Radiators. Main types

Radiators will not leak if the main criterion when choosing a device for you is how much it is adapted to specific operating conditions, what restrictions on its use are in each specific case.

The main problems that arise during the operation of heating devices are:
– Internal surface corrosion – Chemical and electrochemical corrosion – Water hammer – Gassing in aluminum radiators

All over the world, a two-pipe heating system has been adopted – through one pipeline the coolant is supplied to the devices, through the second it is removed. This is the so-called parallel connection of devices. In Russia, in the overwhelming majority of cases, the heating system is one-pipe, with a series connection of devices. Therefore, in order to ensure the required heat transfer of the devices connected in this way, it is necessary to ensure a large mass flow rate of the coolant per unit of time, which entails an increase in the characteristics, both in pressure and in temperature. Another disadvantage of a one-pipe system is its difficult adjustment, since changing the operating parameters of one device entails changes in the operation of others. The two-pipe system is free from this drawback. The use of a one-pipe system entails the use of heating devices with a large margin of safety and low hydraulic resistance.,

Another important point in the operation of a heating system is the requirement that it must be constantly filled with water. Corrosion processes in a system filled with air are much more intense. The heating system must be started smoothly, with a gradual increase in pressure (switching on the circulation pumps using frequency converters). Failure to comply with this condition when starting the system very often leads to water hammer, which simply destroys the radiator.

The main types of heating devices

1. Panel radiators (convectors) – devices with predominantly convection radiation. In Russia, these are Kermi, Demrad, DeLonghi, Purmo, and at least two dozen other manufacturers of products. High heat transfer per unit volume, affordable prices, good appearance made these devices the most used in the world..

In Russia, these radiators are impeccably good for cottage construction with autonomous boiler rooms, and can be used in multi-storey buildings with autonomous heating points. However, these radiators do not tolerate hydraulic shocks and require a high quality coolant, which practically blocks their way into the existing urban development. Currently, a number of European factories (Kermi, etc.) have begun to produce convectors up to 300 mm high with a water jacket wall thickness of up to 2 mm, which will allow them to be used in our urban heating systems..

2. Steel tubular radiators. Interest in them is determined by the high level of design solutions and the hygiene of the devices. In Russia there are Arbonia, Zehnder, Kermi, KZTO (Russia), Italian-made radiators. Tubular devices have no problems with pressure, but the thickness of the metal does not exceed 1.5 mm, which, unfortunately, does not provide grounds for long-term optimism when used in existing urban development. Tubular radiators “RS”, “Harmony” manufactured by KZTO (Russia) with an internal anti-corrosion polymer coating and the design of the best European radiators have practically no restrictions on their use.

Radiator “Harmony” has a higher heat transfer compared to other tubular radiators due to a large proportion of the convection component (air is heated by the inner surface of the radiator) and is much cheaper than its European prototype WULKAN (Poland-Germany).

3. Cast iron radiators. They are practically immune to the poor quality of the coolant, which determines the rather warm attitude of the domestic consumer towards them. If we take into account the presence on the market of products of the Ferroli, DemirDokum (Ridem) factories with high quality casting and perfect design at a relatively low price, then the interest in them will continue to be high. The design of domestic radiators and their construction have also radically changed over the past 3 years..

But, unfortunately, cast iron radiators, including domestic ones, do not tolerate hydraulic shocks well and this must be taken into account when choosing them. Domestic radiators, unlike imported ones, require mandatory broaching of intersectional joints before installation and additional painting.

4. Aluminum radiators. Beautiful aluminum casting, sectional design, low weight, high heat transfer attract the attention of both specialists and specific consumers. Aluminum radiators are available in two versions:
Die-cast aluminum radiators, where each section is cast as a single piece. Extrusion radiators, where each section consists of three elements mechanically connected to each other. Sealing of joints is carried out either by sealing elements or through an adhesive joint. Moreover, in most cases, the assembly of sections is carried out in the form of blocks of 2, 3 or more sections..

Taking into account the specifics of Russian heating systems, there are models designed for high pressure. The Russian market is dominated by Italian firms such as Fondital, Sira (Alux), Global, IPS.

The main problem in their operation is the need to maintain the pH value (acidity of the coolant) in a very narrow range, which is problematic in the existing urban development, and in individual construction it is also not always feasible. The second problem is gassing in appliances, which can lead to constant airing of the heating system if it is not designed with this factor in mind. The strength parameters of extrusion and cast radiators are comparable. You also need to be careful about the presence of antagonist metals in the heating system..

5. Bimetallic radiators. Despite the “aluminum” appearance, they should still be included in a special group of radiators that have perfectly acclimatized in Russia. The Sira plant (Italy) has been producing these radiators for over 30 years, in Russia the history of their operation is about 15 years. The design of these radiators, protected by the Sira patent, is such that the safety factor exceeds all possible pressures in the system many times, the contact of the coolant with aluminum is practically zero..

It should also be noted the original unit for connecting the sections, which minimizes physical efforts and labor costs during assembly and disassembly with high connection reliability. Sira’s new RS-Bimetal radiator incorporates the latest technology and design developments. New versions of bimetallic radiators (Global, Bimex, Santekhprom) are currently actually being tested in real operation in Russia.

6. Floor convectors. Modern architectural solutions with glass walls leave no room for traditional heating appliances. Therefore, in the last 5-10 years, there has been a sharp increase in both demand and production of embedded devices. Jaga, Mollenhof and KZTO (Russia) are represented in Russia.

They have comparable technical characteristics. The heat exchangers are made of copper tubes with aluminum fins. KZTO devices (Model BREEZE) are also made of steel pipes. The main issue that you need to pay attention to is the compatibility of copper pipelines with the existing heating system. For example, the presence of elements from copper antagonist metals in it can lead to significant problems.

7. Skirting convectors. These are heating devices that are located not only under windows, but mainly along the outer walls, while occupying a small space (no more than 10 cm in depth and 20-25 cm in height).

Their use is typical for heating systems in North America. In Russia, for about 10 years, American devices on copper pipes with aluminum fins have been sold. Since 2002, KZTO has also begun to produce similar devices with both copper and steel pipelines..

8. Convectors on steel pipes with steel fins (UNIVERSAL type). Currently, it is the most used heating device in new buildings in Moscow and other cities. It is attracted primarily by its relatively low price (in the version without a thermostat). But unfortunately, this is also the device that is massively replaced by other types of radiators when tenants move into houses. These devices certainly have a very high survivability, but their not quite modern design and insufficient heat transfer in new-built apartments lead to their massive replacement.