Calculation of the heating network. Hydraulic calculation of heating networks: concept, definition, calculation methodology with examples, tasks and design

Heating network route

On the plan of a residential area, draw the route of the heating network from the heat supply source to each block. It is recommended to use a radial heating network diagram. When routing, you should strive for the shortest network length and two-way load of highways. One input should be provided for each quarter, and only in certain large quarters two inputs should be allowed. It is advisable to connect opposing blocks at one point.

Within urban areas, the installation of heating networks according to architectural conditions should be carried out using underground channels. In areas outside the city limits, the student can choose at his discretion to lay the heating network underground or above ground on low supports.

The task hydraulic calculation is to determine the diameters of pipes and pressure losses in them.

The estimated consumption of network water to determine the diameters of pipes in water heating networks should be determined separately for heating, ventilation and hot water supply, followed by the summation of these costs.

The estimated flow rate of network water, kg/h, to determine the diameters of pipes in water heating networks with high-quality regulation of heat supply should be determined separately for heating, ventilation and hot water supply using the formulas:

a) for heating

b) for ventilation

; (2.41)

c) for hot water supply in open systems heating supply:

hourly average

; (2.42)

maximum

; (2.43)

d) for hot water supply in closed systems heating supply:

hourly average, at parallel circuit connection of water heaters

; (2.44)

maximum, with parallel connection of water heaters

; (2.45)

hourly average, with two-stage water heater connection schemes

; (2.46)

maximum, with two-stage water heater connection schemes

; (2.47)

In formulas (2.40 - 2.47) the calculated heat flows are given in W,

heat capacity With is taken to be 4.198 kJ/(kg °C).

Total estimated costs network water, kg/h, in two-pipe heating networks in open and closed heat supply systems with high-quality regulation of heat supply should be determined by the formula

Coefficient k 3, taking into account the share of average hourly water consumption for hot water supply when regulating according to the heating load, should be taken according to table 4. When regulating according to the combined load of heating and hot water supply, the coefficient k 3 accepted equal to zero.

Table 4 – Coefficient values k 3

To carry out a hydraulic calculation, a design diagram of the network is drawn up, which shows the source of heat supply, the route of the heating network and the central heating stations or node chambers of the blocks connected to it. The route is divided into calculated sections, indicating on each the number, length and coolant flow.

Fig.3. Design diagram of a heating network (example).

The consumption of network water among residential areas is distributed in proportion to their heat load (or area).

In order to reduce similar calculations, it is allowed to perform a hydraulic calculation of the main direction (from the source to the most remote block) and one branch of the route.

For preliminary calculations, specific pressure losses (R Λ) can be taken for sections of the main route up to 80 Pa/m, for sections of the branch route up to 300 Pa/m.

The calculation starts from the head section, i.e. from the source to the first branch. Based on the calculated coolant flow rate in the area and previously accepted specific pressure losses according to the nomogram for hydraulic calculations, in accordance with Appendix 5 of this teaching aid, and also using tables and nomograms to find the diameter of the pipeline. According to tables 3.4 and 3.7 “Steel pipes”, select a standard pipe diameter close to that previously obtained from the nomogram. For a standard pipe, the specific pressure loss and coolant flow rate are specified. For the area under consideration, an installation diagram is developed, which indicates pipelines, fittings, fixed supports, compensators, rotation angles, and transitions. The types of local resistances are identified and the equivalent length of the section is calculated. The calculations are summarized in Table 5.

Table 5 – Hydraulic calculation of water heating network

The heating network pipelines in the diagram are shown in two parallel lines and are designated T1 and T2. The supply pipeline T1 is necessarily located to the right along the coolant flow from the source. All branch points are fixed with fixed supports and are designated UT - pipeline units. Shut-off valves are installed on the branches of the heating network - steel valves, for the maintenance of which thermal chambers are provided [Appendix 16 of this manual].

Transcript

1 . dio.naro d.ru Software module: Hydraulic calculation heating networks (Version 5.) Algorithm software module made on the basis existing methodology(SNiP): Specific pressure loss: R 6.7 0 3 λ G Dр5 in m.w.g./m G - coolant (water) flow rate: G Q g, t/h; 000 Q thermal energy consumption, Gcal/h; g - coolant flow per Gcal: g, t/Gcal T Dр calculated internal diameter of the pipeline; in the density of water (accepted 958 kg/m3); ΔT is the temperature difference between the coolant in the supply and return pipelines. coefficient of hydraulic friction; 0.5 K 68 λ 0, e Hydraulic friction coefficient: Dр Re К e equivalent pipe roughness (assumed 0.5 mm); Re - Reynolds number. V Dp Reynolds number: Re V coolant velocity in the pipeline/s, Coolant velocity: V 0.354 G/s Pressure loss in one pipe: H R L ex. Dp in 000 L ex. reduced section length: L approx L K approx K approx . reduction coefficient (approximately takes into account local resistance, Kpr. = 4.9). Iteration boundary conditions: R Rma ; V Vma; Hcon. Hmin Hcon. available head at the end of the section..

