Most often, owners purchase bimetallic radiators for replacement. cast iron batteries, which for one reason or another failed or began to heat the room poorly. In order for this model of radiators to cope well with its task, you need to familiarize yourself with the rules for calculating the number of sections for the entire room.
Necessary data for calculation
Himself the right decision will turn to experienced specialists. Professionals can calculate the amount bimetallic radiators heating is quite accurate and efficient. This calculation will help determine how many sections will be needed not only for one room, but for the entire room, as well as for any type of object.
All professionals take into account the following data to calculate the number of batteries:
- what material was the building made of;
- what is the thickness of the walls in the rooms;
- the type of windows that were installed in this room;
- in what climatic conditions is the building located?
- is there any heating in the room above the room where the radiators are installed;
- how many “cold” walls are there in the room;
- what is the area of the calculated room;
- what is the height of the walls?
All this data allows us to make the most accurate calculation for installing bimetallic batteries.
Heat loss coefficient
To make the calculation correctly, you must first calculate what will be heat losses, and then calculate their coefficient. For accurate data, one unknown must be taken into account, that is, the walls. This applies primarily to corner rooms. For example, the room contains following parameters: height – two and a half meters, width – three meters, length – six meters.
- F is the area of the wall;
- a – its length;
- x – its height.
The calculation is carried out in meters. According to these calculations, the wall area will be equal to seven and a half square meters. After this, it is necessary to calculate heat loss using the formula P = F*K.
Also multiply by the difference in temperature indoors and outdoors, where:
- P is the area of heat loss;
- F is the area of the wall in square meters;
- K is the thermal conductivity coefficient.
For correct calculation temperature must be taken into account. If the temperature outside is approximately twenty-one degrees, and the room is eighteen degrees, then to calculate this room you need to add two more degrees. To the resulting figure you need to add P windows and P doors. The result obtained must be divided by a number indicating thermal power one section. As a result simple calculations and you will be able to find out how many batteries are needed to heat one room.
However, all these calculations are correct only for rooms that have average insulation rates. As you know, there are no identical rooms, so for an accurate calculation it is necessary to take into account the correction factors. They need to be multiplied by the result obtained using the formula. The correction coefficient for corner rooms is 1.3, for rooms located in very cold places - 1.6, for attics - 1.5.
Battery power
To determine the power of one radiator, it is necessary to calculate how many kilowatts of heat will be needed from installed system heating. The power needed to heat each square meter is 100 watts. The resulting number is multiplied by the number of square meters of the room. The figure is then divided by the power of each individual section of a modern radiator. Some battery models consist of two or more sections. When making calculations, you need to choose a radiator that has a number of sections close to ideal. But still, it should be a little more than calculated.
This is done in order to make the room warmer and not freeze on cold days.
Manufacturers of bimetallic radiators indicate their power for certain heating system data. Therefore, when buying any model, it is necessary to take into account the thermal pressure, which characterizes how the coolant is heated, as well as how it heats the heating system. Technical documentation often indicates the power of one section for a heat pressure of sixty degrees. This corresponds to a water temperature in the radiator of ninety degrees. In those houses where the rooms are heated with cast iron radiators, this is justified, but for new buildings, where everything is more modern, the temperature of the water in the radiator may well be lower. The heat pressure in such heating systems can be up to fifty degrees.
The calculation here is also not difficult. You need to divide the power of the radiator by the number indicating the thermal pressure. The number is divided by the figure indicated in the documents. In this case, the effective power of the batteries will become slightly less.
It is precisely this that must be included in all formulas.
Popular methods
For deduction required quantity sections in the installed radiator, not one formula, but several can be used. Therefore, it is worth evaluating all the options and choosing the one that is suitable for obtaining more accurate data. To do this, you need to know that according to SNiP standards, per 1 m², one bimetallic section can heat one meter and eighty centimeters of area. To calculate how many sections are needed for 16 m², you need to divide this figure by 1.8 square meters. The result is nine sections. However, this method is quite primitive and for a more accurate determination it is necessary to take into account all the above data.
There is another simple method for doing the calculation yourself. For example, if we take small room 12 m², then very strong batteries are of no use here. You can take, for example, the heat transfer of just one section is two hundred watts. Then using the formula you can easily calculate the number required for the selected room. To get the desired figure, you need 12 - this is the number of squares, multiply by 100, power per square meter and divide by 200 watts. This, as you can understand, is the heat transfer value per section. As a result of the calculations, the number six will be obtained, that is, exactly how many sections will be needed to heat a room of twelve squares.
You can consider another option for an apartment with an area of 20 m². Let’s assume that the power of the section of the purchased radiator is one hundred and eighty watts. Then, substituting all the available values into the formula, you get the following result: 20 needs to be multiplied by 100 and divided by 180 will equal 11, which means that this number of sections will be needed to heat a given room. However, such results will really correspond to those rooms where the ceilings are no higher than three meters and the climatic conditions are not very harsh. And also the windows, that is, their number, were not taken into account, so it is necessary to add several more sections to the final result, their number will depend on the number of windows. That is, you can install two radiators in a room, each with six sections. In this calculation, another section was added taking into account windows and doors.
By volume
To make the calculation more accurate, you need to calculate by volume, that is, take into account three measurements in the selected heated room. All calculations are made almost identically, only the basis is the power data calculated per cubic meter, which is equal to forty-one watts. You can try to calculate the number of sections of a bimetallic battery for a room with the same area as in the option discussed above, and compare the results. In this case, the ceiling height will be two meters and seventy centimeters, and the square footage of the room will be twelve square meters. Then you need to multiply three by four, and then by two and seven.
