Bimetallic radiators. Bimetallic radiators - which are better, characteristics, comparison of advantages and disadvantages What are bimetallic batteries

The first heating radiators made of two metals (bimetallic) appeared in Europe more than sixty years ago. Such radiators coped well with the assigned function of maintaining a comfortable temperature in the room during the cold season. At present, the production of bimetallic radiators has been resumed in Russia, while various radiators made of aluminum alloy prevail in the European market.

Bimetallic radiators are frame made of steel or copper hollow pipes (horizontal and vertical), inside which the coolant circulates. Aluminum radiator fins are attached to the outside of the pipes. They are attached by spot welding or by special injection molding. Each section of the radiator is connected to the other by steel nipples with heat-resistant (up to two hundred degrees) rubber gaskets.

In Russian city apartments with centralized heating, radiators of this type perfectly withstand pressure up to 25 atmospheres (when pressurized up to 37 atmospheres) and, due to their high heat transfer, perform their function much better than their cast-iron predecessors.

Radiator - photo

Externally, it is quite difficult to distinguish between bimetallic and aluminum radiators. You can be sure of the correctness of the choice only by comparing the weight of the indicated radiators. Bimetallic due to the steel core will be about 60% heavier than its aluminum counterpart, and you will make a purchase unmistakably.

Video - Bimetallic radiator

Positive aspects of using bimetallic radiators

• Panel-type bimetallic radiators fit perfectly into the design of any interior (residential buildings, offices, etc.) without taking up much space. The front side of the radiator can be one or both, the size and color scheme of the sections are varied (self-painting is allowed). The absence of sharp corners and too hot panels makes aluminum and steel radiators suitable even for children's rooms. In addition, there are models on the market that are installed vertically without the use of brackets due to the addition of stiffeners.
• The service life of radiators made of an alloy of two metals reaches 25 years.
• Bimetal is suitable for all heating systems, including central heating. As you know, a low-quality coolant in municipal heating systems adversely affects radiators, reducing their service life, however, bimetal radiators are not afraid of high acidity and low quality of coolants due to the high corrosion resistance of steel.
• Bimetallic radiators are the standard of strength and reliability. Even if the pressure in the system reaches 35-37 atmospheres, this will not damage the batteries.
• High heat transfer is one of the main advantages of bimetal radiators.
• The heating temperature is controlled by a thermostat almost instantly due to the small cross-section of the channels in the radiator. The same factor makes it possible to halve the volume of the heat carrier used.
• Even if it becomes necessary to repair one of the radiator sections, thanks to the well-thought-out design of the nipples, the work will take a minimum of time and effort.
• The number of radiator sections required for heating a room is easy to calculate mathematically. This eliminates unnecessary financial costs for the purchase, installation and operation of radiators.

Negative sides of using bimetallic radiators

• As mentioned above, bimetallic radiators are suitable for operation with a low quality coolant, but the latter significantly reduces the service life of the radiator.
• The main disadvantage of a bimetallic battery is a different coefficient of expansion for aluminum alloy and steel. After prolonged operation, creaking and a decrease in the strength and durability of the radiator may occur.
• When operating radiators with a low-quality coolant, steel pipes can quickly become clogged, corrosion can occur, and the level of heat transfer decreases.
• The contested disadvantage is the cost of bimetal radiators. It is higher than that of radiators made of cast iron, steel and aluminum, but considering all the advantages, the price is fully justified.

How to calculate the number of radiator sections

Thanks to a simple mathematical formula, you can calculate and find out how many radiator sections are needed to heat the room.

Before making calculations, you need to know the area of ​​the heated room and the power of the radiator. The second value is indicated on the packages with the goods or provided in the price lists by radiator manufacturers.

So, to find out the number of radiator sections (A), the area of ​​the room (S) should be multiplied by 100 and divided by the radiator power (P).

A = S× 100 ÷P

With a room area of ​​20 square meters and a radiator power of 180 watts, we get:

A = 20 × 100 ÷ 180

Accordingly, the number of sections can be 11 or 12. But, since radiators with more than 10 sections warm up less efficiently, it is better to install two or three radiators with fewer sections.

Installation (assembly) of bimetallic heating radiators

The design of the heating system includes pipes and a radiator itself. The connection of the radiator and pipes is made by spot welding. Installation is carried out by plumbers or other qualified specialists in a short time without serious damage to the wall partitions. Self-installation is possible if you have the necessary tools, devices and an idea of ​​\ u200b \ u200bthe procedure for the work carried out. Installation instructions from the manufacturer usually come with bimetallic radiators.

As practice shows, pipes made of polypropylene (reinforced with fiberglass or aluminum) are most successfully combined with bimetallic radiators. When using deeply embedded aluminum reinforcement pipes, the shaver and stripping process becomes unnecessary. This significantly reduces the installation time of the radiators. Less popular pipes for connecting bimetal radiators due to frequent leaks and blockages are iron (steel) and metal-plastic pipes in combination with collet clamps.

The installation of bimetallic heating radiators is carried out in place of the dismantled old ones after the preparation of the working area, which includes the dismantling of pipelines from the riser, marking the place for the installation of a new radiator and drilling holes for the brackets.

