Specific consumption of thermal energy for heating a building: familiarity with the term and related concepts. Establishment of levels of specific annual consumption of thermal energy for heating, ventilation and hot water supply of apartment buildings and providing them with

What is it - the specific consumption of thermal energy for heating a building? Is it possible to calculate the hourly heat consumption for heating in a cottage with your own hands? We will devote this article to the terminology and general principles for calculating the need for thermal energy.

The basis of new building projects is energy efficiency.

Terminology

What is specific heat consumption for heating?

We are talking about the amount of thermal energy that must be brought inside the building in terms of each square or cubic meter in order to maintain normalized parameters in it, comfortable for work and living.

Usually, a preliminary calculation of heat losses is carried out according to enlarged meters, that is, based on the average thermal resistance of the walls, the approximate temperature in the building and its total volume.

Factors

What affects the annual heat consumption for heating?

• Duration of the heating season (). It, in turn, is determined by the dates when the average daily temperature in the street for the last five days falls below (and rises above) 8 degrees Celsius.

Useful: in practice, when planning the start and stop of heating, the weather forecast is taken into account. Long thaws occur in winter, and frosts can strike as early as September.

• Average temperatures of the winter months. Usually when designing heating system the average monthly temperature of the coldest month, January, is taken as a guideline. It is clear that the colder it is outside, the more heat the building loses through the building envelope.

• The degree of thermal insulation of the building greatly affects what will be the rate of thermal power for him. An insulated facade can reduce the need for heat by half compared to a wall made of concrete slabs or bricks.
• building glazing factor. Even when using multi-chamber double-glazed windows and energy-saving spraying, noticeably more heat is lost through windows than through walls. How most of the facade is glazed - the greater the need for heat.
• The degree of illumination of the building. On a sunny day, a surface oriented perpendicular to the sun's rays is capable of absorbing up to a kilowatt of heat per square meter.

Clarification: in practice, the exact calculation of the amount of solar heat absorbed will be extremely difficult. Those same glass facades, which lose heat in cloudy weather, will serve as heating in sunny weather. The orientation of the building, the slope of the roof, and even the color of the walls will all affect the ability to absorb solar heat.

Calculations

Theory is theory, but how heating costs are calculated in practice country house? Is it possible to estimate the estimated costs without plunging into the abyss of complex heat engineering formulas?

Consumption of the required amount of thermal energy

Instructions for calculating the estimated amount required heat relatively simple. The key phrase is an approximate amount: for the sake of simplifying calculations, we sacrifice accuracy, ignoring a number of factors.

• The base value of the amount of thermal energy is 40 watts per cubic meter of cottage volume.
• To the base value is added 100 watts for each window and 200 watts for each door in the exterior walls.

• Further, the obtained value is multiplied by a coefficient, which is determined by the average amount of heat loss through the outer contour of the building. For apartments in the center apartment building take the coefficient equal to one: only losses through the facade are noticeable. Three of the four walls of the contour of the apartment border on warm rooms.

For corner and end apartments, a coefficient of 1.2 - 1.3 is taken, depending on the material of the walls. The reasons are obvious: two or even three walls become external.

Finally, in a private house, the street is not only along the perimeter, but also from below and above. In this case, a coefficient of 1.5 is applied.

Please note: for apartments on the extreme floors, if the basement and attic are not insulated, it is also quite logical to use a coefficient of 1.3 in the middle of the house and 1.4 at the end.

• Finally, the received thermal power is multiplied by a regional coefficient: 0.7 for Anapa or Krasnodar, 1.3 for St. Petersburg, 1.5 for Khabarovsk and 2.0 for Yakutia.

In the cold climate zone- special heating requirements.

Let's calculate how much heat is needed for a cottage measuring 10x10x3 meters in the city of Komsomolsk-on-Amur, Khabarovsk Territory.

The volume of the building is 10*10*3=300 m3.

Multiplying the volume by 40 watts/cube will give 300*40=12000 watts.

Six windows and one door is another 6*100+200=800 watts. 1200+800=12800.

Private house. Coefficient 1.5. 12800*1.5=19200.

