What are bimetal radiators made of? Which bimetallic batteries are better: we compare the characteristics of which batteries are better than aluminum or bimetallic. Parameters of bimetallic radiators

Bimetallic heating radiators have recently become an integral part of the heating system. When planning a major overhaul of a residential or office space, it is impossible to ignore the work on updating heating appliances. The most progressive and cost-effective is the use of bimetal radiators, which are able to supply heat evenly and are also attractive from the point of view of modern interior aesthetics.

More and more we see how the apartments of compatriots are changing. Repair acquires a broader concept than the banal plastering of cracks. Increased attention is paid to design. Even choosing ordinary batteries for an apartment, the owners tend to buy bimetallic heating radiators with a concise, attractive appearance.

Why exactly bimetallic heating radiators? - you ask. D reality, common sense and optimal prices make this productwe will answer the most popular heating batteries. And we will try to reveal all the pros and cons, while not forgetting to take into account the internal content of the devices.

Uniform distribution of heat by bimetal heating radiators

Bimetallic heating radiators in modern heating appliances

Cast-iron radiators have long been replaced by bimetallic radiators. They are distinguished from post-Soviet models by their beautiful design, lightness and protection against corrosion. The reputation of the best and most reliable batteries for heating an apartment is so great that even desperate skeptics do not argue with this.

The very name of the batteries suggests that bimetallic heating radiators are made up of two different metals. passes through steel pipes, which are least susceptible to corrosion. The steel is wrapped in aluminum, which has good heat dissipation qualities and a beautiful appearance.

Note that in addition to steel, a system of copper pipes can be packed into aluminum by the manufacturer. Such a design is indispensable if the batteries for the apartment are mounted in systems where it is used. The presence of glycol-containing heat transfer fluids will require the owner to make a choice bimetallic radiators heating on models where copper is used as a core, as it is more stable in such an aggressive environment.

You can find on sale and semi-bimetallic options. Here, the internal filling of the radiator is represented by a double core. The horizontal elements are made of aluminum and the vertical ones are made of steel. This increases heat dissipation but reduces durability.

Internal filling of bimetallic heating radiators

As we noted, bimetallic heating radiators include two metal elements in their design, in addition, they are made in an all-metal case or contain composite sections. Despite the fact that there are semi-bimetallic options, however, bimetallic heating radiators have the main division into only two categories:

modification steel plus aluminum;
modification of copper plus aluminum.

Category of radiators “steel plus aluminum”, includes two steel pipes running horizontally like a collector, they are connected to each other by vertical columns that are mounted in. The coolant flows inside the steel tubes without coming into contact with aluminum.

The constructive solution allows you to use all the charms of an aluminum radiator, additionally counting on a working temperature of + 110 C with a pressure of up to 40 bar. Sealing the joints of the sections allows you to exclude leaks, provided there is no frank marriage. To the advantages of sectional models of bimetallic heating radiators, a simple increase in the number of sections is added at the request of the consumer.

Copper plus aluminum design does not involve sectional modeling, bimetallic heating radiators with a copper core are always made in a single and integral case. Inside the aluminum case battery, there is a copper alloy coil. Brazed coil, capable of operating with a working pressure of 50 bar.

The advantages are not only in the increased working pressure, the thermal conductivity of copper metal is higher, respectively, the radiators have an increased thermal output. The most important advantage of a bimetallic heating radiator with a copper core is the low susceptibility to the occurrence of carbonate deposits in it during the corrosion process.

The radiator is perfect for a system where the coolant includes various antifreezes. In this battery, the coolant comes into contact only with copper. Among other things, bimetallic heating radiators with copper pipes have a low roughness coefficient, which favorably affects the operation of the pumping group.

What to choose - a section or a monolith?

When buying bimetallic heating batteries, you should pay attention to design features. The most common are sectional radiators, as they were among the first to appear on the market. Such radiators will require pressure testing, as there is a possibility of leakage due to insufficiently reliable joints.

Recent modifications are already favorably distinguished by their solidity. The coolant is a one-piece unit made of copper or steel, dressed in an aluminum case. It is these batteries for an apartment that you should choose, since their performance is much higher than that of sectional radiators. Despite the fact that the thermal power of these varieties is almost the same, it is allowed on monolithic operating pressure 5 times higher.

Quality always costs more, so you have to take into account the possibilities of your own budget. If the price does not matter, then it is better to install monolithic bimetallic radiators at home. And design types and modifications of batteries can be selected for every taste.

The use of bimetallic heating radiators is becoming more and more popular not only for private houses and apartments, but also in enterprises and company offices.

The growing popularity is due to the high efficiency of these devices and the attractiveness of their external design. Bimetal radiators fit perfectly into the interior of any style, without violating its harmony and beauty.

Bimetallic radiators: advantages and disadvantages

When compared with aluminum counterparts, bimetallic radiators are slightly inferior to them in heat transfer. But they are significantly superior in strength and service life. Bimetal is less susceptible to corrosion and is able to withstand high pressure water (up to 24 bar). As for the price, it is noticeably higher than that of aluminum radiators. However, the bimetal option will last at least 25 years and will fully justify the high cost.

Buy bimetal radiators for home or office

Today, specialized stores offer wide choose models from different manufacturers supplying excellent products to the consumer market. These are firms such as Global, Rifar, Sira and many others.

Those wishing to buy bimetallic radiators for home or office should take into account the area of the room and purchase a sufficient number of sections, because their number affects the efficiency of the installed radiator. We will not describe the calculation of the number of sections in this article, firstly, this has already been done, and secondly, we are uploading a video clip where the calculation of the number of sections in heating radiators is described in as much detail as possible:

Bargain Rules

In order for bimetallic radiators to serve for a long time, you should purchase them in stores with a solid reputation. Before buying it will be quite superfluous:

make mathematical calculations that will help to coordinate the footage of rooms and the number of sections in the battery;
take into account the features of the selected model;
study consumer reviews;
weigh your financial options.

Heating radiators Sira (Sira) (bimetallic)

The domestic consumer is well aware of the reliable, practical and high-quality products of the Sira Corporation, a reputable Italian manufacturer of heating systems. Made of steel and designed for heating a variety of public, warehouse and residential premises.

The entire model line of bimetallic heating radiators, in addition to the traditional high performance, different actual stylish design, which allows you to use the product without the slightest harm to interior design. The center distance of such a model is only 30 cm, and its depth is 9.5 cm. Also, Sira heating radiators (Sira) (bimetallic) have excellent technical properties and exceptional performance.

The viability of Sira products has been proven by their many years of effective use in domestic conditions and is determined by the multi-level control of all production processes and stages. So, each section of a SIRA bimetallic heating radiator? of a particular product - is subjected to separate testing, and the assembled heating device is necessarily compressed with compressed air.

The entire range of Sira products perfectly resists pneumatic and hydraulic shocks, due to which it is resistant to pressure drops. The calling card of such a radiator is justifiably considered to be its high heat transfer and long service life.

The absence of welding seams of Sira bimetallic heating radiators, which is achieved by pouring the structures under pressure, determines the tightness of the products. The coolant circulates through a special internal channel, which is made of first-class, corrosion-resistant steel.

Heating radiators Sira (Sira) (bimetallic) do not require operational repair intervention or additional maintenance. Maximum comfort and coziness in rooms heated by Sira heating devices is achieved due to the zero level of noise inside the device itself and the ability to quickly and flexibly adjust the temperature regime.

Particular emphasis is the Italian concern manufacturer “ Sira group" makes on the safety of its own products, which is ensured by the absence sharp corners and all sorts of burrs. hallmark bimetal heating radiators Sira is its proper efficiency. Thus, the minimum amount of coolant and the high heat transfer of each design make it possible to optimize the cost of the energy carrier.

Popular bimetallic heating radiator Syrah

The most popular on the market is the Sira RS BIMETALL series. Model Sira RS 300, Sira RS 500 The figure indicates the height of the section, corresponds to the dimensions of the height - 372 mm and 565 mm with the same width - 80 mm and depth - 95 mm.

Convenient overall dimensions make it possible to mount the radiator in rooms with different heights of window sills. The standard sectional assembly comes in even numbers from the factory. Any changes in the individual request are carried out by the seller company. If you wish, within reason, you can order bimetallic heating radiator of suitable length. reasonable limit, Company " Sira Group” limits assembly regulations to no more 20 sections.