- The distance from the bottom of the radiator to the floor level is taken in the range of 60-120 mm. If the radiator is installed above or below the specified height, the heat transfer rate is reduced. In this case, about 20 mm is left from the rear of the radiator to the wall, and at least 50 mm from the top of the radiator to the window sill to improve convection and ease of installation.

- Traditionally, radiators are mounted strictly horizontally under the window, in the center. Moreover, if the room already has radiators, their level must strictly correspond.

After marking (using building levels), holes are drilled on the wall for the brackets and the last are fixed with dowel-nails and cement mortar. The brackets should be positioned so that the hooks slide freely between the horizontal manifolds. In this case, the radiator housing will be securely fixed to the wall.

Before installation, the bimetallic radiator is equipped with everything necessary: ​​a Mayevsky crane (to remove excess air from the system) from above, adapters and fittings at the junction of the radiator with the pipes.

Radiator connection diagrams

— Traditional one-way or side connection... With this option, the pipe supplying the coolant to the radiator is connected to a pipe located on top of the radiator. Accordingly, the outlet pipe is mounted to the lower radiator pipe. Heat loss with this method of connection is not more than two percent.

— Bottom diagram... Practiced when the heating system is hidden or embedded in the floor covering. The pipes for the outlet and supply of the coolant are connected from opposite sides of the radiator, to the lower nozzles. Heat loss reaches 12%.

— Diagonal diagram suitable for radiators with a large number of sections. The coolant supply pipe is connected to the upper branch pipe, and the outlet pipe is connected from the other side, from below.

After connection, the system is filled with a coolant. For this, the stabilizing valve is closed 2/3 to prevent water hammer.

Bimetallic radiators with a decorative coating (two layers of heat-resistant paint) must not be cleaned with abrasive materials and powders. It is recommended to paint it no more than once every ten years. It is strictly forbidden to paint over the thermostat.

Video - Dismantling the old radiator and installing a bimetallic

Bimetallic radiators, which is better

Bimetallic radiators on the Russian market are fully certified, however, they differ not only by the company and the country of manufacture, there are small, but very important nuances that you should pay attention to when buying.

Price is one of the most important aspects that consumers pay attention to. But before judging the quality of a product by its price, one should figure out what makes up the cost of a radiator.

The most inexpensive bimetal radiators represented by manufacturers from China and Russia. The price of one section does not exceed four hundred rubles. The low cost is due to a simplified design, material savings in the production of goods. The working pressure of such radiators is slightly lower than analogs produced in other countries, and the appearance is not perfect.

If you compare bimetallic radiators from the price range from 400 to 600 rubles for each section, then we will meet two manufacturers from Italy (Global, Sira) and another brand from Russia - RIFAR. Radiators of these companies look more aesthetically pleasing and attractive with a coating of snow-white or cream shades. Some models are equipped with an air vent or thermostat. There are different installation methods and some production nuances (center-to-center distance, equipment, etc.), which insignificantly affect the performance (power) and reliability of radiators. But they all managed to prove themselves from the positive side among satisfied consumers.

In the special edition RIFAR MONOLIT models of radiators specially designed for operation at an operating pressure of up to one hundred atmospheres are presented. If it is necessary to choose a radiator not straight, but a rounded shape, the quality and design of the series should be assessed RIFAR FLEX... And if your choice fell on radiators with a copper core, which has increased resistance to corrosion, then the models of such heating devices are presented by the company PILIGRIM.

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 allow replacing the usual cast-iron radiators, while the heat transfer efficiency and durability of the new radiators are not inferior to the traditional ones, and in appearance they are much superior to the old samples. Batteries of this type are successfully used to organize heating of a country cottage and for installation in multi-storey city buildings. The steel core is able to cope with the powerful pressure typical 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 media, which is important in urban conditions, when the coolant is exposed to excessive alkalization or has an increased acid content.

These devices are lightweight, look attractive, have a high level of heat transfer and a long service life. It is not difficult to choose a radiator of the required size, since manufacturers have established the production of various models.

Advantages and disadvantages of bimetallic radiators

The devices under consideration have positive properties that distinguish them from other types of heaters:

• Longer service life. The device, made with high quality without disturbing the technological process, will reliably heat the room for at least 30 years;
• The steel base gives this product increased strength;
• A steel core, especially if it is made of high-carbon steel, is not afraid of a coolant with an excessive content of alkali and acids;
• High degree of heat transfer (up to 190 W per section);
• The radiator comes standard with a temperature controller that allows you to reduce or increase heat transfer;
• A large selection of colors and many design solutions for the 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 filter on the supply;
• 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. Usually 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 the standard value of the heating network of 70 ° C. Using this indicator,
• calculate the required number of sections for a specific object;
• The strength of the material. This characteristic is important when determining the type of heater based on the pressure of the heating network. It is measured in bar and ranges from 15-35 units;
• The limiting level of the temperature of the coolant. Any bimetallic radiator can handle temperatures of + 90 ° C;
• Dimensions. It is important to determine the center distance and relate it to the dimensions of the liner. There are models with this indicator from 200 to 800 mm. Height, width and thickness of the product must comply with the recommended standards for installing a radiator indoors;
• Volume. They characterize the capacity of the radiator in liters, ranging from 0.15 to 0.4 liters;
• Weight. Standard products with dimensions 580x80x80 mm weigh about 2 kg.

