For thermal evaluation of design and planning solutions and for estimated calculation heat loss of buildings use the indicator - specific thermal characteristic buildings q.
The value q, W / (m 3 * K) [kcal / (h * m 3 * ° C)], determines the average heat loss of 1 m 3 of the building, referred to the calculated temperature difference equal to 1 °:
q \u003d Q zd / (V (t p -t n)).
where Q zd - estimated heat loss by all rooms of the building;
V - the volume of the heated part of the building to the external measurement;
t p -t n - the estimated temperature difference for the main premises of the building.
The value of q is determined as a product:
where q 0 - specific thermal characteristic corresponding to the temperature difference Δt 0 =18-(-30)=48°;
β t - temperature coefficient, taking into account the deviation of the actual calculated temperature difference from Δt 0 .
The specific thermal characteristic q 0 can be determined by the formula:
q0=(1/(R 0 *V))*.
This formula can be converted into a simpler expression using the data given in the SNiP and taking, for example, the characteristics for residential buildings as a basis:
q 0 \u003d ((1 + 2d) * Fc + F p) / V.
where R 0 - heat transfer resistance of the outer wall;
η ok - coefficient taking into account the increase in heat loss through the windows compared to the outer walls;
d - the proportion of the area of the outer walls occupied by windows;
ηpt, ηpl - coefficients that take into account the reduction in heat loss through the ceiling and floor compared to the outer walls;
F c - area of outer walls;
F p - area of the building in terms of;
V is the volume of the building.
The dependence of the specific thermal characteristic q 0 on the change in the design and planning solution of the building, the volume of the building V and the resistance to heat transfer of the outer walls β relative to R 0 tr, the height of the building h, the degree of glazing of the outer walls d, the heat transfer coefficient of the windows k he and the width of the building b.
The temperature coefficient β t is:
βt=0.54+22/(t p -t n).
The formula corresponds to the values of the coefficient β t , which are usually given in the reference literature.
Characteristic q is convenient to use for thermal evaluation of possible design and planning solutions for the building.
If we substitute the value of Q zd into the formula, then it can be brought to the form:
q=(∑k*F*(t p -t n))/(V(t p -t n))≈(∑k*F)/V.
The value of the thermal characteristic depends on the volume of the building and, in addition, on the purpose, number of storeys and the shape of the building, the area and thermal protection of external fences, the degree of glazing of the building and the construction area. The influence of individual factors on the value of q is obvious from the consideration of the formula. The figure shows the dependence of qo on various characteristics of the building. The reference point in the drawing, through which all the curves pass, correspond to the values: q o \u003d O.415 (0.356) for the building V \u003d 20 * 103 m 3, width b \u003d 11 m, d \u003d 0.25 R o \u003d 0.86 (1.0), k ok =3.48 (3.0); length l=30 m. Each curve corresponds to a change in one of the characteristics (additional scales along the abscissa) with other things being equal. The second scale on the y-axis shows this relationship as a percentage. It can be seen from the graph that the degree of glazing d and the width of the building b have a noticeable effect on qo.
The graph reflects the effect of thermal protection of external fences on the total heat loss of the building. According to the dependence of qo on β (R o \u003d β * R o.tr), it can be concluded that with an increase in the thermal insulation of the walls, the thermal characteristic decreases slightly, while when it decreases, qo begins to increase rapidly. With additional thermal protection of window openings (scale k ok), qo noticeably decreases, which confirms the feasibility of increasing the heat transfer resistance of windows.
The q values for buildings of various purposes and volumes are given in reference manuals. For civil buildings, these values vary within the following limits:
The heat demand for heating a building can differ markedly from the amount of heat loss, therefore, instead of q, you can use the specific thermal characteristic of the heating of the building qot, when calculating which, according to the upper formula, the numerator is substituted not for heat loss, but for the installed heat output of the heating system Qot.set.
Q from.set \u003d 1.150 * Q from.
where Q from - is determined by the formula:
Q from \u003d ΔQ \u003d Q orp + Q vent + Q texn.
where Q orp - heat loss through external enclosures;
Q vent - heat consumption for heating the air entering the room;
Q texn - technological and household heat releases.
qot values can be used to calculate the heat demand for heating a building according to enlarged meters according to the following formula:
Q \u003d q from * V * (tp-t n).
The calculation of heat loads on heating systems according to enlarged meters is used for approximate calculations when determining the heat demand of a district, city, when designing central heat supply, etc.
Specific thermal characteristic of the building- one of the important technical parameters. It must be contained in the energy passport. The calculation of these data is necessary for design and construction work. Knowledge of such characteristics is also necessary for the consumer of thermal energy, since they significantly affect the amount of payment.
Thermal imaging inspection of buildings
Before talking about calculations, it is necessary to define the basic terms and concepts. Under the specific characteristic, it is customary to understand the value of the largest heat flux required for heating a building or structure. When calculating the specific characteristics of the temperature delta (the difference between street and room temperature) is taken as 1 degree.
In fact, this parameter determines the energy efficiency of the building. Average indicators are determined by regulatory documentation (construction rules, recommendations, SNiP, etc.). Any deviation from the norm - regardless of which direction it is - gives an idea of the energy efficiency of the heating system. The calculation of the parameter is carried out according to the current methods and SNiP "Thermal protection of buildings".
It can be calculated-normative and actual. Calculation and normative data are determined using formulas and tables. Actual data can also be calculated, but accurate results can only be achieved with a thermal imaging survey of the building.
The calculated indicators are determined by the formula:
In this formula, F 0 is the area of the building. The remaining characteristics are the area of walls, windows, floors, coatings. R is the transmission resistance of the respective structures. A coefficient is taken for n, which varies depending on the location of the structure relative to the street. This formula is not unique. The thermal characteristic can be determined according to the methods of self-regulatory organizations, local building codes, etc.
Calculation actual characteristics is determined by the formula:
In this formula, the main data are:
This equation is simple, so it is used very often. However, it has a significant drawback that reduces the accuracy of calculations. This disadvantage lies in the fact that the formula does not take into account the temperature difference in the rooms inside the calculated building.
To obtain more accurate data, you can use calculations with the determination of heat consumption:
For this purpose, the formula of N. S. Ermolaev can be used:
Ermolaev proposed to use data on the planning characteristics of the building (p - perimeter, S - area, H - height) to determine the actual specific characteristics of buildings and structures. The ratio of the area of glazed windows to wall structures is transmitted by the coefficient g 0. The heat transfer of windows, walls, floors, ceilings is also applied as a coefficient.
Self-regulatory organizations use their own methods. They take into account not only the planning and architectural data of the building, but also the year of its construction, as well as correction factors for outdoor air temperatures during the heating season. Also, when determining actual indicators, it is necessary to take into account heat losses in pipelines passing through unheated premises, as well as the costs of ventilation and air conditioning. These coefficients are taken from special tables in SNiP.
Data on specific thermal characteristics are the basis for determining the energy efficiency class of buildings and structures. Since 2011, the energy efficiency class in without fail should be determined for multi-apartment residential buildings.
The following data are used to determine energy efficiency:
Each class has set minimum and maximum values for energy consumption during the year. The energy efficiency class must be included in energy passport Houses.
Often, calculations show that the energy efficiency of a building is very low. It is possible to achieve its improvement, which means that it is possible to reduce heating costs by improving thermal insulation. Law "On Energy Saving" defines methods for improving energy efficiency apartment buildings.
Penoizol for wall insulation
Residents can also take care of the heat saving of their apartments.
A good effect can be achieved in the following ways:
There are other ways to improve energy efficiency. One of the most effective is to reduce the cost of ventilation of the room.