2 Software module: Calculation of the extension of a bellows compensator (Version 5.) The algorithm of the software module is based on the existing methodology (IYANSH TU): The maximum distance between the fixed supports of a heating network section with axial bellows compensators is determined by the formula: nλ Lma 0.9 α Tma Tmon .min n number of blocks in the compensator (n=,); λ amplitude (±) of the axial stroke of one compensator block; α coefficient of linear expansion of the material (for St0 α=, 0-5 C -); Tma maximum working temperature pipeline, C; Tmon.min minimum pipeline temperature when installing the compensator (accepted -8C); 0.9 safety factor (0% safety margin). The amount of stretch of the bellows compensator before installation is determined by the formula: Δ L α L Tma Tmon.min Tmon. T maximum operating temperature of the pipeline, C; ma T mon. pipeline temperature when installing the compensator (varies from 8 to 30C); L section length (L<=L ma). 5 силф. Усилие от одного трубопровода на неподвижную опору: F P 0 c P ma максимальное давление в трубопроводе, атм.; λ амплитуда (±) осевого хода одного блока (одного сильфона)м; с жёсткость одного блока (одного сильфона), Н/мм. Усилие от одного трубопровода на противоположную неподвижную опору: F тр. суммарная сила трения в подвижных опорах, кг. Fтр. μ P z, кг ma эф. λ, кг 0 силф. эф. эффективная площадь сильфона; F F Fтр., кг коэффициент трения в подвижных опорах (принят 0,3); P z вес трубопровода длиной L.

3 Software module: Calculation of the starting compensator settings (Version 9.) The algorithm of the software module is based on the existing methodology (SP): The maximum distance between the fixed supports (real or imaginary) of the heating network section with starting compensators (ductless installation) is determined by the formula: σadd . Art.tr. Lma 0.8 σ add. maximum permissible stress in the pipe (σ permissible =50 N/mm); Art.tr. cross-sectional area of the pipe wall; f tr. specific friction force of the pipe shell on the ground, N/m. f tr. μ 0.5 sin ρ Z П D q, N/m rev. coefficient of friction of the shell on the ground (adopted 0.4); φ angle of natural repose of the soil (adopted 30); ρ soil density, N/m 3 ; Z depth of the pipeline (distance from the surface of the earth to the axis of the pipeline); P number Pi (3,); D vol. outer diameter of the pipeline shell; q specific gravity of the pipeline, N/m. The amount of compression of the compensator with increasing pipeline temperature: L Δ L α L Tpr. Tmon. 4Est.tr. α coefficient of linear expansion of the material (for St0 α=, 0-5 C -); T ave. warm-up temperature (T ave. Const 70 C); T pipe temperature during installation (varies from 0 to 5C); L section length (L<=L ma); мон. E модуль упругости материала (для стали 0 E= 0 5 Н/мм). Δ ma T мон. Формула приближённого метода: L α L T Величина сжатия компенсатора перед установкой на трубопровод: P λ L

4 Software module: Layout of mats (“L” shaped compensator) (Version 5.) The algorithm of the software module is based on the existing methodology (SP): The maximum distance between a fixed support (real or imaginary) and the “L” shaped compensator for ductless installation of a heating network , is determined by the formula: add. Art.tr. Lma σ σ add. maximum permissible stress in the pipe (for steel 0 σ permissible =50 N/mm); Art.tr. cross-sectional area of the pipe wall; f tr. specific friction force of the pipe shell on the ground, N/m. 0.5 sin ρ Z П Dob. μ q, N/m coefficient of friction of the shell on the ground (adopted 0.4); φ angle of natural repose of the soil (adopted 30); ρ soil density, N/m 3 ; Z depth of the pipeline (distance from the surface of the earth to the axis of the pipeline); P number Pi (3,); D vol. outer diameter of the pipeline shell; q specific gravity of the pipeline, N/m. The magnitude of the thermal expansion of the pipeline during channelless installation: L Δ L α L Tma Tmon.min E st.p. α coefficient of linear expansion of the material (for steel 0 α=, 0-5 C -); L section length (L<=L ma); T ma максимальная рабочая температура трубы (принимается по Т=30С); T мон.min минимальная температура трубы при монтаже (принята 0С); E модуль упругости материала (для стали 0 E= 0 5 Н/мм).

