A reference guide covering the design of heat networks is the “Designer's Handbook. Design of thermal networks. The handbook can to a certain extent be considered as a guide to SNiP II-7.10-62, but not to SNiP N-36-73, which appeared much later as a result of a significant revision of the previous edition of the norms. Over the past 10 years, the text of SNiP N-36-73 has undergone significant changes and additions.

Thermal insulation materials, products and structures, as well as the methodology for their thermal calculations, together with instructions for the implementation and acceptance of insulation work, are described in detail in the Builder's Handbook. Similar data on thermal insulation structures are included in SN 542-81.

Reference materials on hydraulic calculations, as well as on equipment and automatic regulators for heating networks, heating points and heat use systems are contained in the “Handbook for the Adjustment and Operation of Water Heating Networks”. As a source of reference materials on design issues, books from the series of reference books "Heat power engineering and heat engineering" can be used. The first book "General Issues" contains rules for the design of drawings and diagrams, as well as data on the thermodynamic properties of water and steam, more detailed information is given in. In the second book of the series “Heat and mass transfer. Thermal Engineering Experiment" includes data on the thermal conductivity and viscosity of water and steam, as well as on the density, thermal conductivity and heat capacity of some building and insulating materials. In the fourth book "Industrial heat power engineering and heat engineering" there is a section on district heating and heat networks

www.engineerclub.ru

Gromov - Water heating networks (1988)

The book contains regulatory materials used in the design of heat networks and heat points. Recommendations are given on the choice of equipment and heat supply schemes. Calculations related to the design of heat networks are considered. Information is given on the laying of heating networks, on the organization of construction and operation of heating networks and heating points. The book is intended for engineering and technical workers involved in the design of thermal networks.

Residential and industrial construction, fuel economy and protection requirements environment predetermine the feasibility of intensive development of district heating systems. The generation of thermal energy for such systems is currently carried out by thermal power plants, boiler houses of regional significance.

Reliable operation of heat supply systems with strict observance of the necessary parameters of the coolant is largely determined by the right choice schemes of heating networks and heating points, gasket designs, equipment used.

Considering that the correct design of heat networks is impossible without knowledge of their design, operation and development trends, the authors tried to provide design recommendations in the reference manual and give a brief justification for them.

GENERAL CHARACTERISTICS OF HEAT NETWORKS AND HEAT POINTS

1.1. District heating systems and their structure

District heating systems are characterized by a combination of three main links: heat sources, heat networks and local systems of heat use (heat consumption) of individual buildings or structures. In heat sources, heat is obtained by burning various kinds organic fuel. Such heat sources are called boiler rooms. In the case of use in heat sources of heat released during the decay of radioactive elements, they are called nuclear power plants (ACT). In some heat supply systems, renewable heat sources are used as auxiliary heat sources - geothermal energy, solar radiation energy, etc.

If the heat source is located together with the heat sinks in the same building, then the pipelines for supplying the coolant to the heat sinks passing inside the building are considered as an element of the local heat supply system. In district heating systems, heat sources are located in separate buildings, and heat is transported from them through pipelines of heating networks, to which the heat use systems of individual buildings are connected.

The scale of district heating systems can vary widely, from small, serving a few neighboring buildings, to the largest, covering a number of residential or industrial areas, and even the city as a whole.

Regardless of the scale, these systems are divided into municipal, industrial and citywide according to the contingent of consumers served. Utilities include systems that supply heat mainly to residential and public buildings, as well as individual buildings for industrial and utility-storage purposes, the placement of which in the residential zone of cities is allowed by the norms.

It is advisable to base the classification of communal systems according to their scale on the division of the territory of a residential area into groups of neighboring buildings (or quarters in areas of old buildings) accepted in the planning and building standards of cities, which are combined into microdistricts with a population of 4-6 thousand people. in small towns (with a population of up to 50 thousand people) and 12-20 thousand people. in cities of other categories. The latter envisage the formation of residential areas with a population of 25-80 thousand people from several microdistricts. The corresponding systems of district heating can be characterized as group (quarterly), micro-district and district.

Heat sources serving these systems, one for each system, can be categorized as group (quarterly), micro-district and district boiler houses, respectively. In large and largest cities (with a population of 250-500 thousand people and more than 500 thousand people, respectively), the norms provide for the unification of several adjacent residential areas into planning areas limited by natural or artificial boundaries. In such cities, the emergence of the largest inter-district systems of communal heat supply is possible.

At large scales of heat generation, especially in citywide systems, it is expedient to jointly generate heat and electricity. This provides significant fuel savings in comparison with the separate generation of heat in boiler houses, and electricity - at thermal power plants by burning the same types of fuel.

Thermal power plants designed for the joint generation of heat and electricity are called combined heat and power plants (CHP).

Nuclear power plants, which use the heat released from the decay of radioactive elements to generate electricity, are also sometimes useful as heat sources in large heating systems. These stations are called nuclear combined heat and power plants (ATES).

District heating systems that use CHP as the main heat sources are called district heating systems. The issues of construction of new district heating systems, as well as expansion and reconstruction of existing systems require special study, based on the prospects for the development of the relevant settlements for the next period (A0-15 years) and the estimated period of 25-30 years).

The norms provide for the development of a special pre-project document, namely, a heat supply scheme for this settlement. In the scheme, several options for technical solutions for heat supply systems are being worked out and, on the basis of a feasibility study, the choice of the option proposed for approval is substantiated.

The subsequent development of projects for heat sources and heat networks should, in accordance with regulatory documents, be carried out only on the basis of decisions made in the approved heat supply scheme for this settlement.

1.2. general characteristics heating networks

Thermal networks can be classified according to the type of coolant used in them, as well as according to its design parameters (pressures and temperatures). Almost the only heat carriers in heating networks are hot water and steam. Water vapor as a heat carrier is widely used in heat sources (boiler houses, CHPPs), and in many cases in heat use systems, especially industrial ones. Municipal heating systems are equipped with water heating networks, and industrial systems are equipped with either only steam or steam in combination with water, used to cover the loads of heating, ventilation and hot water supply systems. This combination of dropsy and steam heat networks is also typical for citywide heat supply systems.

Water heating network mostly performed as two-pipe with a combination of supply pipelines for supply hot water from heat sources to heat recovery systems and return pipelines for returning water cooled in these systems to heat sources for reheating. The supply and return pipelines of water heating networks, together with the corresponding pipelines of heat sources and heat use systems, form closed water circulation circuits. This circulation is supported by network pumps installed in heat sources, and for long distances of water transport, also on the route of networks ( pumping stations). Depending on the adopted scheme for connecting to networks of hot water supply systems, closed and open circuits(the terms “closed and open heat supply systems” are more often used).

In closed systems, the release of heat from networks in the hot water supply system is carried out due to heating, cold tap water in special water heaters.

In open systems, the loads of hot water supply are covered by supplying water to consumers from the supply pipelines of the networks, and during the heating period - mixed with water from the return pipelines of heating and ventilation systems. If, under all modes, for hot water supply, water from the return pipelines can be completely used, then there is no need for return pipelines from the heating points to the heat source. Compliance with these conditions, as a rule, is possible only with the joint operation of several heat sources on common heat networks with the assignment of covering the loads of hot water supply to some of these sources.