For this purpose, you can use:
Warm house
To improve the energy efficiency of an apartment building, the task is real, but it requires huge costs. As a result, it often remains unresolved. Reducing heat loss in a private house is much easier. This goal can be achieved different methods. Approaching the solution of the problem in a complex way, it is not difficult to obtain excellent results.
First of all, heating costs are made up of the features of the heating system. Private houses are rarely connected to central communications. In most cases, they are heated by an individual boiler room. The installation of modern boiler equipment, which is characterized by economical operation and high efficiency, will help reduce heat costs, which will not affect the comfort in the house. The best choice is a gas boiler.
However, gas is not always suitable for heating. First of all, this applies to areas where gasification has not yet taken place. For such regions, you can choose another boiler based on considerations of cheap fuel and the availability of operating costs.
Do not save on additional equipment, options for the boiler. For example, installing only one thermostat can provide fuel savings of about 25%. By installing a number of additional sensors and devices, you can achieve even more significant cost savings. Even choosing expensive, modern, "intelligent" additional equipment, you can be sure that it will pay off during the first heating season. Adding up operating costs over several years, you can clearly see the benefits of additional "smart" equipment.
Most autonomous heating systems are built with forced circulation of the coolant. For this purpose, pumping equipment is built into the network. Without a doubt, such equipment must be reliable, of high quality, but such models can be very, very "gluttonous". As practice has shown, in houses where heating has forced circulation, 30% of the cost of electricity falls on the maintenance of the circulation pump. At the same time, pumps with class A energy efficiency can be found on sale. We will not go into details, due to which the efficiency of such equipment is achieved, it is enough to say that the installation of such a model will pay off already during the first three or four heating seasons.
electric radiator
We have already mentioned the efficiency of using thermostats, but these devices deserve a separate discussion. The principle of operation of the temperature sensor is very simple. It reads the air temperature inside the heated room and turns on / off the pump when the indicators decrease / increase. The response threshold and the desired temperature regime are set by the user. As a result, residents receive a completely autonomous heating system, a comfortable microclimate, and significant fuel savings due to longer periods of boiler shutdown. An important advantage of using thermostats is not only turning off the heater, but also the circulation pump. And this saves the operability of the equipment and expensive resources.
There are other ways to improve the energy efficiency of a building:
All these methods make it possible to increase the actual thermal characteristics of the building relative to the calculated and normative ones. Such an increase is not just numbers, but components of the comfort of the house and the efficiency of its operation.
The calculated-normative and actual specific thermal characteristics are important parameters used by heating specialists. Do not think that these figures do not have any practical value for residents of private and multi-apartment buildings. The delta between the calculated and actual parameters is the main indicator of the energy efficiency of the house, and hence the cost-effectiveness of maintaining engineering communications.
1. Heating
1.1. The estimated hourly heat load of heating should be taken according to standard or individual building designs.
If the value of the calculated outdoor air temperature adopted in the project for designing heating differs from the current standard value for a particular area, it is necessary to recalculate the estimated hourly heat load of the heated building given in the project according to the formula:
where Qo max is the calculated hourly heat load of the heating of the building, Gcal/h;
Qo max pr - the same, according to a standard or individual project, Gcal / h;
tj - design air temperature in the heated building, °С; taken in accordance with Table 1;
to - design outdoor air temperature for designing heating in the area where the building is located, according to SNiP 23-01-99, ° С;
to.pr - the same, according to a standard or individual project, ° С.
Table 1. Estimated air temperature in heated buildings
In areas with an estimated outdoor air temperature for heating design of -31 °С and below, the value of the calculated air temperature inside heated residential buildings should be taken in accordance with the chapter SNiP 2.08.01-85 equal to 20 °С.
1.2. In the absence of design information, the calculated hourly heat load of heating an individual building can be determined by aggregated indicators:
where is a correction factor that takes into account the difference in the calculated outdoor temperature for heating design to from to = -30 °С, at which the corresponding qo value is determined; taken according to table 2;
V is the volume of the building according to the external measurement, m3;
qo - specific heating characteristic of the building at to = -30 °С, kcal/m3 h°С; taken according to tables 3 and 4;
Ki.r - calculated coefficient of infiltration due to thermal and wind pressure, i.e. the ratio of heat losses from a building with infiltration and heat transfer through external fences at an outside air temperature calculated for heating design.
Table 2. Correction factor for residential buildings
Table 3. Specific heating characteristic of residential buildings
External building volume V, m3 | Specific heating characteristic qo, kcal/m3 h °C |
|
building before 1958 | building after 1958 |
|
Table 3a. Specific heating characteristic of buildings built before 1930
Table 4. Specific thermal characteristic of administrative, medical, cultural and educational buildings, children's institutions
Name of buildings | Volume of buildings V, m3 | Specific thermal characteristics |
|
for heating qo, kcal/m3 h °C | for ventilation qv, kcal/m3 h °C |
||
Administrative buildings, offices | |||
over 15000 | |||
over 10000 | |||
Cinemas | |||
over 10000 | |||
over 30000 | |||
The shops | |||
over 10000 | |||
Kindergartens and nurseries | |||
Schools and higher education institutions | |||
over 10000 | |||
Hospitals | |||
over 15000 | |||
over 10000 | |||
Laundries | |||
over 10000 | |||
Catering establishments, canteens, kitchen factories | |||
over 10000 | |||
Laboratories | |||
over 10000 | |||
fire stations | |||
The value of V, m3, should be taken according to the information of a typical or individual design of a building or a technical inventory bureau (BTI).
If the building has an attic floor, the value V, m3, is determined as the product of the horizontal cross-sectional area of the building at the level of its first floor (above the basement floor) and the free height of the building - from the level of the finished floor of the first floor to the upper plane of the attic floor heat-insulating layer, with roofs, combined with attic ceilings - up to the average mark of the top of the roof. Architectural details protruding beyond the surface of the walls and niches in the walls of the building, as well as unheated loggias, are not taken into account when determining the calculated hourly heat load of heating.
If there is a heated basement in the building, 40% of the volume of this basement must be added to the resulting volume of the heated building. The construction volume of the underground part of the building (basement, ground floor) is defined as the product of the horizontal section of the building at the level of its first floor by the height of the basement (ground floor).
The calculated infiltration coefficient Ki.r is determined by the formula:
where g - free fall acceleration, m/s2;
L - free height of the building, m;
w0 - calculated wind speed for the given area during the heating season, m/s; accepted according to SNiP 23-01-99.
It is not necessary to enter into the calculation of the calculated hourly heat load of the heating of the building the so-called correction for the effect of wind, because this quantity has already been taken into account in formula (3.3).
In areas where the calculated value of the outdoor air temperature for heating design is up to -40 ° С, for buildings with unheated basements, additional heat loss through the unheated floors of the first floor at a rate of 5%.
For buildings completed by construction, the calculated hourly heat load of heating should be increased for the first heating period for stone buildings built:
In May-June - by 12%;
In July-August - by 20%;
In September - by 25%;
In the heating period - by 30%.
1.3. The specific heating characteristic of the building qo, kcal / m3 h ° С, in the absence of the qo value corresponding to its construction volume in Tables 3 and 4, can be determined by the formula:
where a \u003d 1.6 kcal / m 2.83 h ° С; n = 6 - for buildings under construction before 1958;
a \u003d 1.3 kcal / m 2.875 h ° С; n = 8 - for buildings under construction after 1958
1.4. If a part of a residential building is occupied by a public institution (office, shop, pharmacy, laundry collection point, etc.), the estimated hourly heating load must be determined according to the project. If the calculated hourly heat load in the project is indicated only for the whole building, or is determined by aggregated indicators, the heat load of individual rooms can be determined from the heat exchange surface area of the installed heating devices using the general equation describing their heat transfer:
Q = k F t, (3.5)
where k is the heat transfer coefficient of the heating device, kcal/m3 h °C;
F - heat exchange surface area of the heating device, m2;
t - temperature difference of the heating device, °С, defined as the difference between the average temperature of the convective-radiative heating device and the air temperature in the heated building.
