Despite the large number of options for heating private houses, many people prefer a proven option - gas or solid fuel boilers. Such a unit is reliable and durable, does not require complex maintenance. In addition, the variety of models makes it possible to accurately select the device for a particular room. Power is the main characteristic of heating devices. It is on how correctly the device is chosen that the comfort of the home microclimate, efficiency, safety of the boiler, and its working life depend. In this article, we will consider how to choose a boiler for heating a private house in terms of power, what factors must also be taken into account.
Why is accurate power calculation necessary?
The choice of a boiler is based on accurate calculations, allowing you to have an idea of the real heat loss of a private house:
- The purchase of a device with an excess resource leads to unjustified fuel consumption.
- A low-power unit will not be able to heat the living space with high quality. In addition, working at the limit of its capabilities, it will quickly fail.
Important! How to choose a boiler according to the area of \u200b\u200bthe house in the easiest way? The simplest boiler calculation is 1 kW of power per 10 “squares” of housing, plus a margin of 15-20%. For example, to heat a house of 100 m², you need a 12,000 W boiler. This calculation is very enlarged and approximate. It can only be used for buildings with good thermal insulation, with low ceilings and for regions with a mild climate. Naturally, not all private houses meet these requirements.
Initial data for calculation
For a house made according to a standard project, with ceilings 3.0 m high, it is not difficult to calculate the required power of the heating device. Consider how a gas boiler is selected for a private house by area. The calculation is based on 2 parameters:
- The total area of the house.
- Boiler specific power (UMK). This indicator varies for different climatic zones.
The value of the UMC is:
- For the southern regions - 0.7-0.9 kW.
- For the middle band - 1.0-1.2 kW.
- For the northern regions - 1.5-2.0 kW.
The formula for the calculation will look like this: M \u003d S x UMK / 10, where
- M - boiler power, kW.
- S is the area of the house,
- UMK - specific power of the boiler.
Important! For example:
- The value of the desired indicator for a house with an area of 100 m², located in the southern region, is: M \u003d 100 x 0.9 / 10 \u003d 9 kW.
- For the same building in the northern regions, the same indicator for a heating boiler will be: M \u003d 100 x 2/10 \u003d 20 kW.
As you can see, the difference is more than doubled. If you want to install a two-circuit unit, increase the figure obtained during the calculation by 20%.
Accounting for heat loss
Even the above calculation is not accurate. For the correct choice of a heating device, it is necessary to have information about real heat losses. One house is well insulated, and the other has old frames of dried wood and walls one brick thick. Heat losses in these buildings, of course, will be different.
Important! According to experts:
- The largest heat leakage (about 35%) falls on insufficiently insulated walls.
- Approximately a quarter of heat loss occurs on an uninsulated or poorly insulated roof.
- Insufficiently thought-out floor insulation is the cause of about 15% of heat leakage.
- Only 10-15% of heat leakage comes from ventilation and open windows.
As you can see, the simplest formula for an accurate calculation is clearly not enough. In each case, the calculation of power will be individual.
Accounting for the dissipation factor
This coefficient is one of the most important indicators of heat exchange between the room and the external environment. When calculating, the following values of this coefficient are taken as a basis:
- 3.0-4.0 - for buildings in which there is no thermal insulation. Most often these are temporary buildings made of wood and metal.
- 2.9-2.0 - for buildings with minimal thermal insulation. This refers to thin-walled houses with uninsulated walls, the simplest roof structure and wooden frames.
- 1.9-1.0. This value of the dispersion coefficient corresponds to the average level of insulation (brick house with insulated or double walls, with an insulated roof and an attic, with double-glazed windows).
- 0.6-0.9. This coefficient is applied to houses built using modern technologies and materials. They are characterized by a well-thought-out ventilation system, insulated floors and roofs, and well-insulated windows.
Important! The most accurate formula for calculating possible heat losses: Qt \u003d V * Pt * k / 860, where
- Qt - possible heat losses;
- V is the volume of the room.
- Ht is the difference between the desired indoor temperature and the minimum outside air temperature characteristic of these latitudes;
- k is the scattering coefficient.
We calculate the heat loss for a house of 100 "squares" with ceilings 3 m high, an average level of thermal insulation:
- The desired room temperature is +20 degrees.
- The minimum air temperature for this region is the same 20 degrees, but with a minus sign.
- Qt \u003d 300 x 40 x 1.9 / 860 \u003d 26.5 kW.
- Taking into account the margin, we multiply the resulting figure by 20%: 26.5 x 1.2 \u003d 31.8 kW.
