Heating power table

If the type of heater is chosen correctly, its subsequent use will not cause any significant difficulties. Let's consider what parameters of radiators really are significant and that it is necessary to make independently independently to make equipment of a premise with the chosen equipment.

General parameters of modern heating devices

First, we define the products that will be included in the list for comparative analysis:

• Steel radiators  in the form of sets of plates today are rarely used. They do not suit modern consumers for aesthetic and technical parameters. Therefore we will not study them in this article.
• Cast-Iron Tools, despite the considerable age of such a design solution, are highly valued by consumers for their reliability and durability. Some new models of such products are created using elements of artistic casting technology. They should not be hidden behind special decorative screens, as they can be real decorations of different in style interiors.
• Aluminum radiators  - the most common type of equipment for heating. They must be studied necessarily.
• Bimetallic devices  appeared on the market relatively recently, but their popularity is gradually growing. They are harmoniously used beneficial features  two different materials.

The following table contains the main parameters for the selected types of radiators. They are united by the fact that they all consist of separate parts. This feature allows you to create a radiator whose power will exactly meet the user's requirements.

The following data are grouped for products with different distances between the axes of the sections (350 and 500 mm). This is done so that the comparison is objective.

What criteria should be considered when choosing

If we use the data given above, we can conclude that the radiators made of two metals are the most effective. In them, the power of the unit section is the largest. The internal frame, the set of pipes is made of strong steel. The outer shell is made of light, well conductive aluminum heat. These products are really good. They can be used, as in urban high-rise buildings, and in private cottages. But it should be borne in mind that the complication of the design makes it necessary to choose carefully a manufacturer capable of providing impeccable quality. Such products from a well-known brand will cost more. The corrosion resistance of such devices is determined by experts, as not high. That is why it is recommended not to remove the coolant from them for a long time.

Aluminum sections  only slightly inferior to bimetallic analogs. They are cheaper. Their light weight facilitates transportation, installation, performance of other operations. The main disadvantages are:

• low resistance to acidic solutions;
• the occurrence of electrochemical destructive corrosion upon contact with other metals;
• relatively rapid formation of gases inside and the need for regular removal of air from the system.

Cast iron radiators  less sensitive to the quality of the coolant, its contamination with mechanical impurities. They can be combined with any pipes of the heating system without restrictions. Limitations for use are the following:

• high inertia;
• large weight;
• low resistance to hydraulic shocks;
• comparatively large volume.

When all the individual features are taken into account, it is necessary to correctly calculate the number of sections that is necessary for heating a certain room. To do this, you can use the calculation in which for 1 cu. m. of living space will be enough 40 watts of thermal power  (for the southern side of buildings it is possible to reduce this value by 4-6 W).

This parameter will be accurate if the insulation of walls, floor and ceiling meets modern requirements. Of course, it will be necessary to eliminate cracks and other defects in window and door blocks. In the kitchen and other rooms, where frequent ventilation is supposed to be done, a small number of sections should be made (increase power by 15-20%).

For a more accurate calculation, special correction factors must be taken into account, which lead heating radiator manufacturers in the technical documentation. The fact is that the above figures are valid for the case when the heat carrier in the supply line has a temperature of + 105 ° C, and in the "return" - exactly + 70 ° C. Such values ​​in the presence of an individual gas boiler are not used. Moreover, the ambient temperature should be taken into account.

The actual heat transfer of aluminum and bimetallic radiators (section capacity) can differ by tens of percent depending on the specific operating conditions. That is why, even when calculating the heating system with correction factors, practitioners are advised to increase the value obtained by 10-15%.

It is not difficult to draw a general conclusion that for the right choice  in each case, take into account the existing features of the property, the corresponding engineering system. For example, the high inertia of a cast iron product can be useful. When disconnected, it will retain heat much longer than other batteries. But such a product has too much weight. It will be difficult to mount it on walls made of gas silicate blocks, in frame buildings.

