Heat loss of hot water. Methodology for determining the actual losses of thermal energy through thermal insulation of pipelines of water heating networks of district heating systems

Heat loss DQ, (W), in the design section of the supply pipeline or riser are determined by the standard specific heat loss or by calculation using the formula:

where TO - heat transfer coefficient of insulated pipeline, K=11.6 W / (m 2 - ° C); t g cf - average water temperature in the system, t g cf, \u003d (t n + t k) / 2,°C; t n, - temperature at the outlet of the heater (hot water temperature at the entrance to the building), °С; t to - temperature at the most remote water-folding device, °С; h- Thermal insulation efficiency (0.6); / - length of the pipeline section, m; dH- outer diameter of the pipeline, m; t 0 - temperature environment, °С.

Water temperature at the most remote water tap t to should be taken 5 °C below the water temperature at the inlet to the building or at the outlet of the heater.

Ambient temperature t0 when laying pipelines in furrows, vertical channels, communication shafts and shafts of sanitary cabins, it should be taken equal to 23 ° C, in bathrooms - 25 ° C, in kitchens and toilet rooms of residential buildings, hostels and hotels - 21 ° C.

Heating of bathrooms is carried out by heated towel rails, therefore heat losses of heated towel rails in the amount of 100p(W), where 100 W is the average heat transfer from one heated towel rail, P - the number of heated towel rails connected to the riser.

When determining the circulation flow rates of water, heat losses by circulation pipelines are not taken into account. However, when calculating hot water supply systems with heated towel rails on circulating risers, it is advisable to add the heat transfer of heated towel rails to the sum of heat losses by the supply heat pipelines. This increases the circulation flow of water, improves heating of heated towel rails and heating of bathrooms. The results of the calculation are entered in the table.

åQp=5591.598 W

Hydraulic calculation of circulation pipelines

The circulation flow of water in the hot water supply system G c (kg / h), is distributed in proportion to the total heat loss:

where åQ c - total heat loss by all supply pipelines, W; Dt - water temperature drop in the supply pipelines of the hot water supply system, Dt=t g -t to =5°C; c is the heat capacity of water, J/(kg°C).

The circulation flow rates of water in the main sections of the hot water supply system consist of the circulation flow rates of the sections and risers, which are located ahead in the direction of water movement.

Riser 1:

Plot 2

Riser 2:

Plot 3:

Riser 3:

Plot 4:

Hydraulic calculation of circulation pipelines of an open hot water supply system.

We determine the discrepancy between pressure losses in two directions through the near and far risers according to the formula: DH cf - pressure loss in the water meter, m; H St - disposable free pressure at the bath mixer (3m); DH cm - losses in the mixer (5 m); N g - the geometric height of the water rise from the axis of the pipeline at the inlet to the axis of the highest located water-folding device (24.2 m).

The water meter is selected according to the water flow at the inlet G and conditional diameter Dy on . Head loss in a water meter DH mid(m) are determined by the formula:

where S is the hydraulic resistance of the water meter, taken according to, (0.32 m / (l / s 2)). We accept the water meter VK-20.

Excess pressure at the input:

Bibliography.

1. Building codes and regulations. SNiP 3.05.01-85. Internal sanitary systems. M: Stroyizdat, 1986.

2. Building codes and regulations. SNiP 2.04.01-85. Internal plumbing and sewerage of buildings. Moscow: Stroyizdat, 1986.

3. Building codes and regulations. SNiP II-34-76. Hot water supply. Moscow: Stroyizdat, 1976.

4. Designer's Handbook. Heating, plumbing, sewerage / Ed. I. G. Staroverova. - M.: Stroyizdat, 1976. part 1.

5. Handbook of heat supply and ventilation / R. V. Shchekin, S. M. Korenevsky, G. E. Bem and others - Kyiv: Budivelnik, 1976. Part 1.

6. Heat supply: Textbook for universities / A. A. Ionin, B. M. Khlybov and others; Ed. A. A. Ionina. Moscow: Stroyizdat, 1982.

7. Heat supply (course design): Textbook for universities on special. "Heat and gas supply and ventilation" / V. M. Kopko, N. K. Zaitseva and others; Ed. V. M. Kopko. - Mn.: Higher. school, 1985.

8. Heat supply: Tutorial for university students / V. E. Kozin, T. A. Levina, A. P. Markov and others - M .: Vyssh. school, 1980.

9. Zinger N. M. Hydraulic and thermal regimes of heating systems. - M.: Energoatomizdat, 1986.

10. Sokolov E.Ya. Heat supply and heat networks. - M.: MPEI Publishing House, 2001.

11. Adjustment and operation of water heating networks: Reference book / V. I. Manyuk, Ya. I. Kaplinsky, E. B. Hizh and others - M .: Stroyizdat, 1988.

UDC 621.64 (083.7)

Developed by: CJSC Research and Production Complex "Vector", Moscow Power Engineering Institute (Technical University)

Performers: Tishchenko A.A., Shcherbakov A.P.

Under the general editorship of Semenov V.G.

Approved by the Head of the Department of State Energy Supervision of the Ministry of Energy of the Russian Federation on February 20, 2004.

The methodology establishes the procedure for determining the actual losses of thermal energy through thermal insulation of pipelines of water heating networks of district heating systems, some of whose consumers are equipped with metering devices. The actual losses of thermal energy for consumers with measuring instruments are determined based on the readings of heat meters, and for consumers not equipped with metering devices, by calculation.

Thermal energy losses determined according to this Methodology should be considered as an initial basis for compiling the energy characteristics of a heating network, as well as for developing technical measures to reduce actual thermal energy losses.

The methodology was approved by the Head of the Department of State Energy Supervision of the Ministry of Energy of the Russian Federation on February 20, 2004.

For organizations that carry out energy audit heat supply enterprises, as well as for enterprises and organizations operating heating networks, regardless of their departmental affiliation and form of ownership.

This "Methodology ..." establishes the procedure for determining the actual losses of thermal energy 1 through thermal insulation of pipelines of water heating networks of district heating systems, some of whose consumers are equipped with metering devices. The actual losses of thermal energy for consumers with measuring instruments are determined based on the readings of heat meters, and for consumers not equipped with metering devices, by calculation.

1 Terms and definitions are given in Appendix A.

The "Methodology ..." is based on the calculation and experimental method for estimating thermal energy losses, set out in.

"Methodology ..." is intended for organizations carrying out an energy audit of heat supply enterprises, as well as for enterprises and organizations operating heating networks, regardless of their departmental affiliation and form of ownership.

Losses of thermal energy determined according to this "Methodology ..." should be considered as the initial basis for compiling the energy characteristics of the heating network, as well as for developing technical measures to reduce actual losses of thermal energy.

1. GENERAL PROVISIONS

The purpose of this "Methodology ..." is to determine the actual losses of thermal energy through thermal insulation of pipelines of water heating networks of district heating systems without conducting special tests. Thermal energy losses are determined for the entire thermal network connected to a single source of thermal energy. Determination of the actual losses of thermal energy for individual sections of the heating network is not carried out.

Determination of thermal energy losses according to this "Methodology ..." assumes the presence of certified thermal energy metering units at the source of thermal energy and at consumers of thermal energy. The number of consumers equipped with metering devices must be at least 20% of the total number of consumers of this heating network.