The result will be this: thirty-two and four cubic meters. It must be multiplied by forty-one and you get one thousand three hundred twenty-eight and four watts. This radiator power will be ideal for heating this room. Then this result must be divided by two hundred, that is, the number of watts. The result will be equal to six point sixty-four hundredths, which means you will need a radiator with seven sections. As you can see, the result of the volume calculation is much more accurate. As a result, you won’t even need to take into account the number of windows and doors.
You can also compare the calculation results in a room with twenty square meters. To do this, you need to multiply twenty by two and seven, you get fifty-four cubic meters - this is the volume of the room. Next, you need to multiply by forty-one and the result is two thousand four hundred and fourteen watts. If the battery has a power of two hundred watts, then this figure must be divided by the result obtained. The result will be twelve and seven, which means that for this room the same number of sections is required as in the previous calculation, but this option is much more accurate.
There are several methods for calculating the number of radiators, but their essence is the same: find out the maximum heat loss of the room, and then calculate the number of heating devices required to compensate for them.
There are different calculation methods. The simplest ones give approximate results. However, they can be used if the premises are standard, or coefficients can be applied that allow one to take into account the existing “non-standard” conditions of each specific room (corner room, access to a balcony, wall-to-wall window, etc.). There is a more complex calculation using formulas. But essentially these are the same coefficients, only collected in one formula.
There is another method. It determines the actual losses. A special device - a thermal imager - determines real heat loss. And based on this data, they calculate how many radiators are needed to compensate for them. Another good thing about this method is that the thermal imager image shows exactly where the heat is lost most actively. This could be a marriage at work or building materials, crack, etc. So at the same time we can improve the situation.
Calculation of heating radiators by area
The easiest way. Calculate the amount of heat required for heating, based on the area of the room in which the radiators will be installed. You know the area of each room, and the heat requirement can be determined according to SNiP building codes:
- for the average climate zone, 60-100 W are required for heating 1 m 2 of living space;
- for areas above 60 o, 150-200 W are required.
Based on these standards, you can calculate how much heat your room will require. If the apartment/house is located in the middle climate zone, heating an area of 16 m 2 will require 1600 W of heat (16*100=1600). Since the standards are average, and the weather is not constant, we believe that 100W is required. Although, if you live in the south of the middle climate zone and your winters are mild, count 60W.
A power reserve in heating is needed, but not very large: with an increase in the amount of power required, the number of radiators increases. And the more radiators, the more coolant in the system. If for those connected to central heating this is not critical, then for those who have or are planning individual heating, a large volume of the system means large (extra) costs for heating the coolant and greater inertia of the system (the set temperature is maintained less accurately). And a logical question arises: “Why pay more?”
Having calculated the room's heat requirement, we can find out how many sections are required. Each heating device can produce a certain amount of heat, which is indicated in the passport. Take the found heat requirement and divide it by the radiator power. The result is the required number of sections to make up for losses.
Let's count the number of radiators for the same room. We determined that 1600W needed to be allocated. Let the power of one section be 170W. It turns out 1600/170 = 9.411 pieces. You can round up or down at your discretion. You can turn it into a smaller one, for example, in the kitchen - there are plenty of additional heat sources there, and a larger one - better in a room with a balcony, a large window or in a corner room.
The system is simple, but the disadvantages are obvious: ceiling heights can be different, wall material, windows, insulation and a number of other factors are not taken into account. So the calculation of the number of sections of heating radiators according to SNiP is approximate. For an accurate result, you need to make adjustments.
How to calculate radiator sections by room volume
This calculation takes into account not only the area, but also the height of the ceilings, because all the air in the room needs to be heated. So this approach is justified. And in this case the technique is similar. We determine the volume of the room, and then, according to the standards, we find out how much heat is needed to heat it:
Let's calculate everything for the same room with an area of 16m2 and compare the results. Let the ceiling height be 2.7m. Volume: 16*2.7=43.2m3.
- IN panel house. The heat required for heating is 43.2m 3 *41V=1771.2W. If we take all the same sections with a power of 170 W, we get: 1771 W/170 W = 10,418 pcs (11 pcs).
- IN brick house. The heat needed is 43.2m 3 *34W=1468.8W. We count the radiators: 1468.8W/170W=8.64pcs (9pcs).
As you can see, the difference is quite large: 11 pieces and 9 pieces. Moreover, when calculating by area, we got the average value (if rounded in the same direction) - 10 pcs.
Adjusting results
In order to obtain a more accurate calculation, you need to take into account as many factors as possible that reduce or increase heat loss. This is what the walls are made of and how well they are insulated, how big windows, and what kind of glazing they have, how many walls in the room face the street, etc. To do this, there are coefficients by which you need to multiply the found values of heat loss in the room.
Window
Windows account for 15% to 35% of heat loss. The specific figure depends on the size of the window and how well it is insulated. Therefore, there are two corresponding coefficients:
- ratio of window area to floor area:
- 10% — 0,8
- 20% — 0,9
- 30% — 1,0
- 40% — 1,1
- 50% — 1,2
- glazing:
- three-chamber double-glazed window or argon in a two-chamber double-glazed window - 0.85
- ordinary double-glazed window - 1.0
- regular double frames - 1.27.
Walls and roof
To account for losses, the material of the walls, the degree of thermal insulation, and the number of walls facing the street are important. Here are the coefficients for these factors.
Thermal insulation degree:
- brick walls two bricks thick are considered the norm - 1.0
- insufficient (absent) - 1.27
- good - 0.8
Availability of external walls:
- interior space - no losses, coefficient 1.0
- one - 1.1
- two - 1.2
- three - 1.3
The amount of heat loss is influenced by whether the room is located on top or not. If there is a habitable heated room on top (the second floor of a house, another apartment, etc.), the reduction factor is 0.7, if there is a heated attic - 0.9. It is generally accepted that unheated attic does not affect the temperature in any way (coefficient 1.0).