The methodology for determining the calculated hourly heat load of heating on the surface of installed heating devices of heating systems is given in.
1.5. When heated towel rails are connected to the heating system, the calculated hourly heat load of these heaters can be determined as the heat transfer of uninsulated pipes in a room with an estimated air temperature tj \u003d 25 ° C according to the method given in.
1.6. In the absence of design data and the determination of the estimated hourly heat load for heating industrial, public, agricultural and other non-standard buildings (garages, heated underground passages, swimming pools, shops, kiosks, pharmacies, etc.) according to aggregated indicators, the values of this load should be refined according to the heat exchange surface area of the installed heating devices of heating systems in accordance with the methodology given in. The initial information for calculations is revealed by a representative of the heat supply organization in the presence of a representative of the subscriber with the preparation of an appropriate act.
1.7. The consumption of thermal energy for the technological needs of greenhouses and conservatories, Gcal/h, is determined from the expression:
, (3.6)
where Qcxi - heat energy consumption per i-e technological operations, Gcal/h;
n is the number of technological operations.
In its turn,
Qcxi \u003d 1.05 (Qtp + Qv) + Qfloor + Qprop, (3.7)
where Qtp and Qv are heat losses through the building envelope and during air exchange, Gcal/h;
Qpol + Qprop - consumption of thermal energy for heating irrigation water and steaming the soil, Gcal/h;
1.05 - coefficient taking into account the consumption of thermal energy for heating domestic premises.
1.7.1. Heat loss through building envelope, Gcal/h, can be determined by the formula:
Qtp = FK (tj - to) 10-6, (3.8)
where F is the surface area of the building envelope, m2;
K is the heat transfer coefficient of the enclosing structure, kcal/m2 h °C; for single glazing, K = 5.5 can be taken, for a single-layer film fence K = 7.0 kcal / m2 h ° C;
tj and to are the process temperature in the room and the calculated outdoor air for the design of the corresponding agricultural facility, °С.
1.7.2. Heat losses during air exchange for greenhouses with glass coatings, Gcal/h, are determined by the formula:
Qv \u003d 22.8 Finv S (tj - to) 10-6, (3.9)
where Finv is the inventory area of the greenhouse, m2;
S - volume coefficient, which is the ratio of the volume of the greenhouse and its inventory area, m; can be taken in the range from 0.24 to 0.5 for small greenhouses and 3 or more m - for hangars.
Heat losses during air exchange for film-coated greenhouses, Gcal/h, are determined by the formula:
Qv \u003d 11.4 Finv S (tj - to) 10-6. (3.9a)
1.7.3. The consumption of thermal energy for heating irrigation water, Gcal/h, is determined from the expression:
, (3.10)
where Fcreep is the useful area of the greenhouse, m2;
n - duration of watering, h.
1.7.4. The consumption of thermal energy for steaming the soil, Gcal/h, is determined from the expression:
2. Supply ventilation
2.1. If there is a standard or individual building design and compliance installed equipment of the supply ventilation system to the project, the calculated hourly ventilation heat load can be taken according to the project, taking into account the difference in the values of the calculated outdoor air temperature for the design of ventilation adopted in the project and the current normative value for the area where the building in question is located.
Recalculation is carried out according to a formula similar to formula (3.1):
, (3.1a)
Qv.pr - the same, according to the project, Gcal / h;
tv.pr is the calculated outdoor air temperature at which the heat load of supply ventilation in the project is determined, °С;
tv is the calculated outdoor air temperature for designing supply ventilation in the area where the building is located, °С; accepted according to the instructions of SNiP 23-01-99.
2.2. In the absence of projects or inconsistency of the installed equipment with the project, the calculated hourly heat load of supply ventilation must be determined from the characteristics of the equipment actually installed, in accordance with the general formula describing the heat transfer of air heaters:
Q = Lc (2 + 1) 10-6, (3.12)
where L is the volumetric flow rate of heated air, m3/h;
- density of heated air, kg/m3;
c is the heat capacity of the heated air, kcal/kg;
2 and 1 - calculated values of air temperature at the inlet and outlet of the calorific unit, °C.
The methodology for determining the estimated hourly heat load of supply air heaters is set out in.
It is permissible to determine the calculated hourly heat load of the supply ventilation of public buildings according to aggregated indicators according to the formula:
Qv \u003d Vqv (tj - tv) 10-6, (3.2a)
where qv is the specific thermal ventilation characteristic of the building, depending on the purpose and construction volume of the ventilated building, kcal/m3 h °C; can be taken from Table 4.
3. Hot water supply
3.1. The average hourly heat load of hot water supply of a consumer of thermal energy Qhm, Gcal/h, during the heating period is determined by the formula:
where a is the rate of water consumption for hot water supply of the subscriber, l / unit. measurements per day; must be approved local authority self-government; in the absence of approved norms, it is adopted according to the table of Appendix 3 (mandatory) SNiP 2.04.01-85;
N - the number of units of measurement referred to the day, - the number of residents studying in educational institutions etc.;
tc - tap water temperature during the heating season, °С; in the absence of reliable information, tc = 5 °С is accepted;
T - the duration of the operation of the hot water supply system of the subscriber per day, h;
Qt.p - heat losses in the local hot water supply system, in the supply and circulation pipelines outdoor network hot water supply, Gcal/h.
3.2. The average hourly heat load of hot water supply in the non-heating period, Gcal, can be determined from the expression:
, (3.13a)
where Qhm is the average hourly heat load of hot water supply during the heating period, Gcal/h;
- coefficient taking into account the decrease in the average hourly load of hot water supply in the non-heating period compared to the load in the heating period; if the value of is not approved by the local government, is taken equal to 0.8 for the housing and communal sector of cities in central Russia, 1.2-1.5 - for resorts, southern cities and towns, for enterprises - 1.0;
ths, th - hot water temperature in non-heating and heating periods, °С;
tcs, tc - tap water temperature during the non-heating and heating period, °C; in the absence of reliable information, tcs = 15 °С, tc = 5 °С are accepted.
3.3. Heat losses by pipelines of the hot water supply system can be determined by the formula:
where Ki is the heat transfer coefficient of a section of an uninsulated pipeline, kcal/m2 h °C; you can take Ki = 10 kcal/m2 h °C;
di and li - diameter of the pipeline in the section and its length, m;
tн and tк - temperature of hot water at the beginning and end of the calculated section of the pipeline, ° С;
tamb - ambient temperature, °С; take the form of laying pipelines:
In furrows, vertical channels, communication shafts of sanitary cabins tacr = 23 °С;
In bathrooms tamb = 25 °С;
In kitchens and toilets tamb = 21 °С;
On stairwells tocr = 16 °С;
In the underground laying channels of the external hot water supply network tcr = tgr;
In tunnels tcr = 40 °С;
In unheated basements tocr = 5 °С;
In attics tambi = -9 °С (at the average outdoor temperature of the coldest month of the heating period tн = -11 ... -20 °С);
- efficiency of thermal insulation of pipelines; accepted for pipelines with a diameter of up to 32 mm = 0.6; 40-70 mm = 0.74; 80-200 mm = 0.81.