Bimetallic battery device

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 stiffness of the steel allows it to successfully withstand high pressures and also resist corrosion.

Outside, the frame is wrapped in an aluminum casing. Aluminum is capable of rapidly heating up and transferring heat to the atmosphere. Also, the casing is equipped with special ribs 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:

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

The convenience of sectional models is the ability to build new sections as needed. It will not work to enlarge 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 20-30% higher than sectional ones.

For heating devices in residential premises and office buildings, both types of bimetallic heating radiators are used. Which is best for an apartment - depends primarily on the design of the heating network. For standard apartments in multi-storey buildings, it is better to use cast products, and in a 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 features 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 during the testing of the product - this indicator should not be less than the peak values ​​of the heating network;
• 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 from 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 be at least 7 cm wide, this size gives the 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 radiator is 20 years or more.

Monolithic or sectional

Monolithic cast products can 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-metal heaters are produced. In these products, the inner core is made not only of steel - it also contains elements of aluminum. Typically, 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-metallic radiators differ little from ordinary aluminum batteries. The joints 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-metallic radiators are a little lighter than the original, so when buying, you should pay attention to this point, since unscrupulous manufacturers may not indicate the exact parameters of the product. These heaters are closer to aluminum in terms of characteristics, so it is better to install them in a private house.

Distance between axles

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

Manufacturing material

Most bimetallic batteries are manufactured with a steel frame and an aluminum shell. The steel core copes well with the overpressure of the network, resists corrosion, and the aluminum shell serves as an excellent heat dissipator. Some manufacturers use high-carbon steel grades to achieve higher strength characteristics and product durability.

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

The best bimetallic radiators

In retail chains, there are many models and brands of bimetallic batteries, both domestically produced and foreign counterparts. 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. The product line of this manufacturer includes 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 values ​​of the center distance from 200 to 500 mm. The quality of the products is confirmed by a 10-year warranty.
• Tenrad. A manufacturer from Germany is engaged in the production of heaters for private houses equipped with an autonomous heating system, but the product line also contains devices that can withstand the high pressure of the centralized heating network.
• WARMA. Joint Russian-Chinese venture. The terms of reference are being developed in Russia, and the assembly of finished products is carried out in China. Radiators of this company are used for both autonomous and central heating systems.
• Könner. A Russian company that produces bimetallic batteries at manufacturing facilities in China. The products of this company are also versatile. The features include increased anti-corrosion resistance of metal and high strength, which allows you to hold powerful water hammers.
• TENRAD. German company placing orders for production in China. All products are quality checked by German engineers.
• Radena. The development of the design of radiators and the control of finished products are carried out in Italy. Made in China. The used center distance is from 150 to 500 mm. Most of the models are perfect for Russian central network conditions.
• 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.

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-to-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.
• Könner. They are produced with a center distance of 350 and 500 mm. Both options withstand a network pressure of 30 atm. Power from 140 to 190 W. The maximum temperature of the coolant 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. 15 year warranty. The cost for one section is about 500 rubles. The number of sections is from 4 to 12.
• TENRAD BM350. The maximum pressure is 24 atm. The power of one section is 120 W. Heat carrier temperature no more than 120 ° С. The volume of one section is 0.15 liters. 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. The number of sections is from 4 to 12. The guarantee is 50 years.
• Radena Bimetall CS 500. Permissible network pressure 25 atm. The power of one section is 120 W. The coolant temperature is not more than 110 ° С. The volume of one section is 0.13 liters. 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. The number of sections is from 4 to 12. The guarantee is 15 years.

Calculation of the number of required sections

To calculate the required number of radiator sections for efficient room 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 to create comfortable living conditions, 0.1 kW (or 100 W) of thermal energy is sufficient per square meter, which means that to obtain the required number of sections, the following calculations must be performed:

1. Find the area (P) of the room (for example, 6 x 3 = 18 m 2).
2. Determine the power (M) of one section in W (for example, 170 W) according to the technical characteristics of the product.
3. To determine the number of sections (K), the area must be multiplied by 100 W and divided 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 come with the equipment and correctly calculate the location of the battery attachment.

The radiator must be located 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 window sill is at least 10 cm. Having marked the installation location, you can proceed to installation. The sequence of actions is as follows:

1. Brackets are installed.
2. A radiator is hung on the brackets.
3. Make a connection to the coolant.
4. Install a thermal valve or drain valve.
5. Install a Mayevsky valve to bleed off excess air.

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

Related Videos

Bimetallic radiators appeared on our market not so long ago, but they are steadily gaining popularity. They are called so because they consist of two metals - steel pipes and fins of air ducts made of silumin aluminum alloy welded onto them. The price for them is about 30% higher than for aluminum ones. Why then are they bought? Because they are more durable and better tolerate the coolants that our boiler houses supply to the network.

From what has been said, it is easy to understand where they are often placed: in high-rise buildings connected to centralized heating. This does not mean that they do not work in individual heating systems. They work very well, but at the same time they have lower heat transfer (a steel frame is not the best heat conductor) and a higher price. There is no sense: the coolant is normal (you yourself control its quality), the pressure is far from critical, so there is simply no point in paying more, it is better to supply.

