Heating devices: purpose, types, requirements, design, main brands, design features. Types and types of heating devices Heating device used in central heating systems

One after another, economic crises are hitting the planet, which, coupled with a rapidly decreasing amount of resources, creates a need for the development and use of energy-saving technologies. This trend has not bypassed heating systems, which strive to maintain or even increase their efficiency while consuming significantly less resources. Let's figure out what new technologies for heating a private house, apartment and industrial premises, decomposing the heating system into four main components: heat generator, heating device, heating system and control system.

The boiler heating system is the most productive, although also the most expensive (after electric heaters) of all modern autonomous heating technologies. Although the boiler itself is an invention with ancient history, modern manufacturers have managed to modernize it, increasing efficiency and adapting it to different types of fuel. Thus, there are three main (fuel-burning) types of boilers - solid fuel, gas, liquid fuel. Electric boilers that are somewhat out of this classification, as well as combined or multi-fuel boilers, combine the qualities of two or three types at once.

Solid fuel boilers

There is an interesting trend of returning to the traditions of the past and active use solid fuel: from ordinary firewood and coal to special pellets (pellets pressed from wood processing by-products) and peat briquettes.

Solid fuel boilers are divided according to the type of fuel into:

Classic ones “accept” any type of solid fuel without any problems, are extremely reliable and simple (in fact, this is the oldest heat generator in the history of mankind), and are cheap. Disadvantages: “capriciousness” in relation to wet fuel, low efficiency, inability to adjust the temperature of the coolant.

A pellet boiler is a heating device that runs on wood waste compressed into small pellets. They are distinguished by high efficiency, long-term operation on one load, an extremely convenient pellet loading system (filled from a bag or bag), and the ability to customize the boiler. The only one significant drawback- quite expensive pellets for heating, the price of which ranges from 6900 to 7700 rubles per ton, depending on the ash content and calorific value.

The next type is pyrolysis heating boilers, operating on pyrolysis gas extracted from wood. The fuel in such a boiler slowly smolders rather than burns, due to which it gives off noticeably more heat. Advantages: high efficiency and reliability, adjustable heat transfer, up to half a day of operation without reloading. The only drawback is the need to connect to the electrical network, which can cause the house to be left without heat during power outages.

Standard boilers long burning loaded with any types of solid fuel, with the exception of wood: coke, brown and hard coal, peat briquettes, pellets. There is another variety, designed specifically for working with wood and slightly different in design. Advantages: work up to five days on oil products and up to two days when loaded with wood. Disadvantages: relatively low efficiency, need for constant cleaning.

Gas boilers

Mains gas is the most economical of all types of fuel, and boilers running on it are considered the most convenient to use and maintain. This is explained by their fully automated operation and absolute safety, for which many sensors and controllers are responsible. They do not have any disadvantages as such, although they do require a gas line or constant delivery of new cylinders.

Liquid fuel boilers

It cannot be said that such heating systems are innovative, but they have been consistently in demand for decades and are therefore worthy of mention. The main types of liquid fuel: diesel fuel and liquefied propane-butane mixture. Advantages over solid fuels: almost complete automation of operation. Disadvantages: extremely high price heating, second only to electricity.

Electric heating

Features the widest variety heating systems and individual devices. These include electric convectors (which in turn are in-floor, floor-mounted and wall-mounted), and electric boilers, and fan heaters, and infrared heaters, and oil radiators, and heat guns, and the well-known warm floor. Their common and so far insurmountable drawback is the extremely high cost of heating. The most economical of them are infrared radiators and heated floors.

Heat pumps

These heating systems are modern in the full sense of the word, despite the fact that they appeared back in the 80s. Then they were available only to wealthy people, but now many have gotten used to collecting them by hand, thanks to which they are slowly but surely gaining popularity. A very simplified principle of their operation is to extract heat from the air, water or ground outside the house and transfer it into the house, where the heat is transferred either directly into the air, or first into the coolant - water.

Solar systems

Another rapidly developing technology is solar heating systems, better known as solar panels.

Advantages:

Flaws:

Thermal panels

They are thin rectangular (usually) plates fixed to the wall. Backside Such a plate is covered with a heat-accumulating substance that can heat up to 90 degrees and receives heat from the heating element. Energy consumption is only 50 watts per 1 square meter, unlike older electric fireplaces that require at least 100 watts for the same area. Heating occurs due to the convection effect.

