Description:

The amount of thermal energy consumed by the heating, ventilation and hot water supply systems of a building is a necessary indicator when determining the thermal efficiency of buildings, conducting energy audits, the activities of energy service organizations, comparing the actual heat consumption of a building measured by a heat meter with the required one based on actual thermal characteristics buildings and the degree of automation of the heating system and in many other cases. In this issue, the editors publish an example of calculating the amount of thermal energy for hot water supply to a residential building

Calculation of the amount of thermal energy for hot water supply

The amount of thermal energy consumed by the heating, ventilation and hot water supply systems of a building is a necessary indicator when determining the thermal efficiency of buildings, conducting energy audits, the activities of energy service organizations, comparing the actual heat consumption of the building, measured by a heat meter, with the required one based on the actual thermal characteristics of the building and the degree of automation of the system heating and in many other cases. In this issue, the editors publish an example of calculating the amount of thermal energy for hot water supply to a residential building*.

Initial data

Object (building):

number of floors in the building – 16;
number of sections in the building – 4;
the number of apartments in the building is 256.

Heating season:

duration of the heating period, z ht = 214 days;
the average temperature of the internal air in the building over the period, t int= 20 °C;
average outside air temperature for the period, t ht= – 3.1 °C;
calculated outside air temperature, t ext= – 28 °C;
average wind speed for the period, v= 3.8 m/s.

Hot water supply:

type of hot water supply system: with uninsulated risers and heated towel rails;
availability of hot water supply networks: in the presence of hot water supply networks after the central heating point;
average water consumption per user, g= 105 l/day;
number of days when hot water supply is turned off, m= 21 days.

Calculation procedure

1. The average calculated volume of hot water consumption per day of the heating period in a residential building V hw is determined by the formula:

V hw = gm h 10 –3 , (1)

Where g– average water consumption per user (resident) during the heating period, equal to 105 l/day. for residential buildings with centralized hot water supply and equipped with devices for stabilizing water pressure at a minimum level (pressure regulators at the entrance to the building, zoning the system by height, installation of apartment pressure regulators); for other consumers - see SNiP 2.04.01–85* " Internal water supply and sewerage of buildings";
m h – number of users (residents), people.

V hw = 105 865 10 –3 = 91 m 3 /day.

In the case of a calculation for an apartment building, taking into account the equipment of apartments with water meters, based on the condition that apartment metering results in a 40% reduction in water consumption, the calculation of hot water consumption will be made using the formula:

Where Kуч – number of apartments equipped with water meters;
K kv – number of apartments in the back.

2. The average hourly consumption of thermal energy for hot water supply Qhw, kW during the heating period is determined in accordance with SNiP 2.04.01–85*. It is allowed to determine the average hourly flow rate Q hw according to the formula:

(2)

where V hw is the average calculated volume of hot water consumption per day of the heating period in a residential building, m 3 / day; determined by formula (1);
t wc – temperature cold water, °C, accept t wc = 5 °C;
k hl – coefficient taking into account heat loss by pipelines of hot water supply systems, is taken according to table. 1;
ρ w – density of water, kg/l, ρ w = 1 kg/l;
c w – specific heat capacity of water, J/ (kg °C); c w = 4.2 J/ (kg °C).

We get Q hw = 299 kW.

3. The amount of thermal energy consumed by the hot water supply system per year, taking into account the inclusion of the system for repairs Q y hw is determined by the formula:

(3)

Where Q hw – determined by formula (2);
k hl, t wc – the same as in formula (2);
m– number of days when hot water supply is turned off, days; in the Moscow region they take m = 14 days;
z ht – duration, days, of the heating period with an average daily outside air temperature below 8 °C (according to SNiP 23-01–99*), and for territories with t ext = –30 °C and below – with an average daily outside air temperature below 10 °C;
α is a coefficient that takes into account the decrease in the level of water withdrawal in residential buildings in the summer: α = 0.9 – for residential buildings; α = 1 – for other buildings;
t wcs – cold water temperature in summer, °C, is taken equal to 15 °C when water is taken from open sources.
We get Q y hw = 2,275,058 kWh.

Description:

A year has passed since the publication in this journal of proposals for standardizing the basic and required specific annual consumption of thermal energy for heating, ventilation and hot water supply for different regions of our country to improve the energy efficiency of residential and public buildings

Clarification of the tables of basic and standardized energy efficiency indicators for residential and public buildings by year of construction

V. I. Livchak, Ph.D. tech. sciences, independent expert

A year has passed since the publication in this journal of proposals for standardizing the basic and specific annual heat energy consumption required for increasing the energy efficiency of residential and public buildings for heating, ventilation and hot water supply for different regions of our country. However, the Ministry of Regional Development of the Russian Federation has not yet published new edition, already nicknamed the ghost order “On approval of energy efficiency requirements for buildings, structures, structures”, with tables of basic and energy efficiency indicators standardized by year of construction, obliging the design of buildings with reduced heat consumption while ensuring comfortable living conditions in them and allowing buildings to be classified by energy efficiency in accordance with the requirements of the Decree of the Government of the Russian Federation No. 18 of January 25, 2011.

In table 8 and 9 SNiP 02/23/2003 provide the values of the standardized specific heat energy consumption for heating (and ventilation during the heating period, supplemented by the author) of residential and public buildings, per 1 m 2 of heated floor area of apartments or usable area of premises [or per 1 m 3 their heated volume] and to the degree-days of the heating period (GSOP), due to the wide variety of climatic conditions in our country. Below is an extract from Table 9 relating to residential buildings.

Extract from Table 9 of SNiP. Normalized specific consumption of thermal energy for heating and ventilation of residential buildings per OP, q h req, kJ/(m 2 days).

In order to compare the calculated specific consumption of thermal energy for heating and ventilation during the heating period (OP) with the normalized (and now, as shown in, becoming the base), clause 5.12 of SNiP, it was recommended that the calculated specific consumption, defined in kJ/m 2 ( and later in kW h/m 2), divide by the GSOP of the construction region, obtaining values in Wh/(m 2 0 C day), and then compare with the standardized one in the same dimension.

Further, in paragraph 7 of the Rules, approved by Decree of the Government of the Russian Federation No. 18, it is written that “For indicators characterizing flow rates energy resources in the building include standardized indicators of total specific annual expenses thermal energy for heating, ventilation and hot water supply, including thermal energy consumption for heating and ventilation (in a separate line)...", since "the energy efficiency class is determined based on a comparison of actual (calculated) and standard values indicators reflecting the specific consumption of thermal energy for heating and ventilation" (clause 5 of the "Requirements for the rules for determining the energy efficiency class apartment buildings...”, approved by the same resolution No. 18).

But to obtain standardized (basic) indicators of the total specific annual consumption of thermal energy for heating, ventilation and hot water supply, it is impossible to arithmetically add the specific consumption of thermal energy for heating and ventilation, expressed in Wh/(m 2 0 C day), with the specific thermal energy consumption for hot water supply in kWh/m2. It is necessary first to convert the specific thermal energy consumption for heating and ventilation into the same dimension kWh/m2. Everything is correct here. But when the task arose of summing up the basic values of specific costs, according to clause 7 of the Rules of Decree No. 18, the opinion was formed that the value from Table 9 of SNiP in W h/(m 2 0C day) could be multiplied by the GSOP of the construction region, divided by 1000 to convert to kWh/m2 and add it with the desired values of the basic specific annual heat energy consumption for hot water supply. This was done in .