Types of bimetallic batteries

First of all, it must be said that not all bimetallic heating devices are made of steel and aluminum. Copper is sometimes used instead of steel. But then they are made not in sectional design, but in panel design. And they are pretty decent, but they have excellent heat dissipation.

There are also models in which the collector is made of stainless steel. They are suitable for networks with high pH levels, as well as for those who like to take all system components with a large margin of safety.

In a fully bimetallic radiator, the entire frame is made of steel, some of them are made of stainless steel

The option "steel + aluminum" is the most common, and when they talk about bimetal, they usually mean it. But radiators made of these metals can be of two types: full or partial.

If inside the section both horizontal and vertical collectors are made of steel, they speak of "full bimetal", sometimes the name "reinforced bimetallic radiator" is also encountered. This is also about him. To increase the heat transfer of the section, two vertical tubes can be placed in it. This is usually done in deep models.

If only a vertical tube is made of steel, this option is called "partial" or "semi" bimetallic.

Which is better

Collectors made of steel completely exclude contact of the coolant with aluminum. This is the moment that interferes with the normal operation of aluminum batteries in our high-rise buildings. The second point is the pressure drops that can occur during system startup and in emergency situations. In general, in a normal state, this indicator in any network is in the range of 6-9 atm. But they try to install heating devices with a multiple reserve: water shocks are very strong. According to these parameters, batteries made of full bimetal are better:

• their working pressure is about 5 atm higher than that of the partial one (on average, 30-40 atm, depending on the manufacturer),
• 100% exclusion of contact with the coolant.

What is the disadvantage of such radiators? They are expensive. The manufacturing technology is complex: first you need to weld the structure, while ensuring the tightness and reliability of the connection, then melt aluminum onto the frame, giving it a certain shape. It is also necessary to ensure a reliable connection of two different metals, which is not easy. All this affects the price.

Another negative point: lower heat output of the section. The difference is about 10% compared to partial bimetal, and 15-20% with a similar aluminum section.

Partial bimetal has lower strength characteristics. Its horizontal collectors are made of aluminum, that is, they are destroyed by the coolant. But the practice of using aluminum radiators has shown that in most cases it is the vertical collectors that are destroyed. So aluminum in horizontal does not greatly affect the durability of heating devices. Nevertheless, the main task and idea has not been fulfilled - to exclude the contract of aluminum and coolant. In any case, they are more demanding on the quality of the coolant (pH should be in the region of 6-9, and preferably 7-8) and have lower burst pressure (and working pressure too).

Now about the pros. These batteries are priced between fully bi-metallic and aluminum. They have a higher heat transfer. Some models can catch up with aluminum. For example, the Rifar Base 500 can draw more than 200 watts from one section (at a delta temperature of 70 o C).

This is the only fully bimetallic radiator from the Russian manufacturer Rifar

So all the same, which bimetallic radiators are better. I will express my own point of view: if we put bimetal, then full. It may be expensive, but reliable. And the manufacturer must be chosen wisely. It is quite possible to find a high-quality full bimetal, which at a price will be only slightly more expensive than a partial one. But I emphasize once again - this is a personal opinion.

In general, you need to approach from the point of view of operating conditions. You will need to find out the following parameters of your heating network:

• Maximum temperature;
• working and maximum pressure;
• the pH of the coolant (the same pH).

Having these data on hand, you can already decide exactly which is better: a bimetallic radiator with a partially steel collector, or you need a frame entirely consisting of steel.

When figuring out your network parameters, don't ask for an official answer. You will be given "protocol" values, which, to put it mildly, do not always correspond to reality. Better to find out from plumbers who know the real picture, and not the official one.

Manufacturers and prices

Looking through the information on the official sites, you can see one pattern. In the description of some models it is clearly stated: all pipes through which the coolant runs are made of steel. There are even drawings and photographs that demonstrate it. In others, not a word about what metals the collectors are made of. And these are models from one manufacturer.

So that's it. Those modifications where there is no mention of materials are partial bimetal. It's just that the manufacturers are silent about it. For what reasons - one can only guess.

Now about the prices. Let's give them in dollars (the exchange rate does not differ in stability, so ...) and approximately. We all know that people have different appetites, but we have deduced the estimated cost. They are taken from online stores, while offline they may differ significantly. More about how the firms were selected (if indicated): these are the most popular and in stores or on forums. And about standard sizes: prices are for models with a center distance of 500 mm.

As you can see, the prices for aluminum radiators (at least from these manufacturers) are not much different. There is, of course, a difference, but it amounts to tens of rubles per section. But the spread on the bimetallic is more than solid.

If you focus on the reviews, then there are very few negative reviews about Global bimetallic radiators, the modestly priced Radena does not have them at all. Moreover, these firms produce only with a completely metal collector. But one has production located in Italy (), and the other - in China ().

All the rest have about the same picture: there are negative reviews. But, it is difficult to determine if the problem is due to an installation error or a manufacturing defect. And another nuance: the prices of the Russian Rifar from the manufacturer are lower. In the table, the prices of intermediaries.

