Design heating system includes this important stage, how to calculate heating radiators by area using a calculator or manually. It helps to calculate the number of sections required to heat a particular room. A variety of parameters are taken, ranging from the area of the premises to the insulation characteristics. The correctness of the calculations will depend on:
- uniform heating of rooms;
- comfortable temperature in the bedrooms;
- lack of cold places in the household.
Let's figure out how heating radiators are calculated and what is taken into account in the calculations.
Thermal power of heating radiators
Calculation of heating radiators for a private house begins with the selection of the devices themselves. The assortment for consumers includes cast iron, steel, aluminum and bimetallic models, differing in their thermal power (heat transfer). Some of them heat better, and some worse - here you should focus on the number of sections and the size of the batteries. Let's see what thermal power these or other structures have.
Bimetallic radiators
Sectional bimetallic radiators are made of two components - steel and aluminum. Their internal base is made of durable steel that can withstand high pressure, resistant to water hammer and aggressive coolant. An aluminum “jacket” is applied over the steel core using injection molding. It is she who is responsible for high heat transfer. As a result, we get a kind of sandwich that is resistant to any negative impacts and characterized by decent thermal power.
The heat transfer of bimetallic radiators depends on the interaxial distance and on the specifically selected model. For example, devices from Rifar boast a thermal power of up to 204 W with an interaxial distance of 500 mm. Similar models, but with an interaxial distance of 350 mm, have a thermal power of 136 W. For small radiators with a center distance of 200 mm, the heat transfer is 104 W.
The heat transfer of bimetallic radiators from other manufacturers may differ to a lesser extent (on average 180-190 W with a distance between the axes of 500 mm). For example, the maximum thermal power of Global batteries is 185 W per section with a distance between the axes of 500 mm.
Aluminum radiators
The thermal power of aluminum devices is practically no different from the heat transfer of bimetallic models. On average, it is about 180-190 W per section with a distance between the axes of 500 mm. The maximum figure reaches 210 W, but you need to take into account high cost such models. Let's give more accurate data using Rifar as an example:
- center distance 350 mm – heat transfer 139 W;
- center distance 500 mm – heat transfer 183 W;
- center distance 350 mm (with bottom connection) – heat transfer 153 W.
For products from other manufacturers, this parameter may differ in one direction or another.
Aluminum appliances are intended for use as part of individual heating systems. They are made in a simple but attractive design, are characterized by high heat transfer and operate at pressures up to 12-16 atm. They are not suitable for installation in centralized heating systems due to the lack of resistance to aggressive coolant and water hammer.
Are you designing a heating system for your own home? We recommend purchasing aluminum batteries for this - they will provide high-quality heating at their minimum sizes.
Steel plate radiators
Aluminum and bimetallic radiators have sectional design. Therefore, when using them, it is customary to take into account the heat transfer of one section. In the case of non-separable steel radiators, the heat transfer of the entire device is taken into account when certain sizes. For example, the heat output of a two-row Kermi FTV-22 radiator with a bottom connection 200 mm high and 1100 mm wide is 1010 W. If we take a panel steel radiator Buderus Logatrend VK-Profil 22-500-900, then its heat output will be 1644 W.
When calculating the heating radiators of a private house, it is necessary to record the calculated thermal power for each room. Based on the data obtained, it is purchased necessary equipment. When choosing steel radiators, pay attention to their rows - with the same dimensions, three-row models have greater heat transfer than their single-row counterparts.
Steel radiators, both panel and tubular, can be used in private houses and apartments - they can withstand pressure up to 10-15 atm and are resistant to aggressive coolant.
Cast iron radiators
The heat output of cast iron radiators is 120-150 W, depending on the distance between the axles. For some models this figure reaches 180 W and even more. Cast iron batteries can operate at coolant pressures of up to 10 bar, resisting destructive corrosion well. They are used both in private houses and in apartments (not counting new buildings, where steel and bimetallic models predominate).
When choosing cast iron batteries for heating your own home, you need to take into account the heat transfer of one section - based on this, batteries with a certain number of sections are purchased. For example, for cast iron batteries MS-140-500 with an interaxial distance of 500 mm, the heat transfer is 175 W. The power of models with a center distance of 300 mm is 120 W.
Cast iron is well suited for installation in private homes, offering a long service life, high heat capacity and good heat dissipation. But their disadvantages must also be taken into account:
- heavy weight - 10 sections with a center distance of 500 mm weigh more than 70 kg;
- inconvenience in installation - this disadvantage smoothly follows from the previous one;
- high inertia - contributes to too long warm-up and unnecessary costs for heat generation.
Despite some disadvantages, they are still in demand.
Calculation by area
A simple table for calculating the power of a radiator for heating a room of a certain area.
How is a heating battery calculated per square meter of heated area? First you need to familiarize yourself with the basic parameters taken into account in the calculations, which include:
- thermal power for heating 1 sq. m – 100 W;
- standard ceiling height – 2.7 m;
- one external wall.
Based on such data, the thermal power required to heat a room of 10 square meters. m, is 1000 W. The resulting power is divided by the heat transfer of one section - the result is required amount sections (or select a suitable steel panel or tubular radiator).