As subsequent arguments showed, this cannot be done, due to the fact that heat loss through external fences cannot increase as many times as the GSOP increases, since with an increase in GSOP the normalized heat transfer resistance of these fences also increases (see Table 4 of SNiP 02/23/2003), as well as in the heat balance of the building, along with components depending on changes in external temperature (heat loss through external fences and heating of air infiltrated through window openings), includes internal (domestic) heat inputs, the specific value of which is not depends on different climatic conditions of the regions and is practically constant for all regions in the latitude range 45-60 0.

In addition, in the table of energy efficiency indicators for apartment buildings, given in, the structure of its breakdown by number of floors is broken in comparison with Table 9 of SNiP, which complicates the work of the designer or energy auditor (when assessing the energy efficiency class based on the results of an energy survey).

We propose to classify (for ease of calculation) the data on line 1 of Table 9 to an even number of floors; for an odd number, the values will be found as arithmetic averages between adjacent columns, and add 2-floor apartment buildings, which are common in small cities and towns. houses, which will facilitate the construction of a table of energy efficiency indicators for single-family houses.

Therefore, we recalculated the basic specific annual consumption of thermal energy for heating and ventilation, taking into account the circumstances listed above, using the methodology set out in Appendix 1.

The calculation results for apartment buildings are summarized in table. 1 (excluding the line with GSOP = 12000 0 C days, since there are no such cities, and adding for ease of use the lines with GSOP = 3000 and 5000 0 C days), where they are presented along with the base values and normalized from 2012, 2016 and 2020. indicators.

Table 1
Basic and standardized specific annual consumption of thermal energy for heating, ventilation and hot water supply of apartment buildings, depending on the year of construction, kWh/m 2

Name of specific indicator	0 C day will heat period	Specific annual heat energy consumption depending on the number of storeys of the building, kWh/m2
Name of specific indicator	0 C day will heat period
		Basic values
for heating, ventilation and hot water supply	2000 3000 4000 5000 6000 8000 10000	215 234 255 272 299 356 411	201 213 229 242 263 309 352	198 208 224 236 256 300 340	195 204 219 230 250 291 329	193 201 215 226 244 284 320	191 199 213 224 241 280 315
including on heating and ventilation separately	2000 3000 4000 5000 6000 8000 10000	66 99 120 137 164 218 273	52 78 94 107 128 171 214	49 73 89 101 121 162 202	46 69 84 95 115 153 191	44 66 80 91 109 146 182	43 64 78 89 106 142 177
		Standardized values established from the date of entry into force of energy efficiency requirements
for heating, ventilation and hot water supply	2000 3000 4000 5000 6000 8000 10000	183 199 217 231 254 303 349	171 181 195 206 224 263 299	168 177 190 201 218 255 289	166 174 186 196 213 247 280	164 171 183 192 207 241 272	162 169 181 190 205 238 268
including heating and ventilation separately	2000 3000 4000 5000 6000 8000 10000	56 84 102 116 139 185 232	44 66 80 91 109 145 182	42 62 76 86 103 138 172	39 59 71 81 98 130 162	37 56 68 77 93 124 155	36 54 66 76 90 121 150
		Normalized values established from 01/01/2016
for heating, ventilation and hot water supply	2000 3000 4000 5000 6000 8000 10000	151 164 179 190 209 249 288	141 149 160 169 184 216 246	139 146 157 165 179 210 238	137 143 153 161 175 204 230	135 141 151 158 171 199 224	134 139 149 157 169 196 221
including heating and ventilation separately	2000 3000 4000 5000 6000 8000 10000	46 69 84 96 115 153 191	36 78 66 75 90 120 150	34 55 62 71 85 113 141	32 48 59 67 81 107 134	31 46 56 64 76 102 127	30 45 55 62 74 99 124
		Normalized values established from 01/01/2020
for heating, ventilation and hot water supply	2000 3000 4000 5000 6000 8000 10000	129 140 153 163 179 214 247	121 213 137 145 158 185 211	119 128 134 142 154 180 204	117 122 131 138 150 175 197	116 121 129 136 146 170 192	115 119 128 134 145 168 189
including heating and ventilation separately	2000 3000 4000 5000 6000 8000 10000	40 59 72 82 98 131 164	31 47 56 64 77 103 128	29 44 53 61 73 97 121	28 41 50 57 69 92 115	26 40 48 55 65 88 109	26 38 47 53 64 85 106

Note. When establishing the basic values of the specific annual consumption of thermal energy for heating and ventilation of apartment buildings, an estimated occupancy of 20 m 2 of the total area of apartments per inhabitant was adopted. Based on this, the standard air exchange in apartments was 30 m 3 / h per person and the specific internal heat input was 17 W / m 2 of living space.

The lower part of Table 1 of the blocks of basic and annualized values shows the specific annual consumption of thermal energy for heating and ventilation, and in the upper part - together with hot water supply. The latter was determined according to the methodology for calculating the annual consumption of thermal energy for hot water supply, based on the recommendations of the specific norm of water consumption from SP 30.13330.2012. This SP contains tables A.2 and A.3 of the calculated (specific) annual average daily water consumption, including hot water, l/day, per 1 resident in residential buildings and per 1 consumer in public and industrial buildings at a design temperature of 60 0 C at the place of consumption, while previously this temperature was taken equal to 55 0 C, and the water consumption rate was the average for the heating period.

To determine the annual heat consumption for hot water supply, these indicators must be recalculated to the average calculated water consumption for the heating period (since they are easier to compare with the measured ones) according to the methodology outlined in Appendix 2. In accordance with this methodology, for apartment buildings with an average annual hot water consumption rate per inhabitant 100 l/day and occupancy of 20 m2 of total apartment area per person, the basic specific annual heat consumption for hot water supply will be for the central region ( z from = 220 days) – 135 kW h/m 2 ; for the region of the north of the European part and Siberia ( z from = 250 days) – 138 kW h/m 2 and for the south of the European part of Russia, taking into account z ot = 160 days and an increasing factor of 1.15 for water consumption in the III and IV climatic regions of construction according to SP 30.13330 - 149 kW h/m 2. This is higher than what was previously accepted in the draft MRR order - 120 kW h/m 2 for all climatic regions in accordance with the then SNiP 2.04.01-85* in force.

To obtain the basic standardized value of the total specific annual heat energy consumption for heating, ventilation and hot water supply of apartment buildings, we add the above values of specific heat consumption for hot water supply, with interpolation depending on the degree-day value of the construction region, to the established values of the basic specific annual consumption thermal energy for heating and ventilation (Table 1, lines of indicators of total heat consumption for heating, ventilation and hot water supply).

To obtain the values of the total specific annual heat energy consumption for heating, ventilation and hot water supply of apartment buildings, standardized by year of construction, the basic indicators of total heat consumption are reduced, respectively, by 15, 30 and 40%, including for heating and ventilation in a separate line (lower 3 block of table 1).

The table of the basic specific annual heat energy consumption for heating and ventilation of single-family houses is preserved as in SNiP 02/23/2003, but with the conversion of kJ/(m 2 0 C day) to Wh/(m 2 0 C day) - see table .2.

table 2
Basic and normalized by year of construction specific annual consumption of thermal energy for heating and ventilation of single-apartment detached and semi-detached houses

Heated house area, m 2	Specific annual consumption of thermal energy for heating and ventilation, referred to degree-days of the heating period, θ en/eff, Wh/(m 2 0 C day)
Heated house area, m 2
	Base
60 or less





1,000 or more
	Normalized from the date of entry into force of the requirements
60 or less





1,000 or more
	Standardized since 2016
60 or less





1,000 or more
Notes: 1. For intermediate values of the heated area of the house in the range of 60–1000 m 2 values θ en/eff, Wh/(m 2 0 C day) should be determined by linear interpolation. 2. The heated area of a single-apartment building is understood as the sum of the areas of heated premises with an estimated internal air temperature above 12 0 C, for blocked houses - the area of the apartment, and for apartment buildings with a common staircase - the sum of the areas of apartments without summer premises.