Metering devices must have an archive with hourly and daily registration of parameters. The depth of the hourly archive should be at least 720 hours, the daily archive - at least 30 days.

The main thing when calculating heat losses is the hourly archive of heat meters. The daily archive is used if hourly data are not available for some reason.

The determination of the actual losses of thermal energy is carried out on the basis of measurements of the flow rate and temperature of the network water in the supply pipeline 1 for consumers with metering devices, and the temperature of the network water at the source of thermal energy. Losses of thermal energy for consumers who do not have measuring instruments, are determined by calculation according to this "Methodology ...".

__________________

1 Symbols for quantities are given in Appendix B.

The sources and consumers of thermal energy in this "Methodology ..." are:

1. in the absence of metering devices directly in buildings: sources of thermal energy - thermal power plants, boiler houses, etc.; consumers of thermal energy - central (DTP) or individual (ITP) heat points;

2. in the presence of metering devices directly in buildings(in addition to paragraph 1): sources of thermal energy - central (CTP) heating points; consumers of thermal energy - directly buildings.

For the convenience of calculating the losses of thermal energy through thermal insulation, the supply pipeline in this "Methodology ..." is delimited into: the main pipeline and a branch from the main pipeline.

Main pipeline- this is a part of the supply pipeline from the source of thermal energy to the thermal chamber, from which there is a branch to the consumer of thermal energy.

Branch from the main pipeline- this is a part of the supply pipeline from the corresponding thermal chamber to the consumer of thermal energy.

When determining the actual losses of thermal energy, standard values ​​of losses are used, determined by the norms of thermal energy losses for thermal networks, the thermal insulation of which was performed according to design standards or (the standards are specified according to the design and executive documentation).

Before making calculations:

initial data on the heating network are collected;

a design diagram of the heat network is drawn up, which indicates the conditional passage (nominal diameter), length and type of laying of pipelines for all sections of the heat network;

data is collected on the connected load of all network consumers;

the type of metering devices, the presence of hourly and daily archives are established.

In the absence of a centralized collection of data from heat metering devices, preparation of the appropriate devices for collection is carried out: an adapter or a laptop computer. A portable computer must be equipped with a special program supplied with the meter, which allows you to read hourly and daily archives from installed heat meters.

To improve the accuracy of determining heat losses, it is preferable to collect data from metering devices for a certain time interval in the non-heating period, when the flow of network water is minimal, having previously checked with the heat supply organization about planned shutdowns in the supply of thermal energy to consumers in order to exclude this time from the period of data collection of measuring devices .

2. COLLECTION AND PROCESSING OF INITIAL DATA

2.1. COLLECTION OF INITIAL DATA ON THE HEAT NETWORK

Based on the design and as-built documentation for the heat network, a table of characteristics of all sections of the heat network is compiled (Table B.1 of Appendix B).

A section of a heat network is considered a section of a pipeline that differs from others by one of the following features (which are indicated in Table B.1 of Appendix B):

conditional passage of the pipeline (conditional diameter of the pipeline);

type of laying (aerial, underground channel, underground channelless);

the material of the main layer of the heat-insulating structure (thermal insulation);

year of laying.

Also in Table. B.1 of Annex B specifies:

the name of the initial and final nodes of the section;

section length.

Based on the data of the meteorological service, a table of average monthly outdoor air temperatures, °С, and soil, °С, is compiled at various depths of the pipelines, averaged over the past five years (Table D.1, Appendix D). The average annual temperatures of the outside air, °С, and the soil, °С, are determined as the arithmetic mean of the average monthly values ​​for the entire period of operation of the heating network.

Based on the approved temperature chart supply of thermal energy at the source of thermal energy, the average monthly temperatures of network water in the supply, °С, and return, °С, pipelines are determined (Table D.1, Appendix D). The average monthly temperature of the network water is determined by the average monthly temperature of the outside air. The average annual temperatures of network water in the supply, °C, and return, °C, pipelines are determined as the arithmetic average of the average monthly values, taking into account the duration of the network by months and per year.

Based on the data of the heat consumption accounting service of the heat supply organization, a table is compiled in which for each consumer it is indicated (Table D.1 of Appendix D):

name of the consumer of thermal energy;

type of heat supply system (open or closed);

connected average load of the hot water supply system;

name (brand) of metering devices;

depth of archives (daily and hourly);

the presence or absence of centralized data collection.

If there is a centralized collection of data based on the results of measurements, a period is selected for which the losses of thermal energy will be determined. In doing so, the following must be taken into account:

to improve the accuracy of determining the losses of thermal energy, it is desirable to choose a period with a minimum consumption of network water (usually this is a non-heating period);

during the selected period, planned disconnections of consumers from the heating network should not be carried out;

measurement data are collected for at least 30 calendar days.

In the absence of centralized data collection, it is necessary to collect hourly and daily archives of metering devices from consumers of thermal energy and at the source of thermal energy within 3-5 days, using an adapter or a portable computer with an installed program for reading data from the corresponding type of heat meter.

To determine the loss of thermal energy, you must have the following data:

consumption of network water in the supply pipeline for consumers of thermal energy;

temperature of network water in the supply pipeline at consumers of thermal energy;

consumption of network water in the supply pipeline at the source of thermal energy;

temperature of network water in the supply and return pipelines at the source of thermal energy;

make-up water consumption at the source of thermal energy.

2.2. PROCESSING OF INITIAL DATA OF METERING INSTRUMENTS

The main task of processing data from metering devices is to convert source files read directly from heat meters into a single format that allows subsequent verification (validation) of the measured values ​​of heat consumption parameters and calculations.

For different types of heat meters, data are read in different formats and require special processing procedures. For the same type of heat meters for different consumers, the parameters stored in the archive may require the use of different coefficients for reducing the initial data to uniform physical quantities. The difference between these coefficients is determined by the diameter of the flow transducer and the characteristics of the pulse inputs of the calculator. Therefore, the initial processing of measurement results requires an individual approach for each source data file.

The daily and hourly values ​​of the coolant parameters are used to verify the measured values. When carrying out this procedure, the main attention should be paid to the following:

temperatures and flow rates of the coolant should not go beyond physically justified limits;

there should be no sharp changes in the coolant flow in the daily file;

the values ​​of the average daily temperature of the heat carrier in the supply pipeline at consumers should not exceed the average daily temperature values ​​in the supply pipeline at the heat source;

the change in the average daily temperature of the heat carrier in the supply pipeline at consumers must correspond to the change in the average daily temperature in the supply pipeline at the heat source.

Based on the results of verification of the initial data of metering devices, a table is compiled in which for each consumer of thermal energy having metering devices, and for the source of thermal energy, the period when the reliability of the initial data is not in doubt is indicated. Based on this table, a general period is selected for which reliable measurement results are available for all consumers and at the heat source (data availability period).

Using the hourly data file obtained at the source of thermal energy, the number of hours in the measurement period is determined n and, the data for which will be used for further processing.

Before determining the measurement period, the time for filling all supply pipelines with coolant t p, s is calculated according to the formula:

where V

The average flow rate of the coolant for the entire measurement period through the supply pipeline at the source of thermal energy, kg/s.