The power of the section is an important but not a defining parameter. For an accurate determination with the purchase of a radiator, it is necessary to carefully study all the factors mentioned above.

Speaking about the efficiency of the heating system, most often mean the main indicator - the heat transfer of the radiators. It is this characteristic that largely determines the microclimate in the house throughout the entire heating season. Heat transfer indicators vary depending on the model, the owner of the building should correctly calculate the problem and select a heating device. The figures in the technical documentation are the radiator's potential, but many factors affect the heat transfer, most of all the connection and flow of the coolant along the contour. How to determine the heat dissipation of radiators and increase it if necessary?

Heat transfer indicators are individual for each model

What is the heat transfer characteristic and how is it measured

This indicator is also called power and is indicated in the technical documentation, which is additionally completed by all radiator models. The unit for measuring the power of the heating devices is Watt, but sometimes the characteristic is indicated in calories / hour. To understand how much this is in Watts, use the formula: 1 W = 859.8 cal / h.

Heating devices  can transmit heat energy in three ways:

• radiation (radiation);
• convection;
• heat transfer (thermal conductivity).

All kinds of heaters transmit energy in all these ways, but in different ratios, so there is a difference in names. Radiators should be called exclusively those devices that emit at least 25% of the heat, and convectors - transmitting heat predominantly convective methods. But in many respects the connection between the names of instruments and the method of transferring thermal energy has already been lost. Now radiators are often called devices that transmit heat more by convection than by radiation.

Ways of transfer of thermal energy - a schematic image

How do the characteristics of heaters differ from different materials

When choosing radiators, you should carefully read the technical documentation. The shape or size of the device is not an objective indicator by which it is possible to calculate the power "by eye". Externally, the same instruments can differ significantly in performance. In many respects it depends on the material of manufacture.

• Cast iron

The material is characterized by low thermal conductivity. Heaters from cast iron transmit heat predominantly by radiation. Convective transmission is carried out only by 20%. The power of the cast iron radiator is about 180 W / section, but you can not rely on this figure, because it is indicated for ideal conditions. In reality, it can be 3-4 times less.

• Steel

More often steel radiators  are panel structures to which ribs can be additionally welded, which enhance convective heat transfer. The power of the steel radiators is not higher than that of the cast iron ones, but they are much easier to erect and look attractive, so many owners of houses and apartments prefer them.

• Aluminum

Heating devices from this metal are rightfully considered to be one of the most powerful. The technical documentation indicates a power rating of 200 W / section, but the actual characteristics may also differ significantly from those stated. Aluminum radiators have a limited scope: they can not be installed in systems with a poor quality of the coolant.

• Bimetal

These are two different metals, most often steel and aluminum, from which the most powerful radiators are made, because designers use the advantages of both materials to the maximum. The heat transfer coefficient of the section is 204 W. The advantage of bimetallic models is the resistance to the action of a chemically active coolant. As a rule, these are beautiful and efficient models, but their cost is higher than aluminum, steel or cast iron.

Structural features  and advantages of bimetallic models

How to calculate the necessary heat dissipation of radiators

The calculation is done for each room separately. It can be approximate, by area and by volume of the room. Usually in approximate calculations proceed from the fact that for high-quality heating 10 sq.m. 1 kW of heat is needed. But these figures do not reflect the real state of things, because in calculations it is impossible to take into account heat loss. For their compensation, usually an additional 30% is added to the obtained number. Since this figure can not be fully considered correct, other methods are often used.

For rooms with standard ceilings, this calculation is suitable: 100 watts of power per 1 sq. M. This figure is usually added to 20% of the "stock". If the ceiling in the room is above 2.7 m, its height should also be included in the calculations. In this case, the formula will look like this: the room volume should be multiplied by 41 W. Calculate the volume in a standard way - multiply the length of the room by the width and height of the ceiling. Fractional numbers round up.