- Rounding the resulting figure to the nearest whole number, we get a power of 32 kW.
This calculation allows you to choose a boiler unit with a sufficiently high accuracy, taking into account the climate in the region and the characteristics of the structure.
Special calculation programs
You can use various programs and online calculators to calculate. The advantage of such programs is that a large number of different factors are taken into account:
- Desired room temperature.
- Average temperature during the cold season.
- The need for hot water.
- Number of floors.
- The presence or absence of a forced ventilation system.
- Ceiling height.
- Wall thickness, floor characteristics.
- The number of windows, their dimensions and characteristics (number of chambers, glass thickness).
By filling in the form fields, you get the exact value of the initial power, and then select the device according to its characteristics.
A gas boiler - universal heat exchanger, providing circulation of hot water for household purposes and space heating.
The device looks like like a small refrigerator.
When installing a heating boiler, it is necessary to correctly calculate its power.
Calculation of the power of a gas heating boiler for a private house
Convenience and safety of being in a room with a boiler depends on its performance.
In any case, you need to take a value greater than the calculated one, so that the boiler has power reserve. The unit should not work at the limit of its characteristics and capabilities, as this will lead to breakage in the coming months after purchase. And also consider the chance of abnormal temperatures in your area. And for country houses, it will not be superfluous to take into account the possibility of expanding and the emergence of new rooms, and therefore an increase in area in the future.
Boiler performance is measured in kW (kilowatts). This value is always indicated in the technical documents of the model.
Attention! It is not necessary to install the boiler if on the street low air temperature.
Why Calculate Power
The calculation of power is very important, because excess heat output will lead to:
- Rapid wear all components of the unit.
- Evaporation of water in the chimney ( condensate).
- Deterioration of the gas boiler and reduced efficiency.
- big expenses- powerful models are more expensive on the market.
- Failure of automation at low loads.
Therefore, choose your device carefully and try to find a boiler with the required capacity.
Data for calculation: ceiling height, area, climate and more
- Ceiling height desirable at least two meters. The room where the unit is located must have fireproof walls. Low ceilings can lead to unsafe design.
- Climatic conditions of the region. Each region has its own climate coefficient, and this indicator is used when calculating the power using the formula. For the central part of Russia, this from 1.2 to 1.5; for the southern regions - about 0.7; and for the northern regions - 1,2—1,5.
- Volume of water for heating also affects the efficiency of the system. The coolant (heated by the boiler) remains in the house, and heat remains with it.
- Room area is an important parameter. The easiest way to calculate since Soviet times is for every ten sq. m. used 1 kW of energy. Now, of course, there are more parameters for calculation, but the area remains an important criterion.
Important! When installing the boiler in the kitchen, there is one rule - use only wall views. It is desirable that it has a closed combustion chamber.
- The degree of insulation of the house and heat loss. In some houses, “warm floor” systems are installed, and household appliances also generate heat. In this case, performance should be increased at least even more. by 20% no matter how strange it may seem.
Photo 1. Heat loss of the house through its various parts, expressed as a percentage.
- House ventilation type. There are special requirements for ventilation when installing the unit - the air volume in the room must change three times per hour. To do this, you need a supply and exhaust system and windows with vents.
- When installing wall-mounted unit, pay attention to the strength of the walls. When installing a floor boiler - for fire resistance and floor strength.
Attention! At the front door, do not forget to do Mesh opening for good air circulation.
- Heating premises with swimming pool not much different from ordinary houses, only the temperature in the room no more than 28 °C. If there is greenhouse, then the temperature will have to be compared with the thermophilicity of the plants in it.
Formula selection
In fact, calculating the performance of a unit for an ordinary house is a very easy task. First count:
- Total floor area in square meters(S).
- Climate coefficient(the coefficients are painted a little higher) (CL).
With these parameters, you can find the power by substituting the data into the formula: MK=S*CL/10. MK - performance in kilowatts. For example, for home in 100 sq. meters, located in the central part of Russia, MK will be 11 kW.
Important! This formula is suitable for calculating the power of a single-circuit system, only for heating a house. If you need a double-circuit boiler, which, in addition to heating, will heat water, increase the power even more. by 25%.
A more accurate calculation method for an individual building project is MK \u003d Qt * Kz, where:
- Qt - room heat loss.
- Kz- a safety factor equal to approximately 1,2.
Heat loss is measured by a different formula: Qt=V*k*Pt, where:
- V- the volume of the building in cubic meters.
- Pt is the difference between the outside and inside temperatures in degrees Celsius.
