How to calculate the power of a gas boiler

Autonomous heating of home ownership requires the installation of a heating source. Traditional gas boilers remain in demand, despite the abundance of equipment operating using other resources. This is due to the low price of gas used and the comfort of use in everyday life.

Calculation of boiler power

The initial characteristic of the heat source is power. Depending on individual operating requirements, a value of a given value is selected, which is measured in kilowatts (kW). Manufacturers of heating equipment offer a large selection of models with various parameters to satisfy users of all categories and capabilities. To understand what capacity a boiler should have, the amount of thermal energy spent on heating a house and preparing hot water is calculated.

Single circuit

To maintain a comfortable temperature of a private house in the winter, in the absence of the need to heat hot water, the calculation of the boiler thermal power is based on the characteristics of the structure.

A simple calculation of detached buildings uses a square meter measurement, which is multiplied by 0.1, because the method requires 1 kW per 10 square meters. m. After that add 15-20% (for middle latitudes) and take the resulting value - as calculated. For example, we calculate the required amount of heat for a cottage, an area of ​​130 square meters. m:

130x0.1 = 13 kW;

13 + 15% = 14.95 kW.

We round, we get 15 kW necessary for heating a house with an area of ​​130 square meters. m. It is of such power that a heat source is selected.

The calculation is very approximate, because it does not take into account all the factors that affect the required amount of thermal energy. Building Norms and Rules (SNIPA) recommend for the middle latitudes to use the calculated value of 41 W, necessary for heating 1 cubic meter of the room. The same regulatory documents regulate the need to use raising and lowering coefficients, which depend on the parameters:

  • object insulation;
  • the number of windows, their area;
  • method of connecting heating devices;
  • desired temperature;
  • the presence of adjacent buildings and structures;
  • coolant temperature;
  • heat loss.

REFERENCE! Local standards used by construction organizations during work in the Moscow region recommend using a value of 50 W per 1 cubic meter. m, to calculate the thermal power of detached buildings!

Now we calculate the necessary parameter using building codes. The same house, the ceiling height is 3.2 m. Window openings have an increased area, the walls are insulated with polystyrene, 10 cm thick. First, we calculate the volume: 130x3.2 = 416 cubic meters. m, then we multiply by the recommended value for the 1st cube: 416x41 = 17056 kW.

Now we apply the correction factors regulated by SNIPA:

  • insulation - 0.85;
  • increase in window openings - 1.05;
  • isolation of the building - 1.2.

Now apply and get: 17056x0.85x1.05x1.2 = 18.267 kW

We round up to 18.5 and we see the difference between the approximate and refined calculation, which is recommended by regulatory documents. Given that finding a boiler with a power of 18.5 or 19 kW will not be easy, the user will have to make a choice on a 20 kW unit.

Bypass

The peculiarity of using a double-circuit boiler allows you to heat the required room and provide all its residents with heated water, up to 40-45 degrees. In this regard, the calculation of the selected unit is complicated. In addition to the value due to which it is possible to maintain a comfortable air temperature, determine the power necessary for the preparation of water, disassembled at one, two or more points at the same time.

The preparation of hot water, as well as heating, is influenced by a large number of factors:

  • number of water points;
  • diameter of water pipes;
  • pressure in the highway;
  • cold water temperature;
  • length of pipelines.

The average value of the required amount of heat for heating water to 40-45 degrees. makes 6-8 kW. The owners of geysers in old houses know that their power, for two points, was 12-16 kW. Using the average value, we calculate the necessary parameters of a double-circuit boiler for a cottage with an area of ​​130 square meters. m

Suppose that the cottage has two toilets, a bathroom, a shower and a kitchen. The provision of hot water will be required at three points of drawdown. A simple calculation shows: 7x3 = 21 kW. It is such an amount of thermal energy that will be required while turning on three hot water taps.

Now we have two values ​​for determining the power of the boiler. One for the heating circuit and the other for the preparation of hot water. The accuracy of further calculations is based on the principle of operation of dual-circuit equipment.

The specifics of the unit's operation does not provide for the simultaneous heating of two circuits: if the analysis of hot water supply is turned on, the automation turns off the heating of the coolant in the heating system and actively heats the water preparation heat exchanger. Therefore, in order to correctly determine the required power of a gas double-circuit boiler, in no case can the calculated values ​​be added. The initial value is a large value, which is taken as a basis when choosing the necessary equipment. In the considered example, it is 21 kW.

ATTENTION! If the calculated parameters differ several times, then anyway, the determining value is a larger value, regardless of whether it was calculated when calculating heating or preparing hot water!

With a boiler

Calculation of thermal power for a cottage in which it is planned to install an electric water heater is reduced to calculation with a single-circuit boiler. This is due to the lack of the need for a gas heat source to spend energy on the preparation of hot water. The energy of the boiler will be directed only to maintaining a comfortable temperature in the building.

Why do you need an accurate calculation of the power of a gas boiler

The two calculation methods described above for a single-circuit unit show a large difference in values ​​between a rough and a refined calculation. It is more correct to use the second method. This will help maintain a comfortable microclimate in the building, in any frost and wind. Using the data of the first calculation will lead to underheating of the building with a significant decrease in temperature on the street.

The rough calculations that are used to determine thermal power serve as an indicative indicator when choosing a heat source. The choice of equipment based on an approximate calculation will lead to the necessity of operating the unit at a maximum capacity, which will lead to a reduction in the life of the boiler. To be sure of the accuracy of the calculations, they use all the recommendations of construction standards.

Additional factors to consider when installing the boiler

When installing a heat source, it is possible to supply air (for closed combustion chambers) and exhaust exhaust products. The correct installation of a coaxial or simple chimney will save the room from the accumulation of harmful gases and maintain the required microclimate. To prevent the formation of condensate, the installation of the smoke exhaust channel is carried out subject to all necessary rules and regulations.

IMPORTANT! According to the method of installing the heat source, two types of structures are distinguished: wall or floor. This factor can affect the arrangement of the interior of the room in which the unit will be mounted.

Is excess power needed

Some craftsmen, after carrying out a rough calculation, argue about the need to use heating equipment with a power reserve of 1.5-2 times, so as not to miscalculate. Operation of a more powerful heat source will lead to increased gas consumption, especially in an economical mode of maintaining the required temperature of the coolant. In addition, the cost of the boiler will differ by an order of magnitude from the unit with lower power indicators. The acquisition and installation of a heat source corresponding to the calculations made will allow more efficient use of the capabilities of the heating unit.

Having studied the methodology for calculating power, a consumer can independently calculate the required boiler parameters for his home ownership and help friends and relatives solve this issue.

Watch the video: New Gas Boiler Not Working No Power , Fault Finding Heating Gas Engineer (March 2024).

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