Khabarovsk region. We multiply the need for heat by another one and a half times: 19200 * 1.5 = 28800. In total - at the peak of frost, we need about a 30-kilowatt boiler.

Calculation of heating costs

The easiest way to calculate the consumption of electricity for heating: when using an electric boiler, it is exactly equal to the cost of thermal power. With continuous consumption of 30 kilowatts per hour, we will spend 30 * 4 rubles (approximate current price of a kilowatt-hour of electricity) = 120 rubles.

Fortunately, the reality is not so nightmarish: as practice shows, the average heat demand is about half the calculated one.

• Firewood - 0.4 kg / kW / h. Thus, the approximate norms for the consumption of firewood for heating in our case will be equal to 30/2 (the rated power, as we remember, can be divided in half) * 0.4 \u003d 6 kilograms per hour.
• The consumption of brown coal in terms of a kilowatt of heat is 0.2 kg. The consumption rates of coal for heating are calculated in our case as 30/2*0.2=3 kg/h.

Brown coal is a relatively inexpensive heat source.

• For firewood - 3 rubles (the cost of a kilogram) * 720 (hours in a month) * 6 (hourly consumption) \u003d 12960 rubles.
• For coal - 2 rubles * 720 * 3 = 4320 rubles (read others).

Conclusion

You can, as usual, find additional information on cost calculation methods in the video attached to the article. Warm winters!

As noted in the introduction, when choosing the requirements of the thermal protection indicator "c", the value of the specific consumption of thermal energy for heating is normalized. This is a complex value that takes into account energy savings from the use of architectural, construction, heat engineering and engineering solutions, aimed at saving energy resources, and therefore it is possible, if necessary, in each specific case to establish less than the normalized resistance to heat transfer for certain types enclosing structures. Specific consumption thermal energy depends on the heat-shielding properties of enclosing structures, space-planning decisions of the building, heat generation and the amount of solar energy entering the premises of the building, efficiency engineering systems maintaining the required microclimate of premises and heat supply systems.

, kJ / (m 2 ° C day) or [kJ / (m 3 ° C day)], is determined by the formula

or

, (5.1)

where is the consumption of thermal energy for heating the building during the heating period, MJ;

Heated area of ​​apartments or useful area of ​​premises, m 2;

Heated volume of the building, m 3;

D - degree-day of the heating period, °С day (1.1).

Specific consumption of thermal energy for heating buildings must be less than or equal to the specified value

≤ .(5.2)

5.1. Determination of heated areas and building volumes

for residential and public buildings.

1. The heated area of ​​the building should be defined as the area of ​​floors (including the attic, heated basement and basement) of the building, measured within the inner surfaces of the outer walls, including the area occupied by partitions and interior walls. At the same time, the area staircases and elevator shafts is included in the floor area.

The heated area of ​​the building does not include the areas of warm attics and basements, unheated technical floors, basement (underground), cold unheated verandas, unheated stairwells, as well as the cold attic or its part not occupied by the attic.

2. When determining the area attic floor takes into account the area with a height of up to sloped ceiling 1.2 m at an inclination of 30 ° to the horizon; 0.8 m - at 45° - 60°; at 60 ° and more - the area is measured to the plinth.

3. The area of ​​residential premises of the building is calculated as the sum of the areas of all common rooms(living rooms) and bedrooms.

4. The heated volume of a building is defined as the product of the heated floor area and the internal height, measured from the floor surface of the first floor to the ceiling surface of the last floor.

With complex forms of the internal volume of a building, the heated volume is defined as the volume of space bounded by the internal surfaces of external fences (walls, coverings or attic floor, basement).

5. The area of ​​external enclosing structures is determined by the internal dimensions of the building. The total area of ​​the outer walls (including window and doorways) is defined as the product of the perimeter of the outer walls along the inner surface by the inner height of the building, measured from the surface of the floor of the first floor to the surface of the ceiling of the last floor, taking into account the area of ​​window and door slopes with a depth from the inner surface of the wall to the inner surface of the window or door block. The total area of ​​windows is determined by the size of the openings in the light. The area of ​​the outer walls (opaque part) is determined as the difference between the total area of ​​the outer walls and the area of ​​windows and outer doors.