Water networks, consisting only of supply pipelines, are called single-pipe and are the most economical in terms of capital investments in their construction. The make-up of heating networks in closed and open systems is carried out due to the operation of make-up pumps and make-up water treatment plants. In an open system, their required performance is 10-30 times greater than in a closed one. As a result, with an open system, capital investments in heat sources turn out to be large. At the same time, in this case, there is no need for tap water heaters, and therefore the costs for the nodes for connecting hot water supply systems to heating networks are significantly reduced. Thus, the choice between open and closed systems in each case, it must be justified by technical and economic calculations, taking into account all links of the district heating system. Such calculations should be performed when developing a heat supply scheme for a settlement, that is, before designing the corresponding heat sources and their heat networks.

In some cases, water heating networks are made with three or even four pipes. Such an increase in the number of pipes, usually provided only in certain sections of the networks, is associated with doubling either only the supply (three-pipe systems) or both the supply and return (four-pipe systems) pipelines for separate connection to the corresponding pipelines of hot water supply systems or heating and ventilation systems . This separation greatly facilitates the regulation of heat supply to systems for various purposes, but at the same time leads to a significant increase in capital investments in the network.

In large district heating systems, there is a need to divide water heating networks into several categories, each of which can be used own schemes vacation and heat transport.

The norms provide for the division of heat networks into three categories: main lines from heat sources to inputs to microdistricts (quarters) or enterprises; distribution from main networks to networks to individual buildings: networks to individual buildings in the form of branches from distribution (or in some cases from main) networks to the nodes of connection to them of heat use systems of individual buildings. It is advisable to clarify these names in relation to the classification of district heating systems adopted in § 1.1 according to their scale and contingent of consumers served. So, if in small systems from one heat source heat is supplied only to a group of residential and public buildings within a microdistrict or industrial buildings one enterprise, then there is no need for main heat networks and all networks from such heat sources should be considered as distribution networks. This situation is typical for the use of group (quarterly) and micro-district boiler houses as heat sources, as well as industrial boilers serving one enterprise. In the transition from such small systems to regional, and even more so to inter-district, a category of main heating networks appears, to which distribution networks of individual microdistricts or enterprises of one industrial region join. The connection of individual buildings directly to the main networks, in addition to distribution networks, is highly undesirable for a number of reasons, and therefore is used very rarely.

Large heat sources of district and inter-district district heating systems, according to the norms, should be located outside the residential area in order to reduce the impact of their emissions on the state of the air basin of this area, as well as to simplify the systems for supplying liquid or solid fuel to them.

In such cases, the initial (head) sections of trunk networks of considerable length appear, within which there are no nodes for connecting distribution networks. Such transport of the coolant without passing its distribution to consumers is called transit, while it is advisable to single out the corresponding head sections of the main heating networks into a special category of transit ones.

The presence of transit networks significantly worsens the technical and economic indicators of coolant transport, especially when these networks are 5–10 km or more in length, which is typical, in particular, when nuclear thermal power plants or heat supply stations are used as heat sources.

1.3. General characteristics of heat points

An essential element of district heating systems are installations located at the nodes of connection to heat networks of local heat use systems, as well as at the junctions of networks of various categories. In such installations, the operation of heat networks and heat use systems is monitored and controlled. Here, the parameters of the coolant are measured - pressures, temperatures, and sometimes flow rates - and the regulation of heat supply at various levels.

The reliability and efficiency of heat supply systems as a whole depend to a large extent on the operation of such installations. These installations in the regulatory documents are called heat points (previously, the names “connection nodes of local heat use systems”, “heat centers”, “subscriber installations”, etc.) were also used.

However, it is advisable to somewhat clarify the classification of heat points adopted in the same documents, since in them all heat points are either central (CTP) or individual (ITP). The latter include only installations with nodes for connecting to heat networks of heat use systems of one building or part of them (in large buildings). All other heat points, regardless of the number of buildings served, are central.

In accordance with the accepted classification of heat networks, as well as various levels of regulation of heat supply, the following terminology is used. In terms of heating points:

local heating points (MTP), service systems heat utilization of individual buildings;

group or micro-district heating points (GTP) serving a group of residential buildings or all buildings within the micro-district;

district heating substations (RTP) serving all buildings within a residential

In terms of regulation levels:

central - only at heat sources;

district, group or microdistrict - at the respective heating points (RTP or GTP);

local - at local heating points of individual buildings (MTP);

individual on separate heat receivers (devices of heating, ventilation or hot water supply systems).

Heating networks design reference guide

Home Mathematics, Chemistry, Physics Designing a heating system for a hospital complex

27. Safonov A.P. Collection of tasks on district heating and heating networks Textbook for universities, M.: Energoatomizdat. 1985.

28. Ivanov V.D., Gladyshey N.N., Petrov A.V., Kazakova T.O. Engineering calculations and test methods for thermal networks Lecture notes. SPb.: SPb GGU RP. 1998.

29. Instructions for the operation of thermal networks M .: Energia 1972.

30. Safety regulations for the maintenance of heating networks M: Atomizdat. 1975.

31. Yurenev V.N. Thermotechnical reference book in 2 volumes M.; Energy 1975, 1976.

32. Golubkov B.N. Heat engineering equipment and heat supply industrial enterprises. Moscow: Energy 1979.

33. Shubin E.P. The main issues of designing heat supply systems. M.: Energy. 1979.

34. Guidelines for the preparation of a report of the power plant and the joint-stock company of energy and electrification on the thermal efficiency of equipment. RD 34.0K.552-95. SPO ORGRES M: 1995.

35. Method of determination unit costs fuel for heat, depending on the parameters of the steam used for heat supply RD 34.09.159-96. SPO ORGRES. M.: 1997

36. Guidelines for the analysis of changes in specific fuel consumption at power stations and power associations. RD 34.08.559-96 SPO ORGRES. M.: 1997.

37. Kutovoy G. P., Makarov A. A., Shamraev N. G. Creation of a favorable base for the development of the Russian electric power industry on a market basis "Heat power engineering". No. 11, 1997. pp. 2-7.

38. V. V. Bushuev, B. N. Gromov, V. N. Dobrokhotov, V. V. Pryakhin, Scientific, technical, organizational and economic problems of introducing energy-saving technologies. "Heat power engineering". No. 11. 1997. pp.8-15.

39. Astakhov N.L., Kalimov V.F., Kiselev G.P. New edition guidelines on the calculation of indicators of thermal efficiency of TPP equipment. "Energy saving and water treatment". No. 2, 1997, p. 19-23.

Ekaterina Igorevna Tarasevich
Russia

Chief Editor -

candidate of biological sciences

RATED HEAT FLOW DENSITY AND HEAT LOSS THROUGH A HEAT-INSULATED SURFACE FOR MAIN HEAT NETWORKS

The article discusses the change in a number of published regulatory documents for the thermal insulation of heat supply systems, which are aimed at ensuring the durability of the system. This article is devoted to the study of the influence of the average annual temperature of heating networks on heat losses. The study relates to heat supply systems and thermodynamics. Recommendations are given for the calculation of normative heat losses through the insulation of heating network pipelines.

