Comparison Roda NSR Bimetal NSR 022/80 1 vs Roda RSR 22 600x700

The general type of radiator determines, first of all, the basic design features.

Nowadays, panel models are most widely used, sectional radiators and a special kind of heaters are also quite popular — convectors. Here is a more detailed description of each variety:

— Panel. In radiators of this type, the front surface is one continuous panel; in general, several panels are often used, and they can be supplemented with convector elements (for more details, see "Type (Panel)"). Anyway, such devices have several advantages: good heat transfer efficiency, low cost, fairly neat appearance and ease of cleaning. Among the disadvantages of panel radiators, one can only note the fixed size of the structure — they cannot be adjusted in width, like sectional ones (see below). However, this point is hardly critical.

— Sectional. Such a radiator consists of separate vertical sections. In modern models, these sections, usually, have a flat front, under which a set of special channels is hidden to create a convection effect. The key advantage of this design is the ability to assemble a radiator from almost any number of sections at your discretion. And in terms of efficiency, such products are not inferior to the panel ones described above. On the other hand, they are more complicated, expensive and difficult to clean: dust accumulates in the channels, w...hich is quite difficult to clean out.
A special kind of sectional radiator are models that are outwardly similar to column ones (see below) and differ only in a collapsible design.

— Convector. Stationary heaters provide heating mostly (if not exclusively) by convection — in contrast to traditional radiators, where thermal radiation also plays an important role. The design of the convector most often provides a hollow body, inside which heating elements are placed in the form of a set of thin vertical plates, usually metal; holes are made in the case in the form of slots, providing air circulation. Most of these models are small in height and are designed to be built into the floor or a low window sill. Accordingly, one of their areas of application is conditions where it is impossible to install a full-sized radiator. In addition, such devices perform well in combination with high windows: the convector creates a thermal curtain that prevents the outflow of heat through such a window. On the other hand, heaters of this type are inferior to traditional radiators in terms of efficiency and uniformity of heating.

The manufacturer's warranty period for this model.

Usually, the terms of the warranty provide free rectification, replacement and/or compensation if the radiator fails during the stated period due to manufacturing defects. The greater the guarantee, the higher the quality of the product and the higher its cost (the latter, however, is usually compensated by high reliability). In modern radiators, the warranty period can be up to 10 years.

Note that the end of the warranty does not mean the product will immediately fail: with proper workmanship, the total service life exceeds the warranty significantly.

The main material used in the design of the radiator.

The most popular nowadays are steel products. Aluminium is also quite common, including in combination with copper; this material is mainly used in convectors (see "Type"), although it is also found among traditional radiators. Rarer options are bimetallic and cast iron. Here is a more detailed description of each of these materials:

— Steel. Relatively inexpensive, but at the same time quite practical material, resistant to corrosion and has good thermal conductivity. The main disadvantage of steel radiators is considered to be low operating pressure and sensitivity to water hammers — this is due to the presence of weak points in the welds. However, the specific reliability of such products may be different, depending on the quality and special solutions used in the design. Nevertheless, in general, such models are inferior to aluminium and, even more so, bimetallic ones in terms of strength. So the main scope of their application is autonomous systems with low pressure, as well as high-rise buildings up to 9 floors high. Also, steel devices are somewhat heavier than aluminium ones; however, this point is rarely critical.

— Aluminium. A material with excellent specs— in particular, it has very low thermal inertia and low weight. In addition, these radia...tors are considered to be less sensitive to water hammers than steel radiators and are better suited for high-pressure heating systems used in apartment buildings. As for the disadvantages, in addition to the relatively high cost, it is worth mentioning the demanding quality of the heating medium: it must have a neutral pH, otherwise, a reaction with hydrogen evolution is possible (which adversely affects the radiator and can lead to clogging). It is also worth considering that not all aluminium devices are designed for high pressure; this point needs to be specified separately.

— Copper/aluminium. A combination used exclusively in convectors: copper tubes for the heating medium, supplemented with aluminium plates (and, most often, an aluminium body). Copper has high reliability, including resistance to pressure drops, as well as good thermal conductivity; and the use of aluminium allows to reduce the cost and weight of the structure without sacrificing specs.

