When replacing batteries or switching to individual heating in an apartment, the question arises of how to calculate the number of heating radiators and the number of instrument sections. If the battery power is insufficient, it will be cool in the apartment during the cold season. An excessive number of sections not only leads to unnecessary overpayments - with a single-pipe heating system, residents of the lower floors will be left without heat. You can calculate the optimal power and number of radiators based on the area or volume of the room, taking into account the features of the room and the specifics of different types of batteries.
Calculation by area
The most common and simple technique is the method of calculating the power of devices required for heating, according to the area of \u200b\u200bthe heated room. According to the average norm, for heating 1 sq. meter area requires 100 watts of thermal power. As an example, consider a room with an area of 15 square meters. meters. According to this method, 1500 W of thermal energy will be required to heat it.
There are a few important things to keep in mind when using this technique:
- the norm is 100 W per 1 sq. meter of area belongs to the middle climatic zone, in the southern regions for heating 1 sq. meter of the room requires less power - from 60 to 90 W;
- for areas with a harsh climate and very cold winters for heating 1 sq. meters require from 150 to 200 W;
- the method is suitable for rooms with a standard ceiling height not exceeding 3 meters;
- the method does not take into account heat loss, which will depend on the location of the apartment, the number of windows, the quality of insulation, and the material of the walls.
Methodology for calculating the volume of the room
The calculation method, taking into account the volume of the ceiling, will be more accurate: it takes into account the height of the ceilings in the apartment and the material from which the outer walls are made. The sequence of calculations will be as follows:
- The volume of the room is determined, for this room area multiplied by the height of the ceiling. For a room of 15 sq. m. and a ceiling height of 2.7 m, it will be equal to 40.5 cubic meters.
- Depending on the material of the walls, a different amount of energy is spent on heating one cubic meter of air. According to the norms of SNiP for an apartment in a brick house, this figure is 34 W, for a panel house - 41 W. This means that the resulting volume must be multiplied by 34 or 41 watts. Then for a brick building for heating a room of 15 squares, 1377 W (40.5 * 34) will be required, for a panel building - 1660.5 W (40.5 * 41).
Adjustment of results
Any of the chosen methods will show only an approximate result if all factors affecting the decrease or increase in heat loss are not taken into account. For an accurate calculation, it is necessary to multiply the obtained value of the power of the radiators by the coefficients below, among which you need to choose the appropriate ones.
Window
Depending on the size of the windows and the quality of the insulation through them, the room can lose 15–35% of heat. Hence, for the calculations we will use two coefficients associated with windows.
The ratio of the area of \u200b\u200bthe windows and the floor in the room:
- 10% - coefficient 0.8;
- 20% – 0,9;
- 30% – 1,0;
- 40% – 1,1;
- 50% – 1,2.
Glazing type:
- for a window with a triple-glazed window or a double-glazed window with argon - 0.85;
- for a window with an ordinary double-glazed window - 1.0;
- for frames with conventional double glazing - 1.27.
Walls and ceiling
Heat loss depends on the number of external walls, the quality of thermal insulation and on which room is located above the apartment. To account for these factors, 3 more coefficients will be used.
Number of outer walls:
- no external walls, no heat loss - coefficient 1.0;
- one outer wall - 1.1;
- two - 1.2;
- three - 1.3.
Thermal insulation coefficient:
- normal thermal insulation (wall with a thickness of 2 bricks or a layer of insulation) - 1.0;
- high degree of thermal insulation - 0.8;
- low - 1.27.
Accounting for the type of the upstairs room:
- heated apartment - 0.8;
- heated attic - 0.9;
- cold attic - 1.0.
Ceiling height
If you used the method of calculating the area for a room with a non-standard wall height, then you will have to take it into account to clarify the result. The coefficient can be found as follows: divide the existing ceiling height by the standard height, which is 2.7 meters. Thus we get the following numbers:
- 2.5 meters - coefficient 0.9;
- 3.0 meters - 1.1;
- 3.5 meters - 1.3;
- 4.0 meters - 1.5;
- 4.5 meters - 1.7.
Climatic conditions
The last coefficient takes into account the air temperature outside in winter. We will start from the average temperature in the coldest week of the year.
- -10 °C - 0.7;
- -15 °C - 0.9;
- -20 °C - 1.1;
- -25 °C - 1.3;
- -35 °C - 1.5.
Calculation of the number of radiator sections
After we know the power required to heat the room, we can calculate the heating batteries.
In order to calculate the number of radiator sections, you need to divide the calculated total power by the power of one section of the device. For calculations, you can use the average statistics for different types of radiators with a standard axial distance of 50 cm:
- for cast iron batteries, the approximate power of one section is 160 W;
- for bimetallic - 180 W;
- for aluminum - 200 watts.
Reference: the axial distance of the radiator is the height between the centers of the holes through which the coolant is supplied and removed.
For example, let's determine the required number of sections of a bimetallic radiator for a room of 15 square meters. m. Suppose that you considered the power in the simplest way by the area of \u200b\u200bthe room. We divide the 1500 watts of power required for its heating by 180 watts. We round the resulting number 8.3 - the required number of sections of the bimetallic radiator is 8.
Important! If you decide to choose batteries of a non-standard size, find out the power of one section from the device's passport.
Dependence on the temperature regime of the heating system
The power of the radiators is indicated for a system with a high temperature thermal regime. If the heating system of your home operates in medium or low temperature thermal conditions, you will have to make additional calculations to select batteries with the required number of sections.
To begin with, let's determine the thermal head of the system, which is the difference between the average temperature of the air and the batteries. The temperature of the heating devices is taken as the arithmetic mean of the supply and discharge temperatures of the coolant.
- High temperature mode: 90/70/20 (supply temperature - 90 °C, return temperature -70 °C, 20 °C is taken as the average room temperature). We calculate the thermal head as follows: (90 + 70) / 2 - 20 \u003d 60 ° С;
- Medium temperature: 75/65/20, heat head - 50 °C.
- Low temperature: 55/45/20, heat head - 30 °C.
To find out how many battery sections you will need for 50 and 30 heat head systems, multiply the total capacity by the radiator nameplate head and then divide by the available heat head. For a room of 15 sq.m. 15 sections of aluminum radiators, 17 bimetallic and 19 cast iron batteries will be required.
For a heating system with a low temperature regime, you will need 2 times more sections.