The relevance of the work is determined by the fact that it addresses little-studied problems in the heat supply system. The quality of thermal insulation structures depends on the heat losses of the system. Proper design and calculation of a thermal insulation structure is much more important than just choosing an insulating material. Results are given comparative analysis heat losses.

Thermal calculation methods for calculating heat losses of pipelines of heating networks are based on the use of standard density heat flow through the surface of the insulating structure. In this article, on the example of pipelines with polyurethane foam insulation, the calculation of heat losses was carried out.

Basically, the following conclusion was made: in the current regulatory documents, the total values ​​of the heat flux density for the supply and return pipelines are given. There are cases when the diameters of the supply and return pipelines are not the same, three or more pipelines can be laid in one channel, therefore, the previous standard must be used. The total values ​​of the heat flux density in the norms can be divided between the supply and return pipelines in the same proportions as in the replaced norms.

Keywords

Literature

SNiP 41-03-2003. Thermal insulation equipment and pipelines. Updated edition. - M: Ministry of Regional Development of Russia, 2011. - 56 p.

SNiP 41-03-2003. Thermal insulation of equipment and pipelines. - M.: Gosstroy of Russia, FSUE TsPP, 2004. - 29 p.

SP 41-103-2000. Design of thermal insulation of equipment and pipelines. M: Gosstroy of Russia, FSUE TsPP, 2001. 47 p.

GOST 30732-2006. Steel pipes and fittings with thermal insulation made of polyurethane foam with a protective sheath. – M.: STANDARTINFORM, 2007, 48 p.

Norms for the design of thermal insulation for pipelines and equipment of power plants and heating networks. Moscow: Gosstroyizdat, 1959. URL: http://www.politerm.com.ru/zuluthermo/help/app_thermoleaks_year1959.htm

SNiP 2.04.14-88. Thermal insulation of equipment and pipelines / Gosstroy USSR. - M .: CITP Gosstroy USSR, 1998. 32 p.

Belyaykina I.V., Vitaliev V.P., Gromov N.K. and etc.; Ed. Gromova N.K.; Shubina E.P. Water heating networks: A reference guide for design. M.: Energoatomizdat, 1988. - 376 p.

Ionin A.A., Khlybov B.M., Bratenkov V.H., Terletskaya E.H.; Ed. A.A. Ionina. Heat supply: Textbook for universities. M.: Stroyizdat, 1982. 336 p.

Lienhard, John H., A heat transfer textbook / John H. Lienhard IV and John H. Lienhard V, 3rd ed. Cambridge, MA: Phlogiston Press, 2003

Silverstein, C.C., “Design and Technology of Heat Pipes for Cooling and HeatExchange,” Taylor & Francis, Washington DC, USA, 1992

European Standard EN 253 District heating pipes - Preinsulated bonded pipe systems for directly buried hot water networks - Pipe assembly of steel service pipe, polyurethane thermal insulation and outer casing of polyethylene.

European Standard EN 448 District heating pipes. Preinsulated bonded pipe systems for directly buried hot water networks. Fitting assemblies of steel service pipes, polyurethane thermal insulation and outer casing of polyethylene

DIN EN 15632-1:2009 District heating pipes - Pre-insulated flexible pipe systems - Part 1: Classification, general requirements and test methods

Sokolov E.Ya. Heat supply and thermal networks Textbook for universities. M.: MPEI Publishing House, 2001. 472 p.

SNiP 41-02-2003. Heating network. Updated edition. - M: Ministry of Regional Development of Russia, 2012. - 78 p.

SNiP 41-02-2003. Heating network. - M: Gosstroy of Russia, 2004. - 41 p.

Nikolaev A.A. Designing of thermal networks (Designer's Handbook) / A.A.Nikolaev [and others]; ed. A.A. Nikolaev. - M.: NAUKA, 1965. - 361 p.

Varfolomeev Yu.M., Kokorin O.Ya. Heating and thermal networks: Textbook. M.: Infra-M, 2006. - 480 p.

Kozin V. E., Levina T. A., Markov A. P., Pronina I. B., Slemzin V. A. Heat supply: A textbook for university students. - M .: Higher. school, 1980. - 408 p.

Safonov A.P. Collection of tasks on district heating and heat networks: Proc. allowance for universities. 3rd ed., revised. M.: Energoatomizdat, 1985. 232 p.

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Determination of coefficients of local losses in heat networks of industrial enterprises

Publication date: 06.02.2017 2017-02-06

Article viewed: 186 times

Bibliographic description:

Ushakov D. V., Snisar D. A., Kitaev D. N. Determination of coefficients local losses in thermal networks of industrial enterprises // Young scientist. - 2017. - No. 6. - S. 95-98. — URL https://moluch.ru/archive/140/39326/ (date of access: 07/13/2018).

The article presents the results of the analysis of the actual values ​​of the coefficient of local losses used in the design of heat networks at the stage of preliminary hydraulic calculation. Based on the analysis of actual projects, averaged values ​​were obtained for networks of industrial sites divided into mains and branches. Equations are found that make it possible to calculate the coefficient of local losses depending on the diameter of the network pipeline.

Keywords : heat networks, hydraulic calculation, local loss coefficient

In the hydraulic calculation of heat networks, it becomes necessary to set the coefficient α , which takes into account the share of pressure losses in local resistances. In modern standards, the implementation of which is mandatory in the design, about the normative method of hydraulic calculation and specifically the coefficient α is not mentioned. In modern reference and educational literature, as a rule, the values ​​recommended by the canceled SNiP II-36–73 * are given. In table. 1 values ​​are presented α for water networks.

Coefficient α to determine the total equivalent lengths of local resistances

Type of compensators

Conditional passage of the pipeline, mm

Branched heating networks

U-shaped with bent branches

U-shaped with welded or curved bends

U-shaped with welded bends

From table 1 it follows that the value α can be in the range from 0.2 to 1. There is an increase in the value with an increase in the diameter of the pipeline.

In the literature, for preliminary calculations, when pipe diameters are not known, the proportion of pressure losses in local resistances is recommended to be determined by the formula of B. L. Shifrinson

where z- coefficient accepted for water networks 0.01; G- water consumption, t/h.

The results of calculations according to formula (1) at various water flow rates in the network are shown in fig. one.

Rice. 1. Addiction α from water consumption

From fig. 1 implies that the value α at high costs it can be more than 1, and at low costs it can be less than 0.1. For example, at a flow rate of 50 t/h, α=0.071.

The literature gives an expression for the coefficient of local losses

where - the equivalent length of the section and its length, respectively, m; - the sum of the coefficients of local resistance in the area; λ - coefficient of hydraulic friction.

When designing water heating networks in a turbulent mode of motion to find λ , use the Shifrinson formula. Taking the value of the equivalent roughness k e=0.0005 mm, formula (2) is converted to the form

.(3)

From formula (3) it follows that α depends on the length of the section, its diameter and the sum of the local resistance coefficients, which are determined by the network configuration. Obviously the value α increases with a decrease in the length of the section and an increase in diameter.