If the calculation was carried out by area, and the ceiling height is non-standard (a height of 2.7 m is taken as the standard), then a proportional increase/decrease using a coefficient is used. It is considered easy. To do this, divide the actual ceiling height in the room by the standard 2.7 m. You get the required coefficient.
Let's do the math for example: let the ceiling height be 3.0m. We get: 3.0m/2.7m=1.1. This means that the number of radiator sections that was calculated by area for a given room must be multiplied by 1.1.
All these norms and coefficients were determined for apartments. To take into account the heat loss of a house through the roof and basement/foundation, you need to increase the result by 50%, that is, the coefficient for a private house is 1.5.
Climatic factors
Adjustments can be made depending on average winter temperatures:
- -10 o C and above - 0.7
- -15 o C - 0.9
- -20 o C - 1.1
- -25 o C - 1.3
- -30 o C - 1.5
Having made all the required adjustments, you will get more exact amount radiators required to heat the room, taking into account the parameters of the premises. But these are not all the criteria that influence the power of thermal radiation. Is there some more technical details, which we will discuss below.
Calculation of different types of radiators
If you are planning to install sectional radiators of a standard size (with an axial distance of 50 cm in height) and have already chosen the material, model and right size, there should not be any difficulties in calculating their quantity. Most reputable companies that supply good heating equipment have on their website the technical data of all modifications, including thermal power. If it is not the power that is indicated, but the coolant flow rate, then it is easy to convert to power: the coolant flow rate of 1 l/min is approximately equal to the power of 1 kW (1000 W).
The axial distance of the radiator is determined by the height between the centers of the holes for supplying/removing coolant.
To make life easier for customers, many websites install a specially designed calculator program. Then the calculation of heating radiator sections comes down to entering data on your premises in the appropriate fields. And at the output you have the finished result: the number of sections of this model in pieces.
But if you're just guessing possible options, then it is worth considering that the radiators are the same size from different materials have different thermal power. The method for calculating the number of sections of bimetallic radiators is no different from calculating aluminum, steel or cast iron. Only the thermal power of one section can be different.
- aluminum - 190W
- bimetallic - 185W
- cast iron - 145W.
If you are just figuring out which material to choose, you can use this data. For clarity, we present the simplest calculation of sections of bimetallic heating radiators, which takes into account only the area of the room.
When determining the number of heating devices made of bimetal of a standard size (center distance 50 cm), it is assumed that one section can heat 1.8 m 2 of area. Then for a room of 16 m 2 you need: 16 m 2 /1.8 m 2 = 8.88 pcs. Let's round up - we need 9 sections.
We calculate similarly for cast iron or steel bars. All you need is the following rules:
- bimetallic radiator - 1.8m2
- aluminum - 1.9-2.0 m 2
- cast iron - 1.4-1.5 m 2.
This data is for sections with an interaxial distance of 50 cm. Today there are models on sale with the most different heights: from 60cm to 20cm and even lower. Models 20cm and below are called curb. Naturally, their power differs from the specified standard, and if you plan to use a “non-standard”, you will have to make adjustments. Either look for passport data, or do the math yourself. We assume that heat transfer thermal device directly depends on its area. As the height decreases, the area of the device decreases, and, therefore, the power decreases proportionally. That is, you need to find the ratio of the heights of the selected radiator with the standard, and then use this coefficient to correct the result.
For clarity, we will calculate aluminum radiators by area. The room is the same: 16m2. We count the number of sections of standard size: 16m 2 /2m 2 = 8 pcs. But we want to use small sections with a height of 40 cm. We find the ratio of radiators of the selected size to standard ones: 50cm/40cm=1.25. And now we adjust the quantity: 8pcs * 1.25 = 10pcs.
Adjustment depending on heating system mode
Manufacturers indicate in their passport data maximum power radiators: in high-temperature mode of use - the coolant temperature in the supply is 90 o C, in the return - 70 o C (indicated by 90/70) in the room there should be 20 o C. But in this mode modern systems The heating works very rarely. Typically, a medium power mode of 75/65/20 or even a low temperature mode with parameters of 55/45/20 is used. It is clear that the calculation needs to be adjusted.
To take into account the operating mode of the system, it is necessary to determine the temperature pressure of the system. Temperature pressure is the difference between the temperature of the air and the heating devices. In this case, the temperature of the heating devices is considered as the arithmetic average between the supply and return values.
To make it clearer, let’s make a calculation cast iron radiators heating for two modes: high temperature and low temperature, sections of standard size (50cm). The room is the same: 16m2. One cast iron section in high temperature mode 90/70/20 heats 1.5 m 2. Therefore, we need 16m 2 / 1.5 m 2 = 10.6 pcs. Round up - 11 pcs. The system plans to use a low temperature mode of 55/45/20. Now let’s find the temperature difference for each of the systems:
- high temperature 90/70/20- (90+70)/2-20=60 o C;
- low temperature 55/45/20 - (55+45)/2-20=30 o C.
That is, if a low-temperature operating mode is used, twice as many sections will be needed to provide the room with heat. For our example, a room of 16 m2 requires 22 sections of cast iron radiators. The battery turns out to be big. This, by the way, is one of the reasons why this type of heating device is not recommended for use in networks with low temperatures.
With this calculation, you can also take into account the desired air temperature. If you want the room to be not 20 o C, but, for example, 25 o C, simply calculate the thermal pressure for this case and find the desired coefficient. Let's do the calculation for the same cast iron radiators: the parameters will be 90/70/25. We calculate the temperature difference for this case (90+70)/2-25=55 o C. Now we find the ratio 60 o C/55 o C=1.1. To ensure a temperature of 25 o C you need 11 pcs * 1.1 = 12.1 pcs.