For the southernmost and coldest northern regions, additional coefficients are applied, both increasing and decreasing, which will be discussed further.
Simple calculation
Table for calculating the required number of sections depending on the area of the heated room and the power of one section.
Calculating the number of sections of heating batteries using a calculator gives good results. Let's give simplest example for heating a room of 10 square meters. m - if the room is not corner and has double glazed windows, the required thermal power will be 1000 W. If we want to install aluminum batteries with a heat dissipation of 180 W, we will need 6 sections - we simply divide the resulting power by the heat dissipation of one section.
Accordingly, if you buy radiators with a heat output of one section of 200 W, then the number of sections will be 5 pieces. Will the room have high ceilings up to 3.5 m? Then the number of sections will increase to 6 pieces. Does the room have two external walls (corner room)? In this case, you need to add another section.
You also need to take into account the thermal power reserve in case of a too cold winter - it is 10-20% of the calculated one.
You can find out information about the heat transfer of batteries from their passport data. For example, calculating the number of sections aluminum radiators heating is carried out based on the heat transfer of one section. The same applies to bimetallic radiators (and cast iron ones, although they are not removable). When using steel radiators, the rated power of the entire device is taken (we gave examples above).
Very accurate calculation
Above we gave an example of a very simple calculation of the number of heating batteries per area. It does not take into account many factors, such as the quality of wall insulation, type of glazing, minimum outside temperature and many others. Using simplified calculations, we can make mistakes, resulting in some rooms being cold and others too hot. The temperature can be corrected using shut-off valves, but it is best to foresee everything in advance - at least for the sake of saving materials.
If during the construction of your house you paid decent attention to its insulation, then in the future you will save a lot on heating.
How is an accurate calculation of the number of heating radiators in a private house made? We will take into account decreasing and increasing coefficients. First, let's touch on the glazing. If the house has single windows, we use a coefficient of 1.27. For double glazing the coefficient does not apply (in fact it is 1.0). If the house has triple-glazed windows, we apply a reduction factor of 0.85.
Are the walls in the house laid with two bricks or is insulation provided in their construction? Then we apply a coefficient of 1.0. If you provide additional thermal insulation, you can safely use a reduction factor of 0.85 - heating costs will decrease. If there is no thermal insulation, we use an increasing factor of 1.27.
Please note that heating a home with single windows and poor thermal insulation leads to large heat (and monetary) losses.
When calculating the number of heating radiators per area, it is necessary to take into account the ratio of the area of floors and windows. Ideally, this ratio is 30% - in this case we use a coefficient of 1.0. if you love big windows, and the ratio is 40%, a coefficient of 1.1 should be applied, and if the ratio is 50%, the power should be multiplied by a coefficient of 1.2. If the ratio is 10% or 20%, we apply reduction factors of 0.8 or 0.9.
Ceiling height – not less important parameter. We apply the following coefficients here:
Table for calculating the number of sections depending on the area of the room and ceiling height.
- up to 2.7 m – 1.0;
- from 2.7 to 3.5 m – 1.1;
- from 3.5 to 4.5 m – 1.2.
Behind the ceiling is an attic or another living room? And here we apply additional coefficients. If there is a heated attic upstairs (or with insulation), we multiply the power by 0.9, and if there is a living space - by 0.8. Behind the ceiling is ordinary unheated attic? We apply a coefficient of 1.0 (or simply do not take it into account).
After the ceilings, let's start with the walls - here are the coefficients:
- one external wall - 1.1;
- two external walls (corner room) – 1.2;
- three external walls ( last room in an elongated house, hut) – 1.3;
- four external walls (one-room house, outbuilding) – 1.4.
Also taken into account average temperature air in the coldest winter period (the same regional coefficient):
- cold down to –35 °C – 1.5 (a very large reserve that allows you not to freeze);
- frosts down to –25 °C – 1.3 (suitable for Siberia);
- temperature down to –20 °C – 1.1 (central Russia);
- temperature up to –15 °C – 0.9;
- temperature up to –10 °C – 0.7.
The last two coefficients are used in hot southern regions. But even here it is customary to leave a substantial reserve in case of cold weather or especially for heat-loving people.
Having received the final thermal power required to heat the selected room, you should divide it by the heat transfer of one section. As a result, we will receive the required number of sections and can go to the store. Please note that these calculations assume a basic heating power of 100 W per 1 sq. m.
If you are afraid of making a mistake in your calculations, seek help from specialized experts. They will do their best accurate calculations and calculate the thermal power required for heating.
Video
The comfort of living in a house or apartment is closely related to an optimally balanced heating system. Creating such a system is the most important issue that cannot be solved without knowledge of modern, proven heating radiator connection diagrams. Before moving on to solving the problem of connecting heating, it is important to take into account the rules for calculating heating radiators.
Peculiarities
Heating radiators are calculated in accordance with the heat loss of a particular room, as well as depending on the area of this room. It would seem that there is nothing difficult in creating a proven heating circuit with pipe contours and a medium circulating through them, but the correct thermal calculations are based on the requirements of SNiP. Such calculations are performed by specialists, and the procedure itself is considered extremely complex. However, with acceptable simplification, you can perform the procedures yourself. In addition to the area of the heated room, some nuances are taken into account in the calculations.