In order to determine the actual coefficients of local losses α , the existing projects of water heating networks of industrial enterprises for various purposes were considered. Having hydraulic calculation forms, for each section the coefficient was determined α according to formula (2). Separately, for the main and branches, the weighted average values ​​of the coefficient of local losses for each network were found. On fig. 2 shows the results of calculations α on calculated highways for a sample of 10 network schemes, and in Fig. 3 for branches.

Rice. 2. Actual values α on calculated highways

From fig. 2 it follows that the minimum value is 0.113, the maximum is 0.292, and the average value for all schemes is 0.19.

Rice. 3. Actual values α by branches

From fig. 3 it follows that the minimum value is 0.118, the maximum is 0.377, and the average value for all schemes is 0.231.

Comparing the obtained data with the recommended ones, we can draw the following conclusions. According to Table. 1 for the schemes considered α =0.3 for mains and α=0.3÷0.4 for branches, while the actual averages are 0.19 and 0.231, which is slightly less than recommended. Actual value range α does not exceed the recommended values, i.e. the tabular values ​​(Table 1) can be interpreted as "no more".

For each pipeline diameter, average values ​​were determined α along highways and branches. The calculation results are presented in table. 2.

Values ​​of actual coefficients of local losses α

From the analysis of Table 2 it follows that with an increase in the diameter of the pipeline, the value of the coefficient α increases. By the method of least squares were obtained linear equations regressions for the main and branches depending on the outer diameter:

On fig. 4 shows the results of calculations according to equations (4), (5), and the actual values ​​for the corresponding diameters.

Rice. 4. Results of coefficient calculations α according to equations (4),(5)

Based on the analysis of real projects of thermal water networks of industrial sites, the averaged values ​​of the coefficients of local losses were obtained, divided into mains and branches. It is shown that the actual values ​​do not exceed the recommended ones, and the average values ​​are slightly less. Equations are obtained that make it possible to calculate the coefficient of local losses depending on the diameter of the network pipeline for mains and branches.

1. Kopko, V. M. Heat supply: a course of lectures for students of the specialty 1–700402 "Heat and gas supply, ventilation and protection of the air basin" of higher educational institutions/ V. M. Kopko. - M: DIA Publishing House, 2012. - 336s.
2. Water heating networks: A reference guide for design / N.K. Gromov [et al.]. - M.: Energoatomizdat, 1988. - 376s.
3. Kozin, V. E. Heat supply: tutorial for university students / V. E. Kozin. - M.: Higher. school, 1980. - 408s.
4. Pustovalov, AP Improving the energy efficiency of engineering systems of buildings through the optimal choice of control valves / AP Pustovalov, DN Kitaev, TV Schukina // Scientific Bulletin of the Voronezh State University of Architecture and Civil Engineering. Series: High tech. Ecology. - 2015. - No. 1. - S. 187–191.
5. Semenov, V. N. The influence of energy-saving technologies on the development of heating networks / V. N. Semenov, E. V. Sazonov, D. N. Kitaev, O. V. Tertychny, T. V. Shchukina // News of higher educational institutions. Construction. - 2013. - No. 8 (656). - pp. 78–83.
6. Kitaev, D. N. Influence of modern heating appliances on the regulation of heat networks / D. N. Kitaev // Scientific journal. Engineering systems and buildings. - 2014. - V.2. - No. 4(17). - pp. 49–55.
7. Kitaev, D.N., Bulygina S.G., Slepokurova M.A. Variant design of heat supply systems taking into account the reliability of the heat network // Young scientist. - 2010. - No. 7. - S. 46–48.
What laws did Vladimir Putin sign on the last day of the outgoing year By the end of the year, a bunch of things always accumulate that you want to complete before the chiming clock. Well not to drag in New Year old debts. State Duma […]
8. Organization FGKU "GC VVE" of the Ministry of Defense of Russia Legal address: 105229, MOSCOW, GOSPITAL PL, 1-3, STR.5 OKFS: 12 - Federal property of OKOGU: 1313500 - Ministry of Defense of the Russian Federation […]

Hydraulic calculation of water heating networks is carried out in order to determine the diameters of pipelines, pressure losses in them, linking the thermal points of the system.

The results of the hydraulic calculation are used to build a piezometric graph, select schemes for local heating points, select pumping equipment and technical and economic calculations.

The pressure in the supply pipelines, through which water with a temperature of more than 100 0 C moves, must be sufficient to prevent vaporization. The temperature of the coolant in the line is assumed to be 150 0 C. The pressure in the supply pipelines is 85 m, which is sufficient to prevent vaporization.

To prevent cavitation, the pressure in the suction pipe of the network pump must be at least 5 m.

With elevator mixing at the subscriber input, the available pressure must be at least 10-15 m.

When the coolant moves along horizontal pipelines, a pressure drop is observed from the beginning to the end of the pipeline, which consists of a linear pressure drop (friction loss) and pressure losses in local resistances:

Linear pressure drop in a pipeline of constant diameter:

Pressure drop in local resistances:

Reduced pipeline length:

Then formula (14) will take the final form:

Let's determine the total length of the settlement highway (sections 1,2,3,4,5,6,7,8):

We will carry out a preliminary calculation (Consists in the determination of diameters and speeds). The share of pressure losses in local resistances can be approximately determined by the formula of B.L. Shifrinson:

where z \u003d 0.01 is the coefficient for water networks; G - coolant flow in the initial section of the branched heat pipeline, t/h.

Knowing the proportion of pressure losses, it is possible to determine the average specific linear pressure drop:

where is the available pressure drop to all subscribers, Pa.

According to the assignment, the available pressure drop is given in meters and is equal to? H \u003d 60 m. pressure losses are distributed evenly between the supply and return lines, then the pressure drop on the supply line will be equal to? H \u003d 30 m. Let's translate this value into Pa as follows:

where = 916.8 kg / m 3 - the density of water at a temperature of 150 0 C.

Using formulas (16) and (17), we determine the proportion of pressure losses in local resistances, as well as the average specific linear pressure drop:

According to the magnitude and flow rates G 1 - G 8, according to the nomogram, we find the diameters of the pipes, the coolant velocity and. The result is entered in table 3.1:

Table 3.1

plot number	Estimation	final settlement

Let's do the final calculation. We specify the hydraulic resistance in all sections of the network with the selected pipe diameters.

We determine the equivalent lengths of local resistances in the design sections according to the table "equivalent lengths of local resistances".

dP \u003d R * (l + l e) * 10 -3, kPa (18)

We determine the total hydraulic resistance for all sections of the design pipeline, which are compared with the pressure drop located in it:

The calculation is satisfactory if the hydraulic resistance does not exceed the available pressure drop and differs from it by no more than 25%. We translate the end result m. Art. to build a piezometric graph. All data is entered in table 3.