In addition to being economical, thermal panels differ in:

There is only one drawback - thermal panels become unprofitable in the spring and early autumn, when the home needs only a little heating from evening to morning.

Monolithic quartz modules

A unique development by S. Sargsyan - Candidate of Technical Sciences. Externally, the plates are very similar to thermal panels, but their operating principle is based on high heat capacity quartz sand. The heating element transfers sand thermal energy, after which it continues to heat the home, even when the device is unplugged. The savings, as in the case of thermal panels, are 50% of the costs of standard electric heaters.

PLEN - film radiant electric heaters

This one innovation system heating device is as simple as it is ingenious: power cable, heating elements, dielectric film and reflective screen. The heater is fixed to the ceiling, and the infrared radiation it produces heats objects located below. These, in turn, transfer heat to the air.

The main advantages of PLEN:

Thermal hydrodynamic pumps

These devices, also known as cavitation heat generators for heating systems, generate heat by heating the coolant using the principle of cavitation.

The coolant in such a pump rotates in a special activator.

At the sites of rupture of an integral mass of liquid, as a result of an instantaneous decrease in pressure, bubbles-cavities appear, bursting almost instantly. This causes a change in the physicochemical parameters of the coolant and the release of thermal energy.

It is interesting that even with the current level of scientific and technological development, the process of cavitation energy generation is poorly understood. A clear explanation for why the energy gain is greater than its costs has not yet been found.

Air conditioner as a heater

Almost everything modern models air conditioners are equipped with a heating function. Oddly enough, the air conditioner has three times the efficiency of standard electric heaters: 3 kW of heat from 1 kW of electricity versus 0.98 kW of heat from 1 kW of electricity.

Thus, an air conditioner for heating in winter can temporarily replace a switched-off heating system or a broken electric fireplace. However, due to the fact that air conditioners do not use heating elements to heat the air, their efficiency drops with every degree of temperature outside the window. Besides, severe frost overloads the device, and operation in this mode can lead to breakdown. The best option There will be use of air conditioning in the off-season.

Convectors

Since a convector heating system is an extremely broad concept, and almost every modern heating device uses the convection effect, we will make a reservation in advance that we are talking here only about individual water and electric convectors. They represent placed in metal case fin heater.

The air circulating between the ribs of the device heats up and rises, and in its place air masses that have already cooled during this time are drawn in.

This endless circulation is called convection. Based on the heat source, convector heaters are divided into water and electric, and based on location - into in-floor, floor-mounted and wall-mounted. Also, any of them can work according to the principle or natural convection, or forced (with a fan).

Although the types of convectors and the features of each of them are a topic for a separate article, we can highlight the general advantages of using these heaters:

So which is more profitable financially?

As a conclusion to this section, let’s compare the cost of heating for different types fuel: wood, pellets, coal, diesel fuel, propane-butane mixture, regular main gas and electricity. With average prices for each type of fuel and with average duration heating season in 7 months during this time you will have to spend:

The leader is obvious.

Heating devices

First of all, modern heating radiators are bimetallic and aluminum models. However, there is a stable demand for both steel and cast iron products, which is due to the new approach of manufacturers to the manufacture of seemingly outdated heating devices. Let us briefly describe the advantages and disadvantages of each type.

Aluminum

They are most popular in the post-Soviet space for their price/quality ratio (cheaper than bimetallic, in many ways more reliable than steel and cast iron).

Advantages:

1. the best heat transfer among all analogues;
2. expensive models can withstand pressure up to 20 bar;
3. little weight;
4. simplest installation.

Disadvantages: poor corrosion resistance, especially noticeable at the junction of aluminum with other metals;

Bimetallic

Generally recognized best type radiators. They got their name due to the combination of steel (inner layer) and aluminum (casing) in their design.

Advantages:

Disadvantages: high price.

Steel

Poorly suited for multi-storey buildings and centralized heating system as a whole, and all its own best properties show up in private homes, fit perfectly into heating systems production premises in factories and factories. You can read more about steel heating radiators.

Advantages:

1. heat transfer is above average;
2. rapid onset of heat transfer;
3. low cost;
4. aesthetic appearance.