The table of the basic specific annual heat energy consumption for heating and ventilation of public buildings retains the absolute values of the values from Table 9 of SNiP 02/23/2003 with the conversion of kJ/(m 3 oC day) to Wh/(m2 0 C day), and for buildings with a floor height of more than 3.6 m per Wh/(m 3 0 C day), but modernized in terms of combining similar buildings in terms of indicators and different in purpose and distinguishing between operating modes - remains as in.

Table 3
Basic and normalized by year of construction specific annual consumption of thermal energy for heating and ventilation of public buildings, related to degree-days of the heating period, Wh/(m 2 0 C day)

Building types	Number of floors of buildings:
Building types
1. Administrative (offices) and general educational purposes*

Standardized since 2012
Standardized since 2016
2.Policlinics and medical institutions with 1.5 shifts operating mode

Standardized since 2012
Standardized since 2016
3. Medical institutions, hospices with round-the-clock operation, preschool institutions

Standardized since 2012
Standardized since 2016
4.Service, cultural, leisure, sports, recreational and production areas**
Base temperature: t int= 20 °C t int= 18 °C t int= 13-17 °C	28,8 26,6 23,9	27,5 25,7 23,0	26,1 23,9 22,1	25,2 23,0 21,2	24,7 22,5 20,7	24,2 22,0 20,2	23,7 21,5 19,7
Standardized since 2012 with: t int= 20 °C t int= 18 °C t int= 13-17 °C	24,5 22,6 20,3	23,4 21,8 19,6	22,2 20,3 18,8	21,4 19,6 18,0	21,0 19,1 17,6	20,6 18,7 17,2	20,1 18,3 16,7
Standardized from 2016 with: t int= 20 °C t int= 18 °C t int= 13-17 °C	20,2 18,6 16,7	19,3 18,0 16,1	18,3 16,7 15,5	17,6 16,1 14,8	17,3 15,8 14,5	16,9 15,4 14,1	16,6 15,1 13,8
Notes: * The top line is with a single-shift operating mode, the bottom line is a 1.5-shift mode; ** In square brackets for buildings with a floor-to-ceiling height of more than 3.6 m - in Wh/(m 3 0 C day) of the heated volume of the usable area of the building, which should include the areas occupied by escalator lines and atriums. The remaining values are per m2 of usable area of the premises. The normalized indicators in positions 1, 2, 3 are given per m 2 with a floor height from floor to ceiling of 3.3 m; For regions that matter GSOP = 8000 0 C day or more, normalized values are reduced by 5%.

To determine the basic specific annual consumption of thermal energy for heating and ventilation of a building being built in a specific region of the country, q from+vent. year.base, kW h/m 2, follows in accordance with the methodology set out in Appendix 1, the indicators of the table. 2 and 3 multiplied by the region's GSOP and by the resulting reg. conversion factor:

q from+vent. year.base = θ en/eff. bases GSOP to reg. 10 -3

where θ en/eff. databases - from tables 2 and 3, the latter was transferred to the website www.site/...;

to reg. – regional conversion factor for specific annual heat energy consumption for heating and ventilation of residential and public buildings when setting the base heat consumption indicator in the dimension Wh/(m 2 0 C day); is accepted depending on the degree-day value of the heating period of the construction region for buildings with GSOP = 3000 0 C day and lower to reg. = 1.1; with GSOP=4900 0 C days and above to reg. = 0.91; with GSOP=4000 0 C day to reg. = 1.0; in the range of 3000-4900 0 C days - by linear interpolation.

To obtain the basic specific total annual consumption of thermal energy for heating, ventilation and hot water supply q from+vent+gv..year.bas, the specific annual consumption of thermal energy for hot water supply qgv.year of single-family residential buildings and public buildings is determined according to the method outlined in Appendix 2, and is added to the indicator of the specific basic annual consumption of thermal energy for heating and ventilation of a given region q from+vent. year base, kW h/m 2:

q from+vent+gv.. year.base = q from+vent. year base + q guard year

Indicators standardized by year of construction are obtained by reducing the basic values of total heat consumption for heating, ventilation and hot water supply, respectively, by 15, 30 and 40%.

In accordance with Decree of the Government of the Russian Federation No. 18 and Order of the Ministry of Regional Development of the Russian Federation No. 161, “the energy efficiency class of buildings is determined based on the deviation of the calculated (actual) value of the specific consumption of energy resources from the standardized base level established by the requirements for the energy efficiency of buildings, structures, structures, after comparison the obtained deviation value with the energy efficiency class table.”

Taking into account the fair remark in, that it is necessary to start the normal class range from scratch and in order to harmonize the table with European standards on the scale of classes (seven) and designations with Latin letters(D, normal class - in the middle), the following version of the table is proposed.

The number and range of classes below normal have been increased, bringing the lowest value closer to the SNiP indicator 02/23/2003, confirmed by the results of measuring the actual heat consumption of existing buildings. And there is no need to introduce unnecessary words “inclusive” into the table, since the very concept “from” means including the specified value, and “to” - excluding the value following “to” in this range.

Table 4
Energy efficiency classes of apartment buildings

Energy efficiency class designation	Name of energy efficiency class	Deviation of the specific annual consumption of energy resources from the base level, % *)
	Very tall**)	40 or less
		from - 30 to - 40
	Elevated	from - 15 to - 30
	Normal
	Reduced	from + 35 to 0
		from + 70 to +35
	Particularly low
Notes: ) at the design stage - only the calculated value of the specific thermal energy consumption for heating and ventilation; *) if necessary, a very high class can be divided into the highest subclasses A+; A++; A+++.

And lastly, but very important for the speedy approval of the draft order of the Ministry of Regional Development “Energy efficiency requirements for buildings, structures, structures” as amended by the current Decree of the Government of the Russian Federation No. 18, in order to open the way to the construction of energy-efficient buildings. In paragraph 5 of the order of the Ministry of Regional Development of the Russian Federation No. 161 “On approval of the rules for determining energy efficiency classes...” it is added: “The energy efficiency class of operating apartment buildings is determined based on the actual indicators of the specific annual consumption of thermal energy for heating, ventilation and hot water supply...”, and in appendix to the class table: “energy efficiency class at the design stage - only based on the calculated value of the specific thermal energy consumption for heating and ventilation.”

The fact is that recently decisions have been imposed that distort the clear and precise provisions of the “Rules for establishing energy efficiency requirements for buildings...”, approved by Decree of the Government of the Russian Federation No. 18, trying to include in the standard value of the consumption of energy resources in a building, in addition to specific annual costs thermal energy for heating, ventilation and hot water supply, specific annual consumption indicator electrical energy for general household needs, the methodology for determining which is absent at both the federal and regional levels. Thus, the regulation of increasing the energy efficiency of buildings will be abandoned indefinitely.

In clause 7 of the Rules approved by Decree of the Government of the Russian Federation No. 18, which was already referenced at the beginning of the article, it is also written that “the indicators characterizing the annual specific values of the consumption of energy resources in a building also include the indicator of the specific annual consumption of electrical energy for general house needs “, but it is not indicated that it is standardized, like those listed earlier for heating, ventilation and hot water supply, and it is not mentioned anywhere when determining energy efficiency classes. In this regard, it is proposed to move the inclusion of electrical energy consumption into the standardized indicators characterizing the annual specific value of energy resources consumption for the general needs of the building at the stage of performing a comparison on the standardized specific consumption of primary energy, which is assumed in paragraph 16 of the same Rules, and is currently in effect in accordance with Decree of the Government of the Russian Federation No. 18.