Technical characteristics of bimetallic heating radiators

This question is no easier than with prices. Manufacturers - dozens, if not hundreds, of models and even more. But we can say about the average (for models with a center distance of 500 mm):

• thermal power of one section (at a temperature delta of 70 o C)
  • full bimetal 160-180 W;
  • partial 170-200 watts.
• operating pressure:
  • full bimetal 35-40 atm;
  • partial 25-30 atm.
• maximum coolant temperature:
  • full bimetal 110 o C;
  • partial 100 o C.
• volume of water in sections (capacity):
  • full bimetal 0.18 -0.22 l;
  • partial 0.18-0.24 l.

It is worth considering that the thermal characteristics of some models may differ both upward and downward. This is due not only to different compositions of materials and technologies, but also to different sizes. For example, the width of the section is standard: 80 mm almost always, and the depth can vary from 70 mm to 95 mm. It is clear that the deeper heat transfer will be greater, moreover, they have a larger number of fins, which further increases the thermal power.

The height of the sections also changes. The center-to-center distance is strictly maintained, but the height of the added ribs can vary. So with a center-to-center distance of 500 mm, the height of the section is 552 mm and 575 mm.

The pressure will also differ: pipes of different thickness are used as a frame, metal of different quality, collectors of different cross-sections and even of different shapes. What remains more or less stable are temperatures. All other characteristics are highly dependent on the manufacturer and on the parameters of the model.

Calculation of bimetallic radiators

All you need to know to calculate the number of radiators per room is its heat output. But there are several calculation methods:

• by area;
• by volume;
• on heat losses.

The most accurate is for heat loss. This parameter is calculated by a heating engineer. In principle, the operating organization should have apartment-specific data. You can find out the heat loss of your premises from them. For the owners of private houses, everything is not so simple: you need to order a heat engineering calculation from specialists.

But having these data, everything is considered simple: you divide them by the section capacity of the model you have chosen and get the number of sections that must be installed to maintain a comfortable temperature.

For example, the room loses 1600 W of heat, the radiator power is 180 W. 1600/180 = 8.8 pieces, round up, we get 9 pieces.

Volume calculation method

In the calculation of bimetallic radiators by volume, SNiP standards are used. According to them, to provide heat to one cubic meter of air in panel houses, 41 W of heat is required, in brick houses - 34 W. To determine the number of sections, you will need to calculate the volume of the room (multiply the width, length of the room and the height of the ceilings), and then multiply the found figure by the appropriate rate. We get the amount of heat that is needed to heat this room. Dividing it by the heat output of the radiator, we get the number of sections.

For example, a room has the following parameters: width 3 m, length 4 m, ceiling height 2.5 m. 180 W radiators will be installed. Let's calculate in order:

• We get the volume of the room: 3 * 4 * 2.5 = 30 m 3.
• If the room is located in a brick house, you will need 30 m 3 * 34 W = 1020 W.
• Now we count the number of sections 1020 W / 180 W = 5.66 pcs.
• Rounding up, we get 6 sections.

How to calculate sections by area

The easiest way is to calculate the number of sections by area. But it gives the biggest error. It is assumed that, on average, 100 W of heat is needed to heat one meter of room area. In this case, neither the region, nor the height of the ceilings, nor the material of the walls, etc. are taken into account.

To understand how large the error is, let's calculate the number of sections for the same room.:

• The area is 3 * 4 = 12 m 2.
• One section of a radiator with a capacity of 180 W can heat (based on the norm) 1.8 m 2.
• To find the number of sections, the area of ​​the room is divided by this indicator: 12 m 2 / 1.8 m 2 = 6.66 pieces, we round up, we get 7 pieces.

There is an error, and a considerable one. This method is suitable only for an approximate determination of the number of sections for average insulation in central Russia.

Moreover, both calculations are valid only for those cases when the parameters of the system are as follows: the temperature of the coolant at the supply is 90 o C, in the "return" 70 o C, the room should be 20 o C. The data on the thermal power of bimetallic radiators (and others too) are given precisely for such values ​​(this is established by the norms). With other parameters, the power will be different. In some cases, the manufacturer indicates heat dissipation for other common temperatures.

Moreover, the last two methods give only more or less correct results. Considering this, you can supply either more radiators than required, or less. Both options are not the best. And all because the calculations do not take into account either the area of ​​the windows, or the degree of their insulation. The presence and number of external walls is also not taken into account. Indeed, the more area the wall facing the street occupies, the more heat is required to maintain a normal temperature. To take into account all these and other factors, you need to use correction factors.

Outcomes

Bimetallic radiators are good when a low quality coolant circulates in the network, strong hydraulic shocks are possible. In this case, the steel frame serves as a guarantee of the integrity of the heater. Application in individual heating is advisable only if antifreeze is used. When using water, there is simply no need to pay more.

The efficiency of the batteries determines the speed and quality of heating. The modern equipment market offers all kinds of solutions. One of the worthy options are bimetallic heating radiators that meet the main requirements of the heating network: strength, resistance to water hammer, high heat transfer and durability.

We will tell you how to choose the right heating device, in the manufacture of which two metals were used. The article proposed by us describes in detail the varieties popular among consumers. Their technical characteristics are given, leading manufacturers are listed.