The measurement period must satisfy the following conditions: the average temperature of the network water in the supply pipeline at the heat source for the time t p preceding the start of the measurement period, and the average temperature of the network water in the supply pipeline at the heat source for time t p at the end of the measurement period does not differ more than 5 °C;

the measurement period is entirely contained in the data availability period;

the measurement period must be continuous and be at least 240 hours.

If such a period cannot be selected due to the lack of data from one or more consumers, then the data from the metering devices of these consumers are not used in the further calculation.

The number of remaining consumers who have data from metering devices should be at least 20% of the total number of consumers of this heating network.

If the number of consumers with metering devices has become less than 20%, it is necessary to select another period for data collection and repeat the verification procedure.

For the data obtained at the source of thermal energy, the average temperature of the network water in the supply pipeline over the measurement period, °С, and the average temperature of the network water in the return pipeline over the measurement period, °С, are determined:

where

n and - the number of hours in the measurement period.

For the measurement period, the average soil temperature is determined at the average depth of the pipeline axis, °С, and the average outdoor air temperature, °С.

3. DETERMINATION OF NORMAL HEAT ENERGY LOSSES

3.1. DETERMINATION OF AVERAGE ANNUAL STANDARD LOSSES

THERMAL ENERGY

For each section of the heating network, the average annual specific (per 1 meter of the length of the pipeline) values ​​​​of thermal energy losses are determined according to the design standards or, in accordance with which the thermal insulation of pipelines of heating networks is performed.

The average annual specific losses of thermal energy are determined at the average annual temperatures of the network water in the supply and return pipelines and the average annual temperatures of the outdoor air or soil.

The values ​​of the average annual specific losses of thermal energy at the difference between the average annual temperatures of the network water and the environment, which differ from the values ​​given in the norms, are determined by linear interpolation or extrapolation.

For underground heating network sections with thermal insulation made in accordance with (Table E.1 of Appendix E), the standard specific heat losses are determined in total for the supply and return pipelines q n, W/m, according to the formula:

(3.1)

where - specific losses of thermal energy in total through the supply and return pipelines with a tabular value of the difference in the average annual temperatures of network water and soil, W / m, less than for this network;

Greater than for this network, the tabular value of the difference in the average annual temperatures of network water and soil, ° С.

The difference between the average annual temperatures of network water and soil is determined by the formula:

(3.2)

where , is the average annual temperature of network water in the supply and return pipelines, respectively, °С;

Average annual soil temperature at the average depth of the pipeline axis, °C.

To distribute the specific losses of thermal energy in the sections of underground laying between the supply and return pipelines, the average annual standard specific losses of thermal energy in the return pipeline are determined q but, W / m, which are taken equal to the values ​​\u200b\u200bof the standard specific losses in the return pipeline, given in table. E.1 of Appendix E.

q

q np = q n - q but. (3.3)

For sections of thermal networks of underground laying with thermal insulation made in accordance with (Table I.1 of Appendix I, Table K.1 of Appendix K, Table H.1 of Appendix H), before determining the normative specific losses of thermal energy, it is necessary to additionally determine the difference in average annual temperatures, °С, for each pair of average annual temperatures of network water in the supply and return pipelines and the soil, given in Table. I.1 of Appendix I, Table. K.1 of Appendix K and Table. H.1 Annex H:

(3.4)

where , - respectively, the tabular values ​​of the average annual temperatures of network water in the supply (65, 90, 110 °C) and return (50 °C) pipelines, °C;

Normative value of the average annual soil temperature, °С (assumed to be 5°С).

For each pair of average annual temperatures of network water in the supply and return pipelines, the total standard specific losses of thermal energy are determined, W / m:

where , - respectively, the values ​​of the standard specific losses of thermal energy for underground laying in the supply and return pipelines, given in table. I.1 of Appendix I, Table. K.1 of Appendix K and Table. H.1 Annex H.

The values ​​of the average annual specific losses of thermal energy for the considered heat network with a difference in the average annual temperatures of the network water and the environment, which differs from the values ​​determined by formula 3.4, are determined by linear interpolation or extrapolation.

Values ​​of total specific losses of thermal energy q n, W/m, are determined by formulas 3.1 and 3.2.

Average annual standard specific losses of thermal energy in the supply pipeline q np, W/m, are determined by the formula:

(3.6)

where , - specific losses of thermal energy through the supply pipeline with two adjacent, respectively, smaller and larger than for a given network, tabular values ​​​​of the difference in the average annual temperatures of network water and soil, W / m;

Adjacent, respectively smaller and larger than for a given network, tabular values ​​of the difference in the average annual temperatures of the network water in the supply pipeline and the soil, ° С.

The average annual values ​​of the temperature difference between the network water and the soil for the supply pipeline are determined by the formula:

where is the average annual temperature of the soil at the average depth of the pipeline axis, °С.

The tabular values ​​of the difference in the average annual temperatures of the network water in the supply pipeline and the soil are determined by the formula:

Average annual standard specific losses of thermal energy in the return pipeline q but, W / m, are determined by the formula:

q but = q n - q e.g. (3.9)

For all sections of above-ground heating networks with thermal insulation made in accordance with, (Table G.1 of Appendix G, Table L.1 of Appendix L, Table P.1 of Appendix P), the standard specific heat losses are determined separately for the supply and return pipelines, respectively, q np and q but, W / m, according to the formulas:

(3.10)

(3.11)

where , - specific losses of thermal energy through the supply pipeline with two adjacent, respectively, smaller and larger than for a given network, tabular values ​​​​of the difference in the average annual temperatures of network water and outdoor air, W / m;

The value of the difference in the average annual temperatures of network water and outdoor air, respectively, for the supply and return pipelines for a given heating network, ° С;

Adjacent, respectively smaller and larger than for a given network, tabular values ​​of the difference in the average annual temperatures of the network water in the return pipeline and the outside air, ° С.

The values ​​of the difference in the average annual temperatures of network water and outdoor air for the supply and return pipelines are determined by the formulas:

where is the average annual temperature of the outside air, °C.

For laying in through and semi-through channels, tunnels, basements specific losses of thermal energy of sections are determined according to the relevant standards for laying in rooms (Table M.1 of Appendix M, Table P.1 of Appendix P) at average annual ambient temperatures: tunnels and passage channels - +40 ° С, for basements - + 20 °C.

For each section of the heat network, the normative average annual values ​​of heat energy losses are determined separately for the supply and return pipelines:

where - average annual standard losses of thermal energy through the supply pipeline, W;

L

b - coefficient of local thermal energy losses, taking into account thermal energy losses by fittings, compensators and supports, taken in accordance with equal to 1.2 for underground channel and above-ground laying for pipeline nominal passages up to 150 mm and 1.15 for nominal passages of 150 mm and more , as well as for all conditional passages with channelless laying.

3.2. DETERMINATION OF NORMAL HEAT ENERGY LOSSES

FOR THE PERIOD OF MEASUREMENTS

For each section of the heating network, the normative averages for the measurement period of the loss of thermal energy in the supply, W, and return, W, pipelines are determined.

For underground heating network sections

For sections of the above-ground heating network normative average losses of thermal energy for the measurement period are determined by the formulas:

(3.18)

(3.19)

where , is the average temperature of the network water over the measurement period in the supply and return pipelines at the source of thermal energy, °С;

The average annual temperature of network water in the supply and return pipelines, respectively, °С;

The average temperature of the soil and the outside air over the measurement period, respectively, °С;

The average annual temperature of the soil and outdoor air, respectively, °C.