Literature

Livchak V.I. Regulatory support for increasing the energy efficiency of buildings under construction.“Energy saving” // No. 8-2012.
Gorshkov A.S., Baykova S.A., Kryanev A.S. Regulatory and legislative support for the State program on energy saving and increasing the energy efficiency of buildings and an example of its implementation at the regional level. " Engineering systems» No. 3 - 2012. ABOK North-West.
3. Livchak V.I. Actual heat consumption of buildings as an indicator of quality and reliability of design. "ABOK", No. 2-2009.

Annex 1.

Calculation method and justification for changing the table of basic and normalized by year of construction energy efficiency indicators of apartment buildings for different regions of Russia.

When calculating the standards applicable to all regions of the country, it is customary to determine the standard indicators of other regions by recalculating the standards established for the central regions, depending on the ratio of the calculated temperatures of the internal air of the heated premises of the building and the external air.

Basic ratio of calculated heat losses at GSOP = ( t vn - t n. Wed) z from = 5000 0 C day and the calculated outdoor air temperature t n for heating design. р = -28 0 C is assumed to be equal according to Fig. 2 from the example of an 8-9 apartment building storey building, built according to the requirements of SNiP 23-02-2003:

relative heat loss through the walls is 0.215 of the total with the reduced heat transfer resistance of the walls RW = 3.15 m 2 0 C/W;
relative heat loss through the floor, ceiling – 0.05;
relative heat loss through windows is 0.265 with their reduced resistance to heat transfer RF = 0.54 m 2 0 C/W;
relative heat loss for heating the outside air with a calculated air exchange of 30 m 3 /h per person and an occupancy of 20 m 2 of the total area of apartments without summer premises per inhabitant - 0.47;
total calculated relative heat losses of the building:

q- tp.max. = 0.215 + 0.05 + 0.265 + 0.47 = 1.0. (1)

Share of household heat emissions with a specific value of 17 W/m 2 area living rooms(with an occupancy of 20 m 2 of the total area of apartments in the house per person) – 0.19 q- tp.max. (right side of Fig. 2), relative estimated heat consumption for heating: q- op.max. = 1-0.19 = 0.81. Since in further calculations of annual heat consumption we will take the share of household heat release in relation to this consumption, then the ratio q - vn / q- op.max. = 0.19/0.81 = 0.235.

The recalculation of the indicators of the same house to the changed values of the heat transfer resistance of the external fences is carried out using Fig. 3 from, demonstrating the change in the relative heat loss through each external fence depending on the value of its reduced heat transfer resistance.

For example, for the same house being built in the central region, but with external fences that meet the requirements of SP 50.13330 for the northern region with GSOP = 10000 0 C day, the relative heat loss of the walls with an increase in the basic heat transfer resistance with RW = 3.15 m 2 0 C /W to RW = 4.9 m 2 0 C/W will decrease from 0.302 to 0.19 and amount to 0.19/0.302 = 0.629 from the previous value. Relative heat loss through windows, with an increase in their basic heat transfer resistance from RF = 0.54 to 0.75 m 2 0 C/W, will decrease from 0.63 to 0.48 and amount to 0.48/0.63 = 0.762 from the previous value. Relative ventilation heat losses will remain at the same level, since the air exchange has not changed, and while we are assessing the change in heat losses in the conditions of the central region.

To establish the total calculated relative heat losses of a similar house in the conditions of the selected northern region with GSOP. = 10000 0 C per day close to the city of Yakutsk, z from = 252 days and t n. р = -52 0 С required total calculated heat loss of a house located in the central region, but with increased heat transfer resistance of external enclosures corresponding to the northern region, divided by the calculated temperature difference between the internal and external air of the central region and multiplied by the corresponding calculated temperature difference of the northern region using the following equation:

Combining the relative heat losses through the walls, ceiling and floor, accepting (as can be seen from Fig. 3) that the latter also change as through the walls, and substituting the values calculated above, we obtain the total calculated relative heat losses of the same house built near the city of Yakutsk with GSOP=10000 0 C day:

As we can see, despite the decrease in relative heat loss through external fences in the northern region, the total calculated heat loss, including heating of outdoor air for ventilation, increased by 1.258 times relative to the central region. Moreover, the share of heat loss through ventilation increased from 0.47 to 0.56.

Internal heat gains by absolute value and in shares of the total calculated heat losses of the central region remained constant, therefore, to establish the relative calculated heat consumption for heating an analogue house built in a region with GSOP = 10000 0 C day, it is necessary from the value of the relative (in relation to the central region) total calculated heat loss subtract relative (to the same region) internal heat gain:

To determine how the amount of heat consumption for heating will change during the estimated heating period, we will use equation (2) from , recalculating it from hourly consumption to annual consumption. Original equation:

Where
Q- from – relative consumption of thermal energy for heating at the current outside temperature t n, determined taking into account the constant value of internal heat input during the heating period Q vn, in relation to the calculated thermal energy consumption for heating Q from p;
Q in – the estimated value of internal (domestic) heat input throughout the house, kW;
Q from р – calculated consumption of thermal energy for heating at the calculated outside air temperature for heating design t n r, kW.

Then, first we write this equation to determine the consumption of thermal energy for heating in kW at the average outdoor temperature for the heating period t n wed:

and recalculate it from the hourly consumption to the annual one, referred to m2 of the total area of the apartments or the usable area of the premises of a public building, qot.+vent.year, multiplying both sides of the equality by the duration of the heating period 24.zot.p and replacing the product (tв – tнср) . zot.p = GSOP, and the ratio of absolute values to relative ones, including Qref = ot.max qref (with GSOP = 5000), kW-h/m2. In general, the transformed equation will be:

By relating the specific annual consumption of thermal energy for heating and ventilation of a house built in a region with GSOP=10000 0 C day to the same consumption of a similar house built in a region with GSOP=4000 0 C day, taken as the initial value for comparison and equal in absolute value from Table 9 SNiP 02/23/2003 q from+vent. year.base.4000 = (76/3.6) 4000 10 -3 = 84 kW h/m 2, and substituting the above values, we obtain the value of the basic specific annual heat energy consumption for heating and ventilation of an 8-floor residential building at GSOP=10000 0 C day from the proportion equation:

After reducing (qot..r(at GSOP=5000) 0.024) and transferring qot.+vent.year.base.4000 = 84 to the other part of the equality, we get:

If the basic values of specific annual heat energy consumption for heating and ventilation, expressed in kJ/(m 2 0 C day) or Wh/(m 2 0 C day), were recalculated only by multiplying by GSOP, without taking into account the increase in heat transfer resistance with an increase in GSOP and the constant internal heat input from the outside air temperature, then q from.+vent. year base 10000 = (76/3.6) 10000 10 -3 = 211 kWh/m2, and the energy efficiency requirements for this region would be underestimated by 10%.

Next, using a similar method, we recalculated the required basic specific annual consumption of thermal energy for heating and ventilation of the analogue house for all the required GSOP values, taking as the initial value with which all the others are compared and at which the recalculation is performed by multiplying only by GSOP, the values of GSOP original = 5000, 6000 and 4000 0 C day. (see the following tables), in order to establish the pattern of changes in specific annual consumption depending on the GSOP through the regional correction coefficient kreg, determined by:

It turned out that at GSOPikh = 5000 0 C day, there is no pattern in the change to reg and there is a very small gap in the indicators q from + vent. year base for GSOP = 5000 and 4000, which is not plausible:

GSOP, 0 C day
qfrom+vent.year.base
to reg,

The same lack of pattern in the change in the correction factor to reg is also observed at GSOP out = 6000 0 C day:

GSOP, 0 C day
qfrom+vent.year.base
to reg,

And at GSOP out = 4000 0 C day, at which from Table 9 SNiP 02/23/2003 q from+vent. year.base = (76/3.6) 4000 10 -3 = 84 kW h/m 2, it can be traced:

GSOP, °C day
qfrom+vent.year.bases
Craig,

The results of intermediate calculations with all initial data and calculations using formulas (1 - 5) are summarized in the following table A.1.