Dependence of radiator power on connection and location
In addition to all the parameters described above, the heat transfer of the radiator varies depending on the type of connection. Considered optimal diagonal connection with supply from above, in this case there is no loss of thermal power. The greatest losses are observed when lateral connection- 22%. All others are average in efficiency. Approximate percentage losses are shown in the figure.
The actual power of the radiator also decreases in the presence of obstructing elements. For example, if a window sill hangs from above, the heat transfer drops by 7-8%; if it does not completely block the radiator, then the loss is 3-5%. When installing a mesh screen that does not reach the floor, the losses are approximately the same as in the case of an overhanging window sill: 7-8%. But if the screen completely covers the entire heating device, its heat transfer is reduced by 20-25%.
Determining the number of radiators for single-pipe systems
There is another very important point: all of the above is true for when a coolant with the same temperature enters the input of each radiator. It is considered much more complicated: there, increasingly colder water flows to each subsequent heating device. And if you want to calculate the number of radiators for a one-pipe system, you need to recalculate the temperature every time, and this is difficult and time-consuming. Which exit? One of the possibilities is to determine the power of the radiators as for a two-pipe system, and then, in proportion to the drop in thermal power, add sections to increase the heat transfer of the battery as a whole.
Let's explain with an example. The diagram shows a single-pipe heating system with six radiators. The number of batteries was determined for two-pipe wiring. Now we need to make an adjustment. For the first heating device everything remains the same. The second one receives coolant with a lower temperature. We determine the % drop in power and increase the number of sections by the corresponding value. In the picture it turns out like this: 15kW-3kW=12kW. We find the percentage: the temperature drop is 20%. Accordingly, to compensate, we increase the number of radiators: if 8 pieces were needed, there will be 20% more - 9 or 10 pieces. This is where knowing the room will come in handy: if it’s a bedroom or a children’s room, round up, if it’s a living room or other similar room, round down. You also take into account the location relative to the cardinal directions: in the north you round up, in the south you round down.
This method is clearly not ideal: after all, it turns out that the last battery in the branch will have to be simply enormous in size: judging by the diagram, a coolant with a specific heat capacity equal to its power is supplied to its input, and in practice it is unrealistic to remove all 100%. Therefore, usually when determining the power of a boiler for single-pipe systems, they take a certain reserve, install shut-off valves and connect radiators through a bypass so that the heat transfer can be adjusted and thus compensate for the drop in coolant temperature. One thing follows from all this: the number and/or sizes of radiators in single pipe system you need to increase it, and as you move away from the beginning of the branch, install more and more sections.
Results
An approximate calculation of the number of sections of heating radiators is simple and quick. But clarification depending on all the features of the premises, size, type of connection and location requires attention and time. But you can definitely decide on the number of heating devices to create comfortable atmosphere in winter.
If you decide to completely change the batteries in your home and are going to provide a truly warm environment in winter, you need to learn how to correctly calculate the number of sections of a bimetallic radiator. Any mistakes in choosing the correct size and number of batteries can ultimately lead to the room being constantly cold or, conversely, hot.
In particular, it is worth noting several advantages of such radiators.
- Durability. It is worth saying that in fact, the maximum durability of bimetallic radiators has not yet been established, since not a single device has yet worked for a full period, however, most manufacturers provide a guarantee for such equipment for about 20 years.
- Power. Only some aluminum devices can provide as much heat as the kW in a bimetallic radiator. Due to this, the calculation of such devices is simpler.
- Design. Bimetallic batteries can easily fit into absolutely any interior, which is why they have become so widespread.
All this has made relatively young bimetallic radiators the most popular heating option.
However, as is known, the only drawback of this heating option is the cost of bimetallic radiators, because they are an order of magnitude more expensive than their analogues. This is why it is important to know how to calculate the number of sections. Bimetallic radiators must be installed in the required quantity so as not to overpay for unnecessary equipment.
It is quite natural that the most efficient and optimal calculation of the number of sections can be done by experts who have great experience work in this area, so it is best to use the services of specialists. A professional calculation of the number of sections of bimetallic heating radiators is as accurate as possible and provides the opportunity to optimally determine how many devices need to be used not only in each individual room, but also in any type of object.
The professional calculation method takes into account a huge number of different parameters, including:
- the material used to construct the building, as well as the thickness of the walls;
- the type of windows that were installed in this room;
- general climatic conditions;
- is there heating in the room directly above the one in question;
- how many are present external walls;
- room area;
- ceiling height.
All this allows us to achieve maximum accuracy of the calculations.
Calculation of bimetallic radiators for 1 m 2 independently
If you want to completely independent calculation what exact number of sections you need, then in this case there is a fairly simple and available method, which allows for calculation.
First, you should decide which bimetallic heating radiators you are going to buy. Calculating the area will allow you to determine their number in the future.
Initially, a standard is selected indicating the required thermal power that each m2 requires. Thus, you must first correctly determine the number of Watts that will be required to heat 1 m2 in your room with a standard ceiling height.
For rooms with a single window and only one outer wall It may take about 100 W to ensure normal heating of each m2.
If there is only one window in the room, but two walls go outside at once (for example, a corner room), then in order to ensure normal heating of each m2 it will be necessary to install radiators with a power of 120 W. All this is also reliable only when the room has a ceiling with a height of up to 2.7 m;
If the room has a completely standard ceiling height, but at the same time has 2 windows and 2 external walls, then in this case it will be necessary to about 130 W in order to heat each m2 of it.
Bimetallic heating radiators: video
Calculation of radiator power for the entire room
By multiplying such values by the total area of your room, you can calculate exactly how many kW of heat you need from the installed heating radiator.