Bimetal heating radiators of the Sira brand are allowed to be connected both in the gravitational and in the forced circuit system. The acidity range of the coolant should not exceed (6.5−9 pH). The design temperature should not exceed 110 degrees.

The heating system of any room is an important part of communications, the effectiveness of which depends on its competent assembly. The main element in it are batteries. Today, the plumbing market offers a huge selection of heating appliances. After traditional cast-iron radiators, bimetallic models are most in demand.

What it is?

The main design idea is to use two metal alloys with different technical and chemical characteristics. As a rule, the inner surface of the heater is made of stainless steel, since it has to constantly contact with the liquid heat carrier. Steel also has an anti-corrosion effect, moreover, it is resistant to pressure surges. The outer side is made of aluminum, which is characterized by a high heat transfer rate. Thanks to this combination of metals, the heating element has increased efficiency. Such models are most convenient for an apartment connected to a central heating system, since pressure surges are possible in it, and the use of low-quality coolant.

High-quality bimetallic heating batteries must comply with the requirements of GOST, which will allow them to be used without problems during the entire service life (about 25 years).

Device and principle of operation

The main elements of bimetallic heating batteries are two parts.

The core is filled with coolant. Since it interacts with an aggressive environment, it is made of steel or copper. These metals are highly resistant to corrosion. In the composition of the internal element, two components can be distinguished, such as:
- collectors are made of steel. They are necessary for connecting radiators to the heating system. Stainless steel is able to withstand pressure surges, and copper is additionally resistant to electrochemical processes;
- heat-conducting steel channels.

outer layer. For its production, aluminum is used as an excellent heat conductor. The aluminum case is able to quickly change its temperature, which makes it possible to regulate heat transfer. The general design consists of two horizontal steel pipes connected by vertical steel pipe jumpers, through which a heat-carrying liquid or steam is passed. This system is covered on top with aluminum fins or a monolithic body. The heat exchanger has a complex configuration due to convection ducts. Sections are connected by spot welding during production. During installation, structural parts are mounted using rubber gaskets or nipples made of steel.

Radiator operation is based on the physical phenomena of convection and radiation.

The principle is as follows:

the heat-carrying liquid is heated to a high temperature in boilers and transferred centrally through pipes. Thus, the coolant enters the heating batteries;
steel core, interacting with the heated liquid, transmits thermal energy aluminum housing, which in turn heats the room.

In some cases, when connecting bimetallic batteries to a centralized heating network, a problem arises - the first two or three sections from the tap heat up, and the ones following them remain slightly warm or completely cold. Experienced specialists first of all check radiators for airing. Air may have entered during installation.

If this is not the problem, then the following methods should be used:

connect the radiator diagonally;
use a flow extender that increases the efficiency of heat transfer.

It should be noted that the second option is only suitable for radiators that are connected to the heating system using stop valves with an American. In addition, experts note that flow extensions are not easy to buy in stores, so it is better to use various manuals and instructions for making such a part with your own hands.

The instruction looks like this:

for work, you need a piece of copper pipe with an outer diameter of 18 mm. The wall thickness must be at least 1 mm. In addition, you will need a solder sleeve, silicone gaskets, solder, gas-burner, as well as a set of tools that will allow you to cut the desired piece of pipe and clean the metal after cutting;
before starting work, turn off the tap and drain the coolant fluid;
remove the radiator from the brackets, since it is more convenient to carry out installation work on a flat floor surface;
check the condition of the silicone gasket. If there is damage, it is better to replace it;

the required length is cut from the copper pipe using a pipe cutter. To obtain an even cut, experts advise placing it strictly perpendicular to the tool;
the edges are bevelled and cleaned with a stiff brush. In no case should you use sandpaper, since then it will be extremely difficult to solder copper parts;
further, the process of soldering the sleeve with the pipe is carried out, for which flux is applied to them with a brush, which must be done carefully, in an even thin layer. If you overdo it, then frozen drops of flux will cause a booming sound when the coolant circulates inside the radiator. The prepared parts are inserted into each other and heated with a burner. As soon as the flux has acquired a silver tint, solder is applied to the joint. Due to the high temperature of the pipe, it will spread on its own and fill all the voids. If the flux began to curl into drops, the process should be stopped;

pipes should be pressed against each other for 1–2 minutes until completely cooled;
length adjustment is made depending on the water supply;
the resulting extension is inserted inside the battery in the opposite direction to facilitate the movement of the coolant in the radiator with side connection;
the battery is returned to its place and connected to the central heating system;
if necessary, excess air is removed.

When installing a flow extension, it should be borne in mind that it is used in case of a large number sections of a bimetallic radiator.

Main types

The classification of radiators depends on various parameters and factors.

By type of material

For the manufacture of heating batteries use various materials.

Cast iron. Cast iron models appeared in the 19th century. The material is characterized by low inertia. This means that it heats up slowly, so it will take some time for the room to warm up. However, cast iron also cools slowly, therefore, heat is retained for a long time, providing a comfortable microclimate. The material is quite strong and durable, it does not corrode and is cheap. The impressive weight is the most significant drawback of cast iron radiators.
Steel. The thermal conductivity of this material is similar to cast iron. Since the wall thickness is less than that of cast iron counterparts, the steel heats up faster. High inertia allows the use of thermostats in the design of heating products. Steel parts allow you to diversify the design of radiators. A significant disadvantage is the low resistance to corrosion, which reduces the service life.

Aluminum. For the manufacture of sections, an aluminum alloy with a silicon additive is used. The metal is very light, so the weight of the batteries is small. Aluminum has a high degree of thermal conductivity and an excellent heat transfer coefficient. Aluminum batteries have all the advantages of this material, including good inertia, which allows you to control the temperature. A significant disadvantage is the softness of aluminum, so the radiators are characterized by low resistance to physical impact and a weak threaded connection. And also aluminum heating products depend on the quality of the coolant, its acidity.
Bimetal. The radiator is made of two types of materials: copper or steel as the core and aluminum for the body.

By type of construction

There are two types of bimetallic radiators depending on the type of construction.

Sectional models are a prefabricated structure consisting of several sections. Such models allow you to choose the power by changing the number of individual sections. Various seals are used for connection. The main negative factor is the presence of joints, which increase the risk of leaks. And also the joints are exposed to a coolant with high chemical activity, for example, antifreeze.
Monolithic radiators are more stable and reliable. Their technical characteristics are higher than sectional analogues. Due to the lack of joints, heating devices can withstand heavy loads.

If we compare the performance of these two types of bimetallic radiators, we get the following result:

the operational life of monolithic models reaches 50 years, while for sectional models it is a maximum of 25 years;
operating pressure in the heating system for the second type is allowed within 100 atmospheres, for the first - up to 35 atmospheres;
thermal power of one section in both options - from 100 to 200 W;
the cost of monolithic options is higher;
modifications with a solid core cannot be changed technical specifications, sectional ones have such an opportunity.

By location

Depending on the location of the battery, it is worth highlighting several types.

Horizontal Batteries- This is the default option. They are installed most often. Such models have a huge range. The changing parameters are: dimensions, performance and design. To attract consumers, manufacturers pay attention not only to the technical component of the bimetallic radiator, but also develop unique design lines. Now on the market are colored, textured, combined options using different design techniques.

vertical radiator. Houses with high ceilings and large rooms need more radiator space. It is vertical models that are designed to cope with this task, since in the case of horizontal options they will have to encircle the entire room along the perimeter. Such modifications will help solve the heating problem if there is no space under the window, for example, windows start right from the floor. They can be installed in inter-door and inter-window partitions, which will save usable space in the room without losing the functionality of the batteries. Bimetallic vertical radiators not only heat, but also serve as a unique piece of furniture. The simplest option in the form of chrome-plated stainless steel wall pipes is used in modern styles with an industrial twist.

Embedded model. Radiators of this type appeared due to new technological possibilities. They are a win-win option in cases where conventional batteries are impossible or difficult to install. For example, in a room with a large glazing area, experts offer bimetallic radiators built into the floor. For their installation, special channels are made in the floor, and on top they are covered with a special protective grill made of wood or metal.

Underground models are of two types.

Case. In this case, the heating structure is built into a special box, which plays the role of a channel. The body is made of a thin sheet of galvanized metal and covered with thermal insulation. The dimensions of the produced case models of bimetallic radiators are as follows: width is 5-25 cm, height - 10-70 cm, length - from half a meter to several meters. Powerful models are additionally supplied with fans powered by electricity.
Frameless. In order to mount these models in the floor, you must first build a box yourself, since it is not included in the kit. As a rule, the channel is made rectangular, its size should be 10 cm larger than the size of the radiator in order to ensure natural air circulation.