Flaws:

Cast iron

It should be understood that modern cast iron heating radiators are no longer lumpy and heavy relics of the past that “decorated” almost every house during the Soviet era. Modern manufacturers significantly improved them appearance, making them almost indistinguishable from bimetallic or aluminum models. Moreover, there is a growing fashion for the so-called, the shapes and patterns of which bring the atmosphere of the early 20th century into the house.
Advantages:

Disadvantages: huge weight and the ensuing difficulties with installation (special supports-legs are often required).

Heating system

In most modern country houses A horizontal heating system is used, the main difference of which from vertical distributions is the partial (less often - complete) absence of vertical risers.

In Russia, such a type of horizontal system as a single-wire heating system (or single-pipe) is especially popular.

She assumes the natural, without circulation pump movement of water. From the heating device, the coolant flows through a riser to the second floor of the building, where it is distributed over radiators and transmission risers.

Water circulation without a pump is made possible by changing the density of hot and cold water.

A single-pipe system has a number of advantages over a two-pipe system:

Control system

Additional benefits can be provided by a heating system controller - a miniature computer device capable of:

The heating system uses heating devices that serve to transfer heat to the room. Manufactured heating devices must meet the following requirements:

1. Economic: low cost of the device and low material consumption.
2. Architectural and construction: the device must be compact and match the interior of the room.
3. Production and installation: mechanical strength of the product and mechanization in the manufacture of the device.
4. Sanitary and hygienic: low temperature surface, small area horizontal surface, ease of cleaning surfaces.
5. Thermal engineering: maximum heat transfer into the room and heat transfer control.

Classification of devices

The following indicators are distinguished when classifying heating devices:

• — the magnitude of thermal inertia (large and small inertia);
• - material used in manufacturing (metallic, non-metallic and combined);
• — method of heat transfer (convective, convective-radiative and radiation).

Radiation devices include:

• ceiling radiators;
• sectional cast iron radiators;
• tubular radiators.

Convective-radiation devices include:

• floor heating panels;
• sectional and panel radiators;
• smooth-tube devices.

Convective devices include:

• panel radiators;
• finned tubes;
• plate convectors;
• tubular convectors.

Let's consider the most applicable types of heating devices.

Aluminum sectional radiators

Advantages

1. high efficiency;
2. light weight;
3. ease of installation of radiators;
4. efficient operation of the heating element.

Flaws

1. 1. not suitable for use in old heating systems, since heavy metal salts destroy the protective polymer film aluminum surface.
2. 2. Long-term operation leads to the unsuitability of the cast structure and to rupture.

Mainly used in central heating systems. Operating pressure of radiators from 6 to 16 bar. Note that radiators that were cast under pressure can withstand the greatest loads.

Bimetallic models

Advantages

1. light weight;
2. high efficiency;
3. possibility of quick installation;
4. heat large areas;
5. withstand pressure up to 25 bar.

Flaws

1. have a complex structure.

These radiators will last longer than others. Radiators are made of steel, copper and aluminum. Aluminum material conducts heat well.

Cast iron heating devices

Advantages

1. not subject to corrosion;
2. transfer heat well;
3. withstand high pressure;
4. it is possible to add sections;
5. The quality of the coolant does not matter.

Flaws

1. significant weight (one section weighs 5 kg);
2. fragility of thin cast iron.

The operating temperature of the coolant (water) reaches 130°C. Cast iron heating devices last quite a long time, about 40 years. Heat transfer rates are not affected by mineral deposits inside the sections.

There is a wide variety of cast iron radiators: single-channel, two-channel, three-channel, embossed, classic, enlarged and standard.

In our country economical option cast iron appliances are most widely used.

Steel panel radiators

Advantages

1. increased heat transfer;
2. low pressure;
3. easy cleaning;
4. simple installation of radiators;
5. light weight compared to cast iron.

Flaws

1. high pressure;
2. metal corrosion, in the case of using ordinary steel.

Today, a steel radiator heats up better than a cast iron one.

Steel heating appliances have built-in thermostats that provide constant temperature control. The design of the device has thin walls and responds fairly quickly to the thermostat. Discreet brackets allow you to mount the radiator on the floor or wall.

The low pressure of steel panels (9 bar) does not allow them to be connected to a central heating system with frequent and significant overloads.

Steel tubular radiators

Advantages

1. high heat transfer;
2. mechanical strength;
3. aesthetic appearance for interiors.