5 . dio.naro d.ru Software module:. Calculation of support parameters (overground laying) (Version 8.) Standard version Option on a support pad (without recess) Vertical arrangement of pipes Calculation option as a fixed support The software module algorithm is based on the existing methodology:. Calculation of the rack Required moment of resistance of the rack: Wtotal. 00 M 0.9 σ additional, cm3 M total moment acting on the support column, kgm; σ add. maximum permissible stress in the cross section of the support column structure, kg/cm; Total moment: M Fhor. H, kgm Fhor. total horizontal force acting at height H; H stand height. For movable support: Fhor. μ Pz, kg coefficient of friction in the movable support; Pz vertical load on the support. Pz n L q, kg; n number of pipes on the support; L is the length of the pipeline between the supports; q specific gravity of the pipeline, kg/m. Calculation of support parameters (overground laying) Sheet of Sheets

6. Calculation of the dimensions of the foundation of the support for soil compression Condition for the stability of the support: σgr. σ calculated, kg/cm σ gr. permissible stress in the soil (soil resistance), kg/cm; σ calc. stress in the soil created by the support foundation: P M M y σ calc. Σ, kg/cm W W Σ P total weight load (along the Z axis): ΣP P z H 0 ρbet., kg area of the support sole: a b ; a and b - dimensions of the support foundation; H height of the support foundation; 0 ρ bet. concrete density, kg/m3; M moment acting on the support in the XZ plane, kgm; M y moment acting on the support in the YZ plane, kgm; W moment of resistance of the support sole in the XZ 3 plane; W y moment of resistance of the support sole in the YZ plane 3. (axial loads along the X axis, lateral along the Y axis, vertical along the Z axis) W M ab ba 3 Wy 6 6 F H H M F H H y 3, kgm; 0 y y 0, kgm F force on the support acting at height H along the X axis, kg; F y force on the support acting at height H along the Y axis, kg; H stand height; H 0 - height of the support foundation. 3. Check calculation of the dimensions of the foundation of the support for overturning Stability condition: M M and y My M, kgm M moment from the total weight load acting in the XZ plane, kgm; y M moment from the total weight load acting in the YZ plane, kgm. M Σ P a, kgm M y Σ P b, kgm Σ P total weight load (along the Z axis); a and b dimensions of the support foundation. Calculation of support parameters (overground laying) Sheet of Sheets

7 Software module: Calculation of the diameter of the working reinforcement of a panel support (Version 6.) The algorithm of the software module is based on the existing methodology: arm. 4 Design diameter of working fittings: d m Π arm. cross-sectional area of one rod; P is the number Pi (3,). Cross-sectional area of one rod: arm. Arm. total m arm. total the total required cross-sectional area of all working rods; n number of working rods. Arm. Mma 00 total m σ add. δ M ma maximum moment acting on the support shield, kgm; σ add. maximum permissible stress in the working rod, kg/cm; δ δ 0, shield δ shield thickness. shield n

8 Software module: Calculation of the diameter of the drainage device (Version 8.) The algorithm of the software module is based on the existing methodology (SNiP): The diameter of the fitting for draining water from a sectioned section of the pipeline, which has a slope in one direction, is determined by the formula: L d dpr. m n 4 ipr. d ex. reduced diameter i app. reduced slope j d jl j k dpr. L j i jl j k ipr. L k number of sections; n coefficient depending on the descent time; m valve consumption coefficient (for valves m=0.0). The diameter of the fitting of the drainage device serving two branches (right and left) is determined by the formula: d total. ave. lion d d d approx. diameter of the fitting for the right branch; d lion diameter of the fitting for the left branch.

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Page 1

Hydraulic calculation is the most important element in the design of heating networks.

The task of hydraulic calculation includes:

1. Determination of pipeline diameters,

2. Determination of pressure drop in the network,

3. Establishment of pressure values at various points in the network,

4. Linking pressures at various points of the system in static and dynamic modes of its operation,

5. Establishment of the necessary characteristics of circulation, booster and make-up pumps, their quantity and placement.