Measuring the area is quite simple - the width of the room is multiplied by its length. It is worth noting that if your room has a rather complex perimeter, then in this case you can also take rougher measurements, but the error should always be interpreted on the larger side.
You should also decide on the height of each section of the bimetallic radiator so that it fits where it is installed. At the same time, if you have high ceilings or an increased window area, then in this case you should also multiply the value you obtained by the correction factor in order to understand in what quantity to install bimetallic radiators. Thus, we will calculate how many sections of a bimetallic radiator are needed a little differently.
In order to decide how many radiator sections you need, you need to divide the power that, in accordance with the calculations, required to heat your room, by the power that the sections of the model you like have. Often the section capacity is mandatory is indicated in the passport of each device, so it is not difficult to find out how many kW is in a bimetallic radiator. As a last resort, you can look up the power on the Internet.
As is already known, the power required for normal heating of each m2 is approximately 100-120 W. In order to determine the battery power for your room, you can multiply its area by 100, and then divide by the power that each section of the bimetallic battery you choose has. The resulting number will be the number of radiator sections you need.
Separately, it should be said that certain models of modern radiators may have a number of sections that is a multiple of two, and some devices do not provide adjustment options and have a strictly fixed number of sections.
In such a situation, you should choose a battery with the most approximate number of sections, but their number must be greater than the calculated one, because it is better to make the room a little warmer than to freeze all winter.
30*100/200 = 15.
That is, to heat such a room it is necessary to install a radiator with 15 sections. The use of this formula is relevant for ordinary premises with a ceiling height of no more than three meters and also only one doorway, window and wall facing the outside of the building. In the event that the calculation of the number of bimetallic heating radiators is carried out for non-standard rooms, that is, those located at the end or in the corner of the building, it will be necessary to multiply the resulting number by the coefficient.
In other words, if the room considered in the above example had 2 external walls and 2 windows, it would be necessary to make a further calculation as 15 * 1.2 = 18. That is, in this situation it would be necessary to install three radiators, each of which has 6 sections.
How many sections of heating radiators are needed depending on the volume of the room
For example, you can take a standard room with an area of 20 m2 and a ceiling height of 2.7 m. Thus, the volume of such a room will be 20 * 2.7 = 54, that is, the volume of the room will be equal to 54 m3. For normal heating of such a room, it will be necessary to provide 54 * 40 = 2160 W, that is, if, again, we take a radiator with a power of 200 W as an example, then 2160/200 = 10.8 will be required. In other words, to properly heat such a room you will need to install 11 sections of this radiator.
It is worth noting the fact that most companies that sell radiators provide fairly convenient and simple calculators on their websites. All calculations by such programs are carried out completely automatically, and the comparative characteristics and cost of a specific heating battery option are ultimately displayed on the screen.
One of the most important issues in creating comfortable conditions living in a house or apartment is a reliable, correctly calculated and installed, well-balanced heating system. That is why the creation of such a system is the most important task when organizing construction. own home or during overhaul in a high-rise apartment.
Despite the modern variety of heating systems various types, the leader in popularity still remains a proven scheme: pipe circuits with coolant circulating through them, and heat exchange devices - radiators installed in the premises. It would seem that everything is simple, the batteries are located under the windows and provide the required heating... However, you need to know that the heat transfer from the radiators must correspond to both the area of the room and a number of other specific criteria. Thermal calculations, based on the requirements of SNiP - a rather complex procedure performed by specialists. However, you can do it on your own, naturally, with acceptable simplification. This publication will tell you how to independently calculate heating radiators for the area of a heated room, taking into account various nuances.
But, first, you need to at least briefly familiarize yourself with existing heating radiators - the results of the calculations will largely depend on their parameters.
Briefly about existing types of heating radiators
- Steel radiators of panel or tubular design.
- Cast iron batteries.
- Aluminum radiators of several modifications.
- Bimetallic radiators.
Steel radiators
This type of radiator has not gained much popularity, despite the fact that some models are given a very elegant design decoration. The problem is that the disadvantages of such heat exchange devices significantly exceed their advantages - low price, relatively low weight and ease of installation.
The thin steel walls of such radiators do not have enough heat capacity - they heat up quickly, but also cool down just as quickly. Problems can also arise with water hammer - welded joints of sheets sometimes leak. Besides, inexpensive models batteries that do not have a special coating are susceptible to corrosion, and the service life of such batteries is short - usually manufacturers give them a fairly short warranty in terms of service life.
In the vast majority of cases steel radiators They are a one-piece structure, and they do not allow varying the heat transfer by changing the number of sections. They have a rated thermal power, which must be immediately selected based on the area and characteristics of the room where they are planned to be installed. An exception is that some tubular radiators have the ability to change the number of sections, but this is usually done to order, during manufacture, and not at home.
Cast iron radiators
Representatives of this type of battery are probably familiar to everyone. early childhood– these are exactly the kind of accordions that were previously installed literally everywhere.
Perhaps such batteries MC -140-500 were not particularly elegant, but they faithfully served more than one generation of residents. Each section of such a radiator provided a heat output of 160 W. The radiator is prefabricated, and the number of sections, in principle, was not limited by anything.
There are currently many modern cast iron radiators on sale. They are already distinguished by a more elegant appearance, smooth outer surfaces that make cleaning easier. Exclusive versions are also produced, with an interesting relief pattern of cast iron casting.
With all this, such models fully retain the main advantages of cast iron batteries:
- The high heat capacity of cast iron and the massiveness of the batteries contribute to long-term retention and high heat transfer.
- Cast iron batteries, with proper assembly and high-quality sealing of connections, are not afraid of water hammer and temperature changes.
- Thick cast iron walls are little susceptible to corrosion and abrasive wear. Almost any coolant can be used, so such batteries are equally good for autonomous and central heating systems.