Externally, bimetallic models resemble ordinary ones. The difference lies in the inner content. The construction of composite products consists of two basic elements: an inner steel tube and an external figured-ribbed body made of aluminum panels. Some radiators use copper instead of steel.

The circulation of the coolant takes place through an internal steel or copper pipeline. Due to their corrosive inertness, radiators do not rust and do not react with a chemically active coolant. External elements and internal manifold are connected by spot welding or pressure molding.

According to their physical and operational properties, the batteries are suitable for installation in apartment buildings of any number of storeys and for arranging a local heating system of cottage buildings.

The bimetallic structure determines the characteristics of the device. The steel core explains the resistance to aggressive environments and resistance to pressure drops, the aluminum "shell" increases heat transfer and lightens the radiator

Features of different heating convectors

It should be understood the differences between different types of batteries made of two metals. Composite products are usually classified according to the following criteria: composition of the inner core, external design and type of metal used.

Bimetallic and semi-bimetallic radiators

Users often confuse true bimetallic batteries with "half-breeds" - semi-bimetallic counterparts.

"Pure" bimetal

Aluminum is used to make the outer casing of the device. The convector core is 100% stainless steel or copper. During the production process, pipes placed in special forms are filled with aluminum under pressure - a sealed structure is formed.

The outer shell is not in contact with the coolant and acts as a heat exchanger. The main feature of bimetallic radiators is high strength and a guarantee against leaks.

A full-fledged bimetal withstands the pressure of a centralized and autonomous heating system.

The internal "skeleton" of the radiator is assembled from two metals: vertical guides - stainless steel, horizontal piping - aluminum. The reverse combination is also possible.

Such an alliance of metals is not able to ensure the proper reliability of district heating communications. The coolant may contain alkali, which, in interaction with aluminum, provokes the appearance of corrosion. Over time, destructive processes "transfer" to the steel components of the radiator.

In addition, the integrity of the product can be compromised by thermal expansion of metals - leaks are possible at boundary temperatures.

Externally, semi-bimetallic radiators do not differ from full-fledged bimetallic counterparts. "Half-breed" gives out lighter weight and lower cost

It is better to refuse to buy a low-quality composite, especially when it comes to centralized heating.

Sectional and monolithic models

Among the variety of bimetallic heating batteries, there are two types of structures:

• sectional:
• monolithic.

Models assembled from sections attract with a variety of characteristics. They provide an opportunity to purchase a device with the exact values ​​of heat transfer required for space heating. Monolithic ones do not have such advantages.

Typesetting systems

Dismountable radiators, the panels of which are connected by means of nipples. The horizontal pipe sections of individual sections have multidirectional threads for joining the fixing nipples and the sealing strip.

Typesetting models are more popular due to their practicality - it is possible to adjust the heat output by adding or subtracting the required number of sections. An additional plus - maintainability

Disadvantages of sectional radiators:

• joints - weak points of collectors, where leaks are likely;
• limited working pressure - up to 20-30 bar.

The partial hit of the coolant on the aluminum "jacket" during the flow is also considered to be a serious disadvantage.

Monolithic devices

Integral modifications are devoid of the listed disadvantages. The cast radiator is able to withstand pressure surges within 100 atmospheres.

Disadvantages of monolithic batteries: there is no possibility to vary the thermal power, overpriced - 20-30% more expensive than sectional models with similar parameters

For high-rise buildings (10 or more floors), experts recommend choosing one-piece radiators, since there will be significant pressure in the heating system.

Copper or steel core?

Most manufacturers offer steel tube frame hybrid batteries. The main reason is the affordability of the metal and good strength characteristics. The symbiosis of steel and aluminum made it possible to achieve resistance to vibrations, increase the level of heat transfer of the convector and reduce its inertia.

In copper + aluminum radiators, the heat exchange tubes are made of copper. Heating panels - aluminum plates, brazed to an inner copper frame

Benefits of Copper Core Batteries:

• the likelihood of corrosion is absent;
• a copper pipeline transfers any water hammer - the best option for operation in domestic centralized heating systems;
• high efficiency of the device - the heat transfer of copper exceeds that of steel.

Copper-aluminum radiators have a service life of over 50 years. The disadvantage of copper modifications is the high price.

Technical and operational characteristics

All basic parameters of the radiator are indicated in the passport of the heater.

In order not to be mistaken with the choice, it is necessary to understand the meaning of the following characteristics:

• heat transfer;
• working pressure and temperature;
• center distance;
• dimensions;
• capacity, section weight.

Thermal power. The parameter indicates the amount of heat transferred from the battery to the atmosphere of the room at a given temperature (+ 70 ° C). The indicator is measured in watts.

The average heat transfer value of a composite radiator is 140-190 W. The run-up of values ​​is explained by the dimensions of the section and the features of the performance of devices from different manufacturers.

Based on the thermal power of one section, the required battery performance is calculated for the entire room.

Work environment metrics. The maximum heating medium pressure depends on the thickness of the steel core. The choice of strength is at the discretion of the manufacturer. The parameter value ranges from 15 to 35 bar and is determined based on the operating conditions of the battery.