6. Determination of methods for connecting subscriber inputs to the heating network.

7. Selection of automatic control circuits and devices.

8. Identification of rational operating modes.

Hydraulic calculations are carried out in the following order:

1) in the graphic part of the project, draw a general plan of the city area on a scale of 1:10000, in accordance with the assignment, indicate the location of the heat source (IT);

2) show a diagram of the heating network from IT to each microdistrict;

3) for the hydraulic calculation of the heating network along the pipeline route, the main design line is selected, as a rule, from the heat source to the most remote heating unit;

4) on the design diagram indicate the numbers of sections, their lengths determined according to the general plan taking into account the accepted scale, and the estimated water consumption;

5) based on the coolant flow rate and, focusing on the specific pressure loss of up to 80 Pa/m, the diameters of pipelines in sections of the main line are assigned;

6) using the tables, determine the specific pressure loss and coolant velocity (preliminary hydraulic calculation);

7) calculate the branches based on the available pressure difference; in this case, the specific pressure loss should not exceed 300 Pa/m, the coolant speed should not exceed 3.5 m/s;

8) draw a pipeline diagram, arrange shut-off valves, fixed supports, compensators and other equipment; the distances between fixed supports for sections of different diameters are determined based on the data in Table 2;

9) based on local resistances, determine equivalent lengths for each section and calculate the reduced length using the formula:

10) calculate the pressure loss in sections from the expression

Where α is a coefficient that takes into account the share of pressure losses due to local resistances;

∆ptr – pressure drop due to friction in a section of the heating network.

The final hydraulic calculation differs from the preliminary one in that the pressure drop across local resistances is taken into account more accurately, i.e. after placing compensators and shut-off valves. Stuffing box expansion joints are used for d ≤ 250 mm; for smaller diameters, U-shaped expansion joints are used.

Hydraulic calculations are performed for the supply pipeline; The diameter of the return pipeline and the pressure drop in it are taken to be the same as in the supply pipeline (clause 8.5).

According to paragraph 8.6, the smallest internal diameter of pipes should be at least 32 mm in heating networks, and at least 25 mm for hot water circulation pipelines.

Preliminary hydraulic calculations begin with the last section from the heat source and are summarized in Table 1.

Table 6 – Preliminary hydraulic calculation

Plot no.	lpr=lx (1+α), m	∆Р=Rхlр, Pa
HIGHWAY









DESIGN BRANCH





		∑∆Rotv =

When hydraulically calculating heating networks, the total flow rate of main hot water for heating, air conditioning, ventilation and domestic hot water is determined. Based on this calculation, the necessary parameters of pumping equipment, heat exchangers and pipe diameters of the main network are determined.

A little about theory and tasks

The main task of the hydraulic calculation of heating networks is the selection of geometric parameters of the pipe and standard sizes of control elements to ensure:

qualitative and quantitative distribution of coolant to individual heating devices;
thermal-hydraulic reliability and economic feasibility of a closed thermal system;
optimization of investment and operating costs of the heat supply organization.

Hydraulic calculation creates the prerequisites for heating and hot water devices to achieve the required power at a given temperature difference. For example, with a T-graph of 150-70 o C, it will be equal to 80 o C. This is achieved by creating the required water pressure or coolant pressure at each heating point.

This mandatory condition for the operation of a heating system is implemented through proper configuration of network equipment in accordance with design conditions, installation of equipment based on the results of hydraulic calculations of heating networks.

Network hydraulic stages:

Pre-launch calculation.
Operational regulation.

The initial hydraulics of the network is performed:

using calculations;
measuring method.

In the Russian Federation, the calculation method is predominant; it determines all the parameters of the elements of the heat supply system in a single design area (house, block, city). Without this, the network will be misregulated, and the coolant will not be supplied to the upper floors of multi-story buildings. That is why the beginning of the construction of any heating supply facility, even the smallest one, begins with a hydraulic calculation of heating networks.

Drawing up a diagram of heating networks

Before hydraulic calculations, a preliminary pipeline diagram is performed indicating the length L in meters and D of utility water pipelines in mm and the estimated volumes of network water for the design sections of the diagram. Pressure losses in heat supply systems are divided into linear, which arise due to the carrier rubbing against the pipe walls, and losses in areas caused by local structural resistance due to the presence of tees, bends, compensators, turns and other devices.

Calculation example: hydraulic calculation of heating networks:

First, a larger calculation is performed in order to determine the maximum network indicators that can fully provide residents with heating services.
Upon completion, qualitative and quantitative indicators of the main and intra-block networks are established, including the final pressure and temperature of the medium at the input nodes of heat consumers, taking into account heat losses.
Perform a test hydraulic calculation of the heating and hot water supply network.
They establish the actual costs in sections of the circuit and at the inputs to residential buildings, the amount of heat received by subscribers when calculating the temperature of the coolant in the supply water pipe of heating systems and the available pressure in the outlet manifold, justification for hydrothermal regimes, and the predicted temperature inside residential premises.
Determine the required heat supply temperature at the outlet.
Set the maximum size T of heated water at the outlet of a boiler room or other heat source, obtained on the basis of a hydraulic calculation of the heating network. It must ensure sanitary standards indoors.