- k- another coefficient depending on the material of the structure (scattering coefficient). For ordinary buildings without thermal insulation, it is 3—4 , for low thermal insulation (brick buildings in one masonry) about 2-2.9; for the middle level (ordinary houses) - 1 ; well, for high levels the coefficient is equal to 0,6 .
Reference. The websites of many gas equipment manufacturers have special calculators to calculate the required performance. This greatly simplifies the task of counting.
Fuel consumption calculation
Fuel consumption must also be calculated. This will require the following data:
- efficiency- the indicator is displayed in the technical passport. The parameter required for the calculation is usually indicated as Hi and it is equal 87—92%.
- Recommended unit power in kW (found by the previous formula).
In technical documents, manufacturers indicate average fuel consumption values. If you calculate everything yourself, it will be clear that on 10 kW power at an efficiency of approx. 92% required per hour 1.12 cubic meters blue fuel.
In terms of power, the comfort of living in the house depends. This also affects the depreciation of boiler equipment, the duration of its operation and fuel consumption, that is, the monthly cost of operating the cottage.
Autonomous home heating is a complex system that requires detailed calculation. One of the important variables is heating boiler power. This article is about how to calculate it correctly, what parameters you should pay attention to and why do it at all - calculate the boiler power. Let's start with the "why" question.
If the capacity of the boiler exceeds the needs, then, of course, it will perform its function of heating the building and preparing hot water. But, firstly, the cost of boiler equipment depends on the power. Therefore, making a purchase without preliminary calculations, you will certainly spend more money in vain.
Secondly, excess power, which exceeds the needs of the building's heat loss, leads to an increased load on the entire hydraulic system. Excessive load leads to unbalanced operation of the system, failures in automation and, ultimately, to a rapid failure of equipment.
Partially, this problem can be overcome if the boiler is equipped with a multi-stage modulating burner, when the flame burning intensity is regulated depending on the requested power. Another option is to install a hydraulic switch in the system, perhaps in addition to a multi-stage burner.
But in this way the issue is only partially solved: if the difference between the required and generated power is significant, then the modulating burner will not work in a multi-stage mode. Therefore, the operation of the boiler will be pulsed, as in equipment with a single-stage burner.
Thirdly, the burner of a powerful boiler, heating the coolant, turns off too quickly, does not have time to completely burn out, but warms up. As a result, we get increased soot deposition in the chimney and on the heat exchanger (the need for frequent cleaning), as well as the formation of excessive condensate. And all the same possible failures in the heating system.
What parameters affect the choice of the boiler
In addition to the financial issue and the type of fuel available, the main parameter when choosing a heating boiler is its power. That is, how much heat does it generate, and is this heat enough for heating and hot water preparation, if hot water supply (hot water supply) is also assigned to this boiler.What affects the ability of heating equipment to heat a house?
Heat loss
The most important parameter that determines whether the house will have a comfortable temperature is heat loss building. No matter how powerful the boiler is and has a high efficiency, if the house is not, then do not expect comfort in it.Most of the heat escapes through the roof and the ventilation system, including chimneys: approximately 25-30% each. Through the outer walls and windows, 10-15% is lost, the junction of the foundation to the ground also takes about 15%, another 10-15% falls on the floor of the first floor and unheated. Therefore, the task of insulating a building is closely related to the choice of heating equipment: it is better to insulate - a boiler will be required for less power.
Simplified boiler power calculation scheme
In practice, a simplified scheme of heat engineering calculations based on the building area is often used. If the building has standard insulation of walls and other enclosing structures, that is, it has calculated heat loss, then it is assumed that 1 kW of power is required for heating every 10 m² of space.To correct calculations for different regional climatic conditions, the following coefficients are used:
- for central Russia - 1-1.5;
- for the northern regions - 1.5-2;
- for the southern regions - 0.7-0.9.
In case of severe abnormal frosts, when calculating, we add a power reserve of 10%, and if the boiler also heats hot water, then we add an additional 25%.
Let's count on specific examples
To make it easier to understand the methodology for calculating the required power of the boiler, consider a specific example. Let's say we have a brick house with walls 2 bricks thick, located in the Kaluga region.House area - 160 m². The height of the ceilings in the rooms is higher than the standard - 3500 mm. And the boiler, in addition to the heating system, is also supposed to be used for hot water supply.
So, let's start the calculations. Our house is with brick walls 500 mm thick (2 bricks). According to building codes, these walls have standard heat loss. We assume that other building envelopes are also made in accordance with standard requirements. We divide the area of \u200b\u200bthe house by ten (160/10 \u003d 16) and we get that a boiler with a capacity of 16 kW is required for heating. Now we use all the coefficients and corrections.