Table 5. Specific heat losses of pipelines of hot water supply systems (according to the place and method of laying)
Place and method of laying | Thermal losses of the pipeline, kcal / hm, with a nominal diameter, mm |
||||||
Main supply riser in a ditch or communication shaft, insulated | |||||||
Riser without heated towel rails, insulated, in the sanitary cabin shaft, furrow or utility shaft | |||||||
Same with towel rails. | |||||||
Riser uninsulated in the sanitary cabin shaft, furrow or communication shaft or open in the bathroom, kitchen | |||||||
Distribution insulated pipelines (supply): | |||||||
in the basement, stairwell | |||||||
in a cold attic | |||||||
in a warm attic | |||||||
Circulation pipelines isolated: | |||||||
in the basement | |||||||
in a warm attic | |||||||
in a cold attic | |||||||
Circulation pipelines uninsulated: | |||||||
in apartments | |||||||
on the stairwell | |||||||
Circulation risers in the duct of a sanitary cabin or bathroom: | |||||||
isolated | |||||||
uninsulated |
Note. In the numerator - specific heat losses of pipelines of hot water supply systems without direct water intake in heat supply systems, in the denominator - with direct water intake.
Table 6. Specific heat losses of pipelines of hot water supply systems (by temperature difference)
Temperature drop, °С | Thermal losses of the pipeline, kcal / h m, with a nominal diameter, mm |
|||||||||||
Note. If the hot water temperature drop is different from its given values, the specific heat losses should be determined by interpolation.
3.4. In the absence of the initial information necessary for calculating heat losses by hot water supply pipelines, heat losses, Gcal / h, can be determined using a special coefficient Kt.p, taking into account the heat losses of these pipelines, according to the expression:
Qt.p = Qhm Kt.p. (3.15)
The heat flow to hot water supply, taking into account heat losses, can be determined from the expression:
Qg = Qhm (1 + Kt.p). (3.16)
Table 7 can be used to determine the values of the coefficient Kt.p.
Table 7. Coefficient taking into account heat losses by pipelines of hot water supply systems
studfiles.net
In houses that were put into operation in last years, usually these rules are met, so the calculation of the heating power of the equipment is based on standard coefficients. An individual calculation can be carried out at the initiative of the owner of the housing or the communal structure involved in the supply of heat. This happens when spontaneous replacement of heating radiators, windows and other parameters.
See also: How to calculate the power of a heating boiler by area of \u200b\u200bthe house
In an apartment served by a utility company, the calculation of the heat load can only be carried out upon transfer of the house in order to track the parameters of SNIP in the premises taken on balance. Otherwise, the owner of the apartment does this in order to calculate his heat losses in the cold season and eliminate the shortcomings of insulation - use heat-insulating plaster, glue the insulation, mount penofol on the ceilings and install metal-plastic windows with a five-chamber profile.
The calculation of heat leaks for the public utility in order to open a dispute, as a rule, does not give a result. The reason is that there are heat loss standards. If the house is put into operation, then the requirements are met. At the same time, heating devices comply with the requirements of SNIP. Replacing batteries and extracting more heat is prohibited, as the radiators are installed according to approved building standards.
Private houses are heated by autonomous systems, which at the same time calculates the load is carried out to comply with the requirements of SNIP, and the correction of heating capacity is carried out in conjunction with work to reduce heat loss.
Calculations can be done manually using a simple formula or a calculator on the website. The program helps to calculate the required capacity of the heating system and heat leakage, typical for the winter period. Calculations are carried out for a certain thermal zone.
The methodology includes a number of indicators that together allow us to assess the level of insulation of the house, compliance with SNIP standards, as well as the power of the heating boiler. How it works:
An individual or average calculation is carried out for the object. The main point of conducting such a survey is that with good insulation and low heat leakage in winter, 3 kW can be used. In a building of the same area, but without insulation, at low winter temperatures, the power consumption will be up to 12 kW. Thus, the thermal power and load are estimated not only by area, but also by heat loss.
The main heat loss of a private house:
These figures may vary for the better and the worst side. They are evaluated depending on the types of windows installed, the thickness of the walls and materials, the degree of insulation of the ceiling. For example, in poorly insulated buildings, heat loss through walls can reach 45% percent, in which case the expression “we drown the street” is applicable to the heating system. Methodology and The calculator will help you evaluate the nominal and calculated values.
This technique can still be found under the name "thermal calculation". The simplified formula looks like this:
Qt = V × ∆T × K / 860, where
V is the volume of the room, m³;
∆T is the maximum difference between indoors and outdoors, °С;
K is the estimated heat loss coefficient;
860 is the conversion factor in kWh.
The heat loss coefficient K depends on building structure, wall thickness and thermal conductivity. For simplified calculations, you can use the following parameters:
These coefficients are averaged and do not allow estimating heat loss and heat load on the room, so we recommend using the online calculator.
gidpopechi.ru
When designing a heating system, whether it is an industrial building or a residential building, it is necessary to carry out competent calculations and draw up a diagram of the heating system circuit. At this stage, experts recommend paying special attention to the calculation of the possible heat load on the heating circuit, as well as the amount of fuel consumed and heat generated.
This term refers to the amount of heat given off by heating devices. The preliminary calculation of the heat load made it possible to avoid unnecessary costs for the purchase of components of the heating system and for their installation. Also, this calculation will help to correctly distribute the amount of heat generated economically and evenly throughout the building.
There are many nuances in these calculations. For example, the material from which the building is built, thermal insulation, region, etc. Experts try to take into account as many factors and characteristics as possible to obtain a more accurate result.
The calculation of the heat load with errors and inaccuracies leads to inefficient operation of the heating system. It even happens that you have to redo sections of an already working structure, which inevitably leads to unplanned expenses. Yes, and housing and communal organizations calculate the cost of services based on data on heat load.
Main Factors
An ideally calculated and designed heating system must maintain the set temperature in the room and compensate for the resulting heat losses. When calculating the indicator of the heat load on the heating system in the building, you need to take into account:
Purpose of the building: residential or industrial.
Characteristics of the structural elements of the structure. These are windows, walls, doors, roof and ventilation system.
Housing dimensions. The larger it is, the more powerful the heating system should be. Be sure to take into account the area of window openings, doors, exterior walls and the volume of each interior space.
Availability of rooms special purpose(bath, sauna, etc.).
Degree of equipment with technical devices. That is, the presence of hot water supply, ventilation systems, air conditioning and the type of heating system.
Temperature regime for a single room. For example, in rooms intended for storage, it is not necessary to maintain a comfortable temperature for a person.
Number of points with hot water supply. The more of them, the more the system is loaded.
Area of glazed surfaces. Rooms with French windows lose a significant amount of heat.
Additional terms. In residential buildings, this can be the number of rooms, balconies and loggias and bathrooms. In industrial - the number of working days in a calendar year, shifts, the technological chain of the production process, etc.
Climatic conditions of the region. When calculating heat losses, street temperatures are taken into account. If the differences are insignificant, then a small amount of energy will be spent on compensation. While at -40 ° C outside the window it will require significant expenses.
Features of existing methods
The parameters included in the calculation of the heat load are in SNiPs and GOSTs. They also have special heat transfer coefficients. From the passports of the equipment included in the heating system, digital characteristics are taken regarding a specific heating radiator, boiler, etc. And also traditionally:
The heat consumption, taken to the maximum for one hour of operation of the heating system,
The maximum heat flow from one radiator,
Total heat costs in a certain period (most often - a season); if an hourly calculation of the load on the heating network is required, then the calculation must be carried out taking into account the temperature difference during the day.