There are also built-in modular structures for walls and other openings. If you install such a model in a partition between rooms, then it can heat two rooms at once at the same time. Some designers embed bimetal convectors in furniture.

Specifications

All bimetallic radiators have a number of important technical characteristics that you need to know before installing them.

All parameters are specified in the technical documentation for the product.

The most important among them is the ability to withstand high pressure inside the heating circuit. It should be understood that this indicator should have a margin of safety, since hydraulic shocks sometimes occur in the central system, at which the pressure becomes sharply higher than the working one. High-quality bimetallic heating batteries must withstand 40 atmospheres or more.
Heat transfer is characterized by such an indicator as the heat output of the radiator. It is measured in W and kW (watts and kilowatts). This indicator depends on the number of sections and may vary, therefore, the power of one section is indicated in the technical data sheet. One section of a bimetallic radiator can have heat dissipation from 100 to 185 watts. The calculation of power for space heating is carried out on the basis of SNiP, which contains a table of heat transfer. For example, for an area of 1 square meter and ceiling heights up to 2.7 meters, the calculated thermal power will be 100 watts.

Another important indicator is the volume of the coolant. The smaller it is, the better. For bimetallic analogues, it is 0.16–0.18 liters per section. For comparison, in aluminum, it varies from 0.25 to 0.46 liters.
Resistance to chemical components of the coolant. The degree of acidity and slagging of the working fluid is important here. For steel and aluminum cores, this coefficient is approximately the same. Copper is chemically more stable. As for abrasive particles and suspensions that are present in the coolant, it is desirable that they be as small as possible. Since the walls of the metal cores are thin, they are susceptible to abrasion, in addition, contamination clogs the pipes. The ideal option for installing bimetallic radiators is your own heating system, but you can also choose a good option with a centralized connection.

The service life is guaranteed by each company itself, but on average for bimetallic analogues it is 25 years.
Overall parameters depend only on the manufacturer.
Depending on the model and dimensions, the weight of the entire product also varies.

Advantages and disadvantages

If we consider the advantages of bimetallic radiators, then it is worth highlighting the following:

high heat transfer coefficient;
the possibility of installing a thermostat, which allows you to independently regulate the temperature and volume of the coolant. This property contributes to the economical use of heat energy and, accordingly, reduces financial costs;
sectional design. The number of sections can be selected depending on the area of the heated room. In addition, it allows you to repair or change sections independently of each other;

reliability. Radiators withstand pressure surges up to 37 atmospheres. Due to corrosion resistance, bimetallic batteries do not fail even with increased acidity of the coolant;
possibility of installation in any heating systems.
durability. Service life within 20–25 years;
streamlined shape improves safety;
the panels do not heat up to a “dangerous” temperature, so they are fearlessly installed in children's rooms and hospital wards;

a large assortment. For example, there are models without hanging on brackets. They can be installed vertically using additional stiffeners;
wide size range;
wide range of colors. There is a possibility of independent coloring of sections;
light weight compared to cast iron counterparts;
simple installation that does not require a lot of time;
easy care.

Like any product, bimetallic radiators have their drawbacks, namely:

the difference between the coefficients of expansion of aluminum and steel. This is the main drawback of such models, which causes the panels to creak during long-term operation, reduces the strength of the structure;
poor quality of the coolant reduces the battery life;
the cost of radiators of this series is higher than other analogues.

Comparison with other types of batteries

When choosing a heating radiator, buyers first of all pay attention to the material from which they are made. Many technical parameters depend on this, and this is the difference between the models.

Cast iron

This is a classic version of the heater, which has been used for a long time. Many believe that he has no alternative in terms of strength and durability. The temperature of the heat-carrying liquid can be up to +150 degrees, the permitted working pressure is 15 atmospheres. The area of use is extensive: from public to residential premises, technical buildings and workshops. The possible thermal power of the section reaches 160 W.

The biggest advantage of cast iron radiators is their low cost. In addition, they are characterized by resistance to any type of coolant and ease of installation work during installation. Thick walls perfectly resist abrasives in the working fluid. If the system is characterized by severe contamination, then it is better not to find cast-iron models. A small degree of inertia does not allow you to adjust the heat transfer, unlike other analogues.

The principle of operation is based on the radiation of thermal energy, and not on convection. The latter warms up the air and makes it drier, in the case of radiation, the objects themselves heat up. The disadvantages include the significant weight of the product. Many note the nondescript appearance as a minus, but this is a moot point.

Since manufacturers offer cast-iron radiators of exquisite shapes, decorated with forging, however, their cost increases significantly.

Steel

Radiators made of steel are produced immediately in ready-made. They are designed for low pressure up to 10 atmospheres and are very sensitive to corrosion. Since the steel surface heats up quickly, the heat transfer rate is good. Thermal power can reach 5700W. In the case of a low coolant temperature in the heating circuit, steel modifications are the best fit.

They are quite suitable for heating small rooms. Unfortunately, the service life of such radiators is the shortest. Experts do not advise connecting them to central heating systems, since they do not have a margin of safety, they can break through with a pressure surge. And they are also afraid of coolants in which there is a large amount of suspension, which leads to blockage of the channels. The most successful option for installing radiators of this design is an autonomous heating system with a gas or electric boiler.

Aluminum

Aluminum batteries have collected all the advantages of steel models: aesthetics, low weight and high heat transfer coefficient. Unlike cast iron modifications, aluminum ones allow you to install thermostats. The main disadvantage is the weak threaded connections. Also, aluminum is subject to corrosion in the presence of a high degree of acidity of the carrier liquid. V private system heating, you can choose this type of coolant to reduce this effect and increase the service life. This condition is not feasible in a centralized circuit, so the use of aluminum radiators is inefficient.

Bimetallic

In most cases, this option wins out among many. Bimetal heating radiators are a product of the use of new technologies in the energy field. They successfully combine the advantages of steel and aluminum products. The steel core allows stronger connections and better resists corrosion. Manufacturers offer options with a copper circuit, which has a higher anti-corrosion effect.

Aluminum body for increased heat dissipation, since the material is characterized by excellent thermal conductivity. The only negative is a certain dependence on the degree of acidity of the coolant and the level of its contamination. And also the high cost of the product. In technical rooms and workshops where it is necessary to heat large areas at low cost and low quality of the carrier liquid, experts still recommend installing cast iron radiators.

Drawing a general conclusion, it can be noted that modern analogues heating batteries win in their form. They are thinner, ergonomic, without sharp corners, with beautiful design. They are characterized by precise geometric lines and shapes, unlike cast iron ones, so it is more convenient and easier to join sections. A high degree of inertia allows installing thermostatic regulators and control sensors on metal counterparts, and supplying them with other technical innovations. Installation work installation has also become easier and faster.

However, they also have disadvantages that cast-iron representatives of radiators do not have. These include durability. Cast iron is more wear-resistant than any steel counterparts. Bimetallic and aluminum batteries are sensitive to contaminated coolants, cast iron ones tolerate them absolutely calmly. The acidity of the carrier fluid is important for the former and not for the latter. In terms of resistance to water hammer, cast-iron radiators have no equal among all representatives of heating devices. Based on the foregoing, the choice must be approached very carefully and carefully, especially with a centralized heating system.

Popular manufacturers and reviews

There are few manufacturers on the market of bimetallic radiators whose products have a unique property of matching price and quality. Compiling a rating based on consumer reviews, these include several Russian brands and Italian firms.

Italy

Global and Sira are the best known companies in the domestic market. Their bimetallic batteries look aesthetically pleasing. The coating is often made in white, milky and cream tones. The line includes adjustable modifications with a thermostat, as well as with an air vent. The range includes models with different ways installations, various configurations and sizes. Firms guarantee high reliability of products.

Global. Italian products successfully withstand the harsh Russian climate. The core of the radiator is endowed with high anti-corrosion protection. The battery is able to withstand pressure up to 50 atmospheres. With all the technical advantages, radiator systems have an excellent appearance and a high heat transfer coefficient. The design consists of high-quality parts, all connections are made using sealed gaskets. Compact and democratic design allows you to fit a bimetallic radiator into any interior. The tests carried out make it possible to guarantee a service life of up to 20 years.