An important characteristic is the boundary temperature of the coolant. All high-grade bimetals are capable of withstanding + 90 ° C. Some manufacturers claim higher thermal resistance.

The maximum temperature declared in the passport of the equipment of different trade positions: Global Style - 110 ° С, Tenrad - 120 ° С, Altermo - 130 ° С, Grandini - 120 ° C

Radiator dimensions. Dimensional characteristics include the following parameters:

1. Center distance- "mileage" between the axes of horizontal collectors. The standard size is 20-80 cm. Vertically oriented models with an increased center distance are used if the layout of the room is not suitable for installing horizontal radiators.
2. Geometric parameters determine the height, width, depth of the section. The total height of the radiator often exceeds the center-to-center range by 6-8 cm. The traditional width of the ribs of bimetallic models is 80 mm.

The section depth is 75-100 mm. Some manufacturers, in addition to external panels, add parallel ribs to the design to increase heating efficiency due to convection flows.

Overall dimensions: a - section height, b - distance between horizontal axes, c - battery depth, d - width of one section. The most popular products with a core height of 35 cm, 50 cm

Volume and mass. In bimetallic modifications, the coolant circulates through a round core, in contrast to aluminum counterparts with an oval section heat conductor. The capacity of one section of the bimetal is less than the volume of the aluminum section with the same standard dimensions.

For example, in convectors with an interaxial range of 500 mm, the filling with a coolant is about 0.2-0.38 liters, with a core height of 350 mm - 0.15-0.25 liters.

The weight of a standard bimetallic battery with dimensions of 580/80/80 mm (height / width / depth, respectively) and a center distance of 50 cm is 1.8-2 kg. Lighter weight is one of the hallmarks of a semi-metal.

Comparative analysis: bimetal and competitors

Before choosing a bimetallic or other radiator, it is advisable to compare its capabilities with the closest competitors. For composite convectors, these are aluminum, cast iron,.

The assessment should be carried out according to the main criteria:

• heat transfer;
• endurance to pressure drops;
• wear resistance;
• ease of installation;
• appearance;
• durability;
• price.

Heat transfer. In terms of heating efficiency, aluminum units are the leaders, bimetal takes an honorable second place. Steel and lose noticeably.

Aluminum is characterized by minimal thermal inertia - after starting the system, the air in the room heats up for 10 minutes

Resistance to water hammer. The most hardy are bimetallic aggregates that can withstand up to 40 atmospheres (sectional models). The maximum operating pressure for an aluminum heating system is 6 bar, a steel one is 10-12 bar, and a cast iron one is 6-9 bar.

It is bimetal that is able to withstand numerous water shocks of a centralized heating system. This property is a key argument in favor of composite radiators for apartment buildings.

Chemical inertness. According to this criterion, the positions were distributed as follows:

1. Cast iron. The material is indifferent to hostile environments. Cast iron radiators can be used for decades, transporting "alkaline", "acidic" environment.
2. Steel and bimetal. The steel core itself is resistant to aggressive components. The weak point of the steel pipeline is the interaction with oxygen, contact with which leads to the formation of rust.
3. Aluminum. The metal reacts with various impurities in the water.

Aluminum walls are especially susceptible to the action of an acidic environment - the pH of the coolant must be within 8. Otherwise, corrosion develops actively.

Ease of installation. In terms of installation, aluminum and bimetallic products are easier. Cast iron radiators are more difficult to install due to their impressive mass.

In terms of durability, the leaders are composite and cast iron batteries. Aluminum and steel products, subject to operational requirements, must be replaced after 10-15 years. Among the designated batteries, the bimetallic ones are the most expensive.

We can make a conclusion. The purchase of a bimetallic radiator is unambiguously justified for assembling a heating network in a multi-storey building, where there are risks of pressure surges and contamination of the coolant. In a private house, with stable operation of the boiler and filtration of the incoming water, it can be used in available aluminum batteries.

What should be considered when choosing a radiator?

To achieve the proper thermal effect, it is necessary to calculate the total power of the battery. Bimetallic equipment is not a cheap purchase, so you should take care of its durability. Conscientious performance of the radiator is guaranteed by trusted manufacturers.

Opportunity Assessment - Thermal Calculation

Having decided on the appropriate technical characteristics and dimensions of bimetallic radiators, it is necessary to calculate the required number of sections.

Basic formula: N = Ptot. / Ppass., Where Ptot. Is the required battery power for the entire room, Ppass. - thermal power of the section according to accompanying documents

The heat transfer index of the section is taken from the radiator passport, and the total power must be calculated.

Area calculation

The normalized value of the thermal power per 1 square meter of living space for the middle climatic zone, subject to standard ceilings (250-270 cm):

• the presence of one window and a wall with access to the street - 100 W;
• a window in the room, two walls adjacent to the street - 120 W;
• several windows and "external" walls - 130 watts.

Example. Section power - 170 W, total area of ​​the heated room - 15 sq. M. Additional conditions: window - 1, outer wall - 1, ceiling height - 270 cm.

N = (15 * 100) / 170 = 8.82.

Rounding up is done. This means that 9 sections of 170 W each must be used to heat the room.

Volume calculation

SNiP separately regulates the amount of heat output per 1 cubic meter of room in the amount of 41 W. Knowing the volume of the heated room, it is easy to calculate the heat transfer of the entire battery.