It is not for nothing that specialists use various techniques to calculate radiators. Their main feature is taking into account the maximum heat loss of the room. Then it is calculated required quantity heating devices that compensate for these losses.
It is clear that the simpler the method used, the more accurate the final results will be. In addition, for non-standard premises, experts use special coefficients.
Non-standard conditions of a particular room include access to a balcony, large windows, and the location of the room, for example, if it is corner. Professional calculations include a number of formulas that are difficult for a non-professional in this area to use.
Specialists often use special devices in their projects. For example, a thermal imager can accurately determine actual heat loss. Based on the data obtained from the device, the number of radiators is calculated that accurately compensate for losses.
This calculation method will show the coldest points of the apartment, the places where heat will be lost most actively. Such points often arise due to construction defects, for example, made by workers, or due to low-quality building materials.
The results of the calculations are closely related to existing species heating radiators. For getting best result Calculations require knowledge of the parameters of the devices planned for use.
The modern range includes the following types of radiators:
- steel;
- cast iron;
- aluminum;
- bimetallic.
To carry out calculations, you need such device parameters as the power and shape of the radiator, and the material of manufacture. The most simple circuit involves placing radiators under each window in the room. Therefore, the calculated number of radiators is usually equal to the number of window openings.
However, before purchasing the necessary equipment, you need to determine its capacity. This parameter is often related to the size of the device, as well as the material used to make the batteries. It is necessary to understand this data in more detail in the calculations.
What does it depend on?
The accuracy of the calculations also depends on how they are made: for the entire apartment or for one room. Experts advise choosing a calculation for one room. The work may take a little longer, but the data obtained will be the most accurate. At the same time, when purchasing equipment, you need to take into account about 20 percent of the reserve. This reserve will be useful if there are interruptions in the operation of the central heating system or if the walls are panel. This measure will also help with an insufficiently efficient heating boiler used in a private home.
The relationship between the heating system and the type of radiator used must be taken into account first. For example, steel devices They come in very elegant shapes, but the models are not particularly popular among buyers. It is believed that main drawback such devices - in poor quality heat exchange. The main advantage is inexpensive price, as well as light weight, which simplifies the work associated with installing the device.
Steel radiators usually have thin walls that heat up quickly, but cool just as quickly. During hydraulic shocks, welded joints steel sheets lets leak. Inexpensive options without special coating they are susceptible to corrosion. Manufacturers' warranties usually have a short period. Therefore, despite the relative cheapness, you will have to spend a lot.
Steel radiators are a one-piece, non-sectional structure. When choosing this option, you should immediately pay attention to the rated power of the products. This parameter must correspond to the characteristics of the room in which the equipment is planned to be installed. Steel radiators with the ability to change the number of sections are usually made to order.
Cast iron radiators are familiar to many because of their ribbed appearance. Such “accordions” were installed both in apartments and in public buildings everywhere. Cast iron batteries are not particularly elegant, but they serve for a long time and with high quality. Some private houses still have them. Positive characteristic of this type radiators is not only quality, but also the ability to supplement the number of sections.
Modern cast iron batteries have been slightly modified appearance. They are more elegant, smooth, and also produce exclusive options with a cast iron pattern.
Modern models have the properties of previous versions:
- retain heat for a long time;
- are not afraid of water hammer and temperature changes;
- do not corrode;
- suitable for all types of coolants.
In addition to their unsightly appearance, cast iron batteries have another significant drawback - fragility. Cast iron batteries are almost impossible to install alone, as they are very massive. Not all wall partitions can withstand the weight of a cast iron battery.
Aluminum radiators have recently appeared on the market. The popularity of this type is due to its low price. Aluminum batteries have excellent heat dissipation. Moreover, these radiators are light in weight and usually do not require a large volume of coolant.
On sale you can find options for aluminum batteries, both sections and solid elements. This makes it possible to calculate the exact number of products in accordance with the required power.
Like any other product, aluminum batteries have disadvantages, such as being susceptible to corrosion. There is a risk of gas formation. The quality of the coolant for aluminum batteries must be very high. If aluminum radiators are of a sectional type, then they often leak at the joints. In this case, it is simply impossible to repair the battery. The highest quality aluminum batteries are made by anodic oxidation of the metal. However, these designs have no external differences.
Bimetallic heating radiators have a special design, due to which they have increased heat transfer, and reliability is comparable to cast iron options. A bimetallic radiator battery consists of sections connected by a vertical channel. The outer aluminum shell of the battery ensures high heat dissipation. Such batteries are not afraid of hydraulic shocks, and any coolant can circulate inside them. The only disadvantage of bimetallic batteries is their high price.
From the variety of products presented, we can conclude that the power of the heating system is calculated not only from the area of the room, but also from the characteristics of the radiators. Let's look at the topic of calculations in more detail.
How to calculate?
The technical parameters of battery radiators made from different materials differ. Experts advise installing cast iron radiators in a private house. It is better to install bimetallic or aluminum batteries in the apartment. The number of batteries is selected based on the square footage of the room. The size of sections is calculated based on possible heat losses.
It is more convenient to take into account heat losses using the example of a private house. Heat will be lost through windows, doorways, ceilings and walls, ventilation systems. For each loss there is a classic coefficient. In professional formulas it is designated by the letter Q.