We will carry out the final calculation for each settlement area:

Plot 1:

The first section has the following local resistance with their equivalent lengths:

Gate valve: l e \u003d 3.36 m

Tee for dividing flows: l e \u003d 8.4 m

We calculate the total pressure loss in the sections according to the formula (18):

dP \u003d 390 * (5 + 3.36 + 8.4) * 10 -3 \u003d 6.7 kPa

Or m. st.:

H \u003d dP * 10 -3 / 9.81 \u003d 6.7 / 9.81 \u003d 0.7 m

Plot 2:

The second section has the following local resistances with their equivalent lengths:

U-shaped compensator: l e \u003d 19 m

dP \u003d 420 * (62.5 + 19 + 10.9) * 10 -3 \u003d 39 kPa

H= 39/9.81=4 m

Plot 3:

The third section has the following local resistances with their equivalent lengths:

Tee for dividing flows: l e \u003d 10.9 m

dP \u003d 360 * (32.5 + 10.9) * 10 -3 \u003d 15.9 kPa

H= 15.9/9.81=1.6 m

Plot 4:

The fourth section has the following local resistances with their equivalent lengths:

Branch: l e \u003d 3.62 m

Tee for dividing flows: l e \u003d 10.9 m

dP \u003d 340 * (39 + 3.62 + 10.9) * 10 -3 \u003d 18.4 kPa

H=18.4/9.81=1.9 m

Plot 5:

The fifth section has the following local resistances with their equivalent lengths:

U-shaped compensator: l e \u003d 12.5 m

Branch: l e \u003d 2.25 m

Tee for dividing flows: l e \u003d 6.6 m

dP \u003d 590 * (97 + 12.5 + 2.25 + 6.6) * 10 -3 \u003d 70 kPa

H= 70/9.81=7.2 m

Plot 6:

The sixth section has the following local resistances with their equivalent lengths:

U-shaped compensator: l e \u003d 9.8 m

Tee for dividing flows: l e \u003d 4.95 m

dP \u003d 340 * (119 + 9.8 + 4.95) * 10 -3 \u003d 45.9 kPa

H= 45.9/9.81=4.7 m

Plot 7:

The seventh section has the following local resistances with their equivalent lengths:

Two branches: l e \u003d 2 * 0.65 m

Tee for dividing flows: l e \u003d 1.3 m

dP \u003d 190 * (107.5 + 2 * 0.65 + 5.2 + 1.3) * 10 -3 \u003d 22.3 kPa

H= 22.3/9.81=2.3 m

Plot 8:

The eighth section has the following local resistances with their equivalent lengths:

Gate valve: l e \u003d 0.65 m

Branch: l e \u003d 0.65 m

dP \u003d 65 * (87.5 + 0.65 +.065) * 10 -3 \u003d 6.2 kPa

H= 6.2/9.81= 0.6 m

We determine the total hydraulic resistance and compare it with the available differential according to (17=9):

Let's calculate the difference in percentage:

? = ((270-224,4)/270)*100 = 17%

The calculation is satisfactory because hydraulic resistance does not exceed the available pressure drop, and differs from it by less than 25%.

Similarly, we calculate the branches and enter the result in table 3.2:

Table 3.2

plot number	Estimation	final settlement

Plot 22:

Available pressure at the subscriber:? H 22 \u003d 0.6 m

On the 22nd section, there are the following local resistances with their equivalent lengths:

Branch: l e \u003d 0.65 m

U-shaped compensator: l e \u003d 5.2 m

Gate valve: l e \u003d 0.65 m

dP \u003d 32 * (105 + 0.65 + 5.2 + 0.65) * 10 -3 \u003d 3.6 Pa

H= 3.6/9.81=0.4 m

Excess pressure in the branch: ?H 22 - ?H \u003d 0.6-0.4 \u003d 0.2 m

? = ((0,6-0,4)/0,6)*100 = 33,3%

Plot 23:

Available pressure at the subscriber: ?H 23 = ?H 8 +?H 7 = 0.6 + 2.3 = 2.9 m

On the 23rd section, there are the following local resistances with their equivalent lengths:

Branch: l e \u003d 1.65 m

Gate valve: l e \u003d 1.65 m

dP \u003d 230 * (117.5 + 1.65 + 1.65) * 10 -3 \u003d 27.8 kPa

H= 27.8/9.81=2.8 m

Excess pressure in the branch:? H 23 -? H \u003d 2.9-2.8 \u003d 0.1 m<25%

Plot 24:

Available pressure at the subscriber: ?H 24 = ?H 23 +?H 6 = 2.9 + 4.7 = 7.6 m

On the 24th section, there are the following local resistances with their equivalent lengths:

Branch: l e \u003d 1.65 m

Gate valve: l e \u003d 1.65 m

dP \u003d 480 * (141.5 + 1.65 + 1.65) * 10 -3 \u003d 69.5 kPa

H=74.1 /9.81=7.1 m

Excess pressure in the branch: ?H 24 - ?H \u003d 7.6-7.1 \u003d 0.5 m<25%

Plot 25:

Available pressure at the subscriber: ?H 25 = ?H 24 +?H 5 = 7.6 + 7.2 = 14.8 m

On the 25th section, there are the following local resistances with their equivalent lengths:

Branch: l e \u003d 2.25 m

Gate valve: l e \u003d 2.2 m

dP \u003d 580 * (164.5 + 2.25 + 2.2) * 10 -3 \u003d 98 kPa

H= 98/9.81=10 m

Excess pressure in the branch: ?H 25 - ?H \u003d 14.8-10 \u003d 4.8 m

? = ((14,8-10)/14,8)*100 = 32,4%

Because the difference in values ​​is more than 25% and it is not possible to install pipes with a smaller diameter, it is necessary to install a throttle washer.

Plot 26:

Available pressure at the subscriber: ?H 26 = ?H 25 +?H 4 = 14.8 + 1.9 = 16.7 m

On the 26th section, there are the following local resistances with their equivalent lengths:

Branch: l e \u003d 0.65 m

Gate valve: l e \u003d 0.65 m

dP \u003d 120 * (31.5 + 0.65 + 0.65) * 10 -3 \u003d 3.9 kPa

H= 3.9/9.81=0.4 m

Excess pressure in the branch: ?H 26 - ?H \u003d 16.7-0.4 \u003d 16.3 m

? = ((16,7-0,4)/16,7)*100 = 97%

Because the difference in values ​​is more than 25% and it is not possible to install pipes with a smaller diameter, it is necessary to install a throttle washer.

Plot 27:

Available head at the subscriber: ?H 27 = ?H 26 +?H 3 = 16.7 + 1.6 = 18.3 m

On the 27th section, there are the following local resistances with their equivalent lengths:

Withdrawal: l e \u003d 1 m

Gate valve: l e \u003d 1 m

dP \u003d 550 * (40 + 1 + 1) * 10 -3 \u003d 23.1 kPa

H= 23.1/9.81=2.4 m

Excess pressure in the branch: ?H 27 - ?H \u003d 18.3-2.4 \u003d 15.9 m

Reducing the diameter of the pipeline is not possible, so it is necessary to install a throttle washer.

Competent and high-quality is one of the main conditions for the quick commissioning of the facility.