Flaws

1. high price.

Tubular radiators are quite often used in room design because they add beauty to the room.

Due to corrosion, normal steel radiators not currently released. If you subject the steel to anti-corrosion treatment, this will significantly increase the cost of the device.

The radiator is made of galvanized steel and is not subject to corrosion. It has the ability to withstand pressure of 12 bar. This type of radiator is often installed in multi-storey buildings. residential buildings or organizations.

Heating devices of convector type

Advantages

1. low inertia;
2. small mass.

Flaws

1. low heat transfer;
2. high requirements for coolant.

Convector-type appliances heat the room quickly enough. They have several manufacturing options: in the form of a plinth, in the form of a wall block and in the form of a bench. There are also in-floor convectors.

This heating device uses copper tube. The coolant moves along it. The tube is used as an air stimulator ( hot air the top goes up and the cold one goes down). The air change process takes place in a metal box, which does not heat up.

Convector-type heating devices are suitable for rooms with low windows. Warm air from a convector installed near a window prevents cold air from entering.

Heating devices can be connected to a centralized system, as it is designed for a pressure of 10 bar.

Heated towel rails

Advantages

1. variety of shapes and colors;
2. high pressure levels (16 bar).

Flaws

1. may not perform its functions due to seasonal interruptions in water supply.

Steel, copper and brass are used as manufacturing materials.

Heated towel rails are available in electric, water and combined types. Electric ones are not as economical as water ones, but they allow buyers not to depend on the availability of water supply. Combined heated towel rails must not be used if there is no water in the system.

Radiator selection

When choosing a radiator, you need to pay attention to the practicality of the heating element. Next, you need to remember the following characteristics:

• overall dimensions of the device;
• power (per 10 m2 area 1 kW);
• operating pressure(from 6 bar - for closed systems, from 10 bar for central systems);
• acidic characteristics of water as a heat carrier (for aluminum radiators this thermal fluid is not suitable).

After clarifying the basic parameters, you can proceed to the selection of heating devices based on aesthetic indicators and the possibility of its modernization.

A heating device is a device for transferring heat from the primary coolant to a directly heated medium, which can be air, water, a technological or household product, etc. In heating systems, such devices are called heating devices, and in centralized hot water supply systems - heated towel rails (registers ) or design radiators, water heaters.

Through the walls of the heating device, heat exchange occurs between the coolant (heated water, water vapor) and the air in the room. All heating devices must meet certain thermal, sanitary and hygienic requirements.

Heating devices made from steel, cast iron, non-ferrous and stainless metals(copper, aluminum), polymer and other materials. The first heating systems used cast iron finned heating devices and pipes connected at flanges.

When choosing a heating device, the following are usually taken into account:

• architectural planning and construction solutions, pre-determining the height, depth and length of the device;
• calculated thermal power of one device;
• category of production in premises according to fire hazard;
• customer requirements for the appearance of the device;
• the price of the device per 1 kW of heat flow;
• the quality of the coolant and the adopted heat supply scheme for the building (from the heating network of a centralized heat supply source or an autonomous source);
• operating pressure in the heating network, heating system.

Currently, the most common types of heating devices are steel and cast iron radiators, convectors and air heaters.

Structurally, they are made in the form of separate sections and, depending on the number of vertical channels in each section, they can be one-, two-, three- and multi-column, multi-row with a varied cross-section of channels.

Cast iron two-column sectional radiators are the main type of heating devices. Manufacturing plants produce them assembled in blocks of 4; 5; 7; 12 sections, with a surface primed for painting. By height (between the denters of the nipple holes) radiators are divided into: high - 1000 mm, medium - 500 mm and low - 300 mm. Factories complete each of them with two blind plugs and two plugs with threaded holes with 1/2" or 3/4" threads according to customer specifications. The sections are assembled into the radiator using threaded nipples (with right-hand and left-hand threads) and sealing gaskets (picture below).

Gaskets for plugs and nipples are made of materials that, when well-fitted, provide reliable tightness at operating temperatures hot water, entering the radiators. When the coolant temperature is less than 100 °C, gaskets made of cardboard impregnated in boiling water are used for seals. natural drying oil. At a coolant temperature of up to 140 °C, in systems with organic coolants, heat-resistant and gasoline-resistant rubber is used, and at a coolant temperature above 140 °C, gaskets made of paronite, klingerite (rubber-asbestos sealant) are used.