Sira. In addition to excellent technical indicators, such as lightness and practicality, fast heating and high heat transfer coefficient, strength, corrosion resistance, the radiators of this Italian brand have a graceful curved shape without sharp corners. The maximum allowable pressure can reach 170 atmospheres. The only drawback is the high price of products, but it is incomparable with absolute comfort and reliability in operation.

Russia

One of the well-known Russian manufacturers is Rifar. The production line is located in the city of Guy, Orenburg region. Products are manufactured using modern technology, new technologies and innovative materials. In particular, Italian-made melting furnaces and robotic lines for applying powder paint are used. The maximum permissible performance characteristics of manufactured bimetallic radiators reach 135 degrees for the temperature range of the coolant and pressure in the system up to 20 atmospheres. Standard models have from 4 to 12 sections. By custom order they are increased to 24 or reduced to two.

Rifar offers different series of radiators that differ in appearance and technical characteristics. However, without exception, all models have high heat dissipation, which is achieved with the help of an aluminum case made of flat ribs.

Rifar Base- This is the most popular one produced. It is represented by three options with different distances between the axles: 500, 350 and 200 mm. The first type is more powerful in the series and is used to heat cold, poorly insulated rooms. Base 200 is characterized by a closed back surface. For installation, an upper and lower connection to the heating system is provided.

Rifar Monolith. This series is designed for use in heating systems with increased pressure up to 100 atmospheres. The design is patented by the company as fundamentally new. Its uniqueness lies in the presence of a non-separable steel multi-channel core. Solidity ensures reliability and no leaks.

The general specifications of this series are as follows:

25 year warranty;
high anti-corrosion protection of channels;
lack of joints between sections;
the ability to use non-freezing liquids as a coolant;
maximum allowable temperature of the working fluid +135 degrees;
nominal pressure up to 100 atmospheres;
simple installation. All connecting parts are standard;
maximum safety allows you to install bimetallic radiators in children's and medical institutions.

The manufacturer offers the following models in this series: Rifar Monolit 500 and Rifar Monolit 350. The number of sections in each of them varies from 4 to 16. Models with 4 and 6 sections are most in demand.

Rifar Flex. Radiators of this series differ in the refined design. They can be given a curved shape while maintaining performance. The warranty period for such modifications is up to 10 years.
Rifar Forza. These radiators are the most powerful among bimetallic batteries and are used for heating large rooms. The manufacturer gives a guarantee for these models up to 15 years.

The Russian brand "Isotherm" produces copper-aluminum convectors of interesting design. An excellent solution is a removable steel polished casing. The range includes wall and floor modifications. Their main difference is the presence of a back wall, because wall-mounted ones do not have it. It is worth considering in more detail the most popular series.

Atoll and Atoll Pro have a copper-aluminum construction, which is hidden by a removable housing made of galvanized powder-coated steel. The design of its surface was developed by leading domestic specialists. Any color scale, any drawing is possible. At the same time, the technical characteristics do not suffer: the nominal pressure is 16 atmospheres, the temperature is up to +130 degrees, the power varies from 243 to 11174 watts. Only water or antifreeze compatible with copper is possible as a heat transfer medium.
Rodos differs from the first modifications in the material from which the body is made. This is polished stainless steel. A mirrored metal surface will be an excellent design find for modern interior styles, such as high-tech.

Piligrim is another brand of domestic production. Products are characterized by increased resistance to corrosion due to the use of copper cores instead of steel.

Other countries

There are manufacturers from other countries on the market of bimetallic radiators. Mars is a South Korean company. The products of this brand produce models with a copper core. Technical indicators are adapted to work in Russian heating systems. They are characterized by high wear resistance, efficiency and economy. The copper collector allows to exclude corrosive reactions for a long time.

As for the design, there is not much variety here. Manufacturers developed similar models, based on the superiority of essence over form, to obtain a radiator of good power with compact dimensions. The design of bimetallic batteries with a copper core Mars is non-separable sectional. Each model consists of an odd number of sections from five to nineteen. On the one hand, solidity provides a more reliable design, reduces the risk of leakage, on the other hand, it also limits the possibility of increasing power by increasing sections.

The general specifications are as follows:

operating pressure up to 20 atmospheres. The maximum possible limit is up to 30;
the temperature range for the heat-carrying liquid is limited to +130 degrees;
acidity of the coolant within Ph 7–9;
standard sizes - 300 and 500 mm;
section depth - 65 mm;
weight, depending on the model, varies from 4 to 23 kg, which in principle is defined as small.

Models with a center distance of 300 mm are able to heat a room up to 19.5 square meters. Modifications 500 mm - area up to 34 sq. m. For city apartments connected to a central heating system, Mars products are quite a suitable option in terms of dimensional parameters and operating pressure. However, when choosing, it is necessary to find out all the chemical components of the heating circuit coolant: acidity and suspended matter content, since these characteristics may not be suitable.

The Polish brand Regulus-system also produces bimetallic batteries using copper. The company gives a guarantee on its products for up to 25 years, although performance is slightly lower than that of the South Korean brand. The production, founded in 1994, mainly produced convector-type radiators. After the reorganization in 2001, the organization expanded, modernized and continued to produce bimetallic radiators. Among the advantages of the company, it should be noted the high professionalism of the staff, multi-stage quality control of products, the latest equipment and technologies. An extensive logistics network allows us to offer customers favorable conditions. The company presents its products in the markets of Russia, Belarus, Ukraine, the Baltic States.

In addition to the basic configuration, it is possible to order an individual version of the angular or radial shape. Mounting is provided for wall, but it is possible to order floor legs. A characteristic feature of the bimetallic radiators of this company is the identity of both sides, so you can mount it from any.

The general technical parameters are as follows:

working pressure should not exceed 15 atmospheres;
coolant temperature - up to +110 degrees;
thermal power, depending on the model, varies from 172 to 6000 watts.

The brand produces several series of bimetallic radiators.

Regulus is the basic version with a rounded top panel and has a convection-radiative principle. Installation of lateral or bottom connection to system of heating is possible. Specifications are in the middle range. The price range makes this model the most popular of the entire product line of the company.
Sollarius. It differs from the basic configuration only in shape, it is more square.

Sollarius Dubel is the higher heat output option. Models from this series are characterized by a doubled depth: 180 mm instead of 90 mm. In addition, skirting modifications with a height of only 12 cm are presented in this series.
Sollarius Decor is a vertical copper-aluminum radiator designed for rooms where there is no space for horizontal models. In addition, it can become an interesting design object in the interior. The complete set was supplemented by an air vent and a thermostat. Connection is only possible for the lower type.
Sollarius S-Corner is a corner version that has gained popularity in rooms with adjacent exterior walls.

Regulus Inside are models that are built into the wall. The manufacturer produces several types, including those with an internal fan. Radiators can be mounted in wall partitions, roofing or furniture niches. The design is modular, therefore, during installation, the quantity is assembled at the request of the customer.
Regulus E-Vent has increased heat dissipation due to the built-in fan, which is connected to electricity. It can be turned off, and then the radiator operates normally.

The Ukrainian plant "Mayak" produces a series of copper-aluminum radiators and convectors "Termia". The design of radiators differs from analogues in that not only the core in the form of a pipe is made of copper, but also the plates attached to it. The structure is covered with an aluminum case covered with powder paint that has undergone a firing procedure. Models have two types of connection to the heating system: side or bottom. For the latter type, a thermostat is provided in the design. Batteries can be mounted using brackets or floor-mounted - with legs. The basic equipment of the product is supplemented with a manual air vent in the form of a Mayevsky crane.

The main technical characteristics of bimetallic radiators are as follows:

dimensions: width is 90 mm, height - from 200 to 600 mm in increments of 100, length - from 400 to 2000 mm;
operating power: 240–4240 W for batteries with a side connection type, 270–4620 W for a bottom connection type without a thermostat;
product weight varies from 1.6 to 15 kg;
operating pressure in the heating system should not exceed 16 atmospheres;
temperature of the heat-carrying liquid up to +30 degrees;
the manufacturer guarantees that the radiators can work with any type of coolant: water, steam, various oils and antifreezes, the main thing is that they are designed for copper pipes.

The design of the convector heat exchanger consists of 4 copper pipes with a cross section of 15 mm, on which aluminum fins with dimensions of 10x10 cm are installed. The distance between the plates is 5.6 mm. Connection - only lateral.