Heat transfer table of radiators

If the necessary heat dissipation is calculated correctly, the room will always be warm and cozy. If necessary, you can increase the efficiency of the radiators. To do this, the heating devices are regularly cleaned from dust and dirt, properly dyed, washed inside cavities, the wall behind them are mounted heat-reflecting screens. All this allows you to maximize the potential of radiators and achieve a comfortable temperature in the house.

Video: calculation of heat dissipation of radiators

The creation of a comfortable temperature in the housing during the heating season depends on many factors: the type of wall, the height of the room, the area of ​​window openings, the nature of the space and much more. Of great importance is the thermal calculation of installed instruments. Traditional methods of calculation require consideration of the above factors, it is rather laborious. To simplify the selection of the type of equipment, a table of radiators is used.

Characteristics of radiators

The efficiency of the batteries depends on the following factors:

• temperature of coolant supply;
• thermal conductivity of the material;
• the surface area of ​​the battery;

The higher these figures, the greater the thermal power of the instruments.

As a unit of measurement of heat transfer of the radiator, it is customary to consider W / m * K, on ​​a par with that in the passport the format cal / h is often indicated. The conversion factor from one unit of measure to another: 1 W / m * K = 859.8 cal / h.

Depending on the materials of manufacture distinguish cast iron, steel, aluminum and bimetallic radiators. Each material has indicators for the following parameters:

• heat transfer of one section;
• working pressure;
• pressure of crimping;
• capacity of one section;
• mass of one section.

Advice! Do not forget about the susceptibility of the material for making batteries to corrosion. This is an important characteristic when buying a heater.

Cast iron batteries

This kind of radiators, which in the people called "harmonies". They have a fairly high efficiency, resistance to corrosion, shock. These batteries are durable enough and have an affordable market price. Due to the large cross-sectional dimensions of one section, clogging for such batteries is not a threat.

The heat transfer of the section of the cast iron radiator is lower than that of the analogs. An hour after the heating is turned off, the cast-iron batteries retain 30% of the heat. Modern manufacturers produce aesthetic cast iron batteries with a smooth surface and elegant shapes, so the demand for them remains high. Comparison cast-iron radiators  heating with other types of devices is given in the table below.

Heat power table of radiators

Aluminum batteries

Heat dissipation of aluminum radiators, as can be seen from the table, is better than cast-iron batteries, but worse than bimetallic ones. They are strong enough, and light weight of their own makes it easier to install instruments. Due to vulnerability to oxygen corrosion, anodizing of aluminum has recently begun.

Bimetal batteries

This type of radiator is a combination of elements made of steel and aluminum. The channel for the movement of the coolant is the pipe, and the connecting parts are threaded connections. As a protection and giving aesthetic appearance, these batteries are covered with a casing of aluminum. The disadvantage of the product is a relatively high cost in comparison with analogues. But this is compensated by the fact that the heat transfer from bimetal radiators is the highest.

Bimetal radiators

Steel batteries

Old steel radiators have a sufficiently high thermal capacity, but they do not keep heat well. They can not be dismantled or build up the number of sections. Radiators of this type are susceptible to corrosion.

At the present time, panel radiators  Steel, which are attractive high heat output at small sizes compared to sectional radiators. The panels have channels through which the coolant circulates. The battery can consist of several panels, in addition, it is equipped with corrugated plates that increase heat transfer.

The thermal power of the steel panels is directly related to the dimensions of the battery, depending on the number of panels and plates (fins). The classification is carried out depending on the fins fins. For example, type 33 is assigned to three-panel heaters with three plates. The range of battery types is from 33 to 10.

The independent calculation of the required heating radiators is associated with a large amount of routine work, so manufacturers began to accompany the products with tables of characteristics that are formed by the records of the test results. These data depend on the product type, installation height, coolant temperature at the inlet and outlet, the standard room temperature and many other characteristics.

Calculation of appliances for room heat loss

The thermal parameters of the installed devices are determined from the calculation of the heat loss by the room. The normative value of the heat required per unit volume of the heated room, for which 1 m 3 is taken, is:

• for brick buildings - 34 W;
• for large-panel buildings - 41 W.