Competently arranged heating system will provide housing with the necessary temperature. To transmit heat to the airspace of residential premises, you need to know the number of batteries, in which the rooms in any weather will be comfortable. p>
Calculation of radiators based on calculations of the heat output required by the installed heaters will help to clarify this. p>
The content of the article: p> Simplified calculation of heat loss compensation
Any calculations are based on certain principles. The basis for calculating the required thermal power of batteries is the understanding that well-functioning heating devices must fully compensate for the heat loss that occurs during their operation due to the characteristics of heated premises. p>
For living rooms located in a well-insulated house, located, in turn, in a temperate climate zone, in some cases, a simplified calculation of compensation for heat leaks will do. For such premises, calculations are based on a standard power of 41 W, which is required for heating 1 cubic meter. living space. p>
In order for the heat energy emitted by heating devices to be directed specifically to space heating, it is necessary to warm walls, attics, windows and floors p>
The formula for determining the heat capacity of radiators necessary to maintain optimal living conditions in the room is as follows: p>
Q = 41 x V p>
where V is the volume of the heated room in cubic meters. p>
The resulting four-digit result can be expressed in kilowatts, reducing it at the rate of 1 kW = 1000 watts. p> Detailed heat calculation formula
With detailed calculations of the number and size of radiators, it is customary to build on the relative power of 100 W, which is necessary for normal heating of 1 m² of a certain standard room. The formula for determining the heat output required from heating devices is as follows: p>
Q = (100 x S) x R x K x U x T x H x W x G x x Y x Z p>
The multiplier S in the calculations is nothing more than the area of the heated room, expressed in square meters. The remaining letters are various correction factors, without which the calculation will be limited. p>
The main thing in thermal calculations is to remember the saying “the heat of the bones does not ache” and not be afraid to err in a big way p>
But even the additional design parameters can not always reflect all the specifics of a particular room. It is recommended, when in doubt, to give preference to indicators with large values. It is easier then to lower the temperature of the radiators with the help of temperature-controlled devices than to freeze with a lack of their thermal power. p>
Further, each of the coefficients involved in the formula for calculating the thermal power of batteries is analyzed in detail. At the end of the article, information on the characteristics of collapsible radiators from different materials is given, and the procedure for calculating the required number of sections and the batteries themselves is considered on the basis of the basic calculation. p>
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A simplified method for calculating the power of radiators necessary for normal heating of a room assumes that for every 10 m3 it is necessary to deliver 1 kW of heat p>
In order for the owners of the premises to have a reserve in case of unexpected heat loss, the calculated power value is multiplied by 1.15, i.e. increase by 15% p>
Compact radiators used in low-temperature heating circuits are no less effective than traditional devices. Their power is calculated according to a similar scheme. p>
If the room is limited by two external walls and there is one window in it, the calculated value of the heat output must be increased by 20%. p>
The power of the appliance heating system installed in a room with a terrace or winter garden, you need to increase by 25% p>
For a room with one external wall and one window, the power of the heater should be multiplied by a correction factor of 1.15 p>
If the heating battery is masked by a box or screen, then its capacity is increased by 15 - 20% depending on the heat-conducting characteristics of the material from which the construction is made p>
When calculating the performance of radiators for the attic with widescreen panoramic windows, the result is increased by 25 - 35% p>
Average heat output of radiators p>
The stock of thermal power devices p>
Low-temperature compact radiators in the interior p>
Radiators in the room with two outer walls p>
Indoor heating with terrace p>
Install the battery in the corner p>
Calculations for closed box radiator p>
Attic heating device p> Orientation of rooms on the cardinal points
And in the most frosty days, the energy of the sun still affects the thermal equilibrium inside the dwelling. From the directionality of the rooms in one direction or another depends on the coefficient "R" of the formula for calculating thermal power. p> Room with a window to the south. During daylight hours, it will receive the maximum additional external heat compared to other rooms. This orientation is taken as the basic, and additional parameter in this case: R = 1.0. The window is to the west. This room will also have time to get its portion of sunlight. Although the sun will glance there in the late afternoon, the location of such a room is more favorable than the eastern and northern: R = 1.0 (for areas with a short winter day, you can take R = 1.05). The room is oriented to the east. An ascending winter star is unlikely to have time to properly heat such a room from the outside. Battery power will require additional watts. Add to the calculation a tangible correction of 10%: R = 1.1. Outside the window - only north. In winter, such a room does not see direct sunlight at all. It is recommended that the calculation of the heat output required from radiators also be adjusted upwards by 10%: R = 1.1 (a resident of northern latitudes who will accept R = 1.15 will not be mistaken).