Table A.1.
Initial data for calculating the regional coefficient to reg

zfrom,

day-
ki

tnR, 0 C

RW,
m 2 0 C/W

The share of heat
losses

Relatively
sewing
shares

RF,
m 2 0 C/W

The share of heat
losses

Relatively
sewing
shares

from.max

vn
/ from. max

qfrom+to
. year.base

So, a logical pattern of changes in the basic parameters has been achieved, which can be transferred to construct a table of basic values of the specific annual consumption of thermal energy for heating and ventilation of residential buildings of other floors. Recalculation is carried out using the data of the standardized specific consumption, q h req given in table. 9 SNiP 02/23/2003, preserving the structure of its breakdown by number of floors and referring (for ease of calculation) the data on line 1 to an even number of floors, for an odd number the values will be found as arithmetic averages between adjacent columns, and adding the common ones in small towns and villages, multi-apartment 2-storey buildings, according to the formula:

Where q h req– standardized specific heat energy consumption for heating buildings, kJ/(m 2 0 C day), from table. 9 SNiP 02/23/2003, line 1.

A recalculated table of the basic and normalized specific annual heat energy consumption for heating, ventilation and hot water supply of apartment buildings depending on the year of construction is given in Table. 1 in the main text of the article.

To confirm the correctness of those adopted in the table. 1 values, let’s compare the basic values of specific annual heat energy consumption for heating and ventilation with the results of calculating a specific house for different degrees-day values of the heating period using the example of a 17-story, 4-section multi-apartment large-panel building of the standard Moscow series P3M/17N1 for 256 apartments with 1st non-residential floor. Area of heated floors of the building A S= 23310 m2; Total area of apartments without summer premises A kv= 16262 m2; Usable area of non-residential, rented premises And the floor= 880 m2; Total area of apartments, including usable area of non-residential premises A square+floor= 17142 m2; Living space(area of living rooms) Well= 9609 m2; The sum of the areas of all external fences of the heated building shell And the ogre. sum= 16795 m2; Heated volume of the building V from= 68500 m3; Compactness of the building And the ogre. sum / V from= 0.25; The ratio of the area of translucent fences to the area of facades is 0.17. Attitude A S / A sq+floor = 23310/17142 = 1,36.

The occupancy of the house is assumed to be 20 m 2 of the total area of the apartments per person, then the normalized air exchange in the apartments will be 30 m 3 / h per inhabitant, and the specific value of household heat input will be 17 W / m 2 of living space. The heating system is a vertical single-pipe with thermostats on the heating devices, connected to the intra-block heating networks through an ITP, the efficiency coefficient of automatic regulation of heat supply in heating systems is ζ = 0.9. System exhaust ventilation with natural impulse and a “warm” attic, for 2 top floors individual duct fans are installed; inflow - through window sashes with fixed opening to ensure normal air exchange.

The calculation results are given in table. P.2, which show that the calculated values of the specific annual consumption of thermal energy for heating and ventilation of a specific 17-story building under construction conditions in regions with different numbers of degree-days of the heating period coincide with the indicators of the basic specific annual consumption determined on the basis of 9 -this. Houses. This confirms the correctness of the established values of the basic specific annual heat energy consumption for heating and ventilation of apartment buildings, given in Table 1.

Table 1
Approximate distribution of boilers by power depending on the area of houses served

Index	Degree-day of the heating period, 0 C day
Index

Estimated outside air temperature, tnR, 0 C
Average outside air temperature during the heating period, tnWed, 0 C
Duration of the heating season, z from, day
Reduced heat transfer resistance, m 2 0 C/W: R st r, walls with an area of 11,494 m 2
R ok r, windows n/living premises (104 m 2)
R ok r, apartment windows (2,046 m2)
R ok r, LLU windows (167 m 2)
R dv r, entrance doors(36 m2)
R b.dv r, blind part of the beam doors (144m 2)
R er r, ceilings under the bay window (16 m 2)
R pok r, LLU coatings (251 m 2)
R ch.p r , attic floors(1,151 m2)
R c.p r, basement floors (1,313 m 2)
R p.g r, floors on the ground entrances (73 m 2)
Driven transmission building heat transfer coefficient, Ktr, W/(m 2 0 C)
Heat loss through external fences during the heating period (OP), Qogreyear, MWh
Ventilation heat loss of the residential part (heating of standard air exchange) behind the OP, Qvent.year, MWh
Infiltration heat loss in the LLU and lower parts behind the OP, Qinf.year, MWh
The sum of ventilation and infiltration heat losses Qvent.year+Qinf.year, MWh
Total heat loss of the building for OP, Qtpyear= Qogreyear+ Qvent.year+Qinf.year, MWh
Internal heat inputs for the OP, Qext.year= 0.024· qvn · Well· zfrom.p, MWh
Heat gain through windows from solar radiation for OP, Qinsyear, MWh
Estimated heat consumption of the building on OB for OP, Qfrom+vent.year, MWh
Estimated specific annual consumption thermal energy on OV, qfrom+vent.year.calculation kWh/m2
Basic specific annual consumption thermal energy on OV, qfrom+vent.year.base, kWh/m 2
System thermal power heating, QfromR, kW
Specific power of the heating system, qfromR, W/m 2

Literature for Appendix 1.

Livchak V.I. Another argument in favor of increasing the thermal protection of buildings.“Energy saving” // No. 6-2012.
Livchak V.I. Duration of the heating season for apartment buildings and public buildings. Operating mode of heating and ventilation systems.

“Energy saving” // No. 6-2013.

Appendix 2.

Methodology for calculating the specific annual consumption of thermal energy for hot water supply of residential and public buildings. 1. Average calculated hot water consumption per day of the heating period per inhabitant in a residential building g gv.sr.ot.p.zh

, l/day, is determined by the formula:

Where The same in public and industrial buildings: a main table A.2 or A.3
– calculated annual average daily consumption of hot water per 1 resident from table. A.2 or 1 consumer of a public and industrial building from table. A.3 SP 30.13330.2012;
365 – number of days in a year;
351 – duration of use of centralized hot water supply throughout the year, taking into account shutdowns for repairs, days; z from.
– duration of the heating period;

α is a coefficient that takes into account the decrease in the level of water withdrawal in residential buildings in the summer, α = 0.9, for other buildings α = 1. 2. Specific average hourly consumption of thermal energy for hot water supply during the heating period q gv

Where , W/m2, is determined by the formula: g gv.sr.ot.p
– the same as in formula (8) or (9); t gv
– the temperature of hot water, taken in places of water supply equal to 60°C in accordance with SanPiN 2.1.4.2496; t xv
– cold water temperature, taken equal to 5°C; k hl – cold water temperature, taken equal to 5°C;– coefficient taking into account heat loss by pipelines of hot water supply systems; accepted according to the following table A.3, for ITP of residential buildings with a centralized hot water system – cold water temperature, taken equal to 5°C; = 0,1;
= 0.2; for ITP of public buildings and for residential buildings with apartment water heatersρw
– water density equal to 1 kg/l; c w
– specific heat capacity of water equal to 4.2 J/(kg 0 C);– the norm of the total area of apartments per 1 resident or the usable area of premises per 1 user in public and industrial buildings, the accepted value depending on the purpose of the building is given in Table A.4.