Applications of the normative method

Hydraulics of networks is carried out on the basis of tables of maximum hourly heat loads and a heat supply diagram for a city or region, indicating the sources, location of the main, intra-block and intra-house engineering systems, indicating the boundaries of the balance sheet ownership of the network owners. Hydraulic calculation of heating network pipelines for each section up to the above diagram is carried out separately.

This calculation method is used not only for heating networks, but also for all pipelines transporting liquid media, including gas condensate and other chemical liquid media. For pipeline heat supply systems, changes must be made taking into account the kinematic viscosity and density of the media. This is due to the fact that these characteristics influence the specific pressure loss in the pipes, and the flow rate is related to the density of the transit medium.

Parameters of hydraulic calculation of water heating network

Heat consumption Q and the amount of coolant G for areas are indicated in the table of maximum hourly heat consumption indicators for the winter and summer seasons separately and corresponds to the amount of heat consumption for the quarters included in the scheme.

An example of a hydraulic calculation of a heating network is presented below.

Since calculations depend on many indicators, they are performed using numerous tables, diagrams, graphs, nomograms, the final value of heat consumption Q for intra-house heating systems is obtained by interpolation.

The amount of liquid circulating in the heating network m 3 / hour, when calculating the hydraulic mode of the heating network, is determined by the formula:

G = (D2 / 4) x V,

G - carrier consumption, m 3 /hour;
D - pipeline diameter, mm;
V - flow velocity, m/s.

Linear pressure drops in the hydraulic calculation of heating networks are taken from special tables. When installing heating systems, dozens and hundreds of auxiliary elements are installed in them: valves, fittings, vents, bends and others that create resistance to the transit environment.

The reasons for the drop in pressure in pipelines also include the internal state of the pipe materials and the presence of salt deposits on them. The coefficient values used in technical calculations are given in the tables.

Standard Methodology and Process Steps

According to the method of hydraulic calculation of heating networks, it is carried out in two stages:

Construction of a diagram of heating networks on which sections are numbered, first in the area of the central main line - a longer and more voluminous network line in terms of load from the connection point to a more distant consumption facility.
Calculation of pressure losses of each pipe section, diagrams. It is carried out using tables and nomograms, which are indicated by the requirements of state norms and standards.

The first to carry out calculations for the main highway is the costs established according to the scheme. In this case, reference data on specific pressure losses in networks are used.

The number of compensators according to the scheme.
Resistances on actually installed heating network elements.

Pressure losses are calculated using formulas and nomograms. Then, having this data for the entire network, they calculate the hydromechanical regime of individual sections from the point of flow splitting up to the end subscriber.

Calculations are linked to the choice of branch pipe diameters. Inconsistency no more than 10%. Excess pressure in the heating network is extinguished at elevator units, throttle nozzles or automatic regulators at in-house control points.

Given the available pressure of the main heating network and branches, first set the approximate resistivity Rm, Pa/m.

The calculations use tables, nomograms for heating networks and other reference literature, which is mandatory for all stages; it is easy to find on the Internet and in specialized literature.

The algorithm for the calculation scheme is established by regulatory and technical documentation, state and sanitary standards and is carried out in strict accordance with the established procedure.

The article provides an example of a hydraulic calculation of a heating network. The procedure is performed in the following sequence:

On the approved city and district, nodal points of calculation, heat source, routing of engineering systems are marked, indicating all branches and connected consumer facilities.
The boundaries of the balance sheet affiliation of consumer networks are clarified.
Assign numbers to the site according to the scheme, starting numbering from the source to the final consumer.

The numbering system should clearly separate the types of networks: intra-block main lines, inter-house ones from the thermal well to the boundaries of the balance sheet, while the section is established as a section of the network, enclosed by two branches.

The diagram shows all the parameters of the hydraulic calculation of the main heating network from the central heating substation:

Q - GJ/hour;
G m 3 /hour;
D - mm;
V - m/s;
L is the length of the section, m.

This heating network is designed for a heat supply system using coolant in the form of steam.

The differences between this scheme and the previous one are caused by temperature indicators and environmental pressure. Structurally, these networks are characterized by a shorter length; in large cities they usually include only main lines, i.e. from the source to the central heating point. They are not used as intra-district and intra-house networks, except at small industrial sites.

The schematic diagram is carried out in the same order as with water coolant. At the sections, all network parameters are indicated for each branch; data is taken from a summary table of maximum hourly heat consumption, with step-by-step summation of consumption indicators from the end consumer to the source.