Technical parameters of copper-aluminum convectors are as follows:

dimensions: depth is 125 mm, height - 450 mm, length varies from 400 to 2000 mm;
heat transfer of the convector even at temperature regime within +40 degrees varies from 710 to 3510 W;
construction weight - from 2 to 14 kg;
operating pressure in the heating system within 10 atmospheres;
manufacturer's warranty - 10 years.

Models of Chinese manufacturers are attracted by their low price, interesting design and unique finishes. However, as practice shows, reduced cost is achieved by using materials of lower quality, due to which the service life is significantly reduced.

Which option is better to choose?

When buying, you need to pay attention to quality certificates, which will save you from unpleasant surprises during use. You can not focus only on the cost of the goods, since often the low price is due to the low quality of the materials used. For example, bimetallic radiators made in China have a simplified design, which lowers the operating pressure threshold. When buying bimetallic modifications of radiators, one of the important criteria is the features of the heated room: dimensions, type of use (public, technical, residential). Depending on this, the model, installation method and power are selected. Variation is achieved by changing the number of sections, the presence of an automatic air vent.

First of all, it is necessary to determine the cross section of pipes extending from the central heating system , which will affect the choice of nozzles. Next, you should ask about the pressure in the general heating circuit. The radiator model should be chosen with a margin of safety so that the radiator can withstand possible surges. For apartment buildings the old type is characterized by pressure in the range of 5–8 atmospheres, while for modern high-rise buildings this figure is higher - 12–15 atm. It is better if the buyer knows the composition of the coolant, so you can choose the most profitable option that will last a long time. After that, measurements are already made to determine the geometric parameters of the battery.

The optimal distances are as follows:

from the window to the battery must be at least 10 cm;
from the floor to the radiator - not less than 6 cm;
if the battery is installed under the window, then its width is 50% of the window width.

When choosing a sectional option, it is important to correctly calculate the number of sections.

To do this, you must follow the following algorithm of actions:

determine the area of the heated room;
find out the power of the radiator. It can be found in the price lists or technical passport of the product;
calculate the number of sections: K \u003d Px100 / M, where K is the number of sections, P is the area of \u200b\u200bthe room in square meters, M is the battery power expressed in watts. For example, if the area of the room is 25 square meters. m, and the radiator power is 180 W, then K \u003d 25x100 / 180 \u003d 13.89. So, you need to install 14 sections.

Experts note that multi-section models are less efficient, therefore it is more reliable to install several small-section batteries. In the proposed example, there are two five-section radiators and one four-section.

The specified calculation is adjusted depending on the number of window openings in the room:

if the apartment is corner and there are two outer walls and two windows in it, then the calculation of sections is increased by 20%;
if the windows in an ordinary room face north, then the calculation should be increased by 10%;
if the choice is on a model built into the floor, then it must be remembered that their principle of operation is somewhat different from the wall-mounted version. The fact is that they will require a preliminary hydraulic calculation and setting the operating mode of the thermostats.

An important factor when choosing is the aesthetic perception of the radiator. As a rule, heaters occupy a prominent place in the room, so they are either trying to hide them using different kinds cases, or turn into an art object, or built into the wall. Many companies are seriously engaged in the design component of bimetallic radiators. It is necessary to take into account the tastes of consumers, without reducing the quality of products. However, it must be remembered that you will have to pay extra for an individual design.

Due to the fact that replacing heating batteries is a costly and troublesome undertaking, it is better to purchase bimetallic radiators from trusted manufacturers that guarantee a long service life of more than 20 years.

Verified licensed companies, in addition to a full package of documentation and guarantees, provide other services: consulting, calculation of the required parameters for a particular room, delivery and installation of radiators on site. When buying, you should check the integrity of the protective coating of the case. Scratches and dents will cause the aluminum to oxidize, a corrosive process will begin, and the appearance will be spoiled in a short time. The price when buying a high-quality bimetallic radiator starts from 400–500 rubles per section. Anything lower is most likely lower quality or fake. Inserts made of steel or copper in a bimetallic radiator must have a thickness no less than the wall thickness of the water pipe.

Master of Architecture, graduated from the Samara State University of Architecture and Civil Engineering. 11 years of experience in design and construction.

The unique characteristics of bimetallic batteries make it possible to replace the usual cast-iron radiators, while the heat transfer efficiency and durability of the new radiators are not inferior to traditional ones, and in appearance they are much superior to old models. Batteries of this type are successfully used for heating country cottage and for installation in high-rise city buildings. The steel core is able to cope with the powerful pressure characteristic of centralized networks, and is also resistant to water hammer, from which urban heating plants are not immune.

In addition to strength characteristics, bimetallic products show high resistance to aggressive environments, which is important in urban environments, when the coolant is subjected to excessive alkalization or there is an increased acid content in it.

These devices are light in weight, look attractive, they have a high level of heat transfer and a long service life. It is not difficult to choose a radiator of the required size, as manufacturers have launched the production of various models.

Advantages and disadvantages of bimetallic radiators

The devices in question have positive properties that distinguish them from other types of heaters:

Extended service life. Device made with high quality without violations technological process, will reliably heat the room for at least 30 years;
The steel basis gives to this product the increased durability;
The steel core, especially if it is made of high-carbon steel, is not afraid of a coolant with an excess content of alkali and acids;
High degree of heat transfer (up to 190 W per section);
As standard, the radiator has a temperature controller that allows you to reduce or increase heat transfer;
Large selection of colors and variety design solutions appearance of the product, allow you to choose a radiator for any interior.

The negative qualities include the following points:

Over the years, the different coefficient of expansion of the material can lead to the occurrence of internal friction, which is expressed in the appearance of noise;
A small inlet and outlet diameter of the radiator pipes, if there are foreign substances in the coolant, can cause clogging. To avoid this problem, it is recommended to install a supply filter;
High price.

Technical and operational characteristics

When choosing a radiator, you should pay attention to its technical characteristics, which are reflected in the product passport. Typically, the following information about the device is important for the consumer:

Power. It is measured in W and determines the ability of the device to transfer the amount of heat to the room at a standard value of the heating network of 70 ° C. Using this indicator,
calculate the required number of sections for a particular object;
Material strength. This characteristic is important when determining the type of heater in terms of heating system pressure. It is measured in bar and ranges from 15-35 units;
The limiting level of the coolant temperature. Any bimetallic radiator copes with a temperature of + 90 ° C;
Dimensions. It is important to determine the center distance and correlate it with the dimensions of the eyeliner. There are models with this indicator from 200 to 800 mm. The height, width and thickness of the product must comply with the recommended standards for installing a radiator in a room;
Volume. Characterize the capacity of the radiator in liters, ranges from 0.15 to 0.4 liters;
Weight. Standard products measuring 580x80x80 mm weigh about 2 kg.

The device of bimetallic batteries

Radiators of this type are produced using a complex technology by combining two types of metals. The basis of the product is a steel frame, inside which the movement of the coolant passes. The rigidity of the steel allows it to successfully withstand high pressure, as well as resist corrosion.

Outside, the frame is clad in an aluminum casing. Aluminum is able to quickly heat up and transfer heat to the atmosphere. Also, the casing is equipped with special fins that direct the flow of warm air into the room.

Prefabricated models are fastened together using nipples with the installation of rubber gaskets. Such connections can withstand temperatures up to 200°C and network pressure up to 35 atm. Cast models have no internal connections.

Types of bimetallic batteries

Bimetallic radiators are produced in two types:

Cast. In this case, the battery case is cast in special molds;
Sectional. This option is assembled from separate sections, which are joined together using a threaded connection.

The convenience of sectional models lies in the ability to build new sections as needed. It will not be possible to increase a monolithic battery in this way, but due to the breadth of the size range of radiators, they can be selected for any task.

The cost of monolithic models is higher than sectional models by 20-30%.

For heating devices in residential premises and office buildings, both types of bimetallic heating radiators are used. Which is better for an apartment - depends primarily on the design of the heating system. For standard apartments in high-rise buildings, it is better to use cast products, and in country house sectional ones will perfectly cope with the load.