Since the Kaluga region is the middle zone of Russia, we will use a coefficient of 1. Our ceilings are higher than the standard ones, so we calculate the correction factor: 3500/2700 = 1.29. Rounding up to the first digit after the decimal point, we get 1.3. We apply the coefficients: 16 kW * 1 * 1.3 \u003d 20.8 kW. We round up to 21 kW.
Since the boiler will, in addition to heating, also heat hot water, let's add another 25%: 21 + 5.3 = 26.3 kW. For abnormal winter temperatures, we add another 10%: 26.3 + 2.1 = 28.4 kW. We round up and look at which model of boilers the power value most closely matches the calculated one.
To finally understand, consider another example.
Log house in the Pskov region. House area - 72 m², ceiling height - 2500 mm. The house is built from a thickness of at least 220 mm. The boiler is not supposed to be used to heat water.
If non-brick is used as the material for the walls, then we correlate the thermal conductivity of the existing structures with the same parameter of a brick wall 500 mm thick. The walls of our house correspond to the standard thermal conductivity of a brick wall of 2 bricks. A log house, given the thickness of the log, is even warmer than a brick house (wood has a lower thermal conductivity than brick). But since the house is old, we will consider that in terms of heat loss, they are the same.
Although the Pskov region belongs to the middle lane, it is still its north, so we will use a regional coefficient of 1.5. So, 72/10=7.2 kW, 7.2*1.5=10.8 kW. Since the ceilings in the house are below standard, we will not use the correction factor, as well as add 25% for hot water supply. We take into account only possible severe frosts: 10% is 1.08 kW. This means that we need to purchase a boiler with a capacity of at least 12 kW.
The above simplified power calculation scheme justifies itself in the selection of heating equipment only for standard projects of detached houses. If your house is blocked, part of a townhouse or an apartment, then the calculations will be different, because the neighbors on the side, below or above reduce the heat loss of the premises. Separate heat engineering calculations will also be required if the house is built according to an individual project.
The heating system is the most important, complex and expensive of all housing communications. The arrangement of heating requires careful design in order to avoid unpleasant consequences, which are often difficult to correct.
There is a large selection of boilers on the market for heating equipment. Many models differ from each other in design, energy source, power. Boilers are produced with a power range: from 4 kW to several thousand kW. Thus, it is possible to choose the optimally suitable boiler for a building of any size, both for a country house and a country cottage. The choice of a boiler of one type or another: solid fuel, electric, liquid fuel or gas largely depends on the region of residence and the level of infrastructure development. Equally important is the availability of acquiring a certain type of fuel and its cost.
One of the key points in planning residential heating is the calculation of the boiler power, while it is necessary to take into account the features inherent in systems operating with different types of heaters. Errors in the selection of boiler power are unacceptable, moreover, both its excess and decrease. If the boiler power is insufficient, the house will be cold. Too much power will result in wasted electricity or fuel.
Calculation of the power of the heating boiler according to the area of \u200b\u200bthe room
One of the main conditions for comfortable housing is the presence of a well-thought-out heating system. The type of heating and the required equipment are chosen at the design stage of the house. Determining the power of the heating boiler by area allows you to get quite objective data.
Basic calculation rules and parameters used in calculations:
- The area of the heated room (S).
- Specific power per 10 m² of heated area - (Wsp). This value is determined with adjustment for the climatic conditions of a particular region.
- Wud. For the Moscow region is - from 1.2 kW to 1.5 kW.
- For the southern regions - from 0.7 kW to 0.9 kW.
- For the northern zone - from 1.5 kW to 2.0 kW.
- The power of the boiler is calculated by the formula: Wcat = (SxWsp.): 10.
It is possible to use a simplified version of the formula, in which Wsp \u003d 1, and the heat output of the boiler is measured as 10 kW per 100 m² of heated area. With this calculation, at least 15% is added to the obtained value in order to get a more realistic figure.
Example: calculation of the power of a heating boiler for a house of 100 m².
Specific power for the Moscow region is 1.2 kW.
Thus, Wboiler = (100x1.2) / 10 = 12 kilowatts.
For a more accurate calculation of the required power of heating devices, it is required to collect an extended list of data:
- Actual heat loss of the room. Heat leakage of any building occurs through doors, windows, roof, floor, walls, ventilation system.
- The temperature difference between inside and outside the building. When calculating the power of the heating boiler, the difference in temperature inside and outside the room is taken into account. The greater the temperature difference, the greater the heat loss.