The calculations include components such as:
- area of a window, door or other structure – S;
- temperature difference inside and outside – DT;
- wall thickness –V;
- thermal conductivity of walls –Y.
The formula is as follows: Q = S*DT /R layer, R = v /Y.
All calculated Q are summed up, and 10-40 percent of losses that may be present due to the presence of ventilation shafts are added to them. The number must be divided by total area home and sum it up with the estimated power of the radiator batteries.
It is also worth considering the heat loss from upper floors with cold attics.
To simplify calculations, experts use a professional table that includes the following columns:
- The name of a room;
- volume in cubic m;
- area in sq. m;
- heat loss in kW.
For example, a room with an area of 20 m2 will correspond to a volume of 7.8. The heat loss of the room will be 0.65. In the calculations, it is worth considering that the orientation of the walls will also matter. Additions for verticals oriented to the north, northeast, northwest will be 10 percent. For walls oriented to the southeast and west - 5 percent. There is no additional factor for the south side. If the room is more than 4 meters high, the additional factor is 2 percent. If the room in question is corner, then the addition will be 5 percent.
In addition to heat loss, other factors must be taken into account. You can select the number of batteries for a room by quadrature. For example, it is known that heating 1 m2 requires at least 100 W. That is, for rooms of 10 m2 you need a radiator with a power of at least 1 kW. This is approximately 8 sections of a standard cast iron battery. The calculation is also relevant for rooms with standard ceilings up to three meters high.
If you need to make a more accurate calculation per square meter, then it is worth taking into account all heat losses. The formula involves multiplying 100 (watt/m2) by the corresponding square meters and by all Q coefficients.
The value found by volume gives the same figures as the formula for calculating by area, SNiP indicators of heat loss in the room panel house with wooden frames 41 W per meter3. A lower figure is needed if modern plastic windows– 34 W per m3.
Heat consumption will be even less if the room has wide walls. The type of wall material is also taken into account in the calculations: brick, foam concrete, as well as the presence of insulation.
To calculate the number of battery sections and estimated power, the following formulas exist:
- N=S*100|P (without heat loss taken into account);
- N=V*41Bt*1.2|P 9 (with heat losses taken into account), where:
- N – number of sections;
- P is the power of a section unit;
- S-area;
- V is the volume of the room;
- 1.2 is the standard coefficient.
The heat transfer of sections of specific types of radiators can be found on the edge of the product. Manufacturers usually indicate indicators as standard.
The average values are as follows:
- aluminum – 170-200 W;
- bimetal – 150 W;
- cast iron - 120 W.
To simplify the task, you can use a special calculator. In order to use the software, you will need all the initial data. The finished result in hand will be faster than with manual calculations.
To simplify calculations, you can make adjustments and round fractional numbers up. It is better to have a reserve of power, and the temperature level will help adjust the thermostat.
If there are several windows in the room, you need to divide the calculated number of sections to install them under each window. Thus, an optimal temperature will be created for cold air penetrating through the double-glazed windows. thermal curtain.
If several walls of one room are outdoors, the number of sections must be added. The same rule applies if the ceiling height is more than three meters.
As an addition, it would not hurt to take into account the features of the heating system. For example, individual or autonomous system usually more effective centralized system, which is present in apartment buildings.
The heat output of radiators will vary depending on the type of connection. The optimal connection is diagonal, with media feeding from above. In this case, the non-thermal output of the radiator will not decrease. At lateral connection the largest ones are usually observed heat losses. All other types of connections have average efficiency.
The actual power of the device will also decrease if there are obstructions. For example, with an overhanging window sill on top of the radiator, heat transfer will drop by 7-8 percent. If the window sill does not cover the entire radiator, then the losses will be approximately 3-5 percent. When installing the screen on the radiator, heat loss will also be observed - approximately 7-8 percent. If the screen is placed over the entire heating device, then the heat transfer from the radiator will decrease by 25 percent.
It is also worth taking into account the temperature of the medium running through the pipes. No matter how efficient radiators are, they will not heat the room with cooled coolant.
The accuracy of the calculations will allow you to collect the maximum comfort system for your home. With the right approach, you can make any room warm enough. A competent approach also entails financial benefits. You will definitely save money without overpaying for unnecessary equipment. You can save even more if you install the equipment correctly.
A single-pipe heating system is particularly complex. Here, each subsequent heating device receives increasingly colder media. To calculate power single pipe system For each radiator separately, you need to recalculate the temperature.
Instead of dealing with complex and lengthy calculations, you can determine the power for both two-pipe system, and then proportionally, depending on the distance of the radiators, add sections. This approach will help increase the heat transfer of batteries in all areas of the house or apartment.
Correctly calculating the required number of sections is, on the one hand, not difficult, but nevertheless a very important task for any homeowner. The comfort of staying in your home will depend on the correctness of the calculation, even in the most very coldy. At the same time, an excessive number of mounted sections will lead to the need for winter period artificially limit the supply of coolant to the heating device or, what is much worse, open the windows and heat the street, which is fraught with additional costs.