The geometric dimensions of pipelines are established based on the results of hydraulic calculations, which are performed in accordance with state norms and regulations, and in particular SNiP. The determining value is the pressure loss of the gas-condensate medium from the heat supply source to the consumer. With a greater pressure loss and a smaller distance between them, the speed of movement will be high, and a smaller diameter of the steam line will be required. The diameter is selected according to special tables, based on the parameters of the coolant. The data is then entered into pivot tables.

Coolant for condensate network

The calculation for such a heating network differs significantly from the previous ones, since condensate simultaneously exists in two states - in steam and in water. This ratio changes as it moves towards the consumer, i.e. the steam becomes more and more wet and eventually turns completely into a liquid. Therefore, calculations for pipes for each of these media are different and are taken into account by other standards, in particular SNiP 2.04.02-84.

The procedure for calculating condensate pipelines:

The internal equivalent roughness of pipes is determined from the tables.
Indicators of pressure loss in pipes in the network section, from the coolant outlet from the heating pumps to the consumer, are taken according to SNiP 2.04.02-84.
The calculation of these networks does not take into account the heat consumption Q, but only the steam consumption.

The design features of this type of network significantly affect the quality of measurements, since the pipelines for this type of coolant are made of black steel; sections of the network after the network pumps, due to air leaks, quickly corrode from excess oxygen, after which low-quality condensate with iron oxides is formed, which causes metal corrosion. Therefore, it is recommended to install stainless steel pipelines in this area. Although the final choice will be made after completion of the feasibility study of the heating network.

Energy losses due to valves, fittings and bends are caused by localized flow disturbances. Energy loss occurs along a finite and not necessarily short section of the pipeline, however, for hydraulic calculations it is generally accepted that the entire volume of this loss is taken into account at the location of the device. For piping systems with relatively long pipes, it is often the case that the resulting losses will be negligible in relation to the total pressure loss in the pipe.

Pipeline losses are measured using actual experimental data and then analyzed to determine a local loss factor that can be used to calculate fitting losses as it varies with the rate of fluid flow through the device.

Pipe Flow Software products make it easy to determine fitting losses and other losses in pressure drop calculations because they come pre-loaded with a valve database that contains many standard factors for various sized valves and fittings. Within a piping system, a pump is often used to add additional pressure to overcome losses due to friction and other resistance.

The pump performance is determined by the curve. The head produced by the pump varies depending on the flow rate, finding the operating point on the pump performance curve is not always an easy task.

Using the Pipe Flow Expert hydraulic design software, it is quite easy to find the exact operating point on the pump curve, ensuring that flows and pressures are balanced throughout the system, to make accurate piping design decisions.

Online calculations are made in order to select the optimal diameter that provides the best operating parameters, low pressure losses and high speeds of fluid movement, which will ensure good technical and economic indicators of heating networks as a whole.

It minimizes effort and provides higher accuracy. It includes all the necessary reference tables and nomograms. Thus, losses per meter of pipes are assumed to be 81 - 251 Pa/m (8.1 - 25.1 mm water column), which depends on the material of the pipes. The water speed in the system depends on the diameter of the installed pipes and is selected in a specific range. The highest water speed for heating networks is 1.5 m/s. The calculation suggests boundary values of water speed in pipelines with an internal diameter:

15.0 mm - 0.3 m/s;
20.0 mm - 0.65 m/s;
25.0 mm - 0.8 m/s;
32.0 mm - 1.0 m/s.
For other diameters no more than 1.5 m/s.
For pipelines of fire protection systems, medium speeds of up to 5.0 m/s are allowed.

GIS Zulu is a geoinformation program for hydraulic calculation of heating networks. The company specializes in research into GIS applications that require visualization of 3D geodata in vectorial and raster versions, topological study and their relationship with semantic databases. Zulu allows you to create different plans and working diagrams, including heat and steam networks using topology, can work with rasters and acquire data from different databases, such as BDE or ADO.

The calculations are carried out in close integration with the geographic information system; they are implemented in an extended module version. The network is easily and quickly entered into the GIS using the mouse or using these coordinates. After which a calculation scheme is immediately created. Afterwards, the circuit parameters are set and the start of the process is confirmed. Calculations are used for dead-end and ring heating networks, including network pumping units and throttling devices, powered from one or many sources. Heating calculations can be performed taking into account leaks from distribution networks and heat losses in heating pipes.

In order to install a special program on a PC, download “Hydraulic calculation of heating networks 3.5.2” on the Internet via torrent.

Structure of definition stages:

Definition of commutation.
Verification hydromechanical calculation of the heating network.
Adjustment thermal-hydraulic calculation of main and intra-quarter pipes.
Design choice of heating network equipment.
Calculation of the piezometric graph.

