Calculation of the power of a gas boiler

Boiler types

When choosing a boiler, you need to consider what type of heater it works on.

Solid fuel boilers

Boilers have the following advantages:

profitability;
autonomy;
simplicity of design and control.

it is necessary to prepare and store fuel;
periodic loading of fuel and cleaning from combustion products is necessary;
daily temperature fluctuations within 5ºС.

The system is far from the best, but in the absence of other sources of fuel, this is the only possible option.

Disadvantages can be reduced by using a bulb or water accumulators. The thermal bulb regulates the air supply to the furnace, thereby increasing the duration of fuel combustion. This increases efficiency and reduces the number of refills. Heat accumulators are designed to increase the inertia of the heating system. A container that is thermally insulated from the outside crashes into the heating circuit. The installation of a thermostatic valve installed at the inlet of the registers limits the supply of cold water from the heat accumulator at its inlet.

Due to this, the coolant heats up quickly, and then the heat accumulator begins to heat up. The heat transfer to the heating system takes much longer. Thus, temperature fluctuations in the house are reduced.

The heating elements built into the heat accumulator with automatic control allow you to turn it on for electric heating at night, when the cost of electricity is minimal. In fact, the heat accumulator performs the function of an electric boiler. The efficiency of a solid fuel boiler is 71-79%. The creation of pyrolysis boilers allows you to raise it up to 85%. It is necessary for everyone to know that this type of boilers works only on wood.

gas boilers

The use of a gas boiler is the best option for home heating. It is simple and safe to operate, has cheap fuel that does not need to be stored and loaded.

It needs a chimney. The boiler room is required only for boilers with an open combustion chamber. The efficiency of gas boilers is 89-91%, but there are even more efficient boilers. Therefore, this indicator is given in the characteristics of each model.

Electric boilers

An electric boiler is the most environmentally friendly source of heat. It can be used to heat hot water through a boiler or as a backup source.

For private houses, models are sold with a power of up to 20 kW. The large power of the boiler may not be pulled by electricity meters that the electrical service installs at the entrance. Despite the high cost of electricity, electric boilers have the highest efficiency of 99%. Step power adjustment ensures their more economical operation.

Conclusion

If you calculate the power of the heating boiler using the above simple methods, you can select the required unit for heating the house. The calculation option through the heat losses of the enclosing structures makes it possible to more accurately determine the required boiler power.

If the house is provided with sufficient insulation, then the boiler will be needed with less power, and the cost of space heating will significantly decrease due to the reduction in heat loss.

What factors are taken into account in the calculations

The decrease in the temperature in the house occurs due to the penetration of cold through the walls, floor, ceiling, windows and doors, as well as the flow of cold air through the ventilation ducts. The power of the gas boiler must compensate for all heat losses and maintain a constant set temperature in all residential premises

When making calculations, the following factors should be taken into account:

The area of floors (floor and ceiling), fences (walls), roofing and glazing.
Thermal conductivity and thickness of the materials used to build the building. At the same time, facing and finishing materials are taken into account.Coefficient tables are easy to find on the Internet or specialized directories, this value is calculated in W / (m * C °).
The minimum temperature in the region during the cold season.
The average room temperature for the comfort of the occupants of the building.

Heating equipment store consultants often recommend calculating the power of a gas boiler based on the following ratio: 40 W per cubic meter of volume or 1 kW per 10 m² with a standard room height of 2.5-2.6 meters. However, such calculations are quite approximate, and as a result, the purchased equipment has a power reserve of 10-25%, depending on the situation, which affects its price and installation method.

When calculating the heating power, it should be taken into account that during ventilation, heat loss can reach 15%, low heat resistance of the walls will lead to a loss of another 35%, non-insulated and low-quality windows and doors - 10-15%, floor - 15%, and roofing - up to 25% .

What are the advantages of a TT boiler

What is the advantage of solid fuel boilers compared to their counterparts running on gas, electricity or liquid fuel? Let's look at their main advantages:

autonomy

They do not depend on gas pipelines and power lines. Wherever your country house is located, you can always use a solid fuel boiler for heating it.

Fuel Availability

Firewood and coal are traditional sources of fuel in Russia and the countries of the former CIS, due to their wide availability. In addition to affordability, wood or coal is significantly cheaper than gas or electricity.

