The choice of the type of heating devices depends on several factors, including the chemical composition and temperature of the coolant, the scheme of the heating system, and the pressure in it. Composite bimetallic radiators are versatile and inexpensive, installed in almost any conditions. A zealous owner should imagine what it is, how to choose reliable samples and mount it correctly.
Design features of bimetallic heating devices
There are two different metals involved in the construction of these batteries. Visually, most of them are similar to conventional sectional aluminum radiators. However, premium units may differ significantly in appearance. In total, the consumer is offered three types of devices:
- sectional (Fe + Al);
- sectional made of "semi-metal" (Fe + Al);
- lamellar (Cu + Al).
The first option received the greatest distribution due to the combination of availability, reliability and heat transfer rate. Outwardly, it is almost impossible to distinguish it from a conventional aluminum battery. Is that with the help of a magnet, by weight (it is heavier than one and a half times) or by looking inside. The main elements transporting the coolant are vertical and horizontal channels made of ordinary or protected steel. They are tightly surrounded by an aluminum shell that transfers heat to the convection fins.
Devices can be both sectional and monolithic while maintaining the sectional size. Monolithic units are more reliable, but much more expensive and cannot be disassembled.
"Semi-bimetallic" or "pseudo-bimetallic" devices differ in that the horizontal channels in them are aluminum. Unscrupulous sellers often pass off such heating batteries as real bimetallic ones. But these "half-breeds" are inferior to their competitors in terms of their parameters:
- resistance to working and pressure pressure, water hammer;
- inertness to atmospheric and electrochemical corrosion.
Copper-aluminum radiators are of the plate type, in which two copper pipes are enclosed in a set of aluminum plates. They are practically devoid of disadvantages - they are only slightly susceptible to electrochemical corrosion. However, they belong to premium products and are rare. Indeed, in this category, as a rule, exquisite cast-iron samples are in the lead in popularity.
Advantages and disadvantages of composite heating appliances
The only obvious drawback of this product is its susceptibility to atmospheric corrosion. In cases of draining water from the heating system or choosing instead of poor-quality antifreeze, the steel channels rust. Because of this, the smoothness of the walls is disturbed and the permeability of the pipe decreases, up to the formation of a plug. It usually does not come to the appearance of through holes. However, more expensive models are sometimes protected from the inside by a special coating.
Electrochemical corrosion is less likely, but possible if there is direct or indirect contact of two different metals, for example, in the device itself or in situations where the pipeline is made of copper or "stainless steel".It is also possible that electrical corrosion occurs when attempting to ground electrical appliances to elements of the heating system.
Advantages of aluminum-steel bimetallic heating radiators:
- resistance to increased operating and pressure testing pressure, as well as water hammer, often found in high-rise buildings;
- mechanical strength of steel;
- service life from 20 years;
- comparative inertness of steel to electrochemical and electrical corrosion;
- inertness of aluminum to atmospheric corrosion;
- neat appearance;
- heat transfer;
- availability.
An implicit drawback of these units can also be called a high probability of counterfeiting, for example, attempts to pass off pseudo-bimetal for bimetal or simply poor-quality assembly. You can avoid an unsuccessful purchase by following simple recommendations when choosing.
Signs of poor quality and technical parameters of devices
- Examine the product - chips and dents indicate a low quality of the casing.
- Shine a flashlight inside, assess the condition of the intersectional fittings - no jams are allowed.
- The simplest magnet from the refrigerator, attached to the ends of the channels, will tell you about the material of their manufacture.
- A ruler (preferably a caliper) will show the thickness of the channel walls (should be 2.5-3.5 mm), as well as the thickness of the ribs (about 1 mm).
- A good option is to take a floor scale with you, a section (500 mm) made of a decent bimetal should weigh at least 1.7 kg, an assembly of 8 sections - at least 13.5 kg.
- Find out the warranty period - it should not be less than 2 years (more is better).
The area of the ribbing does not indicate the likelihood of a fake, but the compliance of the model with its price. An example is sometimes Chinese products passed off as Italian or German. High-quality expensive composite radiators cannot have tapered fins and plates that differ from each other in width.
A self-respecting manufacturer will not save on millimeters. If the depth and width of the section is 80 mm in the passport, it will be so.
Specifications
The characteristics of high-quality bimetallic batteries depend on the category of the model (for example, price), as well as the company and country of the manufacturer. The exact values of the characteristics are usually indicated in the product passport. However, the range of these numbers is known:
- center distance - 200, 350 or 500 mm (standard common values);
- internal volume of the section - 0.2-0.5 l;
- weight - 1-2 kg;
- working / maximum pressure - 6-15 / 25-100 atm. (monolithic products withstand the greatest pressure);
- the maximum temperature of the coolant is 100-130 ° C;
- heat transfer - 110 - 210 W;
- service life - 20-30 years.