How to choose and what to look for

To decide which radiator to choose, it is necessary to take into account the peculiarities of the organization of heat supply at home and the following characteristics of the heaters themselves:

the value of the pressure test, which is determined when testing the product - this indicator should not be less than the peak values \u200b\u200bof the heating system;
with an increased content of alkali or acids in the heating system, you should choose a heater with a stainless steel or copper core;
the outer aluminum casing must be of sufficient thickness and not bend under mechanical stress, and the thickness of the rib protruding from the base must be 1 mm or more;
recommended core wall thickness - more than 3 mm;
in sectional batteries, it is advisable to check the connecting gaskets for elasticity;
the edge of the battery must have a width of at least 7 cm, this size gives maximum heat transfer;
the minimum warranty period (less than two years) indicates the unreliability of this device, since the average service life of this type of radiators is from 20 years.

Monolithic or sectional

Monolithic cast products withstand significant pressure and water hammer, so they should be installed in multi-storey buildings. Sectional products are not able to withstand such tests due to the weakening of the structure by the threaded connection of individual parts, but such heaters are easy to maintain and, if necessary, build up, which is impossible in the case of cast batteries in a private house.

Bimetallic or semi-bimetallic

In addition to standard radiators made of steel (or copper) and aluminum, semi-bimetallic heaters are produced. In these products, the inner core is made not only of steel - it also contains elements of aluminum. Usually aluminum is used to install vertical pipes.

Such a replacement of the base material significantly reduces the strength characteristics of the product, and in terms of durability in aggressive heating systems, semi-bimetallic radiators differ little from conventional aluminum batteries. The junctions of an aluminum pipe with a steel pipe become unusable very quickly due to the difference in the coefficient of expansion of these metals when heated.

Semi-bimetallic radiators are slightly lighter than the original, so when buying, you should pay attention to this point, as unscrupulous manufacturers may not indicate the exact parameters of the product. These heaters are closer in characteristics to aluminum ones, so it is better to install them in a private house.

Distance between axles

All types of produced bimetallic radiators are subdivided according to the distance between the inlet and outlet. Most often, the distance between the axes is 350 or 500 mm, but some manufacturers make batteries with a center distance of 200 and 800 mm.

Production material

Most of the bimetallic batteries are made with a steel frame and an aluminum shell. The steel core perfectly copes with the excess pressure of the network, resists corrosion, and the aluminum shell serves as an excellent heat diffuser. Some manufacturers use high-carbon steel grades, which makes it possible to achieve higher strength characteristics and product durability.

Core.

To a more expensive, but most the best option bimetal radiators, include batteries with a copper core. This is actually an eternal material with high strength. The service life of such products is at least 50 years.

The best bimetal radiators

There are many models and brands of bimetallic batteries in retail chains, both domestically produced and foreign analogues. The rating of bimetallic heating radiators for an apartment in terms of reliability includes several well-known manufacturers.

Reliable manufacturers

The most famous and reliable manufacturers include the following companies:

global style. An Italian brand that produces radiators under the markings: Style, Style Extra, Style Plus. In the product line this manufacturer models with standard characteristics and products with unique strength characteristics.
Sira. Also a manufacturer from Italy, which focuses on the production of premium products.
Rifar. Domestic brand. The company has launched the production of heaters with different center distances from 200 to 500 mm. The quality of products is confirmed by a guarantee of 10 years.
Tenrad. A manufacturer from Germany produces heaters for private houses equipped with an autonomous heating system, but the product line also includes devices that can withstand the high pressure of a centralized heating network.
WARMA. Joint Russian-Chinese venture. The terms of reference are developed in Russia, and the assembly of finished products is carried out in China. The radiators of this company are used for both autonomous and central heating systems.
Konner. A Russian company producing bimetallic batteries at a Chinese production facility. The products of this company are also universal. The features include increased anti-corrosion resistance of the metal and high strength, which makes it possible to hold powerful hydraulic shocks.
TENRAD. A German company placing orders for production in China. All products are quality tested by German engineers.
Radena. The development of the design of radiators and the control of finished products is carried out in Italy. Production China. Used center distance from 150 to 500 mm. Most models are well suited for Russian operating conditions in the central network.
Fondital. Italian manufacturer of predominantly aluminum heaters. Bimetallic products are also present in the product line, and in terms of quality and cost they can be attributed to the premium segment.

This review will allow the consumer not to get lost in a variety of brands and choose a quality product.

Model	Distance between axes, mm	Section size (WxHxD), mm	Maximum working pressure, Bar	Thermal power of the section, W
Rifar (Russia)
Rifar Forza 350	350	4159080	20	136
Rifar Forza 500	500	57010080	20	202
Rifar MONOLIT 350	350	41510080	100	136
Rifar MONOLIT 500	500	57710080	100	194
Global Radiatori (Italy)
Style 350	350	4258080	35	125
Style 500	500	5758080	35	168
Style Plus 350	350	4258095	35	140
Style Plus 500	500	5758095	35	185
Royal Thermo (Italy)
BiLiner Inox 500	500	5748087	20	171
Biliner 500	500	5748087	20	171
Tenrad (Germany)
Tenrad 350	350	4008077	24	120
Tenrad 500	500	5508077	24	161
Gordi (China)
Gordy 350	350	4128080	30	460
Gordy 500	500	5728080	30	181
Sira Industrie (Italy)
Gladiator 200	200	2758080	30	90
Gladiator 350	350	2758080	30	140
Gladiator 500	500	4238080	30	185
Grandini (Italy)
Grandini 350	350	4308082	16	130
Grandini 500	500	5808080	16	167

Models, prices and their characteristics

The most popular and high-quality models include the following bimetallic radiators:

WB350 from WARMA BIMETALL. This product has dimensions: height - 41 cm, depth - 8 cm, center distance - 35 cm. Refers to prefabricated batteries. The number of sections varies from 5 to 6. The power of one section is 140 watts. The maximum network pressure is up to 25 atm. 10 year warranty. The cost is 450 rubles per section.
WB500 from WARMA BIMETALL. Dimensions: height - 56 cm, depth 8 cm, center distance - 50 cm. The number of sections is from 6 to 7. The power of one section is 180 watts. The maximum network pressure is up to 40 atm. 10 year warranty. The cost is 600 rubles per section.
Konner. Are issued with interaxal distance of 350 and 500 mm. Both options withstand a network pressure of 30 atm. Power from 140 to 190 watts. The maximum temperature of the heat carrier is 110°C. The volume of one section is 0.14 - 0.18 liters. Dimensions: height - 413 and 560 mm, depth - 80 mm, width of one section 80 mm. Warranty 15 years. The cost for one section is about 500 rubles. Number of sections from 4 to 12.
TENRAD BM350. The maximum pressure is 24 atm. The power of one section is 120 watts. Heat carrier temperature not more than 120°С. The volume of one section is 0.15 l. Dimensions: height - 400 mm, center distance - 350 mm, depth 77 mm, width of one section 80 mm. The cost is from 600 to 700 rubles per section. Number of sections from 4 to 12. Warranty 50 years.
Radena Bimetall CS 500. Permissible network pressure 25 atm. The power of one section is 120 watts. Heat carrier temperature not more than 110°C. The volume of one section is 0.13 l. Dimensions: height - 552 mm, center distance - 500 mm, depth 85 mm, width of one section 80 mm. The cost is from 650 to 800 rubles per section. Number of sections from 4 to 12. Warranty 15 years.

Calculation of the number of required sections

To calculate the required number of radiator sections for efficient space heating, you will need to determine the area of the room and know the heat transfer power of one section in watts. It is believed that 0.1 kW (or 100 W) of thermal energy per square meter is enough to create comfortable living conditions, which means that the following calculations must be carried out to obtain the required number of sections:

Find the area (P) of the room (for example, 6 x 3 \u003d 18 m 2).
Determine the power (M) of one section in W from the technical characteristics of the product (for example, 170 W).
To determine the number of sections (K), you need to multiply the area by 100 W and divide by the power.

The formula for calculating the number of sections looks like this: K=P*100/M

Installation of bimetallic radiators

If necessary, you can install bimetallic heating radiators yourself. Before starting work, you should read the instructions that came with the equipment and correctly calculate the location of the battery.

The radiator must be placed in the middle of the window opening, the distance from the installation surface is from 3 to 5 cm, the distance from the floor and the window sill is at least 10 cm. Having marked the installation location, you can proceed with the installation. The sequence of actions is as follows:

Brackets are installed.
A radiator is hung on the brackets.
Make a connection to the coolant.
Install a thermostatic valve or drain valve.
A Mayevsky crane is installed to bleed excess air.

Upon completion of all work, the protective film is removed from the surface of the radiator.