Heating network designed to transport heat from heat sources to the consumer. Thermal networks are linear structures and are one of the most complex engineering networks. The design of networks must necessarily include a calculation for strength and temperature deformations. We calculate each element of the heating network for a service life of at least 25 years (or another at the request of the customer), taking into account the specific temperature history, thermal deformations and the number of starts and stops of the network. An integral part of the design of the heating network should be the architectural and construction part (AS) and reinforced concrete or metal structures (KZh, KM), in which fasteners, channels, supports or overpasses are developed (depending on the laying method).

Thermal networks are divided according to the following criteria

1. By the nature of the transported coolant:

2. According to the method of laying heating networks:

• channel heating networks. The design of channel heat networks is carried out if it is necessary to protect pipelines from the mechanical impact of soils and the corrosive effects of soil. Channel walls facilitate the operation of pipelines, therefore, the design of channel heat networks is used for heat carriers with pressures up to 2.2 MPa and temperatures up to 350 ° C. - channelless. When designing channelless laying, pipelines operate in more difficult conditions, since they perceive an additional load of the soil and, with inadequate protection from moisture, are subject to external corrosion. In this regard, the design of networks in this way of laying is provided for at a coolant temperature of up to 180 ° C.
• air (aerial) heating networks. The design of networks by this method of laying has become most widespread in the territories of industrial enterprises and on sites free from buildings. The above-ground method is also designed in areas with high groundwater levels and when laying in areas with very rugged terrain.

3. With regard to schemes, heat networks can be:

• main heating networks. Heating networks, always in transit, without branches transporting the coolant from the heat source to distribution heating networks;
• distribution (quarterly) heating networks. Heating networks distributing the heat carrier over the selected quarter, supplying the heat carrier to the branches to consumers .;
• branches from distribution heat networks to individual buildings and structures. The separation of heat networks is established by the project or the operating organization.

Integrated network design in accordance with project documentation

STC Energoservice performs complex work on, including city highways, intra-quarter distribution and intra-house networks. The design of networks of the linear part of heating mains is carried out using both standard and individual nodes.

Qualitative calculation of heat networks makes it possible to compensate for thermal elongation of pipelines due to the angles of turns of the route and to check the correctness of the planned-altitude position of the route, the installation of bellows expansion joints and fixing with fixed supports.

Thermal elongation of heat pipelines during channelless laying is compensated due to the angles of turns of the route, which form self-compensating sections of the П, Г, Z-shaped form, the installation of starting compensators, and fixing with fixed supports. At the same time, at the corners of the turns, between the trench wall and the pipeline, special polyethylene foam cushions (mats) are installed, which ensure the free movement of pipes during their thermal elongation.

All documentation for design of thermal networks is developed in accordance with the following regulatory documents:

SNiP 207-01-89* Urban planning. Planning and development of cities, towns and rural settlements. Network design standards”;
- SNiP 41-02-2003 "Heat networks";
- SNiP 41-02-2003 "Thermal insulation of equipment and pipelines";
- SNiP 3.05.03-85 "Heat networks" (heat network enterprise);
- GOST 21-605-82 "Heat networks (thermal mechanical part)";
- Rules for the preparation and production of earthworks, arrangement and maintenance of construction sites in the city of Moscow, approved by the Decree of the Government of Moscow No. 857-PP dated 07.12.2004.
- PB 10-573-03 "Rules for the design and safe operation of steam and hot water pipelines".

Depending on the conditions of the construction site, the design of networks may be associated with the reconstruction of existing underground structures that interfere with construction. The design of heat networks and the implementation of projects involves the use of two insulated steel pipelines (supply and return) in special prefabricated or monolithic channels (through and through). To accommodate disconnecting devices, drains, air vents and other fittings, the design of heat networks provides for the construction of chambers.

At network design and their throughput, the problems of uninterrupted operation of hydraulic and thermal modes are relevant. Carrying out the design of heating networks, the specialists of our company use the most modern methods, which allows us to guarantee a good result and durable operation of all equipment.

When carrying out, it is necessary to rely on many technical standards, the violation of which can lead to the most negative consequences. We guarantee compliance with all norms and rules regulated by various technical documentation described above.

I welcome you, dear and respected readers of the site "site". A necessary step in the design of heat supply systems for enterprises and residential areas is the hydraulic calculation of pipelines for water heating networks. It is necessary to solve the following tasks:

1. Determination of the inner diameter of the pipeline for each section of the heating network d V, mm. According to the diameters of the pipeline and their lengths, knowing their material and method of laying, it is possible to determine capital investments in heating networks.
2. Determination of pressure losses of network water or pressure losses of network water Δh, m; ΔР, MPa. These losses are the initial data for successive calculations of the head of network and make-up pumps in heat networks.

Hydraulic calculation of heat networks is also performed for existing operating heat networks, when the task is to calculate their actual throughput, i.e. when there is a diameter, length and you need to find the consumption of network water that will pass through these networks.

Hydraulic calculation of pipelines of heat networks is performed for the following modes of their operation:

A) for the design mode of operation of the heating network (max G O; G B; G DHW);

B) for summer mode, when only G DHW flows through the pipeline

C) for static mode, the network pumps are stopped at the heat supply source, and only make-up pumps are running.

D) for emergency operation, when an accident occurs in one or more sections, the diameter of the jumpers and reserve pipelines.

If heat networks work for a water open heat supply system, then it is also determined:

E) winter mode, when network water for the hot water supply system of buildings is taken from the return pipeline of the heating network.

E) transient mode, when network water for hot water supply of buildings is taken from the supply pipeline of the heating network.

In the hydraulic calculation of pipelines of heat networks, the following quantities must be known:

1. The maximum load on heating and ventilation and the average hourly load on the hot water supply: max Q O, max Q VENT, Q SR DHW.
2. Temperature chart of the heat supply system.
3. Temperature graph of network water, temperature of network water at the break point τ 01 NI, τ 02 NI.
4. The geometric length of each section of heating networks: L 1 , L 2 , L 3 ...... L N .
5. The condition of the inner surface of the pipeline in each section of the heating network (the amount of corrosion and scale deposits). k E - equivalent roughness of the pipeline.
6. The number, type and arrangement of local resistances that are available in each section of the heating network (all gate valves, valves, turns, tees, compensators).
7. Physical properties of water p V, I V.

How the hydraulic calculation of pipelines of heat networks is performed will be considered using the example of a radial heat network serving 3 heat consumers.

Schematic diagram of a radial heating network that transports thermal energy for 3 heat consumers

1 - heat consumers (residential areas)

2 - sections of the heating network

3 - source of heat supply

Hydraulic calculation of the designed heat networks is performed in the following sequence:

1. According to the schematic diagram of heat networks, the consumer is determined, which is the most distant from the source of heat supply. The heat network laid from the source of heat supply to the most remote consumer is called the main highway (main highway), in the figure L 1 + L 2 + L 3. Sections 1.1 and 2.1 are branches from the main line (branch).
2. The estimated direction of movement of network water from the source of heat supply to the most remote consumer is outlined.
3. The calculated direction of movement of network water is divided into separate sections, on each of which the inner diameter of the pipeline and the flow rate of network water must remain constant.
4. The estimated consumption of network water is determined in the sections of the heating network to which consumers are connected (2.1; 3; 3.1):

G SUM UCH \u003d G O R + G B R + k 3 * G G SR

G О Р \u003d Q О Р / С В * (τ 01 Р - τ 02 Р) - maximum heating consumption

k 3 - coefficient taking into account the share of consumption of network water supplied to hot water supply

G V R \u003d Q V R / S V * (τ 01 R - τ V2 R) - maximum flow for ventilation

G G SR \u003d Q GW SR / S V * (τ 01 NI - τ G2 NI) - average consumption for hot water supply

k 3 \u003d f (type of heat supply system, heat load of the consumer).