6. The area of ​​horizontal external fences (covering, attic and basement floors) is defined as the floor area of ​​the building (within the inner surfaces of the outer walls).

With inclined surfaces of the ceilings of the last floor, the area of ​​coverage, attic floor is defined as the area of ​​the inner surface of the ceiling.

The calculation of the areas and volumes of the space-planning decision of the building is carried out according to the working drawings of the architectural and construction part of the project. As a result, the following main volumes and areas are obtained:

Heated volume V h , m 3;

Heated area (for residential buildings - total area of ​​apartments) A h , m 2;

The total area of ​​the external building envelope, m 2.

5.2. Determination of the normalized value of the specific consumption of thermal energy for heating the building

Normalized value of the specific consumption of thermal energy for heating a residential or public building determined according to the table. 5.1 and 5.2.

Normalized specific consumption of thermal energy for heating residential houses single-family separately

standing and blocked, kJ / (m 2 ° C day)

Table 5.1

Normalized specific consumption of thermal energy per

heating of buildings, kJ / (m 2 ° C day) or

[kJ / (m 3 ° C day)]

Table 5.2

5.3. Determination of the estimated specific consumption of thermal energy for heating the building

This item is not performed in the term paper, but in the section of the graduation project is carried out in agreement with the supervisor and consultant.

The calculation of the specific consumption of thermal energy for heating residential and public buildings is carried out using Appendix G of SNiP 23-02 and the methodology of Appendix I.2 ​​of SP 23-101-2004.

5.4. Determination of the calculated indicator of the compactness of the building

This item is carried out in the section of the graduation project for residential buildings and is not included in coursework.

The calculated indicator of the compactness of the building is determined by the formula:

, (5.3)

where and V h are found in clause 5.1.

The calculated indicator of the compactness of residential buildings should not exceed the following normalized values:

0.25 - for 16-storey buildings and above;

0.29 - for buildings from 10 to 15 floors inclusive;

0.32 - for buildings from 6 to 9 floors inclusive;

0.36 - for 5-storey buildings;

0.43 - for 4-storey buildings;

0.54 - for 3-storey buildings;

0.61; 0.54; 0.46 - for two-, three- and four-storey blocked and sectional houses, respectively;

0.9 - for two- and one-story houses with an attic;

1.1 - for one-story houses.

If the calculated value is greater than the normalized value, then it is recommended to change the space-planning solution in order to achieve the normalized value.

LITERATURE

1. SNiP 23-01-99 Building climatology. – M.: Gosstroy of Russia, 2004.

2. SNiP 23-02-2003 Thermal protection buildings. – M.: Gosstroy of Russia, 2004.

3. SP 23-01-2004 Design of thermal protection of buildings. – M.: Gosstroy of Russia, 2004.

4. Karaseva L.V., Chebanova E.V., Geppel S.A. Thermophysics of Enclosing Structures of Architectural Objects: Textbook. - Rostov-on-Don, 2008.

5. Fokin K.F. Structural heat engineering of enclosing parts of buildings / Ed. Yu.A. Tabunshchikova, V.G. Gagarin. – 5th ed., revision. – M.: AVOK-PRESS, 2006.

APPENDIX A

Creating a heating system in your own home or even in a city apartment is an extremely responsible task. It would be completely unwise to acquire boiler equipment, as they say, "by eye", that is, without taking into account all the features of housing. In this, it is quite possible to fall into two extremes: either the power of the boiler will not be enough - the equipment will work “to its fullest”, without pauses, but will not give the expected result, or, conversely, an overly expensive device will be purchased, the capabilities of which will remain completely unclaimed.

But that's not all. It is not enough to purchase the necessary heating boiler correctly - it is very important to optimally select and correctly place heat exchange devices in the premises - radiators, convectors or "warm floors". And again, relying only on your intuition or the "good advice" of your neighbors is not the most reasonable option. In a word, certain calculations are indispensable.