- Thermal insulation characteristics of building structures. The heat-conducting properties of doors, windows, walls and floors depend on the material from which they are made, therefore, heat loss through their surfaces will also be different.
To obtain the necessary indicators and coefficients when determining the power of the boiler, use the building directory.
How to calculate the real heat loss of a building
Heat is lost from the room through walls, windows, floor, roof, ventilation system. The size of heat loss is influenced by many factors: the difference between the temperature inside the building and outside, the heat-conducting properties of building materials. The thermal conductivity of walls, doors, windows, floors and ceilings is different from each other. The unit of measurement of heat transfer resistance is W / m2, this characteristic means the amount of heat lost from 1 m² of the building envelope at a certain temperature range.
Formula No. 1 for determining the resistance to heat transfer: R \u003d ΔT / q
- R - heat transfer resistance (°Схм²/W or °С/W/m²);
- ΔT - temperature difference in the street and in the building (°C);
- q - the amount of heat loss per square meter of the surface of the enclosing structures (W / m²).
When determining the heat transfer resistance R of multilayer structures, the heat transfer resistance indicators of each layer are summarized. This calculation takes into account the average outdoor temperature of the coldest week of the year, reference sources indicate the resistance to heat transfer based on these conditions. For example, the resistance to heat transfer of materials at ΔT = 50°С (Тoutside = –30°С, Тinside = 20°С).
When determining the heat-conducting properties of windows, the following is taken into account:
- Resistance to heat transfer of materials of window structures and their heat loss at ΔT = 50°С. glass thickness (mm).
- The thickness of the gap between the panes in mm.
- Type of gas filling the gap: air or argon.
- The presence of a transparent heat-shielding coating.
A common mistake is the opinion that heat loss can be compensated by choosing a larger boiler. In fact, it is wiser to prevent unwanted heat losses as much as possible by insulating windows, roofs, and doors than to overpay for gas or electricity every month. Double-glazed windows alone reduce heat loss by about 2 times, which saves 800 kWh of electricity per month. More accurately, heat loss is calculated by the proportion method.
Formula No. 2 for determining the resistance to heat transfer of structures made of combined materials: R2 = R1хΔT2/ΔT1
R1 is heat loss at temperature difference ΔT1 = 50°С;
R2 - heat loss at temperature difference ΔT2 according to specific data.
An example of calculating the heat loss of a wall:
- Wall thickness 20 cm,
- The material of the wall is a log cabin. In the reference book of materials, the value of heat transfer resistance R is found. For timber R = 0.806 m² × ° C / W.
The temperature difference ΔT is 50°C. Substituting the values into formula #1:
R = ΔT/q, get the heat loss value for 1m² 50/0.806 = 62 W/m².
Heat losses are determined in the same way for all other materials. The greater the temperature difference between the street and inside the building ΔT, the higher the heat loss.
In most building reference books, for ease of calculation, ready-made indicators of heat loss of various types of building structures are given at certain values of air temperature in winter.
For example, heat losses in corner rooms, where air swirl affects, and non-corner ones, as well as rooms on the upper and lower floors, which also differ in the degree of heating.
Example: calculation of heat loss in a corner room located on the ground floor
1. Initial parameters of the room:
- dimensions and area - 10.0 m x 6.4 m, S = 64.0 m²;
- ceiling height - 2.7 m;
- the number of external walls - 2;
- material and thickness of the outer walls - laying in 3 bricks (76 cm);
- the number of windows with double glazing - 4;
- window dimensions: height - 1.8 m, width - 1.2 m;
- floor - wooden insulated;
- ceilings: below - basement, above - attic;
- estimated temperature in the room +20°С;
- design temperature outside -30°С.
Settlement actions:
2. First, calculate the areas of surfaces that lose heat.
The area of the outer walls, excluding windows (Swalls): (6.4 + 10) x2.7 - 4x1.2x1.8 \u003d 35.64 m². Windows area (Sokon): 4x1.2x1.8 = 8.64 m². Ceiling area (Sceiling): 10.0x6.4 = 64.0 m².
Floor area (Sfloor): 10.0x6.4 = 64.0 m².
There are no indicators of the area of internal partitions and doors in this calculation, so there is no heat loss through them.
3. Determine the heat transfer resistance for a brick wall:
R = ΔT/q where ΔT=50 and brick wall q = 0.592
Thus, R=50/0.592, and is 84.46 m²×°C⁄W.