For sections laid in through and semi-through channels, tunnels, basements normative average losses of thermal energy for the measurement period are determined by formulas (3.18) and (3.19) at an average outdoor temperature equal to the average annual temperature: for tunnels and passage channels - +40 °С, for basements - +20 °С.

For the entire network, the standard averages for the period of measurement of the loss of thermal energy in the supply pipeline are determined, W:

The normative averages for the period of measurement of the loss of thermal energy in the supply pipeline for all sections of the underground laying are determined, W:

(3.21)

The normative averages for the period of measurement of the loss of thermal energy in the return pipeline are determined for all sections of the underground laying, W:

(3.22)

The normative averages for the period of measurement of the loss of thermal energy in the supply pipeline are determined for all sections of the above-ground installation, W:

(3.23)

The normative averages for the period of measurement of the loss of thermal energy in the return pipeline are determined for all sections of the above-ground installation, W:

(3.24)

The normative averages for the period of measurement of the loss of thermal energy in the supply pipeline are determined for all sections located in through and semi-through channels, tunnels, W:

(3.25)

The normative averages for the period of measurement of the loss of thermal energy in the return pipeline are determined for all sections located in through and semi-through channels, tunnels, W:

(3.26)

The normative averages for the period of measurement of the loss of thermal energy in the supply pipeline are determined for all sections located in the basements, W:

(3.27)

The normative averages for the period of measurement of the loss of thermal energy in the return pipeline are determined for all sections located in the basements, W:

(3.28)

4. DETERMINATION OF THE ACTUAL LOSS OF THERMAL ENERGY

4.1. DETERMINATION OF THE ACTUAL LOSS OF THERMAL ENERGY

FOR THE PERIOD OF MEASUREMENTS

At the source of thermal energy and for all consumers of thermal energy with metering devices ( i-th consumers of thermal energy), the average flow rate of the coolant in the supply pipeline for the entire measurement period is determined:

where is the average flow rate of the coolant for the entire measurement period through the supply pipeline at the source of thermal energy, kg / s;

Measured during the measurement period, the values ​​of the coolant flow at the source of thermal energy, taken from the hourly file, t/h;

i-th consumer of thermal energy, kg/s;

Measured during the measurement period, the values ​​of the coolant flow rate y i-th consumer of thermal energy, taken from the hourly file, t/h.

For closed heating system the average consumption of make-up water at the source of thermal energy for the entire measurement period is determined:

(4.3)

where is the average consumption of make-up water at the source of thermal energy for the entire measurement period, kg/s;

Measured during the measurement period, the values ​​of the coolant flow rate for make-up at the source of thermal energy, taken from the hourly file, t/h.

The average flow rate of the heat carrier in the supply pipeline for the entire measurement period, kg / s, for all consumers of thermal energy that do not have metering devices ( j-th consumers of thermal energy), for closed systems heat supply is determined by the formula:

For open heating systems, which do not have round-the-clock consumers of the heat carrier, the average consumption of make-up water at the source of thermal energy at night is determined for the entire measurement period.

To do this, for each day from the measurement period, the night (from 1:00 to 3:00) average hourly consumption of make-up at the source of thermal energy is selected. For the data obtained, the arithmetic mean value of the flow rate is determined, which is the average hourly replenishment of the heating network at night, t/h. To determine the value, kg / s, the formula is used:

(4.5)

For open heat supply systems with industrial consumers consuming the coolant around the clock and having metering devices, the average hourly consumption of the coolant at night is determined. To do this, for each day from the measurement period, the night (from 1:00 to 3:00) average hourly coolant flow rate for each such consumer is selected. For the data obtained, the arithmetic mean value of the flow rate is determined, t/h. To determine the value, kg / s, the formula is used:

(4.6)

The average flow rate of the coolant in the supply pipeline for the entire measurement period for all j th consumers is determined by the formula 4.4.

The average flow rate of the coolant in the supply pipeline for the entire measurement period for each j-th consumer, kg/s, is determined by distributing the total coolant flow among consumers in proportion to the average hourly connected load:

(4.7)

where is the average hourly connected load during the measurement period j-th consumer, GJ/h;

j-th consumers without metering devices during the measurement period, GJ / h.

For everybody i-th consumer, the average losses of thermal energy over the measurement period through the thermal insulation of the supply pipeline are determined, W:

(4.8)

where with p is the specific heat capacity of water, with p= 4.187×10 3 J/(kg×K);

Measured values ​​of the network water temperature in the supply pipeline at the source of thermal energy, taken from the hourly file, °С;

i-th consumer, taken from the hourly file, °C.

Averaged over the measurement period, the total losses of thermal energy in the supply pipelines are determined for all i th consumers with metering devices, W:

(4.9)

The average losses of thermal energy over the measurement period are determined, W, through the thermal insulation of the supply pipeline, referred to i-th consumer, minus the loss of thermal energy in the branch from the main pipeline:

(4.10)

In the first approximation, the loss of thermal energy in a branch from the main pipeline is taken equal to the normative average for the period of measurements of the loss of thermal energy:

(4.11)

where are the normative averages for the measurement period of the loss of thermal energy in the branch from the main supply pipeline to i-th consumer, W.

Total losses of thermal energy, W, in the main supply pipelines for all i-th consumers with metering devices:

Network heat loss coefficient r losses p, J / (kg × m), in the main supply pipelines is determined according to measurement data for consumers with metering devices:

(4.13)

where l i- the smallest distance from the source of thermal energy to the branch from the main pipeline to the consumer with metering devices, m.

When determining the average losses of thermal energy over the measurement period, W, y j th consumers without metering devices, the ratio is used:

where l j j-th consumer without metering devices, m.

The average total losses of thermal energy for the measurement period are determined, W, in the supply pipelines for j th consumers who do not have metering devices:

(4.15)

Actual averages for the measurement period total losses of thermal energy, W, in all supply pipelines:

After determining the actual losses of thermal energy in the supply pipeline for all consumers, the ratio of these losses of thermal energy to the standard losses of thermal energy in the supply pipeline is determined:

and the entire calculation is repeated (second approximation), starting from formula 4.10, and the losses in the branches from the main pipelines are determined by the formula:

(4.18)

After determining the value of the actual losses of thermal energy in the supply pipeline for all consumers in the second approximation, its value is compared with the value of the actual losses of thermal energy in the supply pipeline for all consumers, obtained in the first approximation, and the relative difference is determined:

(4.19)

If the value is > 0.05, then one more approximation is carried out to determine the value, i.e. the entire calculation, starting from formula 4.10, is repeated.

Usually, two or three approximations are sufficient to obtain a satisfactory result. The value of heat losses, obtained by formula 4.16 in the last approximation, is used in further calculations.

Another method of taking into account the influence of branches is possible. After performing calculations according to formulas 4.1 - 4.9, the time of movement of the coolant t, s, from the source of thermal energy to each of the consumers is determined:

(4.21)

where t to - the time of movement of the coolant in a homogeneous section of the heating network, s;

lk

W k

r is the density of water at the average temperature of network water in the supply pipeline at the source of thermal energy for the first day of the data availability period, kg/m 3 ;

F k- cross-sectional area of ​​the pipeline in a homogeneous section, m 2;

G k- coolant flow rate in a homogeneous area, kg/s.