The calculations made are compared with the heat transfer area of the entire system. The index is quite accurate. Some deviations happen. For example, for industrial buildings, it will be necessary to take into account the reduction in heat energy consumption on weekends and holidays, and in residential buildings - at night.
Methods for calculating heating systems have several degrees of accuracy. To reduce the error to a minimum, it is necessary to use rather complex calculations. Less accurate schemes are used if the goal is not to optimize the costs of the heating system.
Basic calculation methods
To date, the calculation of the heat load on the heating of a building can be carried out in one of the following ways.
Three main
One exemplary
There is also a fourth option. It has a fairly large error, because the indicators are taken very average, or they are not enough. Here is the formula - Qot \u003d q0 * a * VH * (tEN - tHRO), where:
Example of a simple calculation
For a building with standard parameters (ceiling heights, room sizes and good thermal insulation characteristics), a simple ratio of parameters can be applied, adjusted for a coefficient depending on the region.
Suppose that a residential building is located in the Arkhangelsk region, and its area is 170 square meters. m. The heat load will be equal to 17 * 1.6 \u003d 27.2 kW / h.
Such a definition of thermal loads does not take into account many important factors. For example, the design features of the structure, temperature, the number of walls, the ratio of the areas of walls and window openings, etc. Therefore, such calculations are not suitable for serious heating system projects.
Calculation of a heating radiator by area
It depends on the material from which they are made. Most often today, bimetallic, aluminum, steel are used, much less often cast iron radiators. Each of them has its own heat transfer index (thermal power). Bimetallic radiators with a distance between the axes of 500 mm, on average, have 180 - 190 watts. Aluminum radiators have almost the same performance.
The heat transfer of the described radiators is calculated for one section. Steel plate radiators are non-separable. Therefore, their heat transfer is determined based on the size of the entire device. For example, the thermal power of a two-row radiator 1100 mm wide and 200 mm high will be 1010 W, and a steel panel radiator 500 mm wide and 220 mm high will be 1644 W.
The calculation of the heating radiator by area includes the following basic parameters:
Ceiling height (standard - 2.7 m),
Thermal power (per sq. m - 100 W),
One outer wall.
These calculations show that for every 10 sq. m requires 1,000 W of thermal power. This result is divided by the heat output of one section. The answer is the required number of radiator sections.
For the southern regions of our country, as well as for the northern ones, decreasing and increasing coefficients have been developed.
Average calculation and exact
Given the factors described, the average calculation is carried out according to the following scheme. If for 1 sq. m requires 100 W of heat flow, then a room of 20 square meters. m should receive 2,000 watts. A radiator (popular bimetallic or aluminum) of eight sections emits about 150 watts. We divide 2,000 by 150, we get 13 sections. But this is a rather enlarged calculation of the thermal load.
The exact one looks a little intimidating. Actually, nothing complicated. Here is the formula:
Qt = 100 W/m2 × S(room)m2 × q1 × q2 × q3 × q4 × q5 × q6 × q7, where:
Using any of the methods described, it is possible to calculate the heat load of an apartment building.
Approximate calculation
These are the conditions. Minimum temperature in the cold season - -20оС. Room 25 sq. m with triple glazing, double-leaf windows, ceiling height of 3.0 m, two-brick walls and an unheated attic. The calculation will be as follows:
Q = 100 W/m2 × 25 m2 × 0.85 × 1 × 0.8(12%) × 1.1 × 1.2 × 1 × 1.05.
The result, 2 356.20, is divided by 150. As a result, it turns out that 16 sections need to be installed in a room with the specified parameters.
If calculation is required in gigacalories
In the absence of a heat energy meter on an open heating circuit, the calculation of the heat load for heating the building is calculated by the formula Q = V * (T1 - T2) / 1000, where:
When closed circuit heat load (gcal/h) is calculated differently:
Qot \u003d α * qo * V * (tin - tn.r) * (1 + Kn.r) * 0.000001, where
The calculation of the heat load turns out to be somewhat enlarged, but it is this formula that is given in the technical literature.
Inspection with a thermal imager
Increasingly, in order to increase the efficiency of the heating system, they resort to thermal imaging surveys of the building.
These works are carried out at night. For a more accurate result, you must observe the temperature difference between the room and the street: it must be at least 15 °. Fluorescent and incandescent lamps are switched off. It is advisable to remove carpets and furniture to the maximum, they knock down the device, giving some error.
The survey is carried out slowly, the data are recorded carefully. The scheme is simple.
The first stage of work takes place indoors. The device is moved gradually from doors to windows, giving Special attention corners and other joints.
The second stage is the examination of the external walls of the building with a thermal imager. The joints are still carefully examined, especially the connection with the roof.
The third stage is data processing. First, the device does this, then the readings are transferred to a computer, where the corresponding programs complete the processing and give the result.
If the survey was conducted by a licensed organization, then it will issue a report with mandatory recommendations based on the results of the work. If the work was carried out personally, then you need to rely on your knowledge and, possibly, the help of the Internet.
highlogistic.ru
First and most milestone in the difficult process of organizing heating of any property (whether Vacation home or an industrial facility) is the competent execution of design and calculation. In particular, it is necessary to calculate the heat loads on the heating system, as well as the volume of heat and fuel consumption.
Thermal loads
Performing preliminary calculations is necessary not only in order to obtain the entire range of documentation for organizing the heating of a property, but also to understand the volumes of fuel and heat, the selection of one or another type of heat generators.
The definition of “heat load on heating” should be understood as the amount of heat that is collectively given off by heating devices installed in a house or other facility. It should be noted that before installing all the equipment, this calculation is made to exclude any troubles, unnecessary financial costs and work.
The calculation of thermal loads for heating will help to organize the smooth and efficient operation of the heating system of the property. Thanks to this calculation, you can quickly complete absolutely all the tasks of heat supply, ensure their compliance with the norms and requirements of SNiP.
A set of instruments for performing calculations
The cost of an error in the calculation can be quite significant. The thing is that, depending on the calculated data received, the maximum expenditure parameters will be allocated in the housing and communal services department of the city, limits and other characteristics will be set, from which they are repelled when calculating the cost of services.
The total heat load on a modern heating system consists of several main load parameters:
Calculation and components of thermal systems at home
The most correctly and competently calculated heat load on heating will be determined only when absolutely everything, even the smallest details and parameters, is taken into account.
This list is quite large and can include:
Also, the load rate, which is determined by heat supplier companies and, accordingly, heating costs, depends on the type of building;
Physical indicators of room cooling - data for calculating the heat load
Equipment that can affect thermal loads
As for a private house, you need to take into account the number of people living, the number of bathrooms, rooms, etc.
Do-it-yourself calculation of the heating load itself is carried out even at the design stage of a country cottage or other real estate object - this is due to simplicity and the absence of extra cash costs. At the same time, the requirements of various norms and standards, TCP, SNB and GOST are taken into account.
The following factors are mandatory for determination during the calculation of thermal power:
Gcal/hour - a unit of measurement of thermal loads of objects
Heat loss in a standard residential building
Advice. With a "margin", thermal loads are calculated in order to exclude the possibility of unnecessary financial costs. This is especially true for a country house, where additional connection of heating elements without preliminary study and preparation will be prohibitively expensive.
As already mentioned earlier, the design parameters of indoor air are selected from the relevant literature. At the same time, heat transfer coefficients are selected from the same sources (passport data of heating units are also taken into account).
The traditional calculation of heat loads for heating requires a consistent determination of the maximum heat flux from heating devices (all actually located in the building heating batteries), the maximum hourly consumption of heat energy, as well as the total cost of heat power for a certain period, for example, the heating season.