If the winds of a certain direction prevail in the area of residence, it is desirable for rooms with windward sides to increase R by up to 20% depending on the force of air (х1,1 ÷ 1,2), and for rooms with walls parallel to cold flows, raise the value of R by 10% (x1,1). p>
Rooms oriented to the north and east, as well as rooms on the windward side will need more powerful heating. p> Accounting for the influence of external walls
In addition to the wall with a window or windows built into it, the other walls of the room may also have contact with the cold outside. The outer walls of the room determine the coefficient “K” of the calculation formula for the heat capacity of radiators. p>
The presence of the premises of one street wall - a typical case: p> K = 1.0.
Two external walls will request 20% more heat to heat a room: p> K = 1,2.
Each subsequent outer wall adds 10% of the required heat transfer to the calculations: p> K = 1.3 - three street walls, K = 1.4 - four external walls. Dependence of radiators on thermal insulation
To reduce the budget for heating the internal space allows housing, correctly and reliably isolated from the winter cold, and significantly. The degree of insulation of street walls is subject to the coefficient "U", which reduces or increases the calculated thermal power of heating devices. p> U = 1.0 for standard exterior walls. Walls are considered as such:
- of climate-appropriate materials and thickness,
- reduced thickness, but with plastered outer surface,
- reduced thickness, but with surface external insulation. p>
If the insulation of street walls was made by special calculation, then: p> U = 0.85.
But, and if external walls are not cold-resistant enough, here: p> U = 1.27.
If the space permits, the walls can be insulated from the inside. And there is always a way to shield the walls from the cold outside. p>
A corner room that is well insulated according to special accounting will give a significant percentage of the cost savings for heating the entire living space of an apartment p> Climate is an important factor in arithmetic
Different climatic zones have different indicators of minimally low street temperatures. When calculating the power of heat transfer from radiators, the coefficient “T” is provided to take into account temperature differences. p>
Normal is considered to be winter weather up to -20 ° C. For areas with the least cold: p> t = 1.0.
For warmer regions, this calculated coefficient will lower the overall result of the calculations: p> T = 0.9 for winters with frost down to -15 ° C, T = 0.7 to -10 ° C.
For regions of a harsh climate, the amount of heat energy required from heating devices will increase: p> T = 1.1 for frosts down to -25 ° C, T = 1.3 - down to -35 ° C, T = 1.5 - below -35 ° C. Features of calculation of high premises
It is clear that of the two rooms with the same area, more heat will be needed for the one whose ceiling is higher. The coefficient “H” helps to take into account the correction for the volume of heated space in the calculations of thermal power. p>
At the beginning of the article it was mentioned about a certain regulatory room. This is considered to be a room with a ceiling of 2.7 meters and below. For her: p> H = 1.0.
For rooms up to 3 meters high already relevant: p> H = 1.05,
Further, the calculation will be added at 5% per half meter height: p> H = 1.1 for a room with a ceiling of up to 3.5 meters, H = 1.15 - up to 4 meters.
If you suddenly need to calculate the need for heat for a higher room, then it is taken: p> H = 1,2.
According to the law of nature, warm heated air rushes up. To mix all its volume heating devices will have to work as it should. p>
With the same floor space, a larger room may require an additional number of radiators connected to the heating system. p> The estimated role of the ceiling and floor
Not only well-insulated external walls lead to a decrease in the thermal power of batteries. A ceiling in contact with a warm room also minimizes heat loss during heating. The coefficient "W" in the calculation formula is just to provide for this. p>
If upstairs is located, for example, an unheated, unheated attic, then: p> W = 1.0.
For an unheated but insulated attic or other insulated room at the top: p> W = 0.9.
But, and if the floor above the room is heated, then: p> W = 0.8.
The W indicator can be corrected upwards for the ground floor rooms if they are located on the ground, above an unheated basement or basement space. Then the numbers will be: p> the floor is insulated + 20% (x1.2); the floor is not insulated + 40% (x1.4). The quality of the frames is a guarantee of heat
Windows - once a weak point in the insulation of living space. Modern frames with double-glazed windows have allowed to significantly improve the protection of rooms from the cold outside. The degree of quality of windows in the formula for calculating thermal power describes the coefficient "G". p>
The calculation is based on a standard single-chamber glass unit, in which: p> G = 1.0.
If the frame is equipped with a double or three-chamber glass unit, then: p> G = 0.85.