Ease of construction and connection

A simple design allows, without special experience and serious costs, to make even a home-made solid fuel pyrolysis boiler with your own hands and install it yourself.

Long service life

Modern boilers are made of cast iron or steel. With proper operation and careful care, they will easily serve you for about 20-30 years.

As you can see, the TT boiler is ideal for heating your summer house or cottage. It has many advantages, it is not surprising that many owners of suburban real estate use a solid fuel boiler as the main source of heating.

Calculation of the power of a gas boiler Photo 1: Two-story country house

What solid fuel boiler is better to choose for your country house? There are many modifications of TT boilers on the Russian market, which is not difficult to get confused. Let's look at their main types:

Traditional

They are characterized by simplicity of design and low cost, compared with more complex modifications. The downside is that they have a relatively low efficiency.

Pyrolysis

Their peculiarity is that gas is released from the fuel, which is burned separately from the solid part. This achieves a significantly higher efficiency, due to significantly better fuel burn-out. The disadvantage of such boilers is that they are 2 times more expensive than classic ones.

long burning

Due to their design features, bookmarks have to be done much less frequently.

We examined the main modifications of solid fuel boilers, now let's figure out what are the main parameters to choose it.

Calculation of the heating boiler power by area

For an approximate assessment of the required performance of a thermal unit, the area of \u200b\u200bthe premises is sufficient. In the simplest version for central Russia, it is believed that 1 kW of power can heat 10 m 2 of area. If you have a house with an area of 160m2, the boiler power for heating it is 16kW.

These calculations are approximate, because neither the height of the ceilings nor the climate are taken into account. To do this, there are coefficients derived empirically, with the help of which appropriate adjustments are made.

The indicated rate - 1 kW per 10 m 2 is suitable for ceilings 2.5-2.7 m. If you have higher ceilings in the room, you need to calculate the coefficients and recalculate. To do this, divide the height of your premises by the standard 2.7 m and get a correction factor.

Calculating the power of a heating boiler by area - the easiest way

For example, the ceiling height is 3.2m. We consider the coefficient: 3.2m / 2.7m \u003d 1.18 rounded up, we get 1.2. It turns out that for heating a room of 160m 2 with a ceiling height of 3.2m, a heating boiler with a capacity of 16kW * 1.2 = 19.2kW is required. They usually round up, so 20kW.

To take into account climatic features, there are ready-made coefficients. For Russia they are:

1.5-2.0 for northern regions;
1.2-1.5 for regions near Moscow;
1.0-1.2 for the middle band;
0.7-0.9 for the southern regions.

If the house is located in the middle lane, just south of Moscow, a coefficient of 1.2 is applied (20kW * 1.2 \u003d 24kW), if in the south of Russia in the Krasnodar Territory, for example, a coefficient of 0.8, that is, less power is required (20kW * 0 ,8=16kW).

Calculation of heating and selection of a boiler is an important stage. Find the wrong power and you can get this result ...

These are the main factors to be considered. But the values found are valid if the boiler will only work for heating. If you also need to heat water, you need to add 20-25% of the calculated figure. Then you need to add a "margin" for peak winter temperatures. That's another 10%. In total we get:

For home heating and hot water in the middle lane 24kW + 20% = 28.8kW. Then the reserve for cold weather is 28.8 kW + 10% = 31.68 kW. We round up and get 32kW. When compared with the original figure of 16kW, the difference is two times.
House in the Krasnodar Territory. We add power for heating hot water: 16kW + 20% = 19.2kW. Now the "reserve" for the cold is 19.2 + 10% \u003d 21.12 kW. Rounding up: 22kW. The difference is not so striking, but also quite decent.

It can be seen from the examples that it is necessary to take into account at least these values. But it is obvious that in calculating the power of the boiler for a house and an apartment, there should be a difference. You can go the same way and use coefficients for each factor. But there is an easier way that allows you to make corrections in one go.

When calculating a heating boiler for a house, a coefficient of 1.5 is applied. It takes into account the presence of heat loss through the roof, floor, foundation. It is valid with an average (normal) degree of wall insulation - laying in two bricks or building materials similar in characteristics.

For apartments, different rates apply. If there is a heated room (another apartment) on top, the coefficient is 0.7, if a heated attic is 0.9, if an unheated attic is 1.0. It is necessary to multiply the boiler power found by the method described above by one of these coefficients and get a fairly reliable value.