A homogeneous section of a heat network is a section where the flow rate of the coolant and the conditional passage of the pipeline do not change, i.e. the constancy of the coolant velocity is ensured.

Thermal energy loss coefficient, determined by the time of movement of the coolant in the supply pipelines, , J / (kg × s):

(4.22)

where t i i-th consumer with metering devices, p.

Average losses of thermal energy over the measurement period through thermal insulation in the supply pipeline, W, referred to j-th consumer without metering devices:

(4.23)

where t j j-th consumer without metering devices, p.

Having determined by formula 4.15, we calculate by formula 4.16. The value of thermal energy losses, obtained by formula 4.16, is used in the further calculation.

The actual losses of thermal energy in the supply pipelines for all sections of the underground installation, W, averaged over the measurement period, are determined:

(4.24)

The actual losses of thermal energy in the supply pipelines for all sections of the above-ground installation, W, averaged over the measurement period, are determined:

(4.25)

The actual losses of thermal energy in the supply pipelines, averaged over the measurement period, are determined for all sections located in through and semi-through channels, tunnels, , W:

(4.26)

The actual losses of thermal energy in the supply pipelines for all sections located in the basements, averaged over the measurement period, are determined, W:

(4.27)

The actual losses of thermal energy in the return pipelines for all sections of the underground installation, W, averaged over the measurement period, are determined:

(4.28)

The actual losses of thermal energy in the return pipelines for all sections of the above-ground installation, W, averaged over the measurement period, are determined:

(4.29)

The actual losses of thermal energy in the return pipelines, averaged over the measurement period, are determined for all sections located in through and semi-through channels, tunnels, , W:

(4.30)

The average actual losses of thermal energy in the return pipelines for all sections located in the basements are determined for the measurement period, , W:

(4.31)

The actual total losses of thermal energy in the return pipelines, W, averaged over the measurement period, are determined:

The actual total losses of thermal energy, W, averaged over the measurement period, in the network are determined:

4.2. DETERMINATION OF THE ACTUAL LOSS OF THERMAL ENERGY FOR THE YEAR

The actual losses of thermal energy for the year are determined as the sum of the actual losses of thermal energy for each month of operation of the heating network.

The actual losses of thermal energy per month are determined under the average monthly conditions for the operation of the heating network.

For all sections of underground laying the actual average monthly losses of thermal energy are determined in total for the supply and return pipelines, W, according to the formula:

For all sections of above-ground laying the actual average monthly losses of thermal energy are determined separately for the supply, W, and return, W, pipelines according to the formulas:

(4.35)

(4.36)

For all sections located in through and semi-through channels and tunnels

(4.37)

(4.38)

For all plots located in basements, the actual average monthly losses of thermal energy are determined separately for the supply, W, and return, W, pipelines according to the formulas:

(4.39)

(4.40)

Actual losses of thermal energy in the entire network for a month, GJ, are determined by the formula:

where n month - duration of operation of the heating network in the month under consideration, h.

The actual losses of thermal energy in the entire network for the year, GJ, are determined by the formula:

(4.42)

APPENDIX A

Terms and Definitions

Water heating system- a heat supply system in which the heat carrier is water.

Closed water heating system- a water heating system that does not provide for the use of network water by consumers by taking it from the heating network.

Individual heating point- a heat point intended for connection of heat consumption systems of one building or its part.

executive documentation - a set of working drawings developed by the design organization, with inscriptions on the compliance of the work performed in kind with these drawings or the changes made to them made by the persons responsible for the execution of the work.

Source of thermal energy (heat)- a heat generating power plant or a combination of them, in which the heat carrier is heated by transferring the heat of the burned fuel, as well as by electric heating or by other, including non-traditional methods, participating in the heat supply of consumers.

Commercial accounting (accounting) of thermal energy- determination, on the basis of measurements and other regulated procedures, of thermal power and the amount of thermal energy and heat carrier in order to carry out commercial mutual settlements between energy supply organizations and consumers.

Boiler room- a complex of technologically related thermal power plants located in separate industrial buildings, built-in, attached or built-on premises with boilers, water heaters (including installations of an unconventional method of obtaining thermal energy) and auxiliary boiler equipment, designed to generate heat.

Norm of thermal energy loss (norm of heat flux density through an insulated surface)- the value of the specific losses of thermal energy by pipelines of the heating network through their heat-insulating structures at the calculated average annual values ​​of the temperature of the coolant and the environment.

Open water heating system- a water heating system in which all or part of the network water is used by taking it from the heating network to meet the needs of consumers in hot water.

heating period- time in hours or days per year during which heat energy is supplied for heating.

make-up water- specially prepared water supplied to the heating network to make up for the loss of the coolant (network water), as well as water intake for heat consumption.

Heat loss- thermal energy lost by the coolant through the insulation of pipelines, as well as thermal energy lost with the coolant in case of leaks, accidents, drains, unauthorized water intake.

Heat consumer- legal or individual, carrying out the use of thermal energy (power) and heat carriers.

Network water- specially prepared water, which is used in the water heating system as a heat carrier.

Heat consumption system- a complex of thermal power plants with connecting pipelines and (or) heating networks, which are designed to meet one or more types of heat load.

Heating system- a set of interconnected heat sources, heat networks and heat consumption systems.

District heating system- sources of thermal energy, thermal networks and consumers of thermal energy united by a common technological process.

Heat load of the heating system (heat load)- the total amount of thermal energy received from thermal energy sources, equal to the sum of heat consumption of thermal energy receivers and losses in thermal networks per unit time.

Heating network- a set of devices designed for the transmission and distribution of coolant and thermal energy.

Thermal point- a complex of devices located in a separate room, consisting of elements of thermal power plants that ensure the connection of these plants to the heating network, their performance, control of heat consumption modes, transformation, regulation of coolant parameters.

Coolant of a thermal power plant, coolant- a moving medium used to transfer thermal energy in a thermal power plant from a more heated body to a less heated body.

Heat consuming plant- a thermal power plant or a set of devices designed to use heat and coolant for the needs of heating, ventilation, air conditioning, hot water supply and technological needs.

Heat supply- providing consumers with thermal energy (heat).

Thermal power plant (CHP)- steam turbine power plant designed for the production of electrical and thermal energy.

Node for commercial metering of thermal energy and (or) heat carriers- a set of duly certified measuring instruments and systems and other devices designed for commercial metering of the amount of thermal energy and (or) heat carriers, as well as to ensure quality control of thermal energy and heat consumption modes.

District heating- heat supply to consumers from a source of thermal energy through a common heat network.

Central heating point (CTP)- a heat point designed to connect two or more buildings.

Operational documentation- documents intended for use during operation, maintenance and repair during operation.

Energy supply (heat supply) organization- an enterprise or organization that is legal entity and owning or in full economic management installations generating electrical and (or) thermal energy, electrical and (or) thermal networks and providing on a contractual basis the transmission of electrical and (or) thermal energy to consumers.