Example. Heating the room with the previous parameters. For the purity of the experiment, the power of the section is left unchanged - 170 W.

N = (15 * 2.7 * 41) / 170 = 9.76.

It is necessary to install a 10-section radiator. The second calculation is considered more accurate. When calculating, attention should be paid to the sources of heat loss inside the room.

The calculated value must be increased by 10% if the apartment is located on the first / last floor, the room has large windows or the wall thickness does not exceed 250 mm

Avoiding Counterfeits: Radiator Inspection

In addition to analyzing passport data, it will be useful to conduct a visual assessment of the goods. Some manufacturers, in pursuit of customers, tend to "embellish" their products by introducing incorrect data into the documentation.

First of all, attention is paid to the thickness of the core and the aluminum "jacket", overall dimensions, weight and quality of components.

The minimum thickness of the steel tube is 3 mm. At smaller standard sizes, the declared strength of the product is significantly reduced - resistance to and the development of corrosion processes.

The walls of thin metal open the coolant access to the aluminum "shell", which, due to its chemical activity, begins to rapidly deteriorate

The result of a poor-quality steel core is the formation of through holes and the creation of emergency situations on the heating network.

Radiator fins. Aluminum panels should be tested for strength - they should not bend from the force of the fingers of one hand. The minimum panel thickness is 1 mm.

Better to choose models with profiled channels between the ribs. The formed confuser increases the air flow rate, increasing the intensity of convective heat transfer.

To reduce the risk of injury, the outer edges of the aluminum panels are rounded. On the surface there should be no streaks, irregularities in color and "gaps"

Dimensions and weight. On an individual order, it is possible to manufacture radiators with a section width of less than 80 mm. However, store models with an inappropriate parameter are most likely fake.

Some manufacturers cut the width of the internal ribs significantly to reduce the cost, "masking" them behind the bezels of the standard size. This measure impairs the heat transfer of the bimetallic radiator.

Battery accessories. It is almost impossible to check the quality of gaskets and nipples on site. Rely on the manufacturer's name and warranty period. Trustworthy companies guarantee up to 15-20 years of trouble-free work.

Popular manufacturers rating

The review includes high-quality foreign heating systems and domestic products adapted to the changeable conditions of heating networks.

• Global Style (Italy);
• Sira (Italy);
• Rifar (Russia);
• Tenrad (Germany).

Place # 1 - Global

It is a recognized leader in the production of heating radiators.

The company produces three series of bimetallic batteries:

• Style - basic characteristics;
• Style Extra - compact dimensions;
• Style Plus - maximum heat dissipation.

The sections are connected with paronite gaskets, which ensure the tightness of the joints. Efficient heat transfer between metals is achieved through the die-casting of the aluminum "jacket".

Additional characteristics: pressure - up to 35 atm, connection diameter - ¾ or ½ inch, coolant temperature - up to 110 ° С, outer shell - double painting

Place # 2 - Sira

The Italian manufacturer positions its products as premium products. The devices have gained popularity among consumers due to their robustness and attractive design. The manufacturer provides a 20-year warranty for a series of full-fledged bimetallic radiators Sira Ali Metal.

Characteristics of Ali Metal products: center distance - 350/500 mm, heat transfer of models - 187/141 W (respectively, center distance), pressure in the heating network - 35 atmospheres

Place # 3 - Rifar

The domestic manufacturer has developed a wide range of bimetallic radiators:

• Base - models with a center distance of 200/350/500 mm, a guarantee from Rifar - 10 years;
• Forza - a reinforced outer coating resistant to scratches and mechanical damage;
• Alp - shallow depth (75 mm);
• Monolit is a one-piece radiator.

Monolit series batteries are distinguished by the highest performance indicator at high pressure of the coolant.

Technical data: working pressure - 10 MPa, breaking pressure - 25 MPa, maximum temperature - 135 ° С, warranty period - 25 years

Location # 4 - Tenrad

Bimetal of German quality is suitable for centralized and. It can be used in gravity, elevator and pumping systems with one- and two-pipe distribution.

Distinctive features:

• thickness of vertical tubes - 1.8 mm, collector walls - 3.6 mm;
• three-row ribbing;
• the side panels are sloped to create a diffuser effect for the convective flow.

Two-layer enamel coating of high-quality paintwork materials - when heated, the device does not emit harmful vapors.

Tenrad products are designed to operate in a system with a heating medium pressure of up to 35 atmospheres. Bimetallic radiators are certified and comply with the European standard EN442

He will acquaint you with the rules for calculating the power and the number of radiators for a heating device, which you should read before purchasing devices.

Conclusions and useful video on the topic

The video review clearly demonstrates the design features of composite radiators and the basic requirements that a high-quality device must meet:

High-grade bimetallic radiators combine the positive characteristics of both materials. The batteries are distinguished by their high thermal power, resistance to water hammer and excellent decorative properties. Their purchase is a worthwhile investment, provided that you purchase a certified product.

Tell us about how you chose a bimetallic heating device for your own apartment or country house. Share what argument was decisive in your choice? Please leave comments in the block below, ask questions, post thematic photos.