Values ​​k 3 depending on the type of heat supply system and heat loads of connection of heat consumers

1. According to the reference data, the physical properties of network water in the supply and return pipelines of the heating network are determined:

P IN POD = f (τ 01) V IN POD = f (τ 01)

P IN OBR = f (τ 02) V IN OBR = f (τ 02)

1. The average values ​​of network water density and its velocity are determined:

P IN SR \u003d (P IN LOD + P IN OBR) / 2; (kg / m 3)

V IN SR \u003d (V IN UNDER + V IN OBR) / 2; (m 2 /s)

1. Hydraulic calculation of pipelines of each section of heating networks is carried out.

7.1. They are set by the speed of movement of network water in the pipeline: V B \u003d 0.5-3 m / s. The lower limit V B is due to the fact that at lower speeds, the deposition of suspended particles on the walls of the pipeline increases, and also at lower speeds, the circulation of water stops and the pipeline may freeze.

V B \u003d 0.5-3 m / s. - the greater value of the velocity in the pipeline is due to the fact that with an increase in velocity of more than 3.5 m / s, a hydraulic shock may occur in the pipeline (for example, when valves are suddenly closed, or when the pipeline is turned in a section of the heating network).

7.2. The internal diameter of the pipeline is calculated:

d V \u003d sqrt [(G SUM PCH * 4) / (p V SR * V V * π)] (m)

7.3. According to the reference data, the closest values ​​of the inner diameter are taken, which correspond to GOST d V GOST, mm.

7.4. The actual speed of water movement in the pipeline is specified:

V V F \u003d (4 * G SUM UCH) / [π * p V SR * (d V GOST) 2]

7.5. The mode and zone of flow of network water in the pipeline is determined, for this a dimensionless parameter is calculated (Reynolds criterion)

Re = (V V F * d V GOST) / V V F

7.6. Re PR I and Re PR II are calculated.

Re PR I = 10 * d V GOST / k E

Re PR II \u003d 568 * d V GOST / k E

For various types of pipelines and various degrees of wear of the pipeline, k E lies within. 0.01 - if the pipeline is new. When the type of pipeline and the degree of their wear are unknown according to SNiP ”Heat Networks” 41-02-2003. The value of k E is recommended to be chosen equal to 0.5 mm.

7.7. The coefficient of hydraulic friction in the pipeline is calculated:

— if the criterion Re< 2320, то используется формула: λ ТР = 64 / Re.

— if the Re criterion lies within (2320; Re PR I ], then the Blasius formula is used:

λ TP =0.11*(68/Re) 0.25

These two formulas must be used for laminar water flow.

— if the Reynolds criterion lies within (Re PR I< Re < =Re ПР II), то используется формула Альтшуля.

λ TP \u003d 0.11 * (68 / Re + k E / d V GOST) 0.25

This formula is used in the transitional movement of network water.

- if Re > Re PR II, then the Shifrinson formula is used:

λ TP \u003d 0.11 * (k E / d V GOST) 0.25

Δh TP \u003d λ TP * (L * (V V F) 2) / (d V GOST * 2 * g) (m)

ΔP TR = p V SR *g* Δh TR = λ TR * / (d V GOST *2) = R L *L (Pa)

R L \u003d [λ TP * r V SR * (V V F) 2] / (2 * d V GOST) (Pa / m)

R L - specific linear pressure drop

7.9. Pressure losses or pressure losses in local resistances in the pipeline section are calculated:

Δh M.S. = Σ£ M.S. *[(V V F) 2 /(2*g)]

Δp M.S. = p B SR *g* Δh M.S. = Σ£ M.S. *[((V V F) 2 * R V SR)/2]

Σ£ M.S. - the sum of the local resistance coefficients installed on the pipeline. For each type of local resistance £ M.S. taken from reference data.

7.10. The total head loss or total pressure loss in the pipeline section is determined:

h = Δh TR + Δh M.S.

Δp = Δp TR + Δp M.S. = p B SR *g* Δh TP + p B SR *g*Δh M.S.

According to this method, calculations are carried out for each section of the heating network and all values ​​​​are summarized in a table.

The main results of the hydraulic calculation of pipelines of sections of the water heating network

For indicative calculations of sections of water heating networks when determining R L, Δr TP, Δr M.S. the following expressions are allowed:

R L \u003d / [p V SR * (d V GOST) 5.25] (Pa / m)

R L \u003d / (d V GOST) 5.25 (Pa / m)

A R \u003d 0.0894 * K E 0.25 - an empirical coefficient that is used for an approximate hydraulic calculation in water heating networks

A R B \u003d (0.0894 * K E 0.25) / r B SR \u003d A R / r B SR

These coefficients were derived by Sokolov E.Ya. and are given in the textbook "Heat supply and heat networks".

Given these empirical coefficients, head and pressure losses are defined as:

Δp TR \u003d R L * L \u003d / [p V SR * (d V GOST) 5.25] \u003d

= / (d In GOST) 5.25

Δh TP = Δp TP / (p B SR *g) = (R L *L) / (p B SR *g) =

\u003d / (p V SR) 2 * (d V GOST) 5.25 \u003d

\u003d / p V SR * (d V GOST) 5.25 * g

Also taking into account A R and A R B; Δr M.S. and Δh M.S. will be written like this:

Δr M.S. \u003d R L * L E M \u003d / p V SR * (d V GOST) 5.25 \u003d

\u003d / (d In GOST) 5.25

Δh M.S. = Δp M.S. / (p B SR *g) \u003d (R L *L E M) / (r B SR *g) \u003d

\u003d / p V SR * (d V GOST) 5.25 \u003d

\u003d / (d In GOST) 5.25 * g

L E \u003d Σ (£ M. C. * d V GOST) / λ TR

The peculiarity of the equivalent length is that the head loss of local resistances is represented as a head drop in a straight section with the same inner diameter, and this length is called equivalent.

Total pressure and head losses are calculated as:

Δh = Δh TR + Δh M.S. \u003d [(R L *L) / (p B SR *g)] + [(R L *L E) / (r B SR *g)] =

\u003d * (L + L E) \u003d * (1 + a M. S.)

Δr \u003d Δr TP + Δr M. S. \u003d R L * L + R L * L E \u003d R L (L + L E) \u003d R L * (1 + a M. S.)

and M.S. - coefficient of local losses in the section of the water heating network.

In the absence of accurate data on the number, type and arrangement of local resistances, the value of a M.S. can be taken from 0.3 to 0.5.