Standard method for calculating a heating radiator
The simplest calculation, often recommended by sellers of this equipment, is based on generally accepted standards, according to which about 100 W of heating device power should be required to heat one square meter of room area. This roughly corresponds, according to their estimates, to one battery section per two square meters of room.
This approach is overly simplistic. The choice of the number of radiator sections or its area is influenced by a number of various factors. First of all, you should understand that heating radiators are selected not depending on the area of the room, but depending on its heat loss, which is determined by the presence of one or more windows, doors, location of the room, incl. angular, as well as a number of other factors.
Thermal power of the section is the most important parameter
Besides, Various types heating devices have different thermal outputs. For aluminum radiators it can reach 185-200 W per section, while for cast iron it rarely exceeds 130 W. But in addition to the material of the sections, the thermal power is also greatly influenced by the parameter (DT), which takes into account the temperature of the coolant entering and exiting the battery. Thus, the high thermal power of an aluminum battery, corresponding to 180 W according to the passport, is achieved at DT = 90/70, that is, the temperature of the incoming water should be 90 degrees, the outlet water should be 70 degrees.
However, you need to understand that the operation of almost any boiler under such conditions is very rare. Wall-mounted boilers have a maximum temperature of 85 degrees, and while the coolant reaches the battery, the temperature will drop even more. Therefore, even when purchasing aluminum batteries, one must proceed from the fact that the thermal power of the section will not exceed the value corresponding to DT = 70/55, i.e. approximately 120 W.
What determines the heat loss of a room?
So, the selection of thermal power of heating devices is made based on the amount of heat losses in order to be able to fully compensate for them.
Factors influencing heat loss:
- The location where the room is located. This is either the south, the north, or the central part of the country, for which the values of the minimum annual temperature vary quite significantly.
- How the room is located relative to the cardinal directions. The presence of windows located on both the north and south sides greatly affects the heat loss of the room.
- Ceiling height. If the height of the building differs from the standard 2.5 meters, it is also necessary to make certain adjustments to the calculation.
- Required temperature. Not all rooms need the same temperature. In the living room, for example, temperatures may be slightly lower than in the bedroom, which is also reflected in the calculation of the required power of heating devices.
- The thickness of walls, ceilings, as well as their composition, the presence of thermal insulation, since the thermal conductivity coefficient of different materials can vary greatly. Concrete, for example, has a maximum coefficient, while thermal insulating foam has a minimum.
- Availability window openings, doors and their number. It is clear that the larger the area in the room, the greater the heat loss in it, since it is through these openings that the main heat losses occur.
- Availability of ventilation. This parameter cannot be ignored, even if there is no room in the room. The so-called infiltration is always present - windows open from time to time, visitors enter the room through doors, etc.
Determine the required thermal power
However, it is possible to fully take into account all possible factors that increase or decrease heat losses using only rather complex calculation methods and professional software. In general, such calculations confirm that for a room in which no special work has been carried out aimed at increasing energy efficiency, the figure of 100 W of heating battery power per square meter is correct. This is true for the middle zone. For northern regions, the parameter should be increased to 150 or even 200 W.
However, if during construction or repairs the floors were also renovated, and the window openings have energy-saving double-glazed windows, then even in a harsh winter, the power of heating devices of even 70 W will be quite enough. This question, of course, is not so significant for apartment owners with central heating, but for owners of private houses, reducing the required heating power will help save money throughout the year.
Calculating the number of battery sections
So, let’s carry out a simple calculation of the number of sections of an aluminum battery required for heating small room with an area of 15 square meters and normal ceiling height. Let's take a value of 100 W per 1 sq. m as the required power of heating devices, and the rated power of one battery section is 120 W. Then the required number of sections can be determined by the formula:
N = S*Qп/Qн, where
- N – number of sections,
- S – room area,
- Qп – required thermal power depending on the type of room,
- Qн – rated thermal power of one battery section.
In our case N = 15*100/120 = 12.5
Table: example of the number of radiator sections depending on the area of the room
However, it must be taken into account that the thermal power of modern batteries, be it not only aluminum, but also bimetallic, depending on the design and manufacturer, can vary greatly, ranging from 120 to 200 W. Accordingly, the number of sections will also vary quite a lot.
There are several different ways to determine required power heating devices. Calculation of heating radiators in an apartment can be carried out using complex methods that involve the use of sufficient complex equipment(thermal imagers) and specialized software.
You can also calculate the number of heating radiators yourself, based on the required power of heating devices when calculating per unit area of the room that is heated.
Schematic calculation of power
In the strip temperate climate(so-called middle climatic zone) accepted standards regulate the installation of heating radiators with a power of 60 - 100 W per square meter of room. This calculation is also called calculation by area.
IN northern latitudes(meaning not Far North, and the northern regions, which lie above 60 ° N) power is accepted in the range of 150 - 200 W per square meter.
Power heating boiler will also be determined based on these values.
- The calculation of the power of heating radiators is carried out using exactly this method. This is exactly the power that heating radiators should have. Heat transfer values cast iron batteries are in the range of 125 - 150 W per section. In other words, a room of fifteen square meters can be heated (15 x 100 / 125 = 12) by two six-section cast iron radiators;
- Bimetallic radiators are calculated in a similar way, since their power corresponds to the power (in fact, it is a little more). The manufacturer must indicate these parameters on the original packaging (in extreme cases, these values are given in standard tables for technical specifications);
- Calculation of aluminum heating radiators is carried out in the same way. The temperature of the heating devices themselves is largely related to the temperature of the coolant inside the system and the heat transfer values of each individual radiator. The total price of the device is also related to this.