Table A.3. *Coefficient value – cold water temperature, taken equal to 5°C;, taking into account heat loss by pipelines of hot water supply systems*

Table A.4.
Norms of daily consumption of hot water by consumers and the specific hourly value of thermal energy for heating it on an average day during the heating period, as well as the values of the specific annual consumption of thermal energy for hot water supply, based on the standard area for the 1st meter for the central region with z from. = 214 days.

	Consumers	Change ri- tel	Hot water consumption rate from Table A.2 SP 30. 13330. 2012 for the year a *hot water supply* , l/day	General norm, useful Noah Square di on 1 izm supporter S A , m 2 /person	Specific average hourly consumption of thermal energy for hot water for the heater. period *q gv,* W/m2	Specific annual consumption of thermal energy for hot water supply *q gv.year,* kWh/m2 total area

	Residential buildings regardless of the number of floors with centralized hot water supply, equipped with washbasins, sinks and bathtubs, with apartment pressure regulators KRD
	The same with washbasins, sinks and showers with KRD
	Residential buildings with water supply, sewerage and baths with gas water heaters
	The same with water heaters running on solid fuel
	Hotels and boarding houses with bathtubs in all private rooms
	Same with showers in all separate rooms

	Hospitals with sanitary facilities close to the wards	1 sick
	Same with shared baths and showers
	Clinics and outpatient clinics (10 m2 per health worker, work in 2 shifts and 6 patients per 1 worker)	1pain- noah on shift
		1 worker per shift
	Children's nurseries with day care for children and canteens operating on semi-finished products	1 child nok
	The same with 24-hour stay of children
	The same with canteens that use raw materials and laundries.
	Comprehensive schools With showers at gymnasiums and canteens at factories	1 student 1 pre- submit vatel
	Sports and recreation complexes with canteens serving semi-finished products
	Cinemas, meeting rooms // theaters, clubs and leisure and entertainment institutions	1 view tel

	Administrative buildings	1 working
	Catering enterprises for preparing food sold in the dining room	1 dish for 1 place
	Grocery stores	1 working
	Department Stores
	Production workshops and technology parks with heat dissipation. less than 84 kJ	1 working
	Warehouses
Notes: - above the line and without the line are basic values, below the line taking into account the equipment of apartments with water meters and from the condition that with apartment metering there is a 40% reduction in heat and water consumption, depending on the % of apartments equipped with water meters: q guards/sch* *year* = q *Guards* *year* · (1-0.4N *kv/sch* / N kv ); Where q *Guards* *year* – according to formula (A.4); N kv – number of apartments in the house; N *kv/sch* – the number of apartments in which water meters are installed. 1. Water consumption rates in column 3 are established for climatic regions I and II; for regions III and IV they should be taken taking into account the coefficient from the table. A.2 SP 30.13330. 2. Water consumption standards are established for main consumers and include all additional costs ( service personnel, visitors, showers for service personnel, for cleaning premises, etc.). Water consumption in group showers and foot baths in domestic premises manufacturing enterprises, for the preparation of food in public catering establishments, as well as for hydrotherapy procedures in hydropathic clinics and the preparation of food included in hospitals, sanatoriums and clinics, should be taken into account additionally. 3. For water consumers of civil buildings, structures and premises not listed in the table, water consumption rates should be adopted as for consumers similar in nature of water consumption. 4. At public catering establishments, the number of dishes (^) sold in one working day can be determined by the formula *U=2.2* · n · m n · T · ψ ; Where n - number of seats; m n - number of seatings accepted for canteens open type and cafe - 2; for student canteens and industrial enterprises- 3; for restaurants -1.5; T - operating hours of the catering establishment, h; ψ - coefficient of unevenness of plantings throughout the working day, accepted: for canteens and cafes - 0.45; for restaurants - 0.55; for other public catering establishments, when justifying, it is allowed to take 1.0. 5. In this table, the specific hourly thermal energy standard q *guards* , W/m2 for heating the rate of hot water consumption on an average day of the heating period, taking into account heat losses in the system pipelines and heated towel rails, corresponds to the accepted value indicated in the adjacent column of the total area of an apartment in a residential building per inhabitant or the usable area of premises in a public building per patient , worker, student or child, S A , m 2 / person. If in reality the total or usable area per person turns out to be different, S A. i , then the specific thermal energy standard for this particular house *q hw.i* should be recalculated according to the following relationship: *q gv.i* = *q guards* · S *A /* S A. i

3. Specific annual consumption of thermal energy consumed by the hot water supply system per m 2 of apartment area or usable area of premises in public and industrial buildings q g. year, kW h/m 2, calculated using formula (11) and shown in table. P.4:

Where q gv, k hl, t hv– the same as in formula (10)
z from, α, – the same as in formula (8);
t hv.l– temperature of cold water in summer, taken equal to 15 0 C when water is taken from open sources.

After substituting known constant quantities into formula (11) instead of notations, it will have the following form.

a) for residential buildings with a centralized hot water supply system and ITP:

b) for residential buildings with hot water supply from apartment water heaters

c) for hotels with showers and heated towel rails in individual rooms and hospitals with sanitary facilities close to the rooms:

d) for hotels and hospitals with shared baths and showers without heated towel rails and other public and industrial buildings:

Notes

The level of heat consumption per 1 resident in SP 30.13330.2012 is higher than in the previous edition of SNiP 2.04.01-85*, due to the fact that in SP the water consumption rate is taken on average per year and at a minimum temperature at water points of 60 0 C, and in SNiP - for the heating period and at a minimum temperature of 55 0 C.
Calculations show that even if we bring the standardized water consumption to the same occupancy of residential buildings and taking into account the reduction of excess heat and water consumption against the normalized one by 40% when calculating using apartment water meters, the specific heat consumption in our country remains 2 times higher than that accepted in European countries. Heat consumption in office buildings, meeting rooms, retail and industrial buildings is approximately the same, but in hospitals, restaurants, sports, recreational and leisure complexes the discrepancies are very large, with Russian standards being too high. To establish the true value, it is necessary to clarify the initial data of specific water consumption in tables A.2 and A.3 SP 30.13330.2012 using full-scale measurements.

Whether it is an industrial building or a residential building, you need to carry out competent calculations and draw up a diagram of the heating system circuit. At this stage, experts recommend paying special attention to calculating the possible thermal load on the heating circuit, as well as the volume of fuel consumed and heat generated.

Thermal load: what is it?

This term refers to the amount of heat given off. A preliminary calculation of the thermal load will allow you to avoid unnecessary costs for the purchase of heating system components and 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 involved 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.

Calculation of 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. And housing and communal services organizations calculate the cost of services based on data on heat load.

Main Factors

An ideally designed and designed heating system should support set temperature indoors and compensate for the resulting heat losses. When calculating the heat load on the heating system in a building, you need to take into account:

Purpose of the building: residential or industrial.

Characteristics structural elements buildings. These are windows, walls, doors, roof and ventilation system.

Dimensions of the home. The larger it is, the more powerful the heating system should be. It is necessary to take into account the area window openings, doors, external walls and the volume of each internal room.

Availability of rooms special purpose(bath, sauna, etc.).

Level of equipment technical devices. That is, the availability of hot water supply, ventilation system, air conditioning and type of heating system.

For a separate room. For example, in rooms intended for storage, it is not necessary to maintain a temperature that is comfortable for humans.

Number of hot water supply points. The more there are, the more the system is loaded.

Area of glazed surfaces. Rooms with French windows lose a significant amount of heat.

Additional terms and conditions. In residential buildings this may be the number of rooms, balconies and loggias and bathrooms. In industrial - the number of working days in calendar year, shifts, technological chain production process etc.