I hope that now it has become clear to everyone how to correctly perform the hydraulic calculation of pipelines and you yourself will be able to perform the hydraulic calculation of heat networks. Tell us in the comments what you think, can you calculate the hydraulic calculation of pipelines in excel, or do you use an online calculator for the hydraulic calculation of pipelines or use a nomogram for the hydraulic calculation of pipelines?

Features of designing a heat network

1. Basic conditions for designing a heat network:

Depending on the geological, climatological features of the area, we choose the type of network laying.

• 2. The source of heat is located depending on the prevailing wind direction.
• 3. We lay pipelines along a wide road so that construction work can be mechanized.
• 4. When laying heating networks, you need to choose the shortest path in order to save material.
• 5. Depending on the relief and development of the area, we try to carry out self-compensation of heating networks.

Rice. 6.

Hydraulic calculation of the heat network

Technique of hydraulic calculation of the heat network.

The heating network is a dead end.

The hydraulic calculation is made on the basis of nanograms for the hydraulic calculation of the pipeline.

We are looking at the main road.

We select the pipe diameters according to the average hydraulic slope, taking specific pressure losses up to? P = 80 Pa / m.

2) For additional sections G, not more than 300 Pa/m.

Pipe roughness K= 0.0005 m.

Record the pipe diameters.

After the diameter of the heating network sections, we calculate the sum of the coefficient for each section. local resistances (?o), using the TS scheme, data on the location of valves, compensators, and other resistances.

After that, for each section, we calculate the length equivalent to the local resistance (Lek).

Based on the pressure loss in the supply and return lines and the required available pressure "at the end" of the line, we determine the required available pressure on the outlet collectors of the heat source.

Table 7.1 - Definition of Leqv. at? W = 1 by du.

Table 7.2 - Calculation of equivalent lengths of local resistances.

		local resistance	Coefficient of seats resistance (o)
		Gate valve 1pc Comp. Saln. 1 PC. Tee 1 piece
		Gate valve 1 pc. Seal comp. 1 PC. Tee 1pc.
		Tee 1pc. Gate valve 1pc.
		Gate valve 1pc.
		Gate valve 1pc. Comp. U-shaped 1pc.
		Gate valve 1pc. Comp. U-shaped 1pc.
		Gate valve 1pc. Tee 1pc.
		Gate valve 1pc. Tee 1pc.
		Gate valve 1pc. Comp. U-shaped 1pc.
		Gate valve 1pc.
		Gate valve 1pc. Tee 1pc.

Every 100m. a thermal expansion compensator was installed.

For pipeline diameters up to 200 mm. we accept U-shaped compensators, more than 200 - stuffing box, bellows.

Losses of pressure DPz are on a nanogram, Pa/m.

The pressure loss is determined by the formula:

DP \u003d DPz * ?L * 10-3, kPa.

V (m3) of the plot is determined by the formula:

Calculation of pipeline water consumption, m (kg / s).

mot+vein = = = 35.4 kg/sec.

mg.c. = = = 6.3 kg/sec.

total \u003d mot + veins + mg.v. = 41.7 kg/s

Calculation of water consumption by plots.

Qkv = z * Fkv

z = Qtotal / ?Fkv = 13320/19 = 701

Qkv1 \u003d 701 * 3.28 \u003d 2299.3 kW

Qkv2 \u003d 701 * 2.46 \u003d 1724.5 kW

Qkv3 \u003d 701 * 1.84 \u003d 1289.84 kW

Qkv4 \u003d 701 * 1.64 \u003d 1149.64 kW

Qkv5 \u003d 701 * 1.23 \u003d 862.23 kW

Qkv6 \u003d 701 * 0.9 \u003d 630.9 kW

Qkv7 \u003d 701 * 1.64 \u003d 1149.64 kW

Qkv8 \u003d 701 * 1.23 \u003d 862.23 kW

Qkv9 \u003d 701 * 0.9 \u003d 630.9 kW

Qkv10 \u003d 701 * 0.95 \u003d 665.95 kW

Qkv11 \u003d 701 * 0.35 \u003d 245.35 kW

Qkv12 \u003d 701 * 0.82 \u003d 574.82 kW

Qkv13 \u003d 701 * 0.83 \u003d 581.83 kW

Qkv14 \u003d 701 * 0.93 \u003d 651.93 kW

Table 7.3 - Water consumption for each quarter.

m1 = = 6.85kg/s	m8 = = 2.57kg/s
m2 = = 5.14kg/s	m9 = = 1.88kg/s
m3 = = 3.84kg/s	m10 = = 1.98kg/s
m4 = = 3.42kg/s	m11 = = 0.73kg/s
m5 = = 2.57kg/s	m12 = = 1.71kg/s
m6 = = 1.88kg/s	m13 = = 1.73kg/s
m7 = = 3.42kg/s	m14 = = 1.94kg/s

The water consumption for each section is (kg / s):

mg4-g5 = m10+ 0.5 * m7 = 1.98+0.5*3.42 = 3.69

mg3-g4 = m11 + mg4-g5 = 3.69+0.73=4.42

mg2-g3 = m12+mg3-g4=4.42+1.71=6.13

mg1-g2 = 0.5*m7 + 0.5*m8+mg2-g3=0.5*3.42+0.5*2.57+6.13=9.12

m2-g1 = m4+0.5*m5+mg1-g2=9.12+3.42+0.5*2.57=13.8

m2-in1=m1+0.5*m2=9.42

m1-2=m2-g1+m2-v1=13.8+9.42=23.22

ma2-a3= m13+m14=3.67

ma1-a2=0.5*m8+m9+ma2-a3=0.5*2.57+1.88+3.67=6.83

m1-а1=0.5*m5+m6+ma1-а2=9.99

m1-b1=0.5*m2+m3=6.41

mi-1=m1-b1+m1-а1+m1-2=6.41+9.99+23.22=39.6

We write the received data in table 8.

Table 8 - Hydraulic calculation of the district heating network. 7.1 Selection of network and make-up pumps.

		Pipe dimensions	Section lengths		Pressure loss Dp
											plot, m3
main highway
Branches from the main

Table 9 - To build a piezometric graph.

		Pipe size	Section lengths		Pressure loss DR
main highway

Hseat=0.75mHad=30 m

H bay = 4 m

V= 16.14 m3/h - to select the make-up pump

hfeed= 3.78 mhTGU= 15 m

hreturn = 3.78 mhsnap = 4 m

hset=26.56 m; m=142.56 m3/h - to select the network pump

For a closed heat supply system operating with an increased control schedule with a total heat flow Q = 13.32 MW and with an estimated coolant flow rate G = 39.6 kg / s = 142.56 m3 / h, select network and make-up pumps.

Required head of the network pump H = 26.56 m

According to the manual, we accept for installation one network pump KS 125-55 providing the required parameters.

The required pressure of the make-up pump Hpn = 16.14 m3/h. Required boost pump head H = 34.75 m

Make-up pump: 2k-20/20.

According to the manual, we accept for installation two series-connected make-up pumps 2K 20-20 providing the required parameters.

Rice. eight.

Table 10 - Technical characteristics of pumps.

Name	Dimension		make-up