APPENDIX B

Symbols for quantities

Actual losses of thermal energy in the entire network for the year, GJ;

Actual losses of thermal energy in the entire network for a month, GJ;

Actual average monthly losses of thermal energy in total for the supply and return pipelines for all sections of underground laying, W;

Actual average monthly losses of thermal energy separately through the supply pipeline for all sections of the above-ground laying, W;

Actual average monthly losses of thermal energy separately through the return pipeline for all sections of the above-ground laying, W;

Actual average monthly losses of thermal energy separately along the supply pipeline for all sections located in through and semi-through channels, tunnels, W;

Actual average monthly losses of thermal energy separately through the return pipeline for all sections located in through and semi-through channels, tunnels, W;

Actual average monthly losses of thermal energy separately through the supply pipeline for all areas located in the basements, W;

Actual average monthly losses of thermal energy separately through the return pipeline for all sections located in the basements, W;

The actual total losses of thermal energy in the network are average for the measurement period, W;

The actual losses of thermal energy in the supply pipelines for all sections of underground laying are average for the measurement period, W;

The actual losses of thermal energy in the supply pipelines for all sections of the above-ground laying are average for the measurement period, W;

Actual losses of thermal energy in the supply pipelines for all sections located in through and semi-through channels, tunnels, average for the measurement period, W;

Actual losses of thermal energy in the supply pipelines for all sections located in the basements, average for the measurement period, W;

The actual losses of thermal energy in the return pipelines for all sections of the underground laying are average for the measurement period, W;

The actual losses of thermal energy in the return pipelines for all sections of the above-ground laying are average for the measurement period, W;

Actual losses of thermal energy in the return pipelines for all sections located in through and semi-through channels, tunnels are average for the measurement period, W;

The actual losses of thermal energy in the return pipelines for all sections located in the basements are average for the measurement period, W;

The actual total losses of thermal energy in all supply pipelines are average for the measurement period, W;

Actual total losses of thermal energy in all return pipelines are average for the measurement period, W;

The total loss of thermal energy in the supply pipelines for j th consumers who do not have metering devices, average for the measurement period, W;

Loss of thermal energy j-th consumers without metering devices average for the measurement period, W;

Total losses of thermal energy in supply pipelines for all i-th consumers with metering devices, average for the measurement period, W;

Loss of thermal energy through the thermal insulation of the supply pipeline for each i-th consumer with metering devices average for the measurement period, W;

Hourly average connected load during the measurement period j-th consumer, GJ/h;

Hourly average connected load of all j-th consumers without metering devices during the measurement period, GJ/h;

Average losses of thermal energy over the measurement period through the thermal insulation of the supply pipeline, referred to i-th consumer, minus the loss of thermal energy in the branch from the main pipeline, W;

Losses of thermal energy in a branch from the main pipeline, W;

Regulatory averages for the period of measurement of the loss of thermal energy in the branch from the main supply pipeline to i-th consumer, W;

Total losses of thermal energy in the main supply pipelines for all i th consumers with metering devices, W;

Regulatory losses of thermal energy in the supply pipeline are average for the measurement period, W;

Regulatory losses of thermal energy in the return pipeline are average for the measurement period, W;

Regulatory averages for the period of measurement of the loss of thermal energy in the supply pipeline for the entire network, W;

Regulatory averages for the period of measurement of the loss of thermal energy in the supply pipeline for all sections of the underground laying, W;

Regulatory averages for the period of measurement of the loss of thermal energy in the return pipeline for all sections of the underground laying, W;

Regulatory averages for the period of measurement of the loss of thermal energy in the supply pipeline for all sections of the above-ground laying, W;

Regulatory averages for the period of measurements of the loss of thermal energy in the return pipeline for all sections of the above-ground laying, W;

Regulatory averages for the period of measurement of the loss of thermal energy in the supply pipeline for all sections located in through and semi-through channels, tunnels, W;

Regulatory averages for the period of measurement of the loss of thermal energy in the return pipeline for all sections located in through and semi-through channels, tunnels, W;

Regulatory averages for the period of measurement of the loss of thermal energy in the supply pipeline for all sections located in the basements, W;

Regulatory averages for the period of measurement of the loss of thermal energy in the return pipeline for all sections located in the basements, W;

Average annual normative losses of thermal energy through the supply pipeline, W;

Average annual normative losses of thermal energy in the return pipeline, W;

Relative difference between the comparison of the actual heat loss in the supply pipeline for all consumers in the second approximation with the actual heat loss in the supply pipeline for all consumers, obtained in the first approximation;

q n - normative specific losses of thermal energy in total for the supply and return pipelines for sections of underground heating networks, W / m;

Specific losses of thermal energy in total through the supply and return pipelines with a tabular value of the difference in the average annual temperatures of network water and soil, W / m, less than for this network;

Specific losses of thermal energy in total through the supply and return pipelines with a tabular value of the difference in the average annual temperatures of network water and soil, W / m, greater than for this network;

q but - average annual standard specific losses of thermal energy in the return pipeline, W / m;

q np - average annual standard specific losses of thermal energy in the supply pipeline, W / m;

Total normative specific losses of thermal energy for underground laying, W/m;

Accordingly, the tabular values ​​of the standard specific losses of thermal energy for underground laying in the supply and return pipelines, W / m;

Specific losses of thermal energy through the supply pipeline with two adjacent, respectively, smaller and larger than for a given network, tabular values ​​of the difference in the average annual temperatures of network water and soil, W / m;

Specific losses of thermal energy through the supply pipeline with two adjacent, respectively, smaller and larger than for a given network, tabular values ​​of the difference in the average annual temperatures of network water and outdoor air, W / m;

Specific losses of thermal energy through the return pipeline with two adjacent, respectively smaller and larger than for a given network, tabular values ​​of the difference in the average annual temperatures of network water and outdoor air, W / m;

Average for the entire measurement period, the flow rate of the coolant through the supply pipeline at the source of thermal energy, kg / s;

Measured values ​​of the coolant flow at the source of thermal energy, taken from the hourly file, t/h;

The average flow rate of the coolant through the supply pipeline for the entire measurement period i-th consumer of thermal energy with metering devices, kg / s;

Measured values ​​of the coolant flow y i-th consumer of thermal energy, taken from the hourly file, t/h;

Average consumption of make-up water at the source of thermal energy for the entire measurement period, kg/s;

Measured values ​​of the coolant consumption for make-up at the source of thermal energy, taken from the hourly file, t/h;

The average flow rate of the coolant in the supply pipeline for the entire measurement period for all consumers of thermal energy that do not have metering devices, kg / s;

Average hourly replenishment of the heating network at night, t/h;

The average hourly consumption of the coolant for each i-th consumer having metering devices at night for each day from the measurement period, t/h;

The average flow rate of the coolant in the supply pipeline for the entire measurement period for each j-th consumer without metering devices, kg/s;

G k- coolant flow rate in a homogeneous area, kg/s;

Average monthly outdoor air temperature, °C;

Average monthly soil temperature at the average depth of the pipeline axis, °С;

Average annual outdoor air temperature, °С;

Average annual soil temperature at the average depth of the pipeline axis, °С;

Average monthly temperature of network water in the supply pipeline, °С;

Average monthly temperature of network water in the return pipeline, °С;

Average annual temperature of network water in the supply pipeline, °С;

Average annual temperature of network water in the return pipeline, °С;

Temperature of network water averaged over the measurement period in the supply pipeline at the source of thermal energy, °С;

Temperature of network water in the return pipeline at the source of thermal energy, averaged over the measurement period, °С;