Climatic conditions of the region. When calculating heat loss, 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 o C outside the window it will require significant expenses.

Features of existing methods

The parameters included in the calculation of the thermal load are found in SNiPs and GOSTs. They also have special heat transfer coefficients. From the passports of the equipment included in the heating system, digital characteristics relating to a specific heating radiator, boiler, etc. are taken. And also traditionally:

Heat consumption, taken to the maximum per hour of operation of the heating system,

The maximum heat flow emanating from one radiator is

Total heat consumption in a certain period (most often a season); if hourly load calculation is required heating network, 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 indicator turns out to be quite accurate. Some deviations do happen. For example, for industrial buildings it will be necessary to take into account the reduction in thermal energy consumption on weekends and holidays, and in residential premises - 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

Today, the calculation of the heat load for heating a building can be carried out using one of the following methods.

Three main

For calculations, aggregated indicators are taken.
The indicators of the structural elements of the building are taken as the basis. Here, the calculation of the internal volume of air used for heating will also be important.
All objects included in the heating system are calculated and summed up.

One example

There is also a fourth option. It has a fairly large error, because the indicators taken are very average, or there are not enough of them. This formula is Q from = q 0 * a * V H * (t EN - t NRO), where:

q 0 - specific thermal characteristic of the building (most often determined by the coldest period),
a - correction factor (depends on the region and is taken from ready-made tables),
V H is the volume calculated along the external planes.

Example of a simple calculation

For a building with standard parameters (ceiling heights, room sizes and good thermal insulation characteristics) you can apply a simple ratio of parameters adjusted for a coefficient depending on the region.

Let's assume 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 = 27.2 kW/h.

This definition of thermal loads does not take into account many important factors. For example, design features buildings, temperatures, number of walls, ratio of wall areas to window openings, etc. Therefore, such calculations are not suitable for serious heating system projects.

It depends on the material from which they are made. The most commonly used today are bimetallic, aluminum, steel, much less often cast iron radiators. Each of them has its own heat transfer (thermal power) indicator. Bimetallic radiators with a distance between the axes of 500 mm have an average of 180 - 190 W. Aluminum radiators have almost the same performance.

The heat transfer of the described radiators is calculated per 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 double-row radiator with a width of 1,100 mm and a height of 200 mm will be 1,010 W, and a steel panel radiator with a width of 500 mm and a height of 220 mm will be 1,644 W.

The calculation of a heating radiator by area includes the following basic parameters:

Ceiling height (standard - 2.7 m),

Thermal power (per sq. m - 100 W),

One external wall.

These calculations show that for every 10 sq. m requires 1,000 W of thermal power. This result is divided by the thermal 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 accurate

Taking into account the described factors, the average calculation is carried out according to the following scheme. If per 1 sq. m requires 100 W of heat flow, then a room of 20 sq. m should receive 2,000 watts. A radiator (popular bimetallic or aluminum) of eight sections produces about 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 scary. Nothing complicated really. Here's the formula:

Q t = 100 W/m 2 × S(room)m 2 × q 1 × q 2 × q 3 × q 4 × q 5 × q 6 × q 7, Where:

q 1 - type of glazing (regular = 1.27, double = 1.0, triple = 0.85);
q 2 - wall insulation (weak or absent = 1.27, wall laid with 2 bricks = 1.0, modern, high = 0.85);
q 3 - the ratio of the total area of window openings to the floor area (40% = 1.2, 30% = 1.1, 20% - 0.9, 10% = 0.8);
q 4 - street temperature (the minimum value is taken: -35 o C = 1.5, -25 o C = 1.3, -20 o C = 1.1, -15 o C = 0.9, -10 o C = 0.7);
q 5 - the number of external walls in the room (all four = 1.4, three = 1.3, corner room = 1.2, one = 1.2);
q 6 - type of calculation room above the calculation room (cold attic = 1.0, warm attic = 0.9, heated residential room = 0.8);
q 7 - ceiling height (4.5 m = 1.2, 4.0 m = 1.15, 3.5 m = 1.1, 3.0 m = 1.05, 2.5 m = 1.3).

Using any of the described methods, you can calculate the heat load of an apartment building.

Approximate calculation

The conditions are as follows. The minimum temperature in the cold season is -20 o C. Room 25 sq. m. m s triple glazing, double-leaf windows, ceiling height 3.0 m, two-brick walls and an unheated attic. The calculation will be as follows:

Q = 100 W/m 2 × 25 m 2 × 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 in gigacalories is required

In the absence of a thermal energy meter on an open heating circuit, the calculation of the heat load for heating the building is calculated using the formula Q = V * (T 1 - T 2) / 1000, where:

V - the amount of water consumed by the heating system, calculated in tons or m 3,
T 1 - a number indicating the temperature of hot water, measured in o C and for calculations the temperature corresponding to a certain pressure in the system is taken. This indicator has its own name - enthalpy. If it is not possible to take temperature readings in a practical way, they resort to an averaged reading. It is within 60-65 o C.
T 2 - cold water temperature. It is quite difficult to measure it in the system, so constant indicators have been developed that depend on the temperature outside. For example, in one of the regions, in the cold season this indicator is taken equal to 5, in the summer - 15.
1,000 is the coefficient for obtaining the result immediately in gigacalories.

In the case of a closed circuit, the heat load (gcal/hour) is calculated differently:

Q from = α * q o * V * (t in - t n.r.) * (1 + K n.r.) * 0.000001, Where

The calculation of the heat load turns out to be somewhat enlarged, but this is the formula given in the technical literature.

Increasingly, in order to increase the efficiency of the heating system, they are resorting to buildings.

This work is carried out in the dark. For a more accurate result, you need to observe the temperature difference between indoors and outdoors: it should be at least 15 o. Fluorescent and incandescent lamps turn off. It is advisable to remove carpets and furniture as much as possible; they knock down the device, causing some error.

The survey is carried out slowly and data is recorded carefully. The scheme is simple.

The first stage of work takes place indoors. The device is moved gradually from doors to windows, paying special attention to corners and other joints.

The second stage - inspection with a thermal imager external walls buildings. 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 the computer, where the corresponding programs complete the processing and produce the result.

If the survey was carried out by a licensed organization, it will issue a report with mandatory recommendations based on the results of the work. If the work was carried out in person, then you need to rely on your knowledge and, possibly, the help of the Internet.

What is a unit of measurement called a gigacalorie? What does it have to do with traditional kilowatt-hours, in which thermal energy is calculated? What information do you need to have in order to correctly calculate Gcal for heating? Finally, what formula should be used during the calculation? This, as well as many other things, will be discussed in today’s article.

What is Gcal?

We should start with a related definition. A calorie refers to the specific amount of energy required to heat one gram of water to one degree Celsius (at atmospheric pressure, of course). And due to the fact that from the point of view of heating costs, say, at home, one calorie is a tiny amount, gigacalories (or Gcal for short), corresponding to one billion calories, are used for calculations in most cases. We've decided on this, let's move on.

The use of this value is regulated by the relevant document of the Ministry of Fuel and Energy, published back in 1995.

Note! On average, the consumption standard in Russia per square meter is 0.0342 Gcal per month. Of course, this figure may vary for different regions, since everything depends on climatic conditions.

So, what is a gigacalorie if we “transform” it into values that are more familiar to us? See for yourself.

1. One gigacalorie is equal to approximately 1,162.2 kilowatt-hours.

2. One gigacalorie of energy is enough to heat a thousand tons of water to +1°C.

What is all this for?

The problem should be considered from two points of view - from the point of view of apartment buildings and private ones. Let's start with the first ones.