There are simple algorithms called general term: calculator for calculating heating radiators, which uses the above methods. Do-it-yourself calculations using such algorithms are quite simple.
Additional factors
The above radiator power values are given for standard conditions, which are adjusted using correction factors depending on the presence or absence of additional factors:
- The height of the room is considered standard if it is 2.7 m. For ceiling heights greater or less than this conditional standard value, the power of 100 W/m2 is multiplied by a correction factor, which is determined by dividing the height of the room by the standard (2.7 m).
For example, the coefficient for a room with a height of 3.24 m will be: 3.24 / 2.70 = 1.2, and for a room with ceilings of 2.43 - 0.8.
- The number of two external walls in the room (corner room);
- Number of additional windows in the room;
- Availability of double-chamber energy-saving double-glazed windows.
Important!
Calculation heating radiators using this method it is better to carry out with some margin, since such calculations are quite approximate.
Heat loss calculation
The above calculation of the thermal power of heating radiators does not take into account many determining conditions. To be more accurate, you must first determine the heat loss values of the building. They are calculated based on data about each wall and ceiling of each room, floor, type of windows and their number, door design, plaster material, type of brick or insulation material.
Calculating the heat transfer of radiator heating batteries based on the indicator 1 kW per 10 m2 has significant drawbacks, which are primarily associated with the inaccuracy of these indicators, since they do not take into account the type of building itself (a separate building or apartment), ceiling height, size of windows and doors .
Formula for calculating heat loss:
TP total = V x 0.04 + TP o x n o + TP d x n d, where
- TP total - total heat loss in the room;
- V – volume of the room;
- 0,04 – standard value heat loss for 1 m3;
- TP o – heat loss from one window (assumed value is 0.1 kW);
- n o – number of windows;
- TP d - heat loss from one door (assumed value is 0.2 kW)
- n d — number of doors.
Calculation of steel radiators
Pst = TPtotal/1.5 x k, where
- Rst – power of steel radiators;
- TPtotal – value total heat loss in room;
- 1.5 – coefficient for adjusting the length of the radiator, taking into account operation in the temperature range of 70-50 °C;
- k – safety factor (1.2 – for apartments in multi-storey building, 1.3 – for a private house)
Calculation example for a steel radiator
We proceed from the conditions that the calculation is performed for a room in a private house with an area of 20 square meters with a ceiling height of 3.0 m, in which there are two windows and one door.
The calculation instructions prescribe the following:
- TPtotal = 20 x 3 x 0.04 + 0.1 x 2 + 0.2 x 1 = 2.8 kW;
- Рst = 2.8 kW/1.5 x 1.3 = 2.43 m.
Calculating steel heating radiators using this method leads to the result that the total length of the radiators is 2.43 m. Taking into account the presence of two windows in the room, it would be advisable to select two radiators of a suitable standard length.
Connection diagram and placement of radiators
Heat transfer from radiators depends on where the heating device is located, as well as the type of connection to the main pipeline.
First of all, heating radiators are placed under the windows. Even the use of energy-saving double-glazed windows does not make it possible to avoid the greatest heat loss through light openings. A radiator that is installed under the window heats the air in the room around it.
Heated air rises to the top. In this case, the layer warm air creates a thermal curtain in front of the opening, which prevents the movement of cold layers of air from the window.
In addition, cold air currents from the window, mixing with warm ascending currents from the radiator, enhance general convection throughout the entire volume of the room. This allows the air in the room to warm up faster.
In order for such a thermal curtain to be effectively created, it is necessary to install a radiator whose length is at least 70% of the width of the window opening.
The deviation of the vertical axes of radiators and windows should not be more than 50 mm.
Important!
In corner rooms, additional radiator panels must be placed along the outer walls, closer to the outer corner.
- When piping radiators that use risers, they must be installed in the corners of the room (especially in the outer corners of blank walls);
- When connecting main pipelines from opposite sides, the heat transfer of the devices increases. From a constructive point of view, one-sided connection to pipes is rational.
Important!
Radiators with more than twenty sections should be connected from different sides. This is also true for such a harness, when there is more than one radiator on one coupling.
Heat transfer also depends on how the places for supplying and removing coolant from heating devices are located. The heat flow will be greater when the supply is connected to the upper part and removed from the lower part of the radiator.
If radiators are installed in several tiers, then in this case it is necessary to ensure sequential movement of the coolant downward in the direction of movement.
Video about calculating the power of heating devices:
Approximate calculation of bimetallic radiators
Almost all bimetallic radiators are produced according to standard sizes. Non-standard ones must be ordered separately.
This makes the calculation of bimetallic heating radiators somewhat easier.
- At standard height ceilings (2.5 - 2.7 m) take one section bimetallic radiator based on 1.8 m2 of living room.
For example, for a room of 15 m2, the radiator should have 8 - 9 sections:
- For volumetric calculation of a bimetallic radiator, the value of 200 W of each section for every 5 m3 of room is taken.