If we do not take into account the external characteristics of old cast iron batteries, then the disadvantages include the fragility of the metal (accentuated impacts are unacceptable), the relative complexity of installation, which is associated largely with massiveness. Moreover, not all wall partitions will be able to withstand the weight of such radiators.
Aluminum radiators
Aluminum radiators, having appeared relatively recently, quickly gained popularity. They are relatively inexpensive, have a modern, quite elegant appearance, and have excellent heat dissipation.
High-quality aluminum batteries can withstand pressures of 15 atmospheres or more and high coolant temperatures of about 100 degrees. At the same time, the thermal output from one section of some models sometimes reaches 200 W. But at the same time, they are lightweight (section weight is usually up to 2 kg) and do not require a large volume of coolant (capacity - no more than 500 ml).
Aluminum radiators are offered for sale as stacked batteries, with the ability to change the number of sections, and as solid products designed for a certain power.
Disadvantages of aluminum radiators:
- Some types are highly susceptible to oxygen corrosion of aluminum, with a high risk of gas formation. This places special demands on the quality of the coolant, so such batteries are usually installed in autonomous systems heating.
- Some aluminum radiators non-demountable design, sections of which are manufactured using extrusion technology, can, under certain conditions unfavorable conditions let the connections leak. In this case, it is simply impossible to carry out repairs, and you will have to replace the entire battery as a whole.
Of all aluminum batteries, the highest quality ones are those made using anodic oxidation of the metal. These products are practically not afraid of oxygen corrosion.
Externally, all aluminum radiators are approximately similar, so you need to read very carefully technical documentation making a choice.
Bimetallic heating radiators
Such radiators compete with cast iron ones in terms of reliability, and with aluminum ones in terms of thermal output. The reason for this is their special design.
Each section consists of two, upper and lower, steel horizontal collectors (item 1), connected by the same steel vertical channel (item 2). The connection into a single battery is made with high-quality threaded couplings (item 3). High heat transfer is ensured by the outer aluminum shell.
Steel internal pipes made of metal that is not subject to corrosion or has a protective polymer coating. Well, under no circumstances does the aluminum heat exchanger come into contact with the coolant, and it is absolutely not afraid of corrosion.
This results in a combination of high strength and wear resistance with excellent thermal performance.
Prices for popular heating radiators
Heating radiators
Such batteries are not afraid of even very large pressure surges, high temperatures. They are, in fact, universal and suitable for any heating systems, however, they still show the best performance in conditions high pressure central system - for circuits with natural circulation they are of little use.
Perhaps their only drawback is high price compared to any other radiators.
For ease of perception, there is a table that shows comparative characteristics radiators. Legend in it:
- TS – tubular steel;
- Chg – cast iron;
- Al – ordinary aluminum;
- AA – aluminum anodized;
- BM – bimetallic.
| Chg | TS | Al | AA | BM | |
|---|---|---|---|---|---|
| Maximum pressure (atm.) | |||||
| working | 6-9 | 6-12 | 10-20 | 15-40 | 35 |
| crimping | 12-15 | 9 | 15-30 | 25-75 | 57 |
| destruction | 20-25 | 18-25 | 30-50 | 100 | 75 |
| Limitation on pH (hydrogen value) | 6,5-9 | 6,5-9 | 7-8 | 6,5-9 | 6,5-9 |
| Susceptibility to corrosion when exposed to: | |||||
| oxygen | No | Yes | No | No | Yes |
| stray currents | No | Yes | Yes | No | Yes |
| electrolytic couples | No | weak | Yes | No | weak |
| Section power at h=500 mm; Dt=70 ° , W | 160 | 85 | 175-200 | 216,3 | up to 200 |
| Warranty, years | 10 | 1 | 3-10 | 30 | 3-10 |
Video: recommendations for choosing heating radiators
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How to calculate the required number of heating radiator sections
It is clear that a radiator installed in the room (one or more) must provide heating to comfortable temperature and compensate for inevitable heat loss, regardless of the weather outside.
The basic value for calculations is always the area or volume of the room. The professional calculations themselves are very complex and take into account very big number criteria. But for household needs you can use simplified methods.
The simplest methods of calculation
It is generally accepted that to create normal conditions in a standard living room, 100 W per square meter pl spare. Thus, you just need to calculate the area of the room and multiply it by 100.
Q = S× 100
Q– required heat transfer from heating radiators.
S– area of the heated room.
If you plan to install a non-separable radiator, then this value will become a guideline for selecting the required model. In the case where batteries will be installed that allow the number of sections to be changed, another calculation should be made:
N = Q/ Qus
N– calculated number of sections.
Qus– specific thermal power of one section. This value must be indicated in the technical data sheet of the product.
As you can see, these calculations are extremely simple and do not require any special knowledge of mathematics - just a tape measure to measure the room and a piece of paper for calculations. In addition, you can use the table below - it shows already calculated values for rooms of different sizes and certain capacities of heating sections.
Section table
However, it must be remembered that these values are for standard height ceiling (2.7 m) of a high-rise building. If the height of the room is different, then it is better to calculate the number of battery sections based on the volume of the room. For this, an average indicator is used - 41 V t t heat output per 1 m³ of volume in a panel house, or 34 W in a brick house.
Q = S × h× 40 (34 )
Where h– ceiling height above floor level.
Further calculations are no different from those presented above.
Detailed calculation taking into account features premises
Now let's move on to more serious calculations. The simplified calculation method given above can present a “surprise” to the owners of a house or apartment. When installed radiators will not create the required comfortable microclimate in residential premises. And the reason for this is a whole list of nuances that the considered method simply does not take into account. Meanwhile, such nuances can be very important.