Apartment buildings

There is nothing complicated here: gigacalories are used in thermal calculations. And if you know how much thermal energy remains in the house, then you can present the consumer with a specific bill. Let's give a small comparison: if centralized heating operates in the absence of a meter, then you have to pay according to the area of the heated room. If there is a heat meter, this in itself implies a horizontal wiring type (either collector or serial): two risers are brought into the apartment (for “return” and supply), and the intra-apartment system (more precisely, its configuration) is determined by the residents. This kind of scheme is used in new buildings, thanks to which people regulate the consumption of thermal energy, making a choice between savings and comfort.

Let's find out how this adjustment is carried out.

1. Installation of a general thermostat on the return line. In this case, the flow rate of the working fluid is determined by the temperature inside the apartment: if it decreases, the flow rate will accordingly increase, and if it increases, it will decrease.

2. Throttling of heating radiators. Thanks to the throttle, maneuverability heating device limited, the temperature decreases, which means the consumption of thermal energy is reduced.

Private houses

We continue to talk about calculating Gcal for heating. Owners country houses They are interested, first of all, in the cost of a gigacalorie of thermal energy obtained from one or another type of fuel. The table below may help with this.

Table. Comparison of cost of 1 Gcal (including transport costs)

* - prices are approximate, since tariffs may differ depending on the region, moreover, they are constantly growing.

Heat meters

Now let’s find out what information is needed in order to calculate the heating. It's easy to guess what this information is.

1. Temperature of the working fluid at the outlet/inlet of a specific section of the pipeline.

2. The flow rate of the working fluid that passes through the heating devices.

Consumption is determined through the use of heat metering devices, that is, meters. These can be of two types, let’s get acquainted with them.

Vane counters

Such devices are intended not only for heating systems, but also for hot water supply. Their only difference from those meters that are used for cold water is the material from which the impeller is made - in this case it is more resistant to elevated temperatures.

As for the mechanism of operation, it is almost the same:

due to the circulation of the working fluid, the impeller begins to rotate;
the rotation of the impeller is transmitted to the accounting mechanism;
transmission is carried out without direct interaction, but with the help of a permanent magnet.

Despite the fact that the design of such counters is extremely simple, their response threshold is quite low; moreover, there is also reliable protection from distortion of readings: the slightest attempts to brake the impeller using external magnetic field are prevented thanks to an antimagnetic screen.

Devices with a difference recorder

Such devices operate on the basis of Bernoulli's law, which states that the speed of a gas or liquid flow is inversely proportional to its static movement. But how does this hydrodynamic property apply to calculations of working fluid flow? It’s very simple - you just need to block its path with a retaining washer. In this case, the rate of pressure drop on this washer will be inversely proportional to the speed of the moving flow. And if the pressure is recorded by two sensors at once, then the flow can be easily determined, and in real time.

Note! The design of the meter implies the presence of electronics. The vast majority of such modern models provide not only dry information (temperature of the working fluid, its flow rate), but also determine the actual use of thermal energy. The control module here is equipped with a port for connecting to a PC and can be configured manually.

Many readers will probably have a logical question: what to do if we are not talking about a closed heating system, but about an open one, in which selection for hot water supply is possible? How to calculate Gcal for heating in this case? The answer is quite obvious: here pressure sensors (as well as retaining washers) are installed simultaneously on both the supply and the “return”. And the difference in the flow rate of the working fluid will indicate the amount of heated water that was used for domestic needs.

How to calculate the consumed thermal energy?

If for one reason or another there is no heat meter, then to calculate thermal energy you must use the following formula:

Vx(T1-T2)/1000=Q

Let's look at what these symbols mean.

1. V denotes the amount of hot water consumed, which can be calculated either in cubic meters or in tons.

2. T1 is the temperature indicator of the hottest water (traditionally measured in the usual degrees Celsius). In this case, it is preferable to use exactly the temperature that is observed at a certain operating pressure. By the way, the indicator even has a special name - enthalpy. But if the required sensor is missing, then you can take that one as a basis temperature regime, which is extremely close to this enthalpy. In most cases, the average is approximately 60-65 degrees.

3. T2 in the above formula also denotes the temperature, but of cold water. Due to the fact that to penetrate the highway with cold water– the matter is quite difficult; this value is used constants, capable of changing depending on the climatic conditions outside. So, in winter, when the heating season is in full swing, this figure is 5 degrees, and in the summer, when the heating is turned off, 15 degrees.

4. As for 1000, this is the standard coefficient used in the formula in order to obtain the result in gigacalories. It will be more accurate than if you used calories.

5. Finally, Q is the total amount of thermal energy.

As you can see, there is nothing complicated here, so we move on. If the heating circuit is of a closed type (and this is more convenient from an operational point of view), then the calculations must be made slightly differently. The formula that should be used for a building with a closed heating system should look like this:

((V1x(T1-T)-(V2x(T2-T))=Q

Now, accordingly, to the decoding.

1. V1 indicates the flow rate of the working fluid in the supply pipeline (typically, not only water, but also steam can act as a source of thermal energy).

2. V2 is the flow rate of the working fluid in the return pipeline.

3. T is an indicator of the temperature of a cold liquid.

4. T1 – water temperature in the supply pipeline.

5. T2 – temperature indicator that is observed at the outlet.

6. And finally, Q is the same amount of thermal energy.

It is also worth noting that the calculation of Gcal for heating in this case depends on several notations:

thermal energy that entered the system (measured in calories);
temperature indicator during the removal of working fluid through the return pipeline.

Other ways to determine the amount of heat

Let us add that there are also other methods by which you can calculate the amount of heat that enters the heating system. In this case, the formula is not only slightly different from those given below, but also has several variations.

((V1x(T1-T2)+(V1- V2)x(T2-T1))/1000=Q

((V2x(T1-T2)+(V1-V2)x(T1-T)/1000=Q

As for the values of the variables, they are the same as in the previous paragraph of this article. Based on all this, we can confidently conclude that it is quite possible to calculate the heat for heating on your own. However, one should not forget about consulting with specialized organizations that are responsible for providing housing with heat, since their methods and principles of calculations may differ, significantly, and the procedure may consist of a different set of measures.

If you intend to equip a “warm floor” system, then prepare for the fact that the calculation process will be more complex, since it takes into account not only the characteristics of the heating circuit, but also the characteristics of the electrical network, which, in fact, will heat the floor. Moreover, the organizations that install this kind of equipment will also be different.

Note! People often encounter the problem of converting calories into kilowatts, which is explained by the use of a unit of measurement in many specialized manuals, which is called “C” in the international system.

In such cases, it is necessary to remember that the coefficient due to which kilocalories will be converted into kilowatts is 850. To put it more in simple language, then one kilowatt is 850 kilocalories. This option The calculation is simpler than those given above, since the value in gigacalories can be determined in a few seconds, since a Gcal, as noted earlier, is a million calories.

In order to avoid possible mistakes, we should not forget that almost all modern heat meters operate with some error, albeit within acceptable limits. This error can also be calculated by hand, for which you need to use the following formula:

(V1- V2)/(V1+ V2)x100=E

Traditionally, now we find out what each of these variable values means.

1. V1 is the flow rate of the working fluid in the supply pipeline.

2. V2 – a similar indicator, but in the return pipeline.

3. 100 is the number by which the value is converted to a percentage.

4. Finally, E is the error of the accounting device.

According to operational requirements and standards, the maximum permissible error should not exceed 2 percent, although in most meters it is somewhere around 1 percent.

As a result, we note that a correctly calculated Gcal for heating can significantly save money spent on heating the room. At first glance, this procedure is quite complicated, but - and you have seen this personally - if you have good instructions, there is nothing difficult about it.