Distribution of heat fluxes from various types heaters
The above instructions for calculating thermal loads, taking into account the surface area of heat exchange, can be applied to various real estate objects. It should be noted that this method allows you to competently and most correctly develop a justification for using efficient heating as well as energy inspections of houses and buildings.
An ideal calculation method for the standby heating of an industrial facility, when temperatures are expected to drop during non-working hours (holidays and weekends are also taken into account).
Currently, thermal loads are calculated in several main ways:
Another method for calculating the loads on the heating system is the so-called enlarged method. As a rule, such a scheme is used in the case when there is no information about projects or such data does not correspond to the actual characteristics.
Examples of heat loads for residential apartment buildings and their dependence on the number of people living and area
For an enlarged calculation of the heat load of heating, a rather simple and uncomplicated formula is used:
Qmax from.=α*V*q0*(tv-tn.r.)*10-6
The following coefficients are used in the formula: α is a correction factor that takes into account the climatic conditions in the region where the building was built (applied when the design temperature is different from -30C); q0 specific heating characteristic, selected depending on the temperature of the coldest week of the year (the so-called "five days"); V is the outer volume of the building.
In the course of calculations (as well as in the selection of equipment), it is taken into account a large number of a wide variety of thermal loads:
Thermal load regulator for boiler equipment
This factor depends on the mass of parameters, including all kinds of windows and doors, equipment, ventilation systems and even air exchange through cracks in the walls and ceilings. It also takes into account the number of people who can be in the room;
Heat loss of a country house
In any room, humidity is affected by:
As you can see in many photos and videos of modern industrial and domestic heating boilers and other boiler equipment, they come with special heat load regulators. The technique of this category is designed to provide support for a certain level of loads, to exclude all kinds of jumps and dips.
It should be noted that RTN can significantly save on heating bills, because in many cases (and especially for industrial enterprises) certain limits are set that cannot be exceeded. Otherwise, if jumps and excesses of thermal loads are recorded, fines and similar sanctions are possible.
An example of the total heat load for a certain area of the city
Advice. Loads on heating, ventilation and air conditioning systems are an important point in designing a house. If it is impossible to carry out the design work on your own, then it is best to entrust it to specialists. At the same time, all formulas are simple and uncomplicated, and therefore it is not so difficult to calculate all the parameters by yourself.
Thermal loads for heating, as a rule, are calculated in combination with ventilation. This is a seasonal load, it is designed to replace the exhaust air with clean air, as well as heat it up to the set temperature.
Hourly heat consumption for ventilation systems is calculated according to a certain formula:
Qv.=qv.V(tn.-tv.), where
Measurement of heat loss in a practical way
In addition to, in fact, ventilation, thermal loads are also calculated on the hot water supply system. The reasons for such calculations are similar to ventilation, and the formula is somewhat similar:
Qgvs.=0.042rv(tg.-tx.)Pgav, where
r, in, tg., tx. - design temperature of hot and cold water, water density, as well as a coefficient that takes into account the values of the maximum load of hot water supply to the average value established by GOST;
Except, in fact, theoretical issues calculation, some practical work is also performed. So, for example, comprehensive thermal surveys include mandatory thermography of all structures - walls, ceilings, doors and windows. It should be noted that such works make it possible to determine and fix the factors that have a significant impact on the heat loss of the building.
Device for calculations and energy audit
Thermal imaging diagnostics will show what the real temperature difference will be when a certain strictly defined amount of heat passes through 1m2 of enclosing structures. Also, it will help to find out the heat consumption at a certain temperature difference.
Practical measurements are an indispensable component of various computational works. In combination, such processes will help to obtain the most reliable data on thermal loads and heat losses that will be observed in a particular building over a certain period of time. A practical calculation will help to achieve what the theory does not show, namely the "bottlenecks" of each structure.
The calculation of thermal loads, as well as the hydraulic calculation of the heating system, is an important factor, the calculations of which must be made before starting the organization of the heating system. If all the work is done correctly and the process is approached wisely, you can guarantee trouble-free operation of heating, as well as save money on overheating and other unnecessary costs.
Heating boilers
One of the main components of comfortable housing is the presence of a well-thought-out heating system. At the same time, the choice of the type of heating and the required equipment is one of the main questions that need to be answered at the design stage of the house. An objective calculation of the heating boiler power by area will eventually allow you to get a completely efficient heating system.
We will now tell you about the competent conduct of this work. In this case, we consider the features inherent in different types of heating. After all, they must be taken into account when carrying out calculations and the subsequent decision to install one or another type of heating.
This value (W beats) is:
Let's do the calculations
The power calculation is carried out as follows:
W cat. \u003d (S * Wsp.): 10
Advice! For simplicity, a simplified version of this calculation can be used. In it Wud.=1. Therefore, the heat output of the boiler is defined as 10kW per 100m² of heated area. But with such calculations, at least 15% must be added to the obtained value in order to get a more objective figure.
Calculation example
As you can see, the instructions for calculating the heat transfer intensity are simple. But, nevertheless, we will accompany it with a specific example.
The conditions will be as follows. The area of heated premises in the house is 100m². Specific power for the Moscow region is 1.2 kW. Substituting the available values into the formula, we get the following:
W boiler \u003d (100x1.2) / 10 \u003d 12 kilowatts.
The degree of efficiency of the heating system depends primarily on right choice her type. And of course, from the accuracy of the calculation required performance heating boiler. If the calculation of the thermal power of the heating system was not carried out accurately enough, then negative consequences will inevitably arise.
If the heat output of the boiler is less than required, it will be cold in the rooms in winter. In the case of excess performance, there will be an overexpenditure of energy and, accordingly, the money spent on heating the building.
House heating system
To avoid these and other problems, it is not enough just to know how to calculate the power of a heating boiler.
It is also necessary to take into account the features inherent in systems using different types heaters (you can see a photo of each of them further in the text):
The choice of one or another type largely depends on the region of residence and the level of infrastructure development. Equally important is the availability of the possibility of acquiring a certain type of fuel. And, of course, its cost.
Power calculation solid fuel boiler must be produced taking into account the features characterized by the following features of such heaters:
solid fuel heater
Another characteristic feature that should be taken into account when calculating the heating power of a solid fuel boiler is the cyclicity of the temperature obtained. That is, in rooms heated with its help, the daily temperature will fluctuate within 5ºС.
Therefore, such a system is far from the best. And if possible, it should be abandoned. But, if this is not possible, there are two ways to smooth out the existing shortcomings:
All this will reduce the required performance of a solid fuel boiler for heating a private house. Therefore, the effect of the application of these measures must be taken into account when calculating the power of the heating system.
Electric boilers for home heating are characterized by the following features:
electric boiler
All these parameters should be taken into account when calculating the power of an electric heating boiler. After all, it is not purchased for one year.
They have the following characteristic features:
Oil heater
In most cases are the most the best option organization of the heating system. household gas boilers heating have the following characteristic features that must be taken into account when calculating the power of the heating boiler:
A gas boiler
Let's say you decide to install a heating radiator with your own hands. But first you need to buy it. And choose exactly the one that suits the power.
Now you know how to calculate the desired performance of the boiler, as well as the heating radiator. Take advantage of our advice and provide yourself with an efficient and at the same time not wasteful heating system. If you need more detailed information, then you can easily find it in the corresponding video on our website.
All this equipment, indeed, requires a very respectful, prudent attitude - mistakes lead not only to financial losses, but to losses in health and attitude to life.
When we decide to build our own private house, we are primarily guided by largely emotional criteria - we want to have our own separate housing, independent of city utilities, much larger in size and made according to our own ideas. But somewhere in the soul, of course, there is an understanding that you will have to count a lot. The calculations relate not so much to the financial component of all work, but to the technical one. One of the most important types of calculations will be the calculation of the mandatory heating system, without which there is no escape.