For example, for a room of 15 m2 and a height of 2.7 m, the number of sections according to this calculation will be 8:
15 x 2.7/5 = 8.1
Important!
200 watts of standard power was adopted by default as standard. Although in practice there are sections of different power from 120 W to 220 W.
Determining heat loss using a thermal imager
Thermal imagers are now widely used to carefully monitor the thermal characteristics of objects and determine thermal insulation properties designs. Using a thermal imager, a quick inspection of buildings is carried out in order to determine the exact value of heat loss, as well as hidden construction defects and poor quality materials.
The use of these devices makes it possible to determine exact values real heat losses through structural elements. Taking into account the given coefficient of heat transfer resistance, these values are compared with the standards. In the same way, places of moisture condensation and irrational piping of radiators in the heating system are determined.
conclusions
Calculation of the power of a heating radiator should be carried out taking into account many criteria on which the values of heat loss in the room depend.
The principle that is adopted when calculating the power of heating devices is suitable for all types of radiators. When calculating panel radiators, the method of recalculating the sectional coefficient is taken into account.
How to calculate heating radiators so that the temperature in the apartment is extremely comfortable is a question that arises for everyone who has decided to renovate. Too few sections will not fully warm the room, and too many will only entail too much spending on public utilities. So, what do you need to consider to correctly size your batteries?
Preliminary preparation
What needs to be taken into account to calculate the power of a heating radiator per room:
- define temperature regime and potential thermal losses;
- develop optimal technical solutions;
- determine the type of thermal equipment;
- establish financial and thermal criteria;
- take into account reliability and technical specifications heating devices;
- draw up heat distribution diagrams and the location of batteries for each room;
Without the help of specialists and additional programs, it is quite difficult to calculate the number of sections of heating radiators. To make the calculation as accurate as possible, you cannot do without a thermal imager or programs specially installed for this.
What happens if the calculations are done incorrectly? The main consequence is more low temperature in the premises, and therefore the operating conditions will not correspond to the desired ones. Heating appliances that are too powerful will lead to excessive spending on both the appliances themselves and their installation, as well as on utilities.
Do-it-yourself calculations
You can roughly calculate what the battery power should be by using only a tape measure to measure the length and width of the walls and a calculator. But the accuracy of such calculations is extremely low. The error will be 15-20%, but this is quite acceptable.
Calculations depending on the type of heating devices
When choosing a model, keep in mind that the thermal power depends on the material from which they are made. The methods for calculating the sizes of sectional batteries are the same, but the results will be different. There are statistical averages. It is worth focusing on them when choosing the optimal number of heating devices. Power of heating devices with sections of 50 cm:
- aluminum batteries - 190 W;
- bimetallic - 185 W;
- cast iron heating devices - 145 W;
- aluminum - 1.9-2 square meters;
- aluminum and steel - 1.8 sq. m.;
- cast iron - 1.4-1.5 sq. m;
Here is an example of calculating the number of sections of aluminum heating radiators. Let's assume that the size of the room is 16 square meters. It turns out that for a room of this size you need 16m2/2m2 = 8 pcs. Use the same principle for cast iron or bimetallic appliances. It is only important to know exactly the norm - the above parameters are correct for models with a height of 0.5 meters.
At the moment, models are produced from 20 to 60 cm. Accordingly, the area that the section can heat will differ. The lowest-power models are curb ones, 20 cm high. If you decide to purchase a heating unit non-standard sizes, then adjustments will have to be made to the calculation formula. Look for the necessary data in the technical passport.
When making adjustments, it is worth considering that the size of the batteries directly affects the heat transfer. Therefore, than less height with the same width, the smaller area, and with them power. For correct calculations, find the ratio of the heights of the selected model and the standard one, and use the data obtained to correct the result.
Let's say you chose models with a height of 40 cm. In this case, the calculation of the number of sections of aluminum heating radiators per room area will look like this:
- Let's use the previous calculations: 16m2/2m2 = 8 pieces;
- calculate the coefficient 50cm/40cm = 1.25;
- correct the calculations using the basic formula - 8 pcs * 1.25 = 10 pcs.
Calculation of the number of heating radiators by volume begins first of all with the collection necessary information. What parameters need to be taken into account:
- Housing area.
- Ceiling height.
- Number and area of door and window openings.
- Temperature conditions outside the window during the heating season.
The norms and rules established for the power of heating outlets regulate the minimum permissible indicator per square meter. meter of apartment - 100 W. Calculation of heating radiators based on the volume of the room will be more accurate than one in which only the length and width are taken as a basis. The final results are adjusted depending on individual characteristics specific room. This is done by multiplying by the adjustment factor.
When calculating the power of heating devices, the average ceiling height is taken - 3 m. For apartments with a ceiling of 2.5 meters, this coefficient will be 2.5 m / 3 m = 0.83, for apartments with high ceilings 3.85 meters - 3.85m/3m = 1.28. Corner rooms will require additional adjustments. The final data is multiplied by 1.8.
Calculation of the number of heating radiator sections according to the volume of the room should be adjusted if there is one window in the room big size or several windows at once (coefficient 1.8).