Of course, ideally, such heat engineering calculations should be carried out by appropriate specialists, but this often costs a lot of money. Isn't it interesting to try to do it yourself? This publication will show in detail how heating is calculated by the area of ​​\u200b\u200bthe room, taking into account many important nuances. By analogy, it will be possible to perform, built into this page, will help you perform the necessary calculations. The technique cannot be called completely “sinless”, however, it still allows you to get a result with a completely acceptable degree of accuracy.

The simplest methods of calculation

In order for the heating system to create comfortable living conditions during the cold season, it must cope with two main tasks. These functions are closely related, and their separation is very conditional.

• The first is maintaining an optimal level of air temperature in the entire volume of the heated room. Of course, the temperature level may vary slightly with altitude, but this difference should not be significant. Quite comfortable conditions are considered to be an average of +20 ° C - it is this temperature that, as a rule, is taken as the initial temperature in thermal calculations.

In other words, the heating system must be able to heat a certain volume of air.

If we approach with complete accuracy, then for individual rooms in residential buildings the standards for the required microclimate have been established - they are defined by GOST 30494-96. An excerpt from this document is in the table below:

• The second is the compensation of heat losses through the structural elements of the building.

The main "enemy" of the heating system is heat loss through building structures.

Alas, heat loss is the most serious "rival" of any heating system. They can be reduced to a certain minimum, but even with the highest quality thermal insulation, it is not yet possible to completely get rid of them. Thermal energy leaks go in all directions - their approximate distribution is shown in the table:

Naturally, in order to cope with such tasks, the heating system must have a certain thermal power, and this potential must not only meet the general needs of the building (apartment), but also be correctly distributed over the premises, in accordance with their area and a number of other important factors.

Usually the calculation is carried out in the direction "from small to large". Simply put, the required amount of thermal energy for each heated room is calculated, the obtained values ​​​​are summed up, approximately 10% of the reserve is added (so that the equipment does not work at the limit of its capabilities) - and the result will show how much power the heating boiler needs. And the values ​​​​for each room will be the starting point for calculating the required number of radiators.

The most simplified and most commonly used method in a non-professional environment is to accept the norm of 100 W of thermal energy per square meter of area:

The most primitive way of counting is the ratio of 100 W / m²

Q = S× 100

Q- the required thermal power for the room;

S– area of ​​the room (m²);

100 — specific power per unit area (W/m²).

For example, room 3.2 × 5.5 m

S= 3.2 × 5.5 = 17.6 m²

Q= 17.6 × 100 = 1760 W ≈ 1.8 kW

The method is obviously very simple, but very imperfect. It should be noted right away that it is conditionally applicable only when standard height ceilings - approximately 2.7 m (permissible - in the range from 2.5 to 3.0 m). From this point of view, the calculation will be more accurate not from the area, but from the volume of the room.

It is clear that in this case the value of specific power is calculated per cubic meter. It is taken equal to 41 W / m³ for reinforced concrete panel house, or 34 W / m³ - in brick or made of other materials.

Q = S × h× 41 (or 34)

h- ceiling height (m);

41 or 34 - specific power per unit volume (W / m³).

For example, the same room, in a panel house, with a ceiling height of 3.2 m:

Q= 17.6 × 3.2 × 41 = 2309 W ≈ 2.3 kW

The result is more accurate, since it already takes into account not only all linear dimensions rooms, but even, to a certain extent, the features of the walls.

But still, it is still far from real accuracy - many nuances are “outside the brackets”. How to perform calculations closer to real conditions - in the next section of the publication.

You may be interested in information about what they are

Carrying out calculations of the required thermal power, taking into account the characteristics of the premises

The calculation algorithms discussed above are useful for the initial “estimate”, but you should still rely on them completely with very great care. Even to a person who does not understand anything in building heat engineering, the indicated average values ​​\u200b\u200bmay certainly seem doubtful - they cannot be equal, say, for Krasnodar Territory and for the Arkhangelsk region. In addition, the room - the room is different: one is located on the corner of the house, that is, it has two external walls ki, and the other on three sides is protected from heat loss by other rooms. In addition, the room may have one or more windows, both small and very large, sometimes even panoramic. And the windows themselves may differ in the material of manufacture and other design features. And this is not a complete list - just such features are visible even to the "naked eye".

