between convectors and radiant systems. So far, this is the most expensive heating option, moreover, it is complex and time-consuming. To install underfloor heating, it is necessary to open the floor, make a screed, lay electric heating mats or a pipeline for hot water.

Therefore, in addition to the cost of the elements themselves, the final price will have to include complex and labor-intensive Finishing work. Moreover, the described system is not mobile, the dismantling and transfer of the main elements is impossible without further overhaul.

Emitting films

Emitting films are the latest know-how that is just beginning to appear in Russia. They are able to become worthy alternative warm floors, but so far the capacity of products is extremely limited.

In addition, the efficiency of the devices is much lower than that of long-wave heaters. Therefore, while radiating films are not very popular. But the future lies with them, and experts are sure of this.

Generalization on the topic

We have given a detailed classification of existing heaters, outlined their technical advantages, as well as the features of each operation. From this information it can be seen that so far there are no perfect designs that could be called universal and effective.

But modern production is able to provide consumers with a huge range of products, making it possible to choose an installation taking into account individual requirements. Until recently, it was difficult to find a couple of alternative options. And today, only a listing of existing models can demonstrate the enormous capabilities of modern heating systems.