The lower connection will also require some adjustments. For this case, the coefficient will be 1.1.
In areas with extreme weather conditions, where winter temperatures reach record lows, power must be doubled.
Plastic double-glazed windows, on the contrary, will require a downward adjustment, using a coefficient of 0.8 as a basis.
The above data shows average values, since they were not additionally taken into account:
- thickness and material of walls and ceilings;
- glazing area;
- flooring material;
- the presence or absence of insulation on the floor;
- curtains and curtains in window openings.
Additional options for more accurate calculations
An accurate calculation of the number of heating radiators per area will not be possible without data from technical documents. This is important to more accurately determine the value of heat loss. It is best to determine the level of heat loss using a thermal imager. The device will quickly identify the coldest areas in the room.
Everything would be much easier if each apartment was built according to a standard layout, but this is far from the case. Each house or city apartment has its own characteristics. Taking into account many characteristics (number of window and doorways, height of walls, area of housing, etc.) the question reasonably arises: how to calculate the number of heating radiators?
The peculiarity of the exact method is that more coefficients are needed for calculations. One of important values, which needs to be calculated is the amount of heat. The formula is different from the previous ones and looks like this: KT = 100 W/m2*P*K1*K2*K3*K4*K5*K6*K7.
More details about each value:
- KT - the amount of heat needed for heating.
- P - room dimensions m2.
- K1 - the value of this coefficient takes into account the quality of window glazing: double - 1.27; plastic windows with double glazing- 1.0; with triple - 0.85.
- K2 - coefficient taking into account the level thermal insulation characteristics walls: low - 1.27; good (for example, two-layer brickwork) - 1.0; high - 0.85.
- K3 - this value takes into account the ratio of the areas of window openings and floors: 50% - 1.2; 40% - 1.1; 30% - 1.0; 20% - 0.9; 10% - 0.8.
- K4 - coefficient depending on the average statistical air temperature in the winter season: - 35 °C - 1.5; — 25 °C - 1.3; — 20 °C - 1.1; — 15 °C - 0.9; -10 °C - 0.7.
- K5 depends on the number external walls buildings, the data for this coefficient are as follows: one - 1.1; two - 1.2; three - 1.3; four - 1.4.
- K6 is calculated based on the type of room located on the floor above: attic - 1.0; heated attic space - 0.9; heated apartment - 0.8.
- K7 is the last of the adjustment values and depends on the ceiling height: 2.5 m - 1.0; 3.0 m - 1.05; 3.5 m - 1.1; 4.0 m - 1.15; 4.5 m - 1.2.
The described calculation of heating radiator sections by area is the most accurate, since it takes into account much more nuances. The number obtained during these calculations is divided by the heat transfer value. The final result is rounded to the nearest whole number.
Adjustment taking into account temperature conditions
The technical data sheet of the heating device indicates maximum power. For example, if the water temperature in the heating pipe is 90°C during supply and 70°C in return mode, the apartment will be +20°C. Such parameters are usually designated as follows: 90/70/20, but the most common powers in modern apartments- 75/65/20 and 55/45/20.
To make a correct calculation, you must first calculate the temperature difference - this is the difference between the temperature of the battery itself and the air in the apartment. Please note that for calculations the average value between the flow and return temperatures is taken.
How to calculate the number of sections of aluminum radiators taking into account the above parameters? For a better understanding of the issue, calculations will be made for aluminum batteries in two modes: high temperature and low temperature (calculation for standard models with a height of 50 cm). The room dimensions are the same - 16 square meters.
One section of an aluminum radiator in 90/70/20 mode heats 2 square meters, therefore, to fully heat the room you will need 16m2/2m2 = 8 pieces. When calculating the battery size for the 55/45/20 mode, you first need to calculate the temperature difference. So, the formulas for both systems:
- 90/70/20 - (90+70)/2-20 = 60°C;
- 55/45/20 - (55+45)/2-20 = 30°C.
Consequently, at low temperatures it is necessary to increase the size of heating devices by 2 times. Taking into account this example on a room of 16 sq. meters you need 16 aluminum sections. Please note that cast iron appliances will require 22 sections for the same room area and the same temperature systems. Such a battery will turn out to be too large and massive, so cast iron is least suitable for low-temperature structures.
Using this formula, you can easily calculate how many radiator sections are needed per room, taking into account the desired temperature regime. To keep your apartment at +25°C in winter, simply change the temperature data in the thermal pressure formula, and substitute the resulting coefficient into the formula for calculating the size of the batteries. Let's say that with parameters 90/70/25 the coefficient will be as follows: (90+70)/2 - 25 = 55°C.
If you don’t want to waste time calculating heating radiators, you can use online calculators or special programs installed on your computer.
How to use an online calculator
Calculate how many sections of heating radiators per square meter. You will need a meter, you can use special calculators that will calculate everything in the blink of an eye. Such programs can be found on the official websites of some manufacturers. These calculators are easy to use. Just enter all the relevant data into the fields and you will instantly receive the exact result. To calculate how many sections of heating radiators are needed per square meter, you need to enter data (power, temperature, etc.) for each room separately. If the rooms are not separated by doors, add up their overall dimensions, and the heat will spread throughout both rooms.