Microsoft Excel for hydraulic calculations in heating networks is the most accessible tool for users. Its comprehensive spreadsheet editor can solve many computing problems. However, when performing calculations of thermal systems, special requirements must be met. These can be listed:

finding the previous section in the direction of movement of the medium;
calculation of the pipe diameter based on a given conditional indicator and reverse calculation;
establishing a correction factor for the size of the specific pressure loss based on the data and the equivalent roughness of the pipe material;
calculating the density of a medium from its temperature.

Of course, the use of Microsoft Excel for hydraulic calculations in heating networks does not make it possible to completely simplify the calculation process, which initially creates relatively large labor costs.

Software for hydromechanical calculations of networks or the GRTS package is a computer application that performs hydromechanical calculations of multi-pipe networks, including a dead-end configuration. The GRTS platform contains formula language functionality that allows you to establish the necessary calculation characteristics and select formulas for the accuracy of their determination. Due to the use of this functionality, the calculator has the opportunity to independently find the computing technology and set the required complexity.

There are two modifications of the GRTS application: 1.0 and 1.1. Upon completion, the user will receive the following results:

calculation, in which the calculation methodology is carefully described;
report in tabular form;
transfer of computational databases to Microsoft Excel;
piezometric graph;
coolant temperature graph.

The GRTS 1.1 application is considered the most modern modification and supports the latest standards:

Calculation of pipe diameters based on given pressures at the end points of the thermal diagram.
The help platform has been modernized. Team "?" Opens the help area of the application on the monitor screen.

Hydraulic calculation of heating networks

An example of the calculation is presented below.

The minimum basic parameters required to design a piping system include:

Characteristics and physical properties of liquid.
The required mass flow (or volume) of the transit medium to be transported.
Pressure, temperature at the starting point.
Pressure, temperature and altitude at the end point.
Distance between two points and equivalent length (pressure loss) installed by valves and fittings.

These basic parameters are necessary for the design of a piping system. Assuming steady flow, there are a number of equations based on the general energy equation that can be used to design a piping system.

Variables associated with liquid, steam or two-phase condensate flow affect the calculation result. This leads to the derivation and development of equations applicable to a particular fluid. Although piping systems and their design can become complex, the vast majority of design problems faced by an engineer can be solved by standard Bernoulli flow equations.

The basic equation developed to represent steady fluid flow is Bernoulli's equation, which assumes that total mechanical energy is conserved for steady, incompressible, inviscid isothermal flow without heat transfer. These constraint conditions may indeed be representative of many physical systems.

The head losses associated with valves and fittings can also be calculated by taking into account the equivalent "lengths" of pipe sections for each valve and fitting. In other words, the calculated head loss caused by the fluid passing through the valve is expressed as an additional pipe length that is added to the actual pipe length when calculating the pressure drop.

All equivalent lengths caused by valves and fittings in the pipe segment will be added together to calculate the pressure drop for the design pipe segment.

To summarize, we can say that the goal of the hydraulic calculation of the heating network at the end point is the fair distribution of thermal loads between subscribers of thermal systems. A simple principle applies here: each radiator - as needed, that is, a larger radiator, which is designed to provide a larger volume of heating to the room, should receive a larger coolant flow. This principle can be ensured by correctly performed network calculations.

Water heating systems are complex hydraulic systems in which the operation of individual parts is interdependent. One of the important conditions for the operation of such systems is the provision in the heating network in front of central or local heating points of available pressures sufficient to supply water flows to subscriber installations corresponding to their thermal load.

Hydraulic calculation is one of the important sections of the design and operation of a heating network. When designing a heating network, the hydraulic calculation includes the following tasks: determining the diameters of pipelines, determining the pressure drop, determining the pressures at various points in the network, linking the entire system under various operating modes of the network. The results of the hydraulic calculation provide the following initial data:

1) To determine capital investments, pipe metal consumption and the main volume of work for the construction of a heating network;

2) Establishing the characteristics of circulation and make-up pumps, the number of pumps and their placement;

3) Clarification of the operating conditions of heat sources, heat networks and subscriber systems for selecting schemes for connecting heat-consuming installations to the heat network;

5) Development of operating modes for heat supply systems.

The initial data for the calculation are usually given: the heating network diagram, the parameters of the coolant at the entrance to the calculated section, the coolant flow rate and the length of the network sections. Since a number of quantities are unknown at the beginning of the calculation, the problem has to be solved by the method of successive approximations in two stages: approximate and verification calculations.

Advance paynemt

1. The available pressure loss in the network is determined based on the provision of the required static pressure at the subscriber input. The type of piezometric graph is determined.