Assembling radiator sections

1 - radiator key; 2 - section; 3 - nipple; 4 - gasket

The heating surface area of ​​one section of M-140-AO-500 is 0.3 m2.

Before installation and additional painting, domestic radiators require mandatory broaching of intersection threaded connections. Although cast iron radiators are designed for a coolant operating pressure of 0.6 MPa, they do not withstand hydraulic shocks that occur in external supply networks. At the same time, they have high corrosion resistance, which is necessary in Russian operating conditions.

IN last years on domestic market In heating and ventilation technology, various designs of steel and aluminum radiators have appeared.

Panel steel radiators are available in several design solutions:

• in the form of panels stamped from sheet steel (1.5 mm thick) with a number of channels from 8 to 20 and a heating surface area from 0.65 to 4 m 2 (type MN6, ZS1, ZS2, PC-10, PC -33, RSV1, RSVZ, RSV9, etc.);
• in the form of sheet-tube coil type (mainly for steam heating systems);
• in the form of convectors.

Stamped radiators are designed for a coolant operating pressure of up to 0.6 MPa and, without special protective internal coatings, quickly fail due to corrosion.

IN steel pipes chat radiators combine convective and radiant types of heat transfer (2 times more efficient than a conventional radiator), and the shape and design make it competitive in the global heating equipment market. Heat output, depending on the number of sections, ranges from 900 to 2520 W.

A convector is a heating device made of steel pipes with sheet steel ribs strung on them. The device received its name due to the predominant convective process (up to 90%) of heat transfer. Currently, this is the most common heating device. It is used in heating systems of residential, public, administrative and municipal buildings with a coolant temperature of up to 150 ° C and pressure of up to 0.6 MPa. The device is distinguished by its low price and trouble-free operation.

Convectors are produced in the following types: steel plinth KP; built-in floor “Breeze”; steel low and high with a casing "Accord" and "Universal", convectors of OJSC "Santekhprom" (short depth with a rated heat flow of 0.4-2.0 kW) and "Santekhprom Avto-S" (medium depth with a rated heat flow flow 1.2-3.0 kW).

Skirting and built-in floor convectors, used for heating external walls with large glazing, when there is no room left for traditional heating devices (they occupy small spaces - no more than 10 cm in depth and 20-25 cm in height), create a reliable thermal curtain from streams of cold air falling from the walls. Their use is typical for heating systems Western Europe, North America and other countries with temperate climates.

Aluminum and bimetallic radiators, which first came to us about 15 years ago as imports from Italy, attracted attention due to their high heat transfer (mainly radiant heat transfer), clean, beautiful casting, and sectional designs. They are available in two versions:

• cast aluminum radiators, where each section is manufactured as a single piece;
• collapsible (extrusion) radiators, consisting of several sections, mechanically assembled into one using seals and glue.

The disadvantages of aluminum radiators are due to the amphoteric properties of aluminum, as a result of which they are very sensitive to the acid-base reaction of water pH, which in some cases causes the release hydrogen gas and carbon dioxide into water and “airing” heating systems. This phenomenon does not exist in bimetallic radiators- the aluminum layer is moved to the top of the structure and replaced from the inside with steel.

Tubular heating devices made of cast iron and smooth steel pipes are installed mainly in buildings of industrial and agricultural enterprises in the form of registers and welded panels for heating external walls, roof lights, the soil of greenhouses and greenhouses, preparing hot water in capacitive heaters and etc.

In recent years for the device underfloor heating for indoor and outdoor heating, metal-polymer pipes began to be used as heating elements of the structure, as well as electrical cables(according to the DEVI cable heating system of the Danish company DEVI).

Heated towel rails for hot water supply systems. In hot water supply systems for residential and public buildings for creating comfortable conditions heated towel rails, registers, and design radiators are installed in bathrooms and for drying clothes. In most cases, they are made of steel tubular elements with a nominal thermal current of 0.3-0.6 kW and are connected in a flow-sequential manner to the hot water supply system, and in some cases to the heating systems of buildings.