In a word, there are a lot of nuances that affect the heat loss of each particular room, and it is better not to be too lazy, but to carry out a more thorough calculation. Believe me, according to the method proposed in the article, this will not be so difficult to do.

General principles and calculation formula

The calculations will be based on the same ratio: 100 W per 1 square meter. But that's just the formula itself "overgrown" with a considerable number of various correction factors.

Q = (S × 100) × a × b × c × d × e × f × g × h × i × j × k × l × m

The Latin letters denoting the coefficients are taken quite arbitrarily, in alphabetical order, and are not related to any standard quantities accepted in physics. The meaning of each coefficient will be discussed separately.

• "a" - a coefficient that takes into account the number of external walls in a particular room.

Obviously, the more external walls in the room, the more area, through which heat loss. In addition, the presence of two or more external walls also means corners - extremely vulnerable places in terms of the formation of "cold bridges". The coefficient "a" will correct for this specific feature of the room.

The coefficient is taken equal to:

- external walls No(indoor): a = 0.8;

- outer wall one: a = 1.0;

- external walls two: a = 1.2;

- external walls three: a = 1.4.

• "b" - coefficient taking into account the location of the external walls of the room relative to the cardinal points.

You may be interested in information about what are

Even on the coldest winter days solar energy still affects the temperature balance in the building. It is quite natural that the side of the house that is facing south receives some heating from the sun's rays, and heat loss through it is lower.

But the walls and windows facing north never “see” the Sun. The eastern part of the house, although it "grabs" the morning sun's rays, still does not receive any effective heating from them.

Based on this, we introduce the coefficient "b":

- the outer walls of the room look at North or East: b = 1.1;

- the outer walls of the room are oriented towards South or West: b = 1.0.

• "c" - coefficient taking into account the location of the room relative to the winter "wind rose"

Perhaps this amendment is not so necessary for houses located in areas protected from the winds. But sometimes the prevailing winter winds can make their own “hard adjustments” to the thermal balance of the building. Naturally, the windward side, that is, "substituted" for the wind, will lose significantly more body, compared to the leeward, opposite.

Based on the results of long-term meteorological observations in any region, the so-called "wind rose" is compiled - a graphic diagram showing the prevailing wind directions in winter and summer. This information can be obtained from the local hydrometeorological service. However, many residents themselves, without meteorologists, know perfectly well where the winds mainly blow from in winter, and from which side of the house the deepest snowdrifts usually sweep.

If there is a desire to carry out calculations with higher accuracy, then the correction factor “c” can also be included in the formula, taking it equal to:

- windward side of the house: c = 1.2;

- leeward walls of the house: c = 1.0;

- wall located parallel to the direction of the wind: c = 1.1.

• "d" - a correction factor that takes into account the peculiarities of the climatic conditions of the region where the house was built

Naturally, the amount of heat loss through all the building structures of the building will greatly depend on the level of winter temperatures. It is quite clear that during the winter the thermometer indicators “dance” in a certain range, but for each region there is an average indicator of the lowest temperatures characteristic of the coldest five-day period of the year (usually this is characteristic of January). For example, below is a map-scheme of the territory of Russia, on which colors show approximate values.

Usually this value is easy to check with the regional meteorological service, but you can, in principle, rely on your own observations.

So, the coefficient "d", taking into account the peculiarities of the climate of the region, for our calculations in we take equal to:

— from – 35 °С and below: d=1.5;

— from – 30 °С to – 34 °С: d=1.3;

— from – 25 °С to – 29 °С: d=1.2;

— from – 20 °С to – 24 °С: d=1.1;

— from – 15 °С to – 19 °С: d=1.0;

— from – 10 °С to – 14 °С: d=0.9;

- not colder - 10 ° С: d=0.7.

• "e" - coefficient taking into account the degree of insulation of external walls.

The total value of the heat loss of the building is directly related to the degree of insulation of all building structures. One of the "leaders" in terms of heat loss are walls. Therefore, the value of thermal power required to maintain comfortable conditions living indoors depends on the quality of their thermal insulation.