Measured values ​​of the network water temperature in the supply pipeline at the source of thermal energy, taken from the hourly file, °С;

Measured values ​​of the temperature of the network water in the return pipeline at the source of thermal energy, taken from the hourly file, °С;

Average soil temperature at the average depth of the pipeline axis during the measurement period, °С;

Average outdoor air temperature for the measurement period, °С;

Accordingly, the tabular values ​​of the average annual temperatures of network water in the supply (65, 90, 110 °C) and return (50 °C) pipelines, °C;

Normative value of the average annual soil temperature, °С;

Measured values ​​for the heating water temperature in the supply pipe i-th consumer, taken from the hourly file, °С;

The value of the difference in the average annual temperatures of network water and soil for a given heating network, ° С;

Less than for this network, the tabular value of the difference in the average annual temperatures of network water and soil, ° С;

Greater than for this network, the tabular value of the difference in the average annual temperatures of network water and soil, ° С;

Difference of average annual temperatures for each pair of values ​​of average annual temperatures in supply and return pipelines and soil, °С;

The value of the difference in the average annual temperatures of network water and soil for the supply pipeline of the considered heating network, ° С;

Adjacent, respectively smaller and larger than for a given network, tabular values ​​of the difference in the average annual temperatures of the network water in the supply pipeline and the soil, ° С;

The value of the difference in the average annual temperatures of network water and outdoor air, respectively, for the supply and return pipelines for a given heating network, ° С;

Adjacent, respectively smaller and larger than for a given network, tabular values ​​of the difference in the average annual temperatures of the network water in the supply pipeline and the outside air, ° С;

Adjacent, respectively smaller and larger than for a given network, tabular values ​​of the difference in the average annual temperatures of the network water in the return pipeline and the outside air, ° С;

V n - the total volume of all supply pipelines of the heating network, m 3;

L- length of the heating network section, m;

l i- the smallest distance from the source of thermal energy to the branch from the main pipeline to i-th consumer with metering devices, m;

l j- the smallest distance from the source of thermal energy to the branch to j-th consumer without metering devices, m (p. 18);

lk- length of a homogeneous section, m;

r is the density of water at the average temperature of network water in the supply pipeline at the source of thermal energy for the first day of the data availability period, kg/m 3 ;

cp- specific heat capacity of water, J/(kg×K);

W k- coolant velocity in a homogeneous area, m/s;

F k- the area of ​​the pipeline passage in a homogeneous section, m 2;

b - coefficient of local losses of thermal energy, taking into account the losses of thermal energy by fittings, compensators and supports;

r losses n - coefficient of losses of thermal energy of the network in the main supply pipelines, J / (kg × m);

Thermal energy loss coefficient, determined by the time of movement of the coolant in the supply pipelines, J / (kg × s);

n and - the number of hours in the measurement period;

n month - the duration of the heating network in the month under consideration, h;

t p - time of filling all supply pipelines with coolant, s;

t is the time of movement of the coolant from the source of thermal energy to each of the consumers, s;

t to - the time of movement of the coolant in a homogeneous section of the heating network, s;

t i- the time of movement of the coolant through the supply pipeline from the source of thermal energy to i-th consumer with metering devices, s;

t j- the time of movement of the coolant along the shortest distance from the source of thermal energy to j-th consumer without metering devices, s;

K- the ratio of the actual losses of thermal energy in the supply pipeline for all consumers to the standard losses of thermal energy in the supply pipeline.

APPENDIX B

Characteristics of sections of the heating network

Table B.1

APPENDIX D

Average monthly and average annual temperatures of the environment and network water

Table D.1

APPENDIX E

Characteristics of consumers of thermal energy and metering devices

Table E.1

APPENDIX E

The norms of heat energy losses by insulated water heat pipelines located in impassable channels and with channelless laying (with an estimated soil temperature of +5 ° С at the depth of the heat pipelines) according to

Table E.1

APPENDIX G

Norms of losses of thermal energy by one insulated water

heat conductor for above-ground laying

(with an estimated average annual outdoor temperature of +5 °С) according to

Table G.1

APPENDIX AND

Norms of heat flux density through the insulated surface of pipelines of two-pipe water heating networks when laying in impassable channels, W / m, according to

Table I.1

APPENDIX K

Norms of heat flux density through the insulated surface of pipelines for two-pipe underground channelless laying of water heating networks, W / m, according to

Table K.1

Coefficient taking into account the change in the norms of the heat flux density when using a heat-insulating layer made of polyurethane foam, polymer concrete, phenolic foam plastic FL

Table K.2

APPENDIX L

Norms of heat flux density through the insulated surface of pipelines of water heat networks when located on outdoors, W/m, according

Table L.1

APPENDIX M

Norms of heat flux density through the insulated surface of pipelines of water heating networks when located indoors and in a tunnel, W / m, according to

Table M.1

APPENDIX H

Norms of heat flux density through the insulated surface of pipelines of two-pipe water heating networks when laying in impassable channels and underground channelless laying, W / m, according to

Table H.1

APPENDIX P

Norms of heat flux density through the insulated surface of pipelines of water heat networks when located outdoors along

Table A.1

APPENDIX P

Norms of heat flux density through the insulated surface of pipelines of water heating networks when located indoors and in a tunnel along

Table P.1

Note. When insulated surfaces are located in the tunnel (through and semi-through channels), a coefficient of 0.85 should be entered to the density standards.

APPENDIX C

List of normative and technical documents to which there are links

1. Determination of actual heat losses through thermal insulation in district heating networks / Semenov V. G. - M .: News of heat supply, 2003 (No. 4).

2. Norms for the design of thermal insulation for pipelines and equipment of power plants and heating networks. - M.: Gosstroyizdat, 1959.

3. SNiP 2.04.14-88*. Thermal insulation of equipment and pipelines. - M.: GUP TsPP Gosstroy of Russia, 1999.

4. Methodology for calculating heat losses in heating networks during transportation. - M.: Firma ORGRES, 1999.

5. Rules technical operation thermal power plants. - M.: Publishing house of NTs ENAS, 2003.

6. Typical instruction on the technical operation of transport and distribution systems of thermal energy (heat networks): RD 153-34.0-20.507-98. - M.: SPO ORGRES, 1986.

7. Methodology for determining the normative values ​​of the indicators of the functioning of water heating networks of communal heat supply systems. - M.: Roskommunenergo, 2002.

9. GOST 26691-85. Thermal power engineering. Terms and Definitions.

10. GOST 19431-84. Energy and electrification. Terms and Definitions.

11. Rules for the development of regulations, circulars, operational instructions, guidelines and information letters in the electric power industry: RD 153-34.0-01.103-2000. - M.: SPO ORGRES, 2000.