Heaters are widely used to heat the air passing through them in ventilation systems, air heating, air conditioning, drying installations, etc. Domestic industry produces heaters:

• steel plate single-pass medium (KFS) and large (KFB) models with heating surface area from 10 to 70 m 2;
• steel finned (spiral-wound) single-pass medium (KFSO) and large (KFBO) models with a heating surface area from 10 to 70 m 2;
• steel plate multi-pass models for water (KMS, KMB);
• steel plate single-pass models for steam (STD-3009V) and for water (STD-ZOYUV) with a heating surface area from 7 to 75 m 2.

Most Applications received air heaters the latest developments type KSkZ and KSk4 with bimetallic finned tubes, with a heating surface area from 10 to 136 m 2.

Infrared (IR) emitters are used in radiant heating systems for working areas of workshops, workshops, hangars, warehouses and other industrial premises large area. In the West, they have become widespread for heating public buildings and structures - sports, shopping, places of worship, airports, train stations, etc. The devices use electromagnetic waves in the range from 0.77 to 340 microns (with a range of 0. 77-15 microns is considered short-wave, from 15 to 100 microns - medium-wave, and from 100 to 340 microns - long-wave). IR emitters with a surface temperature from 700 to 2500 °C, having a wavelength of 1.55-2.55 microns (close to visible light), are called “light”, emitters with a lower surface temperature have a longer length waves, and they are called “dark”. Thermal power they can range from 3-4 kW (street gas lamps and lamps for cafes, snack bars, kiosks) to 200-300 kW (I-K emitters of the “dark” type for industrial buildings), efficiency 92%.

Imported industrial infrared installations include: a heat generator with a capacity of 50 to 300 kW with a gas burner and control unit; ribbon pipe radiator up to 140 m long, smoke exhauster with electric motor; emitter casing made of steel with thermal insulation coating and reflective film.

Domestic industry is represented by designs of gas infrared emitters GII-5 - GII-31 from the Siberian enterprise Sibshvank (power from 5 to 31 kW in one device, with pipe distributors) and models from Moscow Stroyproektservis (power from 11 to 140 kW) .

Based on their design, panel-radiant heating systems are divided into panel heating systems, through the tubes of which superheated water (steam) passes; tubular coils laid during manufacture building structures; gas-air; radiation hanging or wall mounted.

Metal panels are designed for heating large industrial premises that do not require enhanced ventilation (mechanical, tool, model shops, hangars, warehouses).

Radiant panels suspended in the upper zone of such rooms consist of a metal reflective screen with visors, heating pipes are attached to the lower surface of which, and the upper surface is covered with a layer of thermal insulation.

Suspended panels must be structurally such that the heat transfer by radiation downwards is at least 80% of the total heat transfer. Only then is air temperature uniformity achieved across the height of the premises and thermal energy is saved compared to convective heating the usual type, especially airy.

Concrete panels with embedded steel heating pipes are used in wall radiant heating systems in prefabricated mass-produced buildings, mainly for heating public and industrial buildings, mainly with enclosing structures made of wall panels.

IN Lately For the purpose of recycling the heat of heated air removed from the premises and extracting the heat of process gases and vapors, special heat exchangers have been developed, which are heat exchangers installed in ventilation and air conditioning systems and allowing the use of heat from the air removed from the premises. Heating devices of a new design - ejection closers - are air distribution devices for preparing an air mixture and supplying it to the room. Closers are used for round-the-clock air conditioning of industrial and civil buildings, having a centralized supply of primary air, coolant and coolant.

K category: Heating systems

Heating devices for central heating systems

System heating devices central heating must satisfy a number of thermal, sanitary, hygienic, aesthetic and economic requirements.

Thermal requirements boil down to the fact that devices must the best way transfer heat from the coolant (water or steam) to the air of heated rooms. It is desirable that radiation emission predominates in the heat transfer of devices, since in this case the lower zone of the room warms up better. If convective heat transfer from devices takes advantage, the heated air rises and warms the upper zone of the room.

In sanitary and hygienic terms, devices with smooth surface; They collect less dust and are easy to clean.

Heating devices should be compact and occupy a small area. The shape of the devices, their decoration and coloring should not spoil the design of the premises.

One of the indicators of the economic assessment of a heating device is the cost of the device per 1 kcal of heat released in 1 hour with a temperature difference of 1° between the room air and the coolant. Another indicator is the thermal intensity of the metal of the device, i.e. the ratio of the amount of heat in kcal given off by 1 m2 of the device in 1 hour when the average temperature difference between the surface of the device and the room air is 1°, to the weight of 1 m2 of the device in kilograms.