- Qwall \u003d 35.64x84.46 \u003d 2956.1 W,
- Qwindows = 8.64x135 = 1166.4 W,
- Qfloor \u003d 64 × 26 \u003d 1664.0 W,
- Q ceiling \u003d 64x35 \u003d 2240.0 W.
Total: the sum of the heat loss of a room with an area of 64 sq.m. Qsum=8026.5W.
In this example, the greatest heat losses occur on the walls, to a lesser extent on the ceiling, floor, windows. The result of the calculation reflects the heat loss of the room in severe frosts at a temperature of -30 C°. The higher the air temperature outside, the less heat leakage from the room.
Calculation of the power of a gas heating boiler
A gas boiler for autonomous heating of a private house is well-deservedly popular. Such a system is convenient, affordable and effective. And if the house is located far from the central heating systems, then there is simply no other alternative. Household gas boilers in most cases are the best option for a heating system due to such indisputable advantages as: simplicity and safety of operation; no need to allocate space for fuel storage, low fuel price, cost-effectiveness.
It is very important when buying a gas boiler to choose the right power. If the capacity exceeds the actual heat demand of the building, the heating costs will be excessive. On the other hand, equipment with low performance is not able to provide sufficient space heating. The most elementary calculation of the power of a gas boiler by area: 1 kW for every 10 sq.m. But these results are very approximate. To perform a more accurate calculation of the power of a gas boiler, a number of factors are taken into account:
- climatic conditions of the region;
- dimensions of the heated room;
- the degree of thermal insulation of the house;
- probable heat loss of the building;
- amount of heat for heating water;
- the amount of energy for heating the air in the forced ventilation system.
As a rule, special software is used in calculations: for the reserve power of a gas boiler, approximately 20% is added in case of a severe cold snap, a decrease in gas pressure in the system, or other unforeseen situations. Modern heating appliances are equipped with an automatic device that regulates gas consumption. This is convenient, as it eliminates excessive fuel consumption and unnecessary costs.
Many mistakenly consider the calculation of the power of a heating boiler to be an unnecessary formality, and that you can simply buy a gas boiler with high power. In fact, an unreasonable excess of heating equipment capacity may cause the need to purchase components, which means increased costs for system repairs, a decrease in the functional efficiency of the boiler, interruptions in the operation of an automatic device, rapid wear of elements, the appearance of condensate in the chimney and other negative consequences.
The calculation of the boiler power and the correct selection of heating equipment will help increase its service life. When choosing a gas or other boiler, you need to carefully study the accompanying documentation. The instructions for the heating boiler indicate the rated power, which is generated at a nominal natural gas pressure of 13-20 mbar. A decrease in pressure in the line will lead to the fact that a boiler with a power of, for example, 30 kW will lose a third of its power. In this case, the boiler will be able to efficiently heat a house with an area of only 200 sq.m, instead of the calculated 300.
The formula for the required power of a gas boiler for buildings according to a standard design: M K \u003d SxUM K / 10
- S is the total area of the heated premises (sq.m);
- UM K - specific power of the boiler per 10 sq.m of surface. The specific power of the boiler depends on climatic conditions and is: 0.7-0.9 kW for the southern regions; 1.0-1.2 kW for areas of the middle band; 1.5-2.0 for the northern regions.
Example: according to the formula, the calculated power of a heating boiler for a house with an area of 200 sq.m, located in a temperate climate zone, will be: 200X1.1 / 10 \u003d 22 kW.
It should be remembered that this formula is used to calculate the power of the boiler, provided that it is used only for heating the house. If it is planned to install a two-circuit system for the purpose of heating water for domestic needs, then the power of the heating equipment is additionally increased by 25%.
In order to correctly calculate the power of a gas heating boiler for a custom-made house with a non-standard layout, a different formula is used.
The formula for calculating the power of a gas boiler for buildings according to an individual project: M K \u003d QthKzap,
- M K is the design power of the boiler (kW);
- Qt - predicted heat losses (kW); Kzap - safety factor equal to 1.15-1.2 (15-20%).
The value of the predicted heat loss of the building is determined by the formula:
Qt \u003d VxPtxk / 860
- V - the volume of the heated room (cubic meters);
- Pt - difference between outdoor and indoor temperature (C);
- k is the scattering coefficient.
The value of the dispersion coefficient depends on the type of building structure and the degree of its thermal insulation. For buildings in the form of simple structures made of wood or corrugated iron without thermal insulation, a dispersion factor of 3.0-4.0 is used.
If the walls of the building are with single brickwork, standard windows and roof, low thermal insulation, then the dispersion coefficient is 2.0-2.9.