1. GENERAL PROVISIONS

2. COLLECTION AND PROCESSING OF INITIAL DATA

2.1. Collection of initial data on the heat network

2.2. Processing of initial data of metering devices

3. DETERMINATION OF NORMAL HEAT ENERGY LOSSES

3.1. Determination of the average annual standard losses of thermal energy

3.2. Determination of normative losses of thermal energy for the measurement period

4. DETERMINATION OF THE ACTUAL LOSS OF THERMAL ENERGY

4.1. Determination of actual losses of thermal energy for the measurement period

4.2. Determination of actual losses of thermal energy for the year

APPS

Appendix A. Terms and definitions

Appendix B. Symbols for quantities

Appendix B. Characteristics of sections of the heating network

Appendix D. Average monthly and average annual temperatures of the environment and network water

Appendix D. Characteristics of consumers of thermal energy and metering devices

Annex E. Norms of thermal energy losses by insulated water heat pipelines located in impassable channels and with channelless laying

Annex G

Appendix I. Norms of heat flux density through the insulated surface of pipelines of two-pipe water heating networks when laying in impassable channels

Appendix K. Norms of heat flux density through the insulated surface of pipelines for two-pipe underground channelless laying of water heating networks

Annex L. Norms of heat flux density through the insulated surface of pipelines of water heating networks when located outdoors

Annex M. Norms of heat flux density through the insulated surface of pipelines of water heating networks when located indoors and in a tunnel

Appendix H. Norms of heat flux density through the insulated surface of pipelines of two-pipe water heating networks when laying in impassable channels and underground channelless laying

Appendix P. Norms of heat flux density through the insulated surface of pipelines of water heat networks when located outdoors

Annex P. Norms of heat flux density through the insulated surface of pipelines of water heating networks when located indoors and in a tunnel

Appendix C. List of normative and technical documents to which there are links

2.2 Determination of heat losses and circulation costs in the supply pipelines of the hot water supply system

Circulation consumption of hot water in the system, l / s:

,(2.14)

where> is the total heat loss by the supply pipelines of the DHW system, kW;

The temperature difference in the supply pipelines of the system to the most remote draw-off point, , is assumed to be 10;

Circulation misalignment coefficient, accepted1

For a system with variable resistance of circulation risers, the value is determined by supply pipelines and water risers at = 10 and = 1

Heat losses in areas, kW, are determined by the formula

Where: q - heat loss of 1 m of pipeline, W / m, taken according to Appendix 7 AAAAAAAAAAAAAAAAAAAAAAAAAAA

l - length of the pipeline section, m, taken according to the drawing

When calculating the heat loss of sections of water risers, the heat loss of a heated towel rail is taken equal to 100 W, while its length is excluded from the length of the floor riser. For convenience, the calculation of heat losses is summarized in one table 2 with the hydraulic calculation of the network.

Determine the heat loss for the entire system as a whole. For convenience, it is assumed that the risers located on the plan in mirror reflection are equal to each other. Then the heat loss of the risers located to the left of the input will be equal to:

1.328*2+0.509+1.303*2+2.39*2+2.432*2+2.244=15.659 kW

And the risers located on the right:

1.328*2+(0.509-0.144) +2.39*2+(0.244-0.155) =7.89 kW

The total heat loss to the house will be 23.55 kW.

Let's define the circulation flow:

l/s

Let us determine the calculated second flow rate of hot water, l/s, in sections 45 and 44. To do this, we determine the ratio qh/qcir, for sections 44 and 45 it is equal to 4.5 and 5.5, respectively. According to Appendix 5, the coefficient Kcir=0 in both cases, therefore, the preliminary calculation is final.

Provided for circulation circulation pump brand WILO Star-RS 30/7

2.3 Water meter selection

acc. with item p a) item 3.4 we check the condition 1.36m<5м, условие выполняется, принимаем крыльчатый водомер METRON Ду 50 мм.

3. Calculation and design of the sewerage system

The sewerage system is designed to remove from the building pollution generated in the process of sanitary and hygienic procedures, economic activities, as well as atmospheric and melt water. The internal sewer network consists of discharge pipelines, risers, outlets, exhaust part, cleaning devices. Outlet pipes are used to drain wastewater from sanitary appliances and transfer them to the riser. Outlet pipes are connected to the water seals of sanitary appliances and laid with a slope towards the riser. The risers are designed to transport wastewater to the sewer outlet. They collect drains from outlet pipes and must have a diameter not less than the largest diameter of the outlet pipe or outlet of the device connected to the riser.

In this project, the intra-apartment wiring is made of socketed PVC pipes with a diameter of 50 mm, risers with a diameter of 100 mm are made of cast iron, also connected by sockets. Connection to the risers is carried out using crosses and tees. Revisions and cleanings are provided on the network to remove blockages.

3.1 Determination of estimated sewerage costs

Total maximum design water flow:

Where: - water consumption by the device, taken equal to 0.3 l / s acc. with adj.4; - coefficient depending on the total number of devices and the probability of their use Рtot

, (7)

Where: - the total consumption rate per hour of the highest water consumption, l, taken in accordance with Appendix 4 equal to 20

The number of water consumers, equal to 104 * 4.2 people

Number of sanitary fixtures, accepted 416 on assignment

Then, the product N*=416*0.019=7.9, therefore, =3.493

The resulting value is less than 8l/s, therefore, the maximum second wastewater flow:

Where: - flow rate from a sanitary - technical device with the highest drainage, l / s, taken according to Appendix 2 for a toilet bowl with a flush tank equal to 1.6

3.2 Calculation of risers

The water consumption for risers K1-1, K1-2, K1-5, K1-6 will be the same, since an equal number of devices are connected to these risers, each with 52 devices.

We accept a riser diameter of 100 mm, a floor outlet diameter of 100 mm, and a floor outlet angle of 90°. Maximum throughput 3.2 l/s. Estimated flow rate 2.95 l/s. Therefore, the riser operates in normal hydraulic mode.

The water consumption for risers K1-3, K1-4 will be the same, since an equal number of devices are connected to these risers, each with 104 devices.

We determine the discrepancy of pressure losses in two directions through the near and far risers according to the formula:

where ΣΔp1, ΣΔp2 are, respectively, pressure losses when calculating directions through the far and near risers.

5. Calculation of heat losses by pipelines of the hot water supply system

Heat losses DQ, (W), in the calculated section of the supply pipeline or riser are determined by the standard specific heat loss or by calculation using the formula:

where K is the heat transfer coefficient of the insulated pipeline, K=11.6 W/(m2-°C); tgav - average water temperature in the system, tgav, = (tn + tk)/2, °С; tn, - temperature at the outlet of the heater (hot water temperature at the entrance to the building), °C; tk - temperature at the most remote water-folding device, ° С; h - thermal insulation efficiency (0.6); / - length of the pipeline section, m; dH - outer diameter of the pipeline, m; t0 - ambient temperature, °С.

The water temperature at the most remote water tap tk should be taken 5 °C lower than the water temperature at the inlet to the building or at the outlet of the heater.

The ambient temperature t0 when laying pipelines in furrows, vertical channels, communication shafts and shafts of sanitary cabins should be taken equal to 23 ° C, in bathrooms - 25 ° C, in kitchens and toilet rooms of residential buildings, hostels and hotels - 21 ° FROM .

The heating of bathrooms is carried out by heated towel rails, therefore, to the heat losses of the riser, heat losses by heated towel rails in the amount of 100p (W) are added, where 100 W is the average heat transfer from one heated towel rail, n is the number of heated towel rails connected to the riser.

When determining the circulation flow rates of water, heat losses by circulation pipelines are not taken into account. However, when calculating hot water supply systems with heated towel rails on circulating risers, it is advisable to add the heat transfer of heated towel rails to the sum of heat losses by the supply heat pipelines. This increases the circulation flow of water, improves heating of heated towel rails and heating of bathrooms. The results of the calculation are entered in the table.