For a comparative assessment of heating devices, a common conventional unit of measurement of their heat-releasing surface has been introduced - an equivalent square meter (abbreviated ecm), which releases 435 kcal of heat per hour to the air of a heated room with a difference in the average temperature of the coolant of the device and the room air of 64.5 ° C.

Heating devices used in central water and steam heating, are divided:
a) according to material - cast iron, steel, concrete;
b) by nature outer surface- smooth and ribbed.

The simplest type of heating device is a smooth steel pipe. Heating devices from smooth pipes can be made in the form of coils or registers.

Smooth pipes have flat surface, easy to clean from dust. In terms of heat engineering, devices made from smooth pipes also have high performance.

For the manufacture of coils and registers, pipes with a diameter of 75-100 mm with a surface area equal to 1 linear meter are usually used. m (0.28-0.34 m2). To obtain a device with a heating surface of 2-3 m2, it is necessary to install 6-9 linear meters. m of pipes of this diameter. It should be noted that, at the same time, devices made from smooth pipes are bulky and inconvenient for placement under windows.

Cast iron finned pipes are manufactured with round fins of length 1000, 1500 and 2000 mm and with the number of ribs 43, 68 and 93, respectively.

The heating surface of a finned pipe is 7-8 times larger than the surface of a smooth pipe of the same diameter and length, and the total heat transfer of a finned pipe is 1 linear. m length is approximately 4 times greater than that of a smooth one. Finned pipes are connected to the pipeline using flanges, and also to each other using double elbows.

Rice. 1. Cast iron finned tube

The presence of fins reduces the hygiene of the pipe, since the interfin space is difficult to clean from dust. As a result, the installation of finned tubes in residential premises, schools, kindergartens, hospitals and other buildings that require increased hygienic conditions, not allowed.

Heating devices Central heating systems are devices for transferring heat from a coolant to a heated room. Heating devices must best transfer heat from the coolant into the room, ensure a comfortable thermal environment in the room, without deteriorating its interior at the lowest cost of funds and materials.

The types and designs of heating devices can be very diverse. The devices are made of cast iron, steel, ceramics, glass, in the form of concrete panels with tubular heating elements embedded in them, etc.

The main types of heating devices are radiators, finned tubes, convectors and heating panels.

The simplest is heating device made of smooth steel pipes . It is usually implemented in the form of a coil or a register. The device has a high heat transfer coefficient and can withstand high coolant pressure. However, devices made from smooth pipes are expensive and take up a lot of space. They are used in rooms with significant dust emissions, for heating skylights in industrial buildings, etc.

The most widely used heating devices are radiators . Their different types differ from each other in size and shape. Radiators are assembled from sections, which allows you to assemble devices of different sizes. Typically the sections are cast from cast iron, but they can be steel, ceramic, porcelain, etc.

Quite widely used in heating systems cast iron finned pipes . The ribs on the surface of the pipe increase the heat-transfer surface area, but reduce the hygienic qualities of the device (dust accumulates, which is difficult to remove) and give it a rough appearance.

Convectors They are steel pipes with sheet steel fins. The most advanced among convectors is a convector in a casing made of steel sheet. The device is equipped with a cap to regulate heat transfer. Intense air circulation occurs between the finned surfaces of the device and the casing under the influence of gravitational pressure. This increases heat removal from the finned surface by 20% or more. Convectors in a casing are compact and have a good appearance. In some designs, convectors are equipped with a special type of fan that provides intense air movement. Artificial stimulation of air movement significantly increases heat removal from the device. Some disadvantage of convectors is the need and difficulty of cleaning from dust.

Concrete heating panels They are slabs with coils of steel pipes embedded in them. Such panels are usually located in the structures of room fencing. Sometimes they are installed freely near walls.

Currently, for heating large industrial workshops, suspended panels with reflective screens .

The use of panels for heating buildings satisfies the requirements of prefabricated construction and allows saving metal spent on heating devices. The disadvantages of panel heating include: large thermal inertia, which complicates the regulation of heat transfer; impossibility of changing the heating surface; the danger of pipe clogging and the difficulty of eliminating it; complexity of system repair; the possibility of internal corrosion and, as a result, a violation of the hydraulic tightness of the pipes.