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Bimetallic radiators, which, as the name implies, are made from a composition of two metals, began to be produced more than fifty years ago in European countries. They quickly gained wide popularity due to their reliability and operating efficiency when installed in any heating system.

Which bimetallic batteries are better to choose, and what should you pay special attention to? This question always arises for all those who decide to replace old heating appliances with more modern options, characterized by high performance and respectable appearance.

Today, the production of bimetallic radiators has been established in Russia. Domestic products are quite popular, and have fully justified themselves when installed in central heating systems.

The design of bimetallic radiators

General design principles

This type of radiators consists of two main parts made of different metals.

The internal channels are made of stainless steel, the outer heat exchanger casing is made of aluminum

Their inner part is made of stainless steel or, more rarely, copper, since these metals are highly resistant to the aggressive environment of a heated coolant. Pipes made of these materials are arranged vertically and horizontally, and it is through them that the coolant circulates.

The outer part of the radiators is, in fact, a casing equipped with fins, which is made of. This metal has excellent thermal conductivity and quickly warms up, giving off heat to the premises, which is why it was chosen for the outer part of the structure.

The inner and outer parts of each section of the radiator are joined together by injection molding or spot welding. Sections are assembled into a battery using steel nipples and heat-resistant rubber gaskets, designed for temperatures up to 200 degrees. However, in addition to such batteries, there are also monolithic radiators made of the same materials.

The crimping passport pressure of bimetallic batteries from different manufacturers may vary - this indicator depends on the material of manufacture of internal pipelines and dimensional parameters. If during the pressure testing of certain models a test pressure of 35 atmospheres was created, then they will be able to withstand water hammer, pressure drops during which reaches 25 ÷ 30. This allows the use of such radiators in central heating systems, which sometimes do not differ in the stability of the coolant pressure.

Due to the high thermal conductivity, bimetallic devices turned out to be even more efficient than the familiar cast-iron batteries.

In appearance, bimetallic radiators practically do not differ from aluminum models. However, they can be distinguished by weight, because due to the steel pipe "core", bimetallic batteries are heavier than aluminum ones, by about 50%. In order not to make a mistake when choosing, you should definitely study the certificate of conformity and other accompanying technical documentation, which must be attached to the batches of products, and is located at the seller of a specialized store.

Bimetallic and semi-bimetallic radiators

In addition to bimetallic, semi-bimetallic radiators are also produced. You need to know how they differ from each other, and which ones are better.

Bimetal devices

In real bimetallic radiators, only the outer casing of the device is made of aluminum.

Their production process consists in the fact that ready-made all-steel cores, laid in special forms, are poured under pressure with aluminum, which conducts heat well, but is not resistant to aggressive environments and high coolant temperatures. In bimetallic versions, aluminum does not come into contact with the liquid medium in any way and serves only as a heat exchanger. A design made according to this principle is ideal for installation in both central and autonomous system heating.

In some models, the core is made of copper, not stainless steel - such batteries are usually used for installation only in an autonomous heating system, where special antifreezes are used as a coolant. Steel pipes, even stainless ones, with some similar antifreezes "behave" not so adequately.

Water is not the only possible type of coolant

For dusting the circuits of an autonomous heating system, in addition to water, other liquids are also used - this may be due to the peculiarities of the operation of the system or the requirements of the boiler equipment. More about - in a special publication of our portal.

Semi-bimetallic batteries

For semi-bimetallic radiators, the internal channels are made of different metals. So, vertical pipes can be stainless steel, and horizontal pipes can be aluminum, as in conventional aluminum radiators. There is also the reverse. In a word, they do not “pull” on full-fledged bimetallic ones.

Be careful - instead of full-fledged bimetallic radiators, there is a chance to purchase lower-quality and reliable semi-bimetallic radiators

This type of battery is not suitable for central heating, since the coolant there is often not of high quality and it is fashionable to contain enough greater concentration alkali. In contact with aluminum, such a composition can cause corrosive processes, which, among other things, will “seize” steel elements installed in combination with aluminum. In addition, the differing thermal expansion of these metals can even cause elements to move when subjected to extremely high temperatures, which can lead to leaks and even more serious accidents.

Such radiators are often confused with bimetallic ones - outwardly they are generally indistinguishable. Not really understanding the intricacies, they are often preferred because of the more affordable cost. However, as can be seen from the description, they differ quite significantly in their reliability.

In extreme cases, a semi-bimetallic type of radiator can be installed in an autonomous system. But still, if it is decided to make the heating of a house or apartment as reliable as possible, then it is better to refuse semi-bimetallic radiators, and opt for real bimetallic samples. Be sure to consider this when buying.

Monolithic or sectional bimetallic radiators

As already noted, collapsible bimetallic radiators are produced, which consist of sections fastened together with nipples, and monolithic non-collapsible ones.

In the sectional version, each of the sections inside the horizontal pipe sections has a multidirectional thread on both sides, designed to screw in the connecting nipples with sealing gaskets.

This design is the main significant drawback of sectional batteries, since these joints can be damaged from, for example, low-quality coolant, which significantly reduces their service life until the next preventive intervention. In addition, leaks most often occur at the joints of the elements, under the influence of high temperatures and high pressure in the system.

To avoid these unpleasant moments, another technology for the production of bimetallic radiators was thought out. It consists in the fact that at first a one-piece welded copper or steel manifold is made, which is placed in a special form and filled with aluminum under pressure. These bimetallic batteries are called monolithic.

And this bimetallic radiator is a monolithic assembly

Both types have their own strengths and weaknesses.

The lack of a collapsible scheme has already been mentioned. And the main advantage of such batteries is that if one of the sections is damaged, you won’t have to change the whole one completely, since it’s quite enough to make a bulkhead - replace or simply remove only the failed element.

In the event of any leakage in a monolithic radiator, it remains only - they have practically no maintainability.

Selective comparative characteristics of radiators of both types are given in the table:

Often the decisive criterion is the question of cost. The fact is that a monolithic type of radiator has a higher price than a sectional one, and this difference can be up to 20%.

When using monolithic bimetallic batteries, it will not be possible to vary the total thermal power- reduce or increase the number of sections. Therefore, before purchasing them, it is necessary to carefully calculate how much power is needed to heat a particular room. It will not be difficult to choose the right option, since monolithic bimetallic radiators are produced in different sizes, both in length and in height.

When choosing between sectional and monolithic batteries, the features of the heating system should also be taken into account. For example, if they are planned to be installed in an apartment of a high-rise building, then it is better to choose a monolithic type of device, since the pressure in the heating system of high-rise buildings is often quite high, water hammer is not excluded. and connecting nodes of sectional batteries may not withstand it and leak.

Selection criteria for bimetallic radiators

When choosing a specific model, in addition to the characteristics already mentioned above, there are other points that will directly affect the quality of the heat exchange devices and the duration of their operation.

The design of the radiator must withstand water hammer and high pressure. This is especially important to consider when installing them in a central heating system. Be sure to pay attention to the test pressure indicator.
The battery material must be inert to the aggressive environment of low-quality coolant with increased level alkali or acidity. This factor also mainly applies to batteries installed in multi-storey buildings.
The material of manufacture must also resist the occurrence of electrochemical corrosion.

Radiators must be resistant to mechanical stress, that is, their outer casing must have sufficient strength. To check the quality of the aluminum (aluminum alloy) used, you should try to bend the fin with your fingers. In a poor-quality product, the ribs bend easily, and sometimes they can even crack or break.

Internal ribbed channels should be made of one metal, and it is better if it is high-quality stainless steel.
The wall thickness of the inner pipe must be at least 3÷3.5 mm.
Gaskets are an important element in the sectional design of the battery, since the reliability of the connections will depend on their quality and elasticity, so they are most often made of rubber or silicone. You can check the quality of the sealing ring by bending it several times with your fingers. If the gasket is rigid and inelastic, then it is clearly not enough for a long time.

Particular attention to the quality of the nipples - they must be made of durable steel

High-quality steel nipples should be installed in the sectional radiator, in which the internal “antennae” will not break when the sections are twisted and the thread will not “gobble up”. The fact that the nipple is of poor quality can be recognized by the softness of the metal of manufacture.

If this element is of poor quality, then when the battery is unwound or twisted, the key hooks will definitely break off, and then the nipple will have to be sawn with a grinder, and then its parts removed from the section holes.

The width of the front part of the radiator fin should not be less than 70 mm, since if this parameter is smaller, the heat transfer from the device is significantly reduced. It is best if the size of the section in the section is 80 × 80 mm - such parameters are guaranteed to give high heat transfer.