First, of course, you need to take up the calculations - a calculator, a piece of paper and a pen will be the first tools
To begin with, decide what is called, in principle, about the methods of heating your home. After all, you have several options for providing heat at your disposal:
You can not do without a detailed plan of the house with a layout of equipment and wiring of all communications
When the solution to the fundamental question of how to provide heat in the house using an autonomous water system has taken place, you need to move on and understand that it will be incomplete if you do not think about
The next step is to create a very accurate diagram of your building with all the elements of the heating system integrated into it. Calculation and installation of heating systems without such a scheme is impossible. The elements of this scheme will be:
The heart of the entire hot water heating system is the heating boiler. Modern boilers are entire systems for providing the entire system with hot coolant
Helpful advice! When it comes to the heating system, this word “coolant” often appears in the conversation. It is possible, with some degree of approximation, to consider ordinary “water” as the medium that is intended to move through the pipes and radiators of the heating system. But there are some nuances that are associated with the way water is supplied to the system. There are two ways - internal and external. External - from an external cold water supply. In this situation, indeed, the coolant will be ordinary water, with all its shortcomings. Firstly, in general availability, and, secondly, purity. When choosing this method of introducing water from the heating system, we highly recommend installing a filter at the inlet, otherwise severe contamination of the system cannot be avoided in just one season of operation. If a completely autonomous filling of water into the heating system is chosen, then do not forget to “flavor” it with all kinds of additives against solidification and corrosion. It is water with such additives that is already called a coolant.
Among the heating boilers available for your choice are the following:
Pay special attention to the quality of all materials used, there is no time for savings, the quality of each component of the system, including pipes, must be perfect
When they talk about the calculation of an autonomous heating system, they first of all mean the calculation of a heating gas boiler. Any example of calculating the heating system includes the following formula for calculating the boiler power:
W \u003d S * Wsp / 10,
The specific power of the boiler is set depending on the climatic conditions of the region of its use:
But, after all, our climate of the XXI century has become so unpredictable that, by and large, the only criterion when choosing a boiler is your acquaintance with the experience of other heating systems. Perhaps, understanding this unpredictability, for simplicity, it has long been accepted in this formula to always take the specific power as a unit. Although do not forget about the recommended values.
Calculation and design of heating systems, to a large extent - the calculation of all junction points, the latest connecting systems, of which there are a huge number on the market, will help here
Helpful advice! This is the desire - to get acquainted with the existing, already working, autonomous heating systems will be very important. If you decide to establish such a system at home, and even with your own hands, then be sure to get acquainted with the heating methods used by your neighbors. Getting a "heating system calculation calculator" first hand will be very important. You will kill two birds with one stone - you will get a good adviser, and maybe in the future a good neighbor, and even a friend, and avoid the mistakes that your neighbor may have made at one time.
The method of supplying the coolant to the system largely depends on the heated area - natural or forced. Natural does not require any additional equipment and involves the movement of the coolant through the system due to the principles of gravity and heat transfer. Such a heating system can also be called passive.
Active heating systems, in which a circulation pump is used to move the coolant, are much more widespread. It is more common to install such pumps on the line from radiators to the boiler, when the water temperature has already subsided and will not be able to adversely affect the operation of the pump.
There are certain requirements for pumps:
The most important component of the entire heating system, which any user constantly encounters, is pipes and radiators.
When it comes to pipes, we have three types of pipes at our disposal:
Steel - the patriarchs of heating systems, used from time immemorial. Now steel pipes gradually disappear "from the stage", they are inconvenient to use, and, in addition, require welding and are subject to corrosion.
Copper pipes are very popular, especially if hidden wiring is carried out. Such pipes are extremely resistant to external influences, but, unfortunately, are very expensive, which is the main brake on their widespread use.
Polymers - as a solution to problems copper pipes. It is polymer pipes that are the hit of use in modern systems heating. High reliability, resistance to external influences, a huge choice of additional auxiliary equipment specifically for use in heating systems ah with polymer pipes.
The heating of the house is largely ensured by the precise selection of the piping system and the laying of pipes.
The thermotechnical calculation of the heating system necessarily includes the calculation of such an indispensable element of the network as a radiator.
The purpose of calculating the radiator is to obtain the number of its sections for heating a room of a given area.
Thus, the formula for calculating the number of sections in a radiator is:
K = S / (W / 100),
Providing heat in the house is a solution to a whole range of tasks, often not related to each other, but serving the same purpose. Installing a fireplace can be one of these standalone tasks.
In addition to the calculation, radiators also require compliance with certain requirements during their installation:
Skillful and accurate placement of radiators ensures the success of the entire end result - here you can not do without diagrams and modeling of the location depending on the size of the radiators themselves
The calculation of the volume of water in the heating system depends on the following factors:
The ideal, of course, is to hide all communications behind plasterboard wall, but it is not always possible to do this, and it raises questions from the point of view of the convenience of future system maintenance
Helpful advice! Accurately calculate required volume water in the system is often not immediately possible with mathematical accuracy. So they act a little differently. First, the system is filled, presumably by 90% of the volume, and its performance is checked. As you work, vent excess air and continue filling. Hence, there is a need for an additional reservoir with a coolant in the system. As the system operates, a natural decrease in the coolant occurs as a result of evaporation and convection processes, therefore, the calculation of the replenishment of the heating system consists in monitoring the loss of water from the additional reservoir.
Many repair work Of course, you can also do housework by yourself. But creating a heating system requires too much knowledge and skills. Therefore, even having studied all the photo and video materials on our website, even having familiarized yourself with such indispensable attributes of each element of the system as an “instruction”, we still recommend that you contact professionals for installing a heating system.
As the top of the entire heating system - the creation of warm heated floors. But the feasibility of installing such floors should be very carefully calculated.
The cost of errors when installing an autonomous heating system is very high. It's not worth the risk in this situation. The only thing left for you is the smart maintenance of the entire system and the call of the masters for its maintenance.
Competently made calculations of the heating system for any building - a residential building, workshop, office, shop, etc., will guarantee its stable, correct, reliable and silent operation. In addition, you will avoid misunderstandings with housing and communal services workers, unnecessary financial costs and energy losses. Heating can be calculated in several stages.
When calculating heating, many factors must be taken into account.
Note! The next step is to check the data. Divide the resulting numbers by the quadrature of the room. Thus, you will get specific heat losses (W/m²). As a rule, this is 50/150 W / m². If the received data is very different from those indicated, then you made a mistake. Therefore, the price of assembling the heating system will be too high.
Heating scheme.
To carry out the heat engineering stage of designing a heating system, you will need initial data.
House project.
After collecting all the data, you can start calculating the heat consumption for heating. As a result of the work, you will collect information on the basis of which you can carry out hydraulic calculations.
Building heat loss.
Calculation of thermal loads on the system should determine the heat losses and boiler output. In the latter case, the formula for calculating heating is as follows:
Mk = 1.2 ∙ Tp, where:
Note! This coefficient The reserve takes into account the possibility of a pressure drop in the gas pipeline system in winter, in addition, unforeseen heat losses. For example, as the photo shows, due to a broken window, poor thermal insulation of doors, severe frosts. Such a margin allows you to widely regulate the temperature regime.
It should be noted that when the amount of thermal energy is calculated, its losses throughout the building are not evenly distributed, on average, the figures are as follows:
Thermal conductivity coefficients of some materials.
As for windows, their heat loss coefficients are:
The larger the windows are relative to the floors, the more heat the building loses.