To demonstrate the progress of calculations, we will calculate the power of a gas heating boiler for an apartment of 65m 2 with 3m ceilings, which is located in central Russia.

We determine the required power by area: 65m 2 / 10m 2 \u003d 6.5 kW.
We make a correction for the region: 6.5 kW * 1.2 = 7.8 kW.
The boiler will heat the water, so we add 25% (we like it hotter) 7.8 kW * 1.25 = 9.75 kW.
We add 10% for cold: 7.95 kW * 1.1 = 10.725 kW.

Now we round the result and get: 11 kW.

The specified algorithm is valid for the selection of heating boilers for any type of fuel. The calculation of the power of an electric heating boiler will not differ in any way from the calculation of a solid fuel, gas or liquid fuel boiler. The main thing is the performance and efficiency of the boiler, and heat losses do not change depending on the type of boiler. The whole question is how to spend less energy. And this is the area of \u200b\u200bwarming.

What data is needed to calculate the power of a gas boiler

For private houses built according to a standard project, with a ceiling height of about 3 meters, the calculation formula looks quite simple. In this case, it is necessary to take into account the building area (S) and the boiler specific power index (UMK), which varies depending on the climatic zone. He hesitates:

From 0.7 to 0.9 kW in the southern regions of the country
From 1 to 1.2 kW in the regions of the middle lane
From 1.2 to 1.5 kW in the Moscow region
1.5 to 2 in the north of the country

Thus, the formula for calculating the power of a gas boiler for a typical private house will look like this:

Let's try to calculate the required power of the unit for a house of 80 m², located in the northern region. Get:

If the consumer chooses a double-circuit boiler. whose task, in addition to heating the home, will also be heating water, experts recommend adding another 20% to the figure obtained using the formula.

Boiler power for apartments

When calculating heating equipment for apartments, you can use the norms of SNiPa. The use of these standards is also called the calculation of boiler power by volume. SNiP sets the required amount of heat for heating one cubic meter of air in standard buildings:

heating 1m 3 in a panel house requires 41W;
in a brick house on m 3 there is 34W.

Knowing the area of \u200b\u200bthe apartment and the height of the ceilings, you will find the volume, then, multiplying by the norm, you will find out the power of the boiler.

Boiler power calculation does not depend on the type of fuel used

For example, let's calculate the required boiler power for rooms in a brick house with an area of 74m 2 with ceilings of 2.7m.

We calculate the volume: 74m 2 * 2.7m = 199.8m 3
We consider according to the norm how much heat will be needed: 199.8 * 34W = 6793W. Rounding up and converting to kilowatts, we get 7kW. This will be the required power that the thermal unit should produce.

It is easy to calculate the power for the same room, but already in a panel house: 199.8 * 41W = 8191W

In principle, in heating engineering they always round up, but you can take into account the glazing of your windows. If the windows have energy-saving double-glazed windows, you can round down

We believe that double-glazed windows are good and we get 8kW.

The choice of boiler power depends on the type of building - brick heating requires less heat than panel

Next, you need, as well as in the calculation for the house, to take into account the region and the need to prepare hot water. The correction for abnormal cold is also relevant. But in apartments, the location of the rooms and the number of floors play a big role.

You need to take into account the walls facing the street:

One outer wall - 1.1
Two - 1.2
Three - 1.3

After you take into account all the coefficients, you will get a fairly accurate value that you can rely on when choosing equipment for heating. If you want to get an accurate heat engineering calculation, you need to order it from a specialized organization.

There is another method: to determine the real losses with the help of a thermal imager - a modern device that will also show the places through which heat leaks are more intense. At the same time, you can eliminate these problems and improve thermal insulation. And the third option is to use a calculator program that will calculate everything for you. You just need to select and / or enter the required data. At the output, get the estimated power of the boiler. True, there is a certain amount of risk here: it is not clear how correct the algorithms are at the heart of such a program. So you still have to at least roughly calculate to compare the results.

This is what a thermal image looks like

We hope you now have an idea of how to calculate the power of the boiler. And you are not confused that this is a gas boiler. rather than solid fuel, or vice versa.

Based on the results of the inspection, heat leaks can be eliminated

You may be interested in articles on how to calculate the power of radiators and the choice of pipe diameters for a heating system. In order to have a general idea of the mistakes that are often encountered when planning a heating system, watch the video.