Optimal depth and width of sections - about 80 mm

Some manufacturers use a marketing ploy - they reduce the price of their products by reducing the size of the sections, which significantly reduces the overall thermal power of the device. Therefore, when choosing a radiator, it is advisable to have a tape measure or ruler in your pocket - so that you can control the optimal size.

For a high-quality battery, the thickness of the protruding ribs should be at least 1 mm.

If the thickness of the fins is less than 1 mm, then this most likely indicates an insufficient quality of the product, since the strength of the radiator casing is reduced in it, and the heat transfer is not so high - due to the low heat capacity of too thin heat exchange plates.

But on this model, the thickness of the ribs is clearly underestimated - it's worth considering ...

You also need to know that if a manufacturer saves on high-quality nipples and gaskets, this indicates that the entire product, with a probability close to 100%, is not of high quality, and it is better to immediately refuse it.
You should not buy devices for which the manufacturer gives a warranty period of only 1–2 years, despite the fact that the life of bimetallic sectional batteries is 25-30 years, and monolithic ones - even about 50. Such a small guarantee suggests that the manufacturer himself is not confident in his products.

Advantages and disadvantages of bimetallic radiators

positive their qualities are as follows:

Bimetal radiators fit perfectly into modern interiors both residential and office space.

This kind of radiators is often produced with different colors. If the desired color is not found, then self-coloring is allowed. For this process, special heat-resistant paint formulations are used that can withstand temperatures up to 150 degrees.
Smooth surfaces and rounded corners make these radiators safe enough from the point of view of the possibility of injury, and therefore suitable for installation in children's rooms.
The advantage is a fairly long guaranteed service life, subject to the choice of high-quality radiators and their correct operation.
Bimetallic radiators can be installed in any heating system, even with low-quality coolant.
This type of device, unlike other modern radiators, is able to withstand high intra-system pressure and temperatures up to 130 degrees.
One of the key advantages of such batteries is a very high heat transfer.
Such devices, as a rule, are equipped with a thermostat, which allows you to set the desired temperature for their heating. Its adjustment occurs almost immediately, due to the small cross-section of the channels.
The number of radiator sections for each particular room can be easily calculated independently using the mathematical formula that will be given below. Correct calculation will help to avoid extra costs when buying radiators, their installation and further operation.

The calculation is carried out for each room separately.
Sequentially enter the requested values or mark the required options in the proposed lists

Specify the area of the room, m²

100 watts per sq. m

Number of external walls

no one two three

External walls look at:

North, Northeast, East South, Southwest, West

The position of the outer wall relative to the winter "wind rose"

Windward side Leeward side parallel to the direction of the wind

The level of negative air temperatures in the region in the coldest week of the year

35 °С and below from - 30 °С to - 34 °С from - 25 °С to - 29 °С from - 20 °С to - 24 °С from - 15 °С to - 19 °С from - 10 °С up to - 14 °С not colder than - 10 °С

What is the degree of insulation of the outer walls?

External walls are not insulated Average degree of insulation External walls are well insulated

Ceiling height in the room

Up to 2.7 m 2.8 ÷ 3.0 m 3.1 ÷ 3.5 m 3.6 ÷ 4.0 m over 4.1 m

What's on the bottom?

Cold floor on the ground or above an unheated room Insulated floor on the ground or above an unheated room Heated room is located below

What is on top?

Cold attic or unheated and not insulated room Insulated attic or other room Heated room

A type installed windows

Ordinary wooden frames with double glazing Windows with single-chamber (2 panes) double-glazed windows Windows with double-glazed (3 panes) double-glazed windows or with argon filling

Number of windows in the room

Window height, m

Window width, m

Doors facing the street or balcony:

Estimated tie-in scheme for heating radiators

Estimated features of the location of radiators

The radiator is installed openly on the wall The radiator is covered from above by a window sill or a shelf The radiator is covered from above by a wall niche The radiator is covered from the front by a decorative screen The radiator is completely covered by a decorative casing

Specify the power of one section of the selected radiator (when calculating for a non-separable model, leave the field blank)

Which manufacturers can you trust?

Bimetallic radiators of both foreign and domestic manufacturers are represented on the Russian market. This comparison table shows quality, field-proven models, with various characteristics. Therefore, for those who are going to buy such devices, it is possible to preliminarily study the main parameters so that when going to the store, they already have a certain idea.

Model Distance between axles (mm) Section dimensions: width × height × depth (mm) Maximum working pressure (bar) Thermal power of the section (Watt) Heat carrier volume in section (liters) Section weight (kg) Maximum heating medium temperature (°C)
«RIFAR» (Russia)
RIFAR Forza 350 350 415×90×80 20 136 0.18 1.36 135
RIFAR Forza 500 500 570×100×80 20 202 0.2 1.84 135
RIFAR MONOLIT 350 350 415×100×80 100 136 0.18 1.5 135
RIFAR MONOLIT 500 500 577×100×80 100 194 0.2 2/0 135
«GLOBAL Radiatori» (Italy)
STYLE 350 350 425×80×80 35 125 0.16 1.56 110
STYLE 500 500 575×80×80 35 168 2 1.97 110
STYLE PLUS 350 350 425×80×95 35 140 0.17 1.5 110
STYLE PLUS 500 500 575×80×95 35 185 0.19 1.94 110
ROYAL Thermo (Italy)
"BiLiner Inox 500" 500 574×80×87 20 171 0.2 2.0 90
"Bi Liner 500" 500 574×80×87 20 171 0.2 2.0 90
TENRAD (Germany)
TENRAD 350 350 400×80×77 24 120 0.15 1.22 120
TENRAD 500 500 550×80×77 24 161 0.22 1.44 120
Gordi China
Gordi 350 350 412×80×80 30 160 0.21 1.4 110
Gordi 500 500 572×80×80 30 181 0.3 1.7 110
SIRA Industrie (Italy)
"Gladiator 200" 200 275×80×80 30 90 0.1 0.65 110
"Gladiator 350" 350 275×80×80 30 140 0.13 0.85 110
"Gladiator 500" 500 423×80×80 30 185 0.42 0.6 110
LITIZ LLC (Ukraine)
"Altermo LRB" 500 575×82×80 18 169 0.15 2.5 130
"Artermo RIO" 500 570×82×80 18 166 0.15 2 130
GRANDINI (Italy)

Model	Distance between axles (mm)	Section dimensions: width × height × depth (mm)	Maximum working pressure (bar)	Thermal power of the section (Watt)	Heat carrier volume in section (liters)	Section weight (kg)	Maximum heating medium temperature (°C)
«RIFAR» (Russia)
RIFAR Forza 350	350	415×90×80	20	136	0.18	1.36	135
RIFAR Forza 500	500	570×100×80	20	202	0.2	1.84	135
RIFAR MONOLIT 350	350	415×100×80	100	136	0.18	1.5	135
RIFAR MONOLIT 500	500	577×100×80	100	194	0.2	2/0	135
«GLOBAL Radiatori» (Italy)
STYLE 350	350	425×80×80	35	125	0.16	1.56	110
STYLE 500	500	575×80×80	35	168	2	1.97	110
STYLE PLUS 350	350	425×80×95	35	140	0.17	1.5	110
STYLE PLUS 500	500	575×80×95	35	185	0.19	1.94	110
ROYAL Thermo (Italy)
"BiLiner Inox 500"	500	574×80×87	20	171	0.2	2.0	90
"Bi Liner 500"	500	574×80×87	20	171	0.2	2.0	90
TENRAD (Germany)
TENRAD 350	350	400×80×77	24	120	0.15	1.22	120
TENRAD 500	500	550×80×77	24	161	0.22	1.44	120
Gordi China
Gordi 350	350	412×80×80	30	160	0.21	1.4	110
Gordi 500	500	572×80×80	30	181	0.3	1.7	110
SIRA Industrie (Italy)
"Gladiator 200"	200	275×80×80	30	90	0.1	0.65	110
"Gladiator 350"	350	275×80×80	30	140	0.13	0.85	110
"Gladiator 500"	500	423×80×80	30	185	0.42	0.6	110
LITIZ LLC (Ukraine)
"Altermo LRB"	500	575×82×80	18	169	0.15	2.5	130
"Artermo RIO"	500	570×82×80	18	166	0.15	2	130
GRANDINI (Italy)