For houses with an average level of thermal protection, with double-brick walls, a regular roof and a small number of windows, a dispersion coefficient of 1.0-1.9 is taken. For houses with a high degree of thermal protection, well-insulated floors, roofs, walls and double-glazed plastic windows, a dispersion coefficient of 0.6-0.9 is used.
The design power of a heating boiler for compact buildings with high-quality thermal insulation can be quite small. It is possible that there simply will not be a suitable gas boiler with the required characteristics on sale. In this case, equipment is purchased, the power of which slightly exceeds the calculated value. Many modern modifications of gas boilers are equipped with automatic heating control devices that allow you to equalize the difference.
Calculation of the power of a gas boiler using a calculator program
For the convenience of customers, manufacturers of gas boilers place special services on their web resources, which makes it easy and quick to calculate the rated power of the boiler. To do this, just enter the following data into the calculator program:
- the temperature that is supposed to be maintained in the room;
- average outdoor temperature for the coldest week of the year;
- the need for hot water supply;
- the presence or absence of a forced ventilation system;
- number of floors in the house;
- ceiling height;
- description of floors;
- dimensions of external walls: thickness and length of each of them;
- description of the materials from which the walls are made;
- number and size of windows;
- description of the type of windows: number of chambers, glass thickness, heat-shielding film, type of gas in the gaps.
After filling in all the fields, click the "Perform calculation" button, and the program will issue the required calculated boiler power.
For even greater convenience, options are offered for ready-made calculations of the power of boilers of various types, clearly presented in the tables. It should be borne in mind that for complex buildings, these calculation methods may not be suitable. For example, the presence in the building of premises of ceilings of different heights, underfloor heating systems, structures that require additional heating (pool, greenhouse, sauna). All these conditions must be taken into account when designing. With any additional load on the heating system, an increase in boiler power is required.
The most optimal calculation of the power of the heating system can only be prepared by specialists, heating engineers.
Calculation of the power of a solid fuel boiler
Solid fuel boilers have recently been used much less frequently than electric and gas boilers. They are characterized by availability, the possibility of autonomous operation, economical operation, and the need for a place to store fuel.
A distinctive feature that should be taken into account when determining the power of a solid fuel boiler is the cyclicity of the temperature obtained. The daily temperature in the heated room fluctuates within 5ºС. If it is not possible to abandon such a system, there are two ways to maintain a stable temperature in the room: using a thermal bulb and using water heat accumulators.
The bulb serves to regulate the air supply, which allows you to increase the burning time and reduce the number of fireboxes. Water thermal accumulators with a volume of 2 to 10 m² are installed in the heating system, reduce energy costs and save fuel. All these measures help to reduce the required performance of a solid fuel boiler for heating a private house. The effect of the application of these measures should be taken into account when determining the power of heating equipment.
Calculation of the power of an electric heating boiler
The heating system using an electric boiler is characterized by a number of positive and negative features: the high cost of fuel - electricity, possible problems due to power outages in the network, environmental friendliness, ease and convenience of control, compact equipment.
Calculation of the power of an electric heating boiler using a calculator program
Often, manufacturers of heating equipment post formulas on their websites for calculating the power of a boiler or even calculators that allow you to take into account several determining factors at once and make the most accurate calculation.
To calculate on a calculator, as a rule, the following information is required:
- Estimated room temperature.
- Average outdoor temperature of the coldest week of the year.
- The need for hot water.
- The presence of a ventilation system.
- Number of floors.
- Ceiling height.
- Top and bottom cover.
- Material. outer walls.
- The length and thickness of the outer walls.
- Number, type and size of windows.
- glass thickness. The size of the gap between the glasses with air or argon. The presence of a heat-shielding transparent coating on the glass.
It should be taken into account that in reality the specific power of the heating system increases to a value of 127 W / m 2 with a small area of \u200b\u200bthe house (100-150 m 2) and decreases to 85-80 W / m 2 for houses with an area of 400-500 m 2, which is not corresponds to the accepted standard value of 100 W/m2, which is usually recommended for the selection of equipment.
This is due to the fact that in houses with a small area heat is inefficiently consumed. With an increase in the total area in the house, more rooms appear adjacent to the heated ones, as well as without external walls and located in the depths of the house. As a result, the specific heat loss of the house is somewhat reduced.
How to calculate the power of a liquid fuel boiler
Heating liquid fuel boilers have both advantages and disadvantages: they are easy to use, but not environmentally friendly, require additional space for fuel storage, are characterized by increased fire hazard, and are quite expensive.