So, the area of the room and the same 100 W per m² are again taken as a basis. But the formula itself already looks a little different:
Q = S× 100 × A × B × C ×D× E ×F× G× H× I× J
Letters from A before J Coefficients are conventionally designated that take into account the characteristics of the room and the installation of radiators in it. Let's look at them in order:
A is the number of external walls in the room.
It is clear that the higher the contact area of the room with the street, that is, the more external walls in the room, the higher total heat loss. This dependence is taken into account by the coefficient A:
- One external wall A = 1.0
- Two external walls - A = 1.2
- Three outer walls - A = 1.3
- All four external walls are A = 1.4
B – orientation of the room to the cardinal points.
The maximum heat loss is always in rooms that do not receive direct sunlight. This is, of course, the northern side of the house, and the eastern side can also be included here - the rays of the Sun appear here only in the mornings, when the luminary has not yet reached its full power.
The southern and western sides of the house are always heated by the Sun much more strongly.
Hence the coefficient values IN :
- The room faces north or east - B = 1.1
- South or west rooms – B = 1, that is, it may not be taken into account.
C is a coefficient that takes into account the degree of insulation of the walls.
It is clear that heat loss from the heated room will depend on the quality of the thermal insulation of the external walls. Coefficient value WITH are taken equal to:
- Medium level - the walls are laid with two bricks, or their surface insulation is provided with another material - C = 1.0
- External walls are not insulated - C = 1.27
- High level of insulation based thermal calculations – C = 0.85.
D – features of the climatic conditions of the region.
Naturally, it is impossible to equate all the basic indicators of the required heating power with the same brush - they also depend on the level of winter negative temperatures, characteristic of a particular area. This takes into account the coefficient D. To select it, the average temperatures of the coldest ten-day period of January are taken - usually this value is easy to check with the local hydrometeorological service.
- — 35° WITH and below – D= 1.5
- — 25÷ — 35 ° WITH – D= 1.3
- up to – 20 ° WITH – D= 1.1
- not lower than – 15 ° WITH – D= 0.9
- not lower than – 10 ° WITH – D= 0.7
E – coefficient of ceiling height of the room.
As already mentioned, 100 W/m² is an average value for standard ceiling heights. If it differs, a correction factor must be entered E:
- Up to 2.7 m – E = 1,0
- 2,8 – 3, 0 m – E = 1,05
- 3,1 – 3, 5 m – E = 1, 1
- 3,6 – 4, 0 m – E = 1.15
- More than 4.1 m – E = 1.2
F – coefficient taking into account the type of room located higher
Installing a heating system in rooms with cold floors is a pointless exercise, and owners always take action in this matter. But the type of room located above often does not depend on them in any way. Meanwhile, if there is a living or insulated room on top, then the overall need for thermal energy will significantly decrease:
- cold attic or unheated room – F= 1.0
- insulated attic (including insulated roof) – F= 0.9
- heated room - F= 0.8
G – factor taking into account the type of windows installed.
Various window designs are subject to heat loss differently. This takes into account the coefficient G:
- ordinary wooden frames with double glazing – G= 1.27
- the windows are equipped with single-chamber double-glazed windows (2 glasses) – G= 1.0
- single-chamber double-glazed window with argon filling or double glazing(3 glasses) — G= 0.85
N – coefficient of the glazing area of the room.
The total amount of heat loss also depends on the total area of windows installed in the room. This value is calculated based on the ratio of the window area to the room area. Depending on the result obtained, we find the coefficient N:
- Ratio less than 0.1 – H = 0, 8
- 0.11 ÷ 0.2 – H = 0, 9
- 0.21 ÷ 0.3 – H = 1, 0
- 0.31÷ 0.4 – H = 1, 1
- 0.41 ÷ 0.5 – H = 1.2
I is a coefficient that takes into account the radiator connection diagram.
Their heat transfer depends on how the radiators are connected to the supply and return pipes. This should also be taken into account when planning the installation and determining the required number of sections:
- a – diagonal connection, supply from above, return from below – I = 1.0
- b – one-way connection, supply from above, return from below – I = 1.03
- c – two-way connection, both supply and return from below – I = 1.13
- d – diagonal connection, supply from below, return from above – I = 1.25
- d – one-way connection, supply from below, return from above – I = 1.28
- e – one-sided bottom connection of return and supply – I = 1.28
J is a coefficient that takes into account the degree of openness of installed radiators.
Much depends on how installed batteries open for free heat exchange with room air. Existing or artificially created barriers can significantly reduce the heat transfer of the radiator. This takes into account the coefficient J:
a – the radiator is located openly on the wall or not covered by a window sill – J= 0.9
b – the radiator is covered from above with a window sill or shelf – J= 1.0
c – the radiator is covered from above by a horizontal projection of the wall niche – J= 1.07
d – the radiator is covered from above by a window sill, and from the front sides — partsdirectly covered with a decorative casing - J= 1.12
e – the radiator is completely covered with a decorative casing– J= 1.2
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Well, finally, that's all. Now you can substitute into the formula required values and coefficients corresponding to the conditions, and the output will be the required thermal power for reliable heating of the room, taking into account all the nuances.
After this, all that remains is to either select a non-separable radiator with the required thermal output, or divide the calculated value by the specific thermal power of one section of the battery of the selected model.
Surely, to many, such a calculation will seem overly cumbersome, in which it is easy to get confused. To make the calculations easier, we suggest using a special calculator - it already contains all the required values. The user can only enter the requested initial values or select the required items from the lists. The “calculate” button will immediately lead to an exact result, rounded up.
It's time to change the batteries.
Comfort during the cold season depends on calculations of the number of nodes.
How to make all the calculations and measurements correctly?
Everything is quite simple if you follow the instructions below.