The value of the coefficient for our calculations can be taken as follows:

- external walls are not insulated: e = 1.27;

- medium degree of insulation - walls in two bricks or their surface thermal insulation with other heaters is provided: e = 1.0;

– insulation was carried out qualitatively, on the basis of heat engineering calculations: e = 0.85.

Later in the course of this publication, recommendations will be given on how to determine the degree of insulation of walls and other building structures.

• coefficient "f" - correction for ceiling height

Ceilings, especially in private homes, can have different heights. Therefore, the thermal power for heating one or another room of the same area will also differ in this parameter.

It will not be a big mistake to accept the following values ​​​​of the correction factor "f":

– ceiling height up to 2.7 m: f = 1.0;

— flow height from 2.8 to 3.0 m: f = 1.05;

– ceiling height from 3.1 to 3.5 m: f = 1.1;

– ceiling height from 3.6 to 4.0 m: f = 1.15;

– ceiling height over 4.1 m: f = 1.2.

• « g "- coefficient taking into account the type of floor or room located under the ceiling.

As shown above, the floor is one of the significant sources of heat loss. So, it is necessary to make some adjustments in the calculation of this feature of a particular room. The correction factor "g" can be taken equal to:

- cold floor on the ground or above unheated room(for example, basement or basement): g= 1,4 ;

- insulated floor on the ground or over an unheated room: g= 1,2 ;

- a heated room is located below: g= 1,0 .

• « h "- coefficient taking into account the type of room located above.

The air heated by the heating system always rises, and if the ceiling in the room is cold, then increased heat losses are inevitable, which will require an increase in the required heat output. We introduce the coefficient "h", which takes into account this feature of the calculated room:

- a "cold" attic is located on top: h = 1,0 ;

- an insulated attic or other insulated room is located on top: h = 0,9 ;

- any heated room is located above: h = 0,8 .

• « i "- coefficient taking into account the design features of windows

Windows are one of the "main routes" of heat leaks. Naturally, much in this matter depends on the quality of the window construction. Old wooden frames, which were previously installed everywhere in all houses, are significantly inferior to modern multi-chamber systems with double-glazed windows in terms of their thermal insulation.

Without words, it is clear that the thermal insulation qualities of these windows are significantly different.

But even between PVC-windows there is no complete uniformity. For example, double glazing(with three glasses) will be much warmer than a single-chamber.

This means that it is necessary to enter a certain coefficient "i", taking into account the type of windows installed in the room:

— standard wooden windows with conventional double glazing: i = 1,27 ;

– modern window systems with a single-chamber double-glazed window: i = 1,0 ;

– modern window systems with two-chamber or three-chamber double-glazed windows, including those with argon filling: i = 0,85 .

• « j» - correction factor for total area room glazing

Whatever quality windows however they were, it will still not be possible to completely avoid heat loss through them. But it is quite clear that it is impossible to compare a small window with panoramic glazing almost on the entire wall.

First you need to find the ratio of the areas of all the windows in the room and the room itself:

x = ∑SOK /SP

∑ SOK- the total area of ​​windows in the room;

SP- area of ​​the room.

Depending on the value obtained and the correction factor "j" is determined:

- x \u003d 0 ÷ 0.1 →j = 0,8 ;

- x \u003d 0.11 ÷ 0.2 →j = 0,9 ;

- x \u003d 0.21 ÷ 0.3 →j = 1,0 ;

- x \u003d 0.31 ÷ 0.4 →j = 1,1 ;

- x \u003d 0.41 ÷ 0.5 →j = 1,2 ;

• « k" - coefficient that corrects for the presence of an entrance door

The door to the street or to an unheated balcony is always an additional "loophole" for the cold

door to the street or outdoor balcony is able to make its own adjustments to the heat balance of the room - each of its opening is accompanied by the penetration of a considerable amount of cold air into the room. Therefore, it makes sense to take into account its presence - for this we introduce the coefficient "k", which we take equal to:

- no door k = 1,0 ;

- one door to the street or balcony: k = 1,3 ;

- two doors to the street or to the balcony: k = 1,7 .