The calculation of the power of a liquid fuel boiler is carried out similarly to gas and electric ones. The more factors that affect the efficiency of the heating system are taken into account, the more accurate the calculation will be, which in turn will make it possible to make the optimal choice of equipment.
The quality of heating primarily depends on the correct choice of the type of heating system and on the accuracy of calculating the required performance of the heating boiler. Design errors will inevitably lead to negative consequences. Therefore, it is very important to collect complete information, perform careful calculations and planning before purchasing heating equipment and installing the system.
Technical consultants of the Termomir company, who have been working with gas boiler equipment for more than a year, often hear the question - How to choose a gas boiler according to the area of \u200b\u200bthe house. Let's deal with this topic in more detail.
A heating gas boiler is a device that, by means of the combustion of fuel (natural or liquefied gas), heats the coolant.
The device (design) of a gas boiler: burner, heat exchanger, thermally insulated housing, hydraulic unit, as well as safety and control devices. Such gas-fired boilers require a chimney to be connected to remove combustion products. The chimney can be either a conventional vertical or coaxial (“pipe in pipe”) for boilers with a closed combustion chamber. Many modern boilers are equipped with built-in pumps for forced circulation of water.
The principle of operation of a gas boiler- the heat carrier, passing through the heat exchanger, heats up and then circulates through the heating system, giving off the received thermal energy through radiators, underfloor heating, heated towel rails, and also providing water heating in an indirect heating boiler (if it is connected to a gas-fired boiler).
Heat exchanger - a metal container in which the coolant (water or antifreeze) is heated - can be made of steel, cast iron, copper, etc. The reliability and durability of a gas boiler depends on the quality of the heat exchanger in the first place. Cast iron heat exchangers are resistant to corrosion and have a long service life, but are sensitive to sudden temperature changes and are quite heavy. Steel containers can suffer from rust, so their internal surfaces are protected with various anti-corrosion coatings that prolong the “life” of the device. Steel heat exchangers are the most common in the manufacture of boilers. Corrosion is not terrible for copper heat exchangers, and due to the high heat transfer coefficient, low weight and dimensions, such heat exchangers are often used in wall-mounted boilers, but of the minuses, it should be noted that they are more expensive than steel ones.
In addition to the heat exchanger, an important part of gas boilers is a burner, which can be of various types: atmospheric or fan, single-stage or two-stage, with smooth modulation, double.
To control the gas boiler, automation is used with various settings and functions (for example, a weather-compensated control system), as well as devices for programming operation and remote control of the boiler.
The main technical characteristics of gas heating boilers are: power, number of heating circuits, type of fuel, type of combustion chamber, burner type, installation method, pump and expansion tank, boiler control automation.
To determine required power gas heating boiler for a private country house or apartment, a simple formula is used - 1 kW of boiler power for heating 10 m 2 of a well-insulated room with a ceiling height of up to 3 m. If heating is required for a basement, glazed winter garden, rooms with non-standard ceilings, etc. the gas boiler output must be increased. It is also necessary to increase the power (about 20-50%) when providing a gas boiler and hot water supply (especially if water heating in the pool is necessary).
The peculiarity of calculating the power of gas boilers: the nominal gas pressure at which the boiler operates at 100% of the power declared by the manufacturer, for most boilers is from 13 to 20 mbar, and the actual pressure in gas networks in Russia can be 10 mbar, and sometimes even lower . Accordingly, a gas boiler often works only at 2/3 of its capacity, and this must be taken into account when calculating. In more detail with a table for calculating the power of a heating boiler, you can
Most gas boilers can switch from natural gas to LPG(ballooned propane). Many models switch to liquefied gas at the factory (check these characteristics of the model when purchasing), or nozzles (jets) are additionally supplied to the gas boiler to switch to bottled gas.
Pros and cons of gas boilers:
Boiler piping- These are devices for the full operation of the heating and water supply system. It includes: pumps, expansion tanks, filters (if necessary), manifolds, check and safety valves, air valves, valves, etc. You will also need to purchase radiators, connecting pipes and valves, thermostats, a boiler, etc. The issue of choosing a boiler is quite serious, so it is better to entrust the selection of equipment and its complete set to professionals.
What is the best boiler? The Russian market of gas boiler equipment has its own leaders in quality and reliability. The best manufacturers and brands of gas boilers are presented in the assortment:
"Premium" or "Lux"- the most reliable and durable, easy to manage, the kit is assembled as a "constructor", more expensive than the others. These manufacturers include German companies