But, and if the window has an old wooden frame, then: p> G = 1.27. Window size matters
Following the logic, it can be argued that the greater the number of windows in a room and the more extensive their overview, the more sensitive the heat leakage through them. The coefficient “X” from the formula for calculating the heat output required from batteries just reflects this. p>
In a room with huge windows and radiators should be of the number and size of frames corresponding to the size and quality of frames. p>
The norm is the result of dividing the area of window openings by the area of a room equal to 0.2 to 0.3. With this result: p> X = 1.0.
If suddenly the windows take up even less space, then: p> X = 0.9 for the ratio of areas from 0.1 to 0.2, X = 0.8, with a ratio of up to 0.1.
With windows larger than normal: p> X = 1.1, if the area ratio is from 0.3 to 0.4, X = 1.2, when it is from 0.4 to 0.5.
If the footage of window openings (for example, in rooms with panoramic windows) goes beyond the proposed ratios, it is reasonable to add to the value of X another 10% with an increase in the area ratio by 0.1. p>
The door in the room, which is regularly used in winter to access an open balcony or loggia, makes its own adjustments to the heat balance. For such a room it would be right to increase X by another 30% (x1.3). p>
Losses of thermal energy are easily compensated by a compact installation under the balcony entrance of a channel water or electric convector. p> Effect of battery closure
Of course, it is better to give heat to the radiator, which is less fenced by various artificial and natural obstacles. In this case, the formula for calculating its thermal power is expanded by the coefficient "Y", which takes into account the operating conditions of the battery. p>
The most common location for heating devices is under the windowsill. In their position: p> Y = 1.0.
If the battery is suddenly completely open on all sides, it is: p> Y = 0.9.
In other options: p> Y = 1.07 when the radiator is obstructed by a horizontal protrusion of the wall, Y = 1.12, if the battery located under the sill is covered with a front cover, Y = 1.2 when the heater is blocked on all sides.
Shifted long blackout curtains also cause a cold snap in the room. p>
The modern design of the radiators allows them to be operated without any decorative covers, thereby ensuring maximum heat transfer p> Efficiency of connecting radiators
The efficiency of its work directly depends on the method of connecting the radiator to the indoor heating installation. Often homeowners sacrifice this indicator in favor of the beauty of the room. The formula for calculating the required heat output takes into account all this in terms of the “Z” coefficient. p>
The inclusion of a radiator in the common circuit of the heating system by the reception "diagonally" is the most justified. For it is accepted: p> Z = 1.0.
Another, the most common due to the small length of the liner, is the “side” attachment option. Here: p> Z = 1.03.
The third method is “bottom from two sides”. Thanks plastic pipes, he quickly got accustomed to the new construction, despite the much lower efficiency: p> Z = 1.13.
Another very inefficient way “from the bottom on one side” deserves consideration only because some radiator designs are supplied with ready-made units with pipes connected to one point and supply and return. Its parameter is: p> Z = 1.28.
To increase the efficiency of heating devices will help them installed in the air vent, which will promptly save the system from the "airing". p>
Before hiding the heating pipes to the floor, using inefficient battery connections, it is worth remembering about the walls and ceiling p>
The principle of operation of any water heater relies on the physical properties of a hot liquid to rise up, and after cooling down to move. Therefore, it is strongly not recommended to use the connections of heating systems to radiators, in which the supply pipe is at the bottom and the return pipes are at the top. p> Practical example of the calculation of thermal power
Initial data: p> A corner room without a balcony on the second floor of a two-story cinder block in a plastered house in a windless area of Western Siberia. The length of the room is 5.30 m X width 4.30 m = area 22.79 sq.m. Window width 1.30 m X height 1.70 m = area 2.21 sq.m. Room height = 2.95 m.
Calculation sequence: p> The area of the room in square meters: S = 22.79. The orientation of the window - to the south: R = 1.0. The number of external walls is two: K = 1.2. Insulation of external walls is standard: U = 1.0. The minimum temperature is -35 ° C: T = 1.3. The height of the room is up to 3 m: H = 1.05. The room at the top is an unheated attic: W = 1.0. Frames - single-pane windows: G = 1.0. The ratio of the area of the window and the room - up to 0.1: X = 0.8. Radiator position - under the window sill: Y = 1.0. Radiator connection - diagonal: Z = 1.0.
Total (do not forget to multiply by 100): Q = 2 986 watts.