• « l "- possible amendments to the connection diagram of heating radiators

Perhaps this will seem like an insignificant trifle to some, but still - why not immediately take into account the planned scheme for connecting heating radiators. The fact is that their heat transfer, and hence their participation in maintaining a certain temperature balance in the room, changes quite noticeably when different types tie-in supply and return pipes.

Illustration	Radiator insert type	The value of the coefficient "l"
	Diagonal connection: supply from above, "return" from below	l = 1.0
	Connection on one side: supply from above, "return" from below	l = 1.03
	Two-way connection: both supply and return from the bottom	l = 1.13
	Diagonal connection: supply from below, "return" from above	l = 1.25
	Connection on one side: supply from below, "return" from above	l = 1.28
	One-way connection, both supply and return from below	l = 1.28

• « m "- correction factor for the features of the installation site of heating radiators

And finally, the last coefficient, which is also associated with the features of connecting heating radiators. It is probably clear that if the battery is installed openly, is not obstructed by anything from above and from the front part, then it will give maximum heat transfer. However, such an installation is far from always possible - more often, radiators are partially hidden by window sills. Other options are also possible. In addition, some owners, trying to fit heating priors into the created interior ensemble, hide them completely or partially with decorative screens - this also significantly affects the heat output.

If there are certain “baskets” on how and where the radiators will be mounted, this can also be taken into account when making calculations by entering a special coefficient “m”:

So, there is clarity with the calculation formula. Surely, some of the readers will immediately take up their heads - they say, it's too complicated and cumbersome. However, if the matter is approached systematically, in an orderly manner, then there is no difficulty at all.

Any good homeowner must have a detailed graphical plan of their "possessions" with dimensions, and usually oriented to the cardinal points. It is not difficult to specify the climatic features of the region. It remains only to walk through all the rooms with a tape measure, to clarify some of the nuances for each room. Features of housing - "neighborhood vertically" from above and below, location entrance doors, the proposed or already existing scheme for installing heating radiators - no one except the owners knows better.

It is recommended to immediately draw up a worksheet, where you enter all the necessary data for each room. The result of the calculations will also be entered into it. Well, the calculations themselves will help to carry out the built-in calculator, in which all the coefficients and ratios mentioned above are already “laid”.

If some data could not be obtained, then, of course, they can not be taken into account, but in this case, the “default” calculator will calculate the result, taking into account the least favorable conditions.

It can be seen with an example. We have a house plan (taken completely arbitrary).

Region with level minimum temperatures within -20 ÷ 25 °С. Predominance of winter winds = northeasterly. The house is one-story, with an insulated attic. Insulated floors on the ground. The optimal diagonal connection radiators that will be installed under the window sills.

Let's create a table like this:

Then, using the calculator below, we make a calculation for each room (already taking into account a 10% reserve). With the recommended app, it won't take long. After that, it remains to sum up the obtained values ​​​​for each room - this will be the required total power of the heating system.

The result for each room, by the way, will help you choose the right number of heating radiators - it remains only to divide by specific thermal power one section and round up.

Explanations to the calculator of the annual consumption of thermal energy for heating and ventilation.

Initial data for calculation:

• The main characteristics of the climate where the house is located:
  • Average outdoor temperature of the heating period t o.p;
  • Duration of the heating period: this is the period of the year with an average daily outdoor temperature of not more than +8°C - z o.p.
• The main characteristic of the climate inside the house: the estimated temperature of the indoor air t w.r, °С
• Main thermal characteristics at home: specific annual consumption of thermal energy for heating and ventilation, referred to degree-days of the heating period, Wh / (m2 °C day).

Climate characteristics.

Climate parameters for calculating heating in cold period for different cities of Russia can be found here: (Map of climatology) or in SP 131.13330.2012 “SNiP 23-01–99* “Construction climatology”. Updated Edition»
For example, the parameters for calculating heating for Moscow ( Parameters B) such:

• Average outdoor temperature during the heating period: -2.2 °C
• Duration of the heating period: 205 days. (for a period with an average daily outdoor temperature of not more than +8°C).