Many indicators are interdependent. For example, weight and heat dissipation are directly related to the spacing, number and size of fins. The internal volume also depends on this size, but also on the diameter of the channels.
The main parameters - heating inertness and heat transfer - are significantly influenced by the characteristics of the coolant (chemical composition, temperature).
Brand rating
In Russia, as a rule, products made in Europe (in particular, in Italy) are trusted. However, do not forget about other producing countries: Ukraine, Russia and China. Domestic and Chinese brands are steadily improving the quality of their products. Nevertheless, European brands traditionally hold the lead in popularity.
- SiraGroup is an Italian company considered to be the pioneer in the manufacture of composite heating devices. Has been working in his field of activity for over 70 years. Carefully monitors the quality of expensive products.
- Global (Italy) and RoyalThermo (Great Britain-Italy) - occupy an increasing market segment due to the combination of quality, reliability and availability.
- Rifar (Russia) is a popular brand that appeared at the turn of the millennium. Initially, the production of products was carried out under the license of Italian manufacturers. Rifar radiators are sharpened for harsh Russian conditions - climate, water quality, pressure in systems.
- Titan, Maxterm, Sti (China) are manufacturers widespread in Russia that have earned their good reputation and value it.
ZehjangFlyhigh, WangdaGroup, YongkangJinbau are Chinese companies included in the open "black" list of manufacturers that produce low-quality products that are hazardous to health.
In addition to the dimensions and location of the ribs, the products differ in the quality of the metals used. For example, you can often find pseudo-aluminum made from various waste. Including - radioactive or containing substances harmful to health (asbestos).
Calculating the number of sections
Sometimes the exact values of the parameters of the heating system and its devices are unknown. In such cases, the number of standard sections is calculated using the formula N = S / 1.8. For a room with an area of 18 m2, 9-10 sections with a center-to-center distance of 500 mm will be required. For an accurate calculation, the following data is required:
- area, heat loss of the room;
- heat dissipation of radiators;
- temperature, heat capacity of the coolant.
More or less average values:
- Q (heat loss) = 100 W * m2;
- Heat transfer of one section Qc = 180 W / h (at water temperature = 80-90 ° C).
Thus, replenishment of heat loss in a room of 18 m2 will require 1800 W of heat per hour. Considering that one section of the "bimetal" radiator gives 180 W, 10 pieces are needed. However, it must be remembered that modern methods of thermal insulation reduce the heat loss at home three times compared to average values. Consequently, the dimensions of the devices are significantly reduced.
Features of the installation of composite radiators
The main nuance of this equipment in terms of installation is poor suitability for low-temperature heating systems. Steel is much more inert to heat than aluminum. Therefore, where the temperature of the coolant is not higher than 50 ° C, products made of soft metal will be optimal.
In high-rise apartment buildings, composite batteries are the best solution. Here, the temperature is usually not lower than 80, and the pressure (with a water hammer) sometimes goes off scale for 25 atm. However, the recommended installation rules for them are the same as for their competitors (Al):
- placement - in the center of the window;
- height from the floor - 10-20 cm;
- distance to the windowsill - 10-20 cm;
- the distance from the back wall to the wall is at least 20 mm;
- number of fasteners - at least three;
- an adjusting valve is placed at the outlet;
- when connecting and supplying water, one must not forget about air discharge;
- a closed tap on the bypass (jumper) will increase heat transfer, but harm the neighbors.
A good tip is to fix the foil insulation on the wall behind the appliance, directed the foil towards it. Considering that about a third of the heat is transmitted by infrared radiation, such a trick will increase the efficiency of the unit.
Operating tips
It is practically impossible to influence the service life and efficiency of bimetal batteries while living in an apartment building. After all, nothing depends on the consumer here. But private homeowners are forced to use various tricks and heed advice:
- The best heat carrier in all respects is distilled water. As a last resort - purified softened.
- It is undesirable to use different metals in the heating system - this will increase the likelihood of destruction of its elements from the effects of electrochemical corrosion.
- All units are recommended to be grounded through a complete ground loop.
- Recommended pressure in the system is 1.5-2 atm., Temperature is 70-80 ° C.
In the case of using an anti-freeze liquid, you should not use one made of poisonous ethylene glycol. It is safer and more reliable to fill in a mixture of distilled water and propylene glycol. In any case, the brand of the composition must correspond to that indicated in the passport for the boiler. It is undesirable to use oil and products based on it, because it is much more viscous and inert when heated than water. In addition, burns caused by contact with hot oil are dangerous, and it itself is fire hazardous.
If the composition of the coolant is different from water, all gaskets, pipes and other non-metallic elements must be oil and petrol resistant.