Before purchasing heating batteries, we will consider ways to calculate the number of their elements.
The first method is based on the area of the room. Construction standards (SNiP) state that for normal heating 1 sq. m. requires 100 W. thermal power. By measuring the length and width of the room, and multiplying these two values, we get the area of the room (S).
To calculate the total power (Q), substitute into the formula, Q=S*100 W., our meaning. The passport for heating radiators indicates the heat transfer of one element (q1). Thanks to this information, we will know the required number. To do this, divide Q by q1.
The second method is more accurate. It should also be used with a ceiling height of 3 meters or more. Its difference lies in measuring the volume of the room. The area of the room is already known, let's measure the height of the ceiling, then multiply these values. We substitute the resulting volume value (V) into the formula Q=V*41 W.
According to building codes, 1 cubic meter. m. should be heated by 41 W. thermal power. Now let's find the ratio of Q to q1, obtaining the total number of radiator nodes.
Let's sum up the interim results data that will be needed for all types of calculations.
- Wall length;
- Wall width;
- Ceiling height;
- Power standards, heating a unit of area or volume of a room. They are given above;
- Minimum heat dissipation radiator element. It must be indicated in the passport;
- Wall thickness;
- Number of window openings.
A quick way to calculate the number of sections
If we are talking about replacing cast iron radiators with bimetallic ones, you can do without scrupulous calculations. Taking into account several factors:
- The bimetallic section gives a ten percent increase in thermal power compared to cast iron.
- Battery efficiency decreases over time. This is due to deposits that coat the walls inside the radiator.
- It's better to be warmer.
The number of elements of a bimetallic battery must be the same as that of its predecessor. However, this number increases by 1 - 2 pieces. This is done to combat future decreases in the heater's efficiency.
For a standard room
We already know this method of calculation. It is described at the beginning of the article. Let's look at it in detail by turning to specific example. Let's calculate the number of sections for a room of 40 square meters. m.
According to the rules of the 1st quarter. m requires 100 W. Let's assume that the power of one section is 200 W. Using the formula from the first section, we will find the required thermal power of the room. Let's multiply 40 square meters. m. at 100 W, we get 4 kW.
To determine the number of sections, divide this number by 200 W. It turns out that a room of a given area will require 20 sections. The main thing to remember is that the formula is relevant for apartments where the ceiling height is less than 2.7 m.
For non-standard
Non-standard rooms include corner, end rooms, With several window openings. Dwellings with a ceiling height of more than 2.7 meters also fall under this category.
For the former, the calculation is carried out according to the standard formula, but the final result is multiplied by a special coefficient, 1 - 1.3. Using the data obtained above: 20 sections, assume that the room is corner and has 2 windows.
The final result is obtained by multiplying 20 by 1.2. This room requires 24 sections.
If we take the same room, but with a ceiling height of 3 meters, the results will change again. Let's start by calculating the volume, multiply by 40 square meters. m. by 3 meters. Remembering that per 1 cu. m requires 41 W., let's calculate the total thermal power. The resulting 120 cc. m multiplied by 41 W.
We get the number of radiators by dividing 4920 by 200 W. But the room is corner with two windows, therefore, 25 needs to be multiplied by 1.2. The final total is 30 sections.
Accurate calculations with many parameters
It is difficult to make such calculations. The above formulas are valid for normal premises central Russia. Geographical position houses and a number of other factors will introduce additional correction factors.
- The final formula for corner room , must have an additional multiplier of 1.3.
- If the house is not located in middle lane countries, the additional coefficient is described building codes this territory.
- It is necessary to consider the installation location of the bimetallic radiator And decorative elements. For example, a niche under a window will take 7%, and a screen up to 25% of the thermal power of the battery.
- What will the room be used for?
- Wall material and thickness.
- How much do frames cost? and glass.
- Door and window openings contribute additional problems. Let's look at them in more detail.
Walls with windows, street and with doorways, change the standard formula. It is necessary to multiply the resulting number of sections by the heat transfer coefficient of the room, but it must first be calculated.
This indicator will be the sum of the heat transfer of the window, doorway and wall. All this information can be obtained by contacting SNiP, according to your type of premises.
Electrical oil radiators, operating principle and how to choose
Useful tips for properly arranging your heating system
Bimetallic radiators come from the factory connected in 10 sections. After calculations, we got 10, but we decided to add 2 more in reserve. So, it's better not to do it. Factory assembly is much more reliable and comes with a warranty of 5 to 20 years.
Assembly of 12 sections will be carried out by the store, and the warranty will be less than a year. If the radiator leaks soon after this period ends, repairs will have to be carried out on your own. The result is unnecessary problems.
Let's talk about the effective power of the radiator. Characteristics of the bimetallic section specified in the product passport, assume that the temperature difference of the system is 60 degrees.
This pressure is guaranteed if the temperature of the coolant in the battery is 90 degrees, which does not always correspond to reality. This must be taken into account when calculating the room radiator system.
Below are Some tips for installing the battery:
- Distance from the window sill to the top edge of the battery must be at least 5 cm. Air masses will be able to circulate normally and transfer heat to the entire room.
- The radiator must be separated from the wall by a length of 2 to 5 cm. If reflective thermal insulation will be attached behind the battery, then you need to purchase extended brackets that provide the specified gap.
- The bottom edge of the battery is allowed a distance from the floor equal to 10 cm. Failure to follow the recommendation will worsen heat transfer.
- A radiator mounted against a wall, and not in a niche under a window, must have a gap with it, at least 20 cm. This will prevent dust from accumulating behind it and help heat the room.
It is very important to make such calculations correctly. This determines how efficient and economical the resulting heating system will be. All the information given in the article is aimed at helping the average person with these calculations.