Indoor air temperature.

You can set your own calculated internal air temperature, or you can take it from the standards (see the table in Figure 2 or in the Table 1 tab).

The value used in the calculations is D d - degree-day of the heating period (GSOP), ° С × day. In Russia, the value of the GSOP is numerically equal to the product of the difference average daily temperature outdoor air during the heating period (OP) t o.p and design indoor air temperature in the building t v.r for the duration of the OP in days: D d = ( t o.p - t w.r) z o.p.

Specific annual heat energy consumption for heating and ventilation

Normalized values.

Specific heat energy consumption for heating residential and public buildings during the heating period should not exceed the values ​​\u200b\u200bgiven in the table according to SNiP 23-02-2003. Data can be taken from the table in picture 3 or calculated on tab Table 2(reworked version from [L.1]). According to it, select the value of the specific annual consumption for your house (area / number of floors) and insert it into the calculator. This is a characteristic of the thermal qualities of the house. All residential buildings under construction permanent residence must meet this requirement. The basic and normalized by years of construction specific annual consumption of thermal energy for heating and ventilation are based on draft order of the Ministry of Regional Development of the Russian Federation "On approval of the requirements for the energy efficiency of buildings, structures, structures", which specifies the requirements for basic characteristics(draft dated 2009), to the characteristics normalized from the moment the order was approved (conditionally designated N.2015) and from 2016 (N.2016).

Estimated value.

This value of the specific heat energy consumption can be indicated in the project of the house, it can be calculated on the basis of the project of the house, it can be estimated based on real thermal measurements or the amount of energy consumed for heating per year. If this value is in Wh/m2 , then it must be divided by the GSOP in ° C days, the resulting value should be compared with the normalized value for a house with a similar number of storeys and area. If it is less than normalized, then the house meets the requirements for thermal protection, if not, then the house should be insulated.

Your numbers.

The values ​​of the initial data for the calculation are given as an example. You can paste your values ​​into the fields on the yellow background. Insert reference or calculated data into the fields on a pink background.

What can the calculation results say?

Specific annual heat energy consumption, kWh/m2 - can be used to estimate required amount of fuel per year for heating and ventilation. By the amount of fuel, you can choose the capacity of the tank (warehouse) for fuel, the frequency of its replenishment.

Annual consumption of thermal energy, kWh is the absolute value of energy consumed per year for heating and ventilation. By changing the values ​​of the internal temperature, you can see how this value changes, evaluate the savings or waste of energy from a change in the temperature maintained inside the house, see how the inaccuracy of the thermostat affects energy consumption. This will be especially evident in terms of rubles.

Degree-days of the heating period,°С day - characterize the climatic conditions external and internal. By dividing by this number the specific annual consumption of thermal energy in kWh / m2, you will get a normalized characteristic of the thermal properties of the house, decoupled from climatic conditions (this can help in choosing a house project, heat-insulating materials).

On the accuracy of calculations.

In the territory Russian Federation climate change is taking place. A study of the evolution of climate has shown that there is currently a period of global warming. According to the assessment report of Roshydromet, the climate of Russia has changed more (by 0.76 °C) than the climate of the Earth as a whole, with the most significant changes occurring on European territory our country. On fig. Figure 4 shows that the increase in air temperature in Moscow over the period 1950–2010 occurred in all seasons. It was most significant during the cold period (0.67 ° C for 10 years). [L.2]

The main characteristics of the heating period are the average temperature of the heating season, °C, and the duration of this period. Naturally, every year real value changes and, therefore, calculations of the annual consumption of thermal energy for heating and ventilation of houses are only an estimate of the actual annual consumption of thermal energy. The results of this calculation allow compare .

Appendix:

Literature:

• 1. Refinement of tables of basic and normalized by years of construction indicators of energy efficiency of residential and public buildings
  V. I. Livchak, Ph.D. tech. Sciences, independent expert
• 2. New SP 131.13330.2012 “SNiP 23-01–99* “Construction climatology”. Updated Edition»
  N. P. Umnyakova, Ph.D. tech. Sci., Deputy Director for Research, NIISF RAASN