The concept of dissipation factor

The dissipation coefficient is one of the important indicators of heat exchange between the living space and the environment. Depending on how well the house is insulated. there are such indicators that are used in the most accurate calculation formula:

3.0 - 4.0 is the dissipation factor for structures in which there is no thermal insulation at all.Most often in such cases we are talking about makeshift houses made of corrugated iron or wood.
A coefficient from 2.9 to 2.0 is typical for buildings with a low level of thermal insulation. This refers to houses with thin walls (for example, one brick) without insulation, with ordinary wooden frames and a simple roof.
The average level of thermal insulation and a coefficient from 1.9 to 1.0 are assigned to houses with double plastic windows, insulation of external walls or double masonry, as well as with an insulated roof or attic.
The lowest dispersion coefficient from 0.6 to 0.9 is typical for houses built using modern materials and technologies. In such houses, the walls, roof and floor are insulated, good windows are installed and the ventilation system is well thought out.

Table for calculating the cost of heating in a private house

The formula in which the value of the dissipation coefficient is used is one of the most accurate and allows you to calculate the heat loss of a particular building. It looks like this:

In the formula, Qt is the level of heat loss, V is the volume of the room (the product of length, width and height), Pt is the temperature difference (to calculate, you need to subtract the minimum air temperature that can be in this latitude from the desired temperature in the room), k is the scattering coefficient.

Let's substitute the numbers into our formula and try to find out the heat loss of a house with a volume of 300 m³ (10 m * 10 m * 3 m) with an average level of thermal insulation at a desired air temperature of + 20 ° C and a minimum winter temperature of - 20 ° C.

Having this figure, we can find out what power the boiler needs for such a house. To do this, the obtained value of heat loss should be multiplied by a safety factor, which is usually from 1.15 to 1.2 (the same 15-20%). We get that:

Rounding the resulting number down, we find the desired number. To heat a house with the conditions we set, a boiler of 38 kW is required.

Such a formula will allow you to very accurately determine the power of the gas boiler required for a particular house. Also, to date, a wide variety of calculators and programs have been developed that allow you to take into account the data of each individual building.

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We calculate the power of the boiler

In order not to make a mistake with the choice, not to lose money and not to stay cold in the winter in a slightly warm house, it is necessary to correctly calculate the power of a solid fuel heating boiler. Before proceeding directly to the calculation, it is necessary to decide for what purposes the solid fuel boiler will be used?

The boiler can be used both exclusively for heating, and for heating and producing hot water for sanitary needs (shower, bath, washing dishes)

For each of the cases, devices of different capacities will be required.
You should also pay attention to the region in which it will be operated. When making calculations, one should take into account the ambient temperature and the fact that the heater must cover the heat loss of the house on the coldest days of the year.
Attention should also be paid to the design of the house itself.

Country houses come in different types, from simple frame and wooden houses to large luxury country cottages. Heat loss from different walls will vary significantly, and this should be taken into account.

Calculation of the power of a gas boiler Photo 3: Installation of the boiler in a country house

For calculations, we need the following parameters:

Room area;
Specific power adjusted for the region;

Specific power for Russian regions:

for Moscow and the Moscow region - 1.2 - 1.5 kW;
for the northern part of Russia - 1.5 - 2.0 kW;
for the southern regions of Russia - 0.7 - 0.9 kW.

The formula for the calculation is as follows:

Boiler power (kW) \u003d (Room area (m2) * Specific power (kW)) / 10

It is also necessary to know the amount of coolant required to fill the heating system. It is equal to approximately 15 liters per 1 kW.

Heat carrier volume (l) = Boiler power (kW) * 15

For instance: It is required to calculate a heating boiler for a country house with an area of 150m2 located in the Moscow region:

Boiler power (kW) = (150 * 1.2) / 10 = 18 kW

Calculate the required volume of liquid to fill the heating system:

Coolant volume (l) \u003d 18 * 15 \u003d 270 l

Such a calculation does not take into account the real heat losses of the house, which are calculated individually for each individual case. Indicative data is as follows:

frame houses 120 - 200 W / m2;
old wooden houses with thermal insulation 90 - 120 W / m2;
brick cottages with plastic windows 60 - 90 W / m2;

Also, if it is necessary to provide hot water supply, about 25-30% is added to the boiler power.

With simplified calculations, the specific heat capacity is usually considered equal to 1, then approximately 1 kW is enough to heat 10 m2 of area.