Below is a description of the calculation of the number of sections of radiators and the required number of batteries. It is based on the results of thermal capacity, taking into account the dimensions of the proposed installation of the heating devices. Regardless of the results, it is recommended to equip in corner rooms with radiators not only subwindow niches. Batteries should be installed near the "blind" external walls or near the corners that are exposed to the greatest frost penetration under the influence of the street cold. p> Specific thermal power of battery sections
Even before the general calculation of the required heat transfer of heating devices is carried out, it is necessary to decide which folding batteries of which material will be installed in the premises. The choice should be based on the characteristics of the heating system (internal pressure, coolant temperature). In this case, do not forget about the very different cost of purchased products. p>
About how to correctly calculate the right amount of different batteries for heating, and will be discussed further. p>
When the coolant is 70 ° C, the standard 500-mm sections of radiators from dissimilar materials have unequal specific heat capacity “q”. p> Cast iron. Radiators from this metal will be suitable for any system of heating. Specific power of one cast-iron section: q = 160 watts. Steel. Steel tubular radiators can operate in the most demanding conditions. Their sections are beautiful in their metallic luster, but have the smallest heat emission: q = 85 watts. Aluminum. Light, aesthetic aluminum radiators should be installed only in autonomous heating systems in which the pressure is less than 7 atmospheres. But in terms of heat release, their sections have no equal: q = 200 watts. Bimetal The interiors of radiators of such a material are made of steel, and the heat sink surface is made of aluminum. These batteries will withstand all modes of pressure and temperature. The specific thermal power of bimetal sections is also at a height: q = 180 watts.
The given q values are rather arbitrary and are used for preliminary calculations. More accurate figures are contained in the passports of purchased heating devices. p>
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The sectional principle of assembling heating devices allows modular elements to get a radiator with the required heat output. p>
Only products from the same manufacturer of the same model are suitable for assembly of the device from separate sections. p>
The section principle is not an innovation; it was used in a heating device with cast-iron radiators. p>
Among the advantages of the sectional assembly technique is the ability to assemble a radiator from parts painted with powder paint in factory conditions. p>
The advantages of the sectional assembly principle p>
Basic rules for assembling heating devices p>
Sections of an outdated cast iron battery p>
Powder coated color sections p> Calculation of the number of sections of radiators
Folding radiators from any material are good because you can add or subtract separate sections to achieve their calculated heat output. To determine the required number of "N" battery sections from the selected material, the following formula is used: p>
N = Q / q - where: p> Q = the previously calculated required thermal power of the room heating devices, q = specific heat capacity of a separate section of the batteries intended for installation.
Having calculated the total required number of sections of radiators in the room, you need to understand how many batteries you need to install. This calculation is based on a comparison of the dimensions of the proposed installation sites for the heaters and the size of the batteries, taking into account the connection. p>
The battery elements are connected by nipples with a multi-directional external thread using a radiator key, and gaskets are installed at the joints simultaneously. p>
For preliminary calculations, you can equip data on the width of sections of different radiators: p> cast iron = 93 mm, aluminum = 80 mm, bimetallic = 82 mm.
In the manufacture of collapsible radiators from steel pipes, manufacturers do not hold on to certain standards. If you want to put such batteries, you should approach the question individually. p>
You can also use our free online calculator to calculate the number of sections: p> Room size (m2) Heat transfer (W) Windows Plastic (double glazing) Conventional glazing Room height up to 2.7 meters from 2.7 to 3.5 meters The room is not angular angular Increasing the efficiency of heat transfer
When the internal air radiator heats the room, there is also an intense heating of the external wall in the area behind the battery. This leads to additional unnecessary heat loss. It is proposed to increase the efficiency of heat transfer from the radiator to shield the heater from the outer wall with a heat-reflecting screen. p>
The market offers a variety of modern insulation materials with a heat-reflecting foil surface. The foil protects the warm air warmed by the battery from contact with the cold wall and directs it into the room. p>
For proper operation, the boundaries of the installed reflector must exceed the dimensions of the radiator and on each side 2-3 cm to speak. The gap between the heater and the thermal protection surface should be 3-5 cm. p>
For the manufacture of heat-reflecting screen can be advised izospan, penofol, alyufom. A rectangle of the required size is cut out of the acquired roll and fixed on the wall at the radiator installation site. p>
It is best to fix the screen that reflects the heat of the heater on the wall with silicone glue or using liquid nails p>
It is recommended to separate the sheet of insulation from the outer wall with a small air gap, for example, using a thin plastic grid. If the reflector is joined from several parts of an insulating material, it is necessary to glue the joints from the side of the foil with metallized adhesive tape. p> The correct video on the topic
Small films will present the practical embodiment of some engineering tips in everyday life. p>
Video №1: Calculation of heating radiators: p>
Video number 2: Change the number of sections of radiators: p>
Video number 3: How to mount the reflector under the battery: p>
Acquired skills of calculating the thermal power of different types of radiators will help the home master in a competent device of the heating system. And housewives will be able to control the correctness of the process of installing batteries by third-party experts. p>
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