— Bimetallic. The combination of aluminium with another metal — steel, occasionally copper. The outer shell is made of aluminium in such products, the inner pipes are made of steel. This design allows to achieve of excellent efficiency combined with high strength and reliability; it is bimetallic radiators that are considered the best option for heating systems in apartment buildings, where there is a high probability of water hammers, and the standard operating pressure for such products usually turns out to be quite high.
The main disadvantage of bimetal is a rather significant cost. Thus, so-called pseudo-bimetallic (semi-bimetallic) radiators can be found on the market — only vertical channels connecting the upper and lower pipes are made of steel. It allows you to reduce the price, but it negatively affects reliability — in terms of operational features, such products are closer to aluminium ones (see above).

— Cast iron. A traditional material for heating radiators, which, however, is rare nowadays. It is due both to the large weight and bulkiness of this material and to significant thermal inertia, which does not allow you to quickly adjust the heating intensity. In addition, cast iron is quite brittle and does not tolerate water hammers. On the other hand, this material is resistant to corrosion, and the mentioned inertia in some cases turns out to be an advantage: so, even after turning off the heating, the batteries remain warm for a long time. And some cast iron products have an original appearance that fits perfectly into retro-style interiors.

The type to which the panel radiator belongs (see Radiator type).

The type is indicated by a number that describes the number of heating panels and convectors in this model. Panels occupy the entire height and width of the radiator, and convectors are special zigzag structures between panels that improve heat output. As for the designation itself, the first digit in it corresponds to the number of panels and the second to the number of convectors. For example, the popular type 22 provides 2 panels and 2 convectors between them (the convectors are located inside the radiator, each is attached to its panel), and in the less popular type 21, there is only one convector, respectively, common to both panels. There are options without convectors at all — for example, the simplest type 10, with just one panel. And one of the most advanced today is type 33, more convectors/panels are extremely rare.

In general, more elements (with the same device size in width and height) improves the overall efficiency of the radiator but it comes at the expense of price, depth, and weight.

The number of individual sections provided in the radiator of the corresponding design (see "Type"). We are talking about the delivery set: the whole radiator is assembled from separate sections, and it is not even necessary to use them all.

The number of sections in itself does not affect the performance of the product. However, this information may be useful when assembling a radiator of a certain thermal power (see "Heat output"). So, by dividing the total heat output of this model by the number of sections, you can determine the specs of one section and calculate how many of them are needed to provide the desired heat output. However, a fairly large number of modern radiators are initially sold in one section — just so that the user can assemble the battery at his discretion. For finished products, 2 – 5 sections is considered a rather modest indicator, 6 – 10 pcs — average, 11 – 15 pcs — above average, and models for 16 – 20 sections or more can have both horizontal and vertical layouts (in the latter case, sections placed one on top of the other, like the floors of a tower).

Radiator operating pressure.

This term usually means the highest pressure of the heating medium that the radiator can sustain without consequences for an indefinitely long time. Higher rates are also allowed for a short time (see "Maximum pressure"). However, the standard operating pressure in the heating system should not exceed the specs of the radiator; otherwise, the product is likely to be damaged. In general, it is believed that this indicator should be at least 2 bar higher than the actual working pressure in the system — this will give an additional margin of safety in case of emergencies.

The highest heating medium pressure that the radiator is capable to sustain without consequences during short-term exposure.

This figure is always greater than the operating pressure (see above). It directly shows the resistance of the product to emergencies, primarily the water hammer. Other things being equal, higher maximum pressure means greater strength and reliability — however, such radiators are more expensive.

The volume of water or other heating medium required to fill the radiator.

This information is relevant mainly when building an autonomous heating system: it is useful when calculating the total volume of heating medium in the system and related parameters. If the radiator is purchased for use in centralized heating, you can not pay much attention to its internal volume.

The maximum heating medium temperature allowed for a radiator is the highest temperature the product can withstand without consequences for a sufficiently long time.

The maximum temperature for heating systems (both centralized and autonomous) is +95 °С as standard. Thus, most radiators have an upper temperature limit of +110 ... 120 °C — this allows you to withstand such conditions confidently.