When calculating the consumption of thermal energy for heating, keep in mind that the material of the walls has the following coefficient values:
At negative temperatures, heat leakage also increases.
When you calculate thermal energy, keep in mind that its loss also depends on how many external walls are in the building:
The greater the number of floors, the more difficult the calculations.
The number of floors or the type of premises located above the living room affect the coefficient K6. When the house has two floors or more, the calculation of heat energy for heating takes into account the coefficient 0.82. If the building has warm attic, the figure changes to 0.91, if this room is not insulated, then to 1.
The height of the walls affects the level of the coefficient as follows:
Among other things, the method for calculating the need for thermal energy for heating takes into account the area of \u200b\u200bthe room - Pk, as well as the specific value of heat losses - UDtp.
The final formula for the necessary calculation of the heat loss coefficient looks like this:
Tp \u003d UDtp ∙ Pl ∙ K1 ∙ K2 ∙ K3 ∙ K4 ∙ K5 ∙ K6 ∙ K7. In this case, UDtp is 100 W/m².
The building for which we will find the load on the heating system will have the following parameters.
Knowing all the numbers, we substitute them into the formula:
Fri = 135 ∙ 100 ∙ 1 ∙ 1 ∙ 1.1 ∙ 0.9 ∙ 1.22 ∙ 1 ∙ 1.05 = 17120.565 W (17.1206 kW).
Mk = 1.2 ∙ 17.1206 = 20.54472 kW.
An example of a hydraulic calculation scheme.
This design stage will help you choose the right length and diameter of pipes, as well as correctly balance the heating system using radiator valves. This calculation will give you the opportunity to choose the power of the electric circulation pump.
High quality circulation pump.
According to the results of hydraulic calculations, you need to find out the following numbers:
The flow rate of the coolant for the heating system is found by the formula:
M = Q/Cp ∙ DPt
In the same way, it is possible to calculate the consumption of water (coolant) in any section of the pipeline. Select sections so that the fluid velocity is the same. According to the standard, division into sections must be carried out before reduction or tee. Next, sum up the power of all batteries to which water is supplied through each pipe interval. Then substitute the value in the above formula. These calculations must be made for the pipes in front of each of the batteries.
DPptr = R ∙ L,
After that, calculate the pressure loss on the resistances (fittings, fittings), the action formula:
Dms = Σξ ∙ V²/2 ∙ P
Note! In order for the circulation pump to sufficiently provide heat to all batteries, the pressure loss on the long branches of the system should not be more than 20,000 Pa. The coolant flow rate should be from 0.25 to 1.5 m/s.
If the speed is above the specified value, noise will appear in the system. Minimum value speeds of 0.25 m / s, snip No. 2.04.05-91 is recommended so that the pipes do not air.
Pipes made of different materials have different properties.
In order to comply with all the voiced conditions, it is necessary to choose the right diameter of the pipes. You can do this according to the table below, which shows the total power of the batteries.
At the end of the article, you can watch a tutorial video on its topic.
For installation, heating design standards must be observed
Numerous companies, as well as individuals, offer the population heating design with its subsequent installation. But do you really, if you are managing a construction site, do you definitely need a specialist in the field of calculation and installation of heating systems and appliances? The fact is that the price of such work is quite high, but with some effort, you can do it yourself.
It is impossible to consider the installation and design of heating systems of all types in one article - it is better to pay attention to the most popular ones. Therefore, let's dwell on the calculations of water radiator heating and some features of boilers for heating water circuits.
Sections can be added and removed by hand
Knumber of sections \u003d S room area * 100 / P power of one section
Panel radiators
P panel radiator power = V volume of heated room * 41 required amount of W per 1 cu.
The radiator must be hung under the window
Covtion gas boiler Bosch Gaz 3000W
gas boiler
Recommendations. There are other types of boilers, but about them now more briefly. So, if you opted for a liquid fuel heater, you can give preference to a unit with a multi-stage burner, thereby increasing the efficiency of the entire system.
Electrode boiler "Galan"
If you prefer electric boilers, then instead of a heating element it is better to purchase an electrode heater (see photo above). This is a relatively new invention in which the coolant itself serves as a conductor of electricity. But, nevertheless, it is completely safe and very economical.
Fireplace for heating a country house
All buildings and structures, regardless of type and classification, have certain technical and operational parameters that must be recorded in the relevant documentation. One of the most important indicators is the specific thermal characteristic, which has a direct impact on the amount of payment for the consumed thermal energy and allows you to determine the energy efficiency class of the structure.
The specific heating characteristic is usually called the value of the maximum heat flux, which is necessary to heat the structure with a difference between the internal and external temperatures equal to one degree Celsius. Average indicators are determined by building codes, recommendations and rules. At the same time, any nature of deviation from the standard values allows us to talk about the energy efficiency of the heating system.
The specific thermal characteristic can be both actual and calculated. In the first case, in order to obtain data as close as possible to reality, it is necessary to examine the building using thermal imaging equipment, and in the second case, the indicators are determined using the table of the specific heating characteristics of the building and special calculation formulas.
Recently, the determination of the energy efficiency class has been a mandatory procedure for all residential buildings. Such information should be included in the energy passport of the building, since each class has a set minimum and maximum energy consumption during the year.
To determine the energy efficiency class of a building, it is necessary to clarify the following information:
Estimated data, in most cases, indicate the low energy efficiency of multi-apartment housing. When it comes to increasing this indicator, it must be clearly understood that it is possible to reduce heating costs only by carrying out additional thermal insulation, which will help reduce heat loss. Reduce heat loss in residential apartment building, of course, it is possible, but the solution of this problem will be a very time-consuming and expensive process.
The main methods for improving the energy efficiency of a multi-storey building include the following:
An additional measure to improve the energy efficiency of residential high-rise building it may become tenants to carry out energy-saving procedures in apartments, for example:
How to improve the energy efficiency of a private house?
It is possible to increase the energy efficiency class of a private house using various methods. An integrated approach to solving this problem will provide excellent results. The size of the cost item for heating a residential building is primarily determined by the characteristics of the heat supply system. Individual housing construction practically does not provide for the connection of private houses to centralized heat supply systems, so heating issues in this case are solved using an individual boiler house. The installation of modern boiler equipment, which is characterized by high efficiency and economical operation, will help to reduce costs.
In most cases, gas boilers are used to heat a private house, but this type of fuel is not always appropriate, especially for areas that have not undergone gasification. When choosing a heating boiler, it is important to take into account the characteristics of the region, the availability of fuel and operating costs. Equally important from an economic point of view for the future heating system will be the availability of additional equipment and options for the boiler. Installing a thermostat, as well as a number of other devices and sensors, will help save fuel.
For the circulation of the coolant in autonomous heat supply systems, pumping equipment is mainly used. Undoubtedly, it must be of high quality and reliable. However, it should be remembered that the operation of equipment for forced circulation of the coolant in the system will account for about 30-40% of the total electricity costs. When choosing pumping equipment, preference should be given to models with an energy efficiency class "A".
The efficiency of using thermostats deserves special attention. The principle of operation of the device is as follows: using a special sensor, it determines the internal temperature of the room and, depending on the indicator obtained, turns off or turns on the pump. The temperature regime and the response threshold are set by the residents of the house independently. The main advantage of using a thermostat is to turn off the circulation equipment and the heater. Thus, residents receive significant savings and a comfortable microclimate.
Increase actual figures The specific thermal characteristics of the house will also be helped by the installation of modern plastic windows with energy-saving double-glazed windows, thermal insulation of walls, protection of premises from drafts, etc. It should be noted that these measures will help not only increase the numbers, but also increase the comfort in the house, as well as reduce operating costs.
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