2. The most distant point of the heating network (calculation main) is selected.

3. The main is divided into sections according to the principle of constant coolant flow and pipeline diameter. In some cases, within a section with equal flow, the diameter of the pipeline changes. The area contains the sum of local resistances.

4. The preliminary pressure drop in this area is calculated, which is also the maximum possible pressure drop in the area under consideration.

5. The share of local losses of this section and the specific linear pressure drop are determined. The share of local losses is the ratio of the pressure drop in local resistances to the linear pressure drop of straight sections.

6. The diameter of the pipeline of the calculated section is preliminarily determined.

Verification calculation

1. The pre-calculated pipe diameter is rounded to the nearest standard pipe size.

2. The linear pressure drop is specified and the equivalent length of local resistances is calculated. The equivalent length of local resistances is a straight pipeline whose linear pressure drop is equal to the pressure drop in the local resistances.

3. The true pressure drop in the section is calculated, which is the total resistance of this section.

4. The pressure loss and available pressure at the end point of the section between the supply and return lines are determined.

All sections of the heating network are calculated using this method and are linked to each other .

To carry out a hydraulic calculation, the diagram and profile of the heating network are usually specified, and then the most distant point is selected, which is characterized by the smallest specific drop of the main line. Estimated temperature of network water in the supply and return lines of the heating network: t1=150 °C, t2=70 °C. The design diagram of the heating network is shown in Fig. 5.1.

Available pressure at the entry point of m. water. Art. Available pressure at all subscriber inputs m. water. Art. Average specific gravity of water γ = 9496 N/m 2, length of the design main line, L(0-11) = 820 m.

We determine the water consumption in the areas in accordance with the calculation scheme and summarize the results in the table. 5.1.

Table 5.1.

Water consumption by area

Plot number	1-2	2-3	3-4	4-5	5-6	6-7	7-8	8-9	9-10
G,t/h	65,545	60,28	47,1175	31,3225	26,6425	18,745	9,6775	6,1675	3,8275
Plot number	10-11	1-1.1	2-2.1	3-3.1	3.1-3.2	3.1-3.3	3.3-3.4	3.3-3.5	3.5-3.6
G,t/h	1,755	0,585	0,585	9,945	0,585	8,19	0,585	5,5575	3,51
Plot number	3.5-3.7	4-4.1	5-5.1	6-6.1	7-7.1	8-8.1	9-9.1	10-10.1	11-1.1
G,t/h	1,17	0,585	0,8775	0,585	0,8775	0,8775	0,8775	2,6325	0,8775

Advance paynemt

Available head loss m. water. Art. We distribute this pressure loss equally between the supply and return lines of the heating network, since the heating network is made in two pipes, the pipes have the same profile . water Art.

Pressure drop in section 1-2, Pa:

δP1-2 = δH*ƴ*L1-2/L1-27=4748

∑Ƹ=∑Ƹrear+∑Ƹ90ᵒ+∑Ƹcomp=2.36

Determining the share of local resistances

0,20

where is the coefficient for the equivalent roughness ..

We preliminarily calculate the specific linear pressure drop, Pa/m and the diameter of section 1-2, m:

where is the coefficient of equivalent roughness for steel pipes, .

Verification calculation

We select the nearest standard internal diameter, mm according to GOST 8731-87 "Steel pipes".

Dв.1-2 = 0.261 mm.

We determine the specific linear pressure drop, Pa/m:

11.40Pa/m,

where is the coefficient for the equivalent roughness, .

We calculate the equivalent length of local resistances, m of the pipeline section in section 1-2

28.68m,

where is a coefficient depending on the absolute equivalent roughness.

Pressure loss in the pipeline section 0-1, Pa:

Pressure loss in pipeline section 0-1, m.water column:

0.13m.

Since the pressure loss in the supply and return lines of the heating network is the same, the available pressure at point 1 can be calculated using the formula:

For other sections of the highway under consideration, calculations are carried out similarly, their results are presented in table. 5.2.

Table 5.2

Hydraulic calculation of the heating pipeline


Preliminary	Verification
№	L,m	δP,Pa	Σξ	A	Rl, Pa/m	d, m	d", m	R", Pa/m	Le, m	δP",Pa	δH", m	ΔH", m
0-1			1,34	0,46	40,69	0,29	0,313	9,40	17,05	348,14	0,04	29,93
1-2			2,36	0,20	49,38	0,28	0,261	11,40	28,68	1238,73	0,13	29,74
2-3		3264,25	1,935	0,24	47,83	0,28	0,261	11,04	23,69	868,90	0,09	29,82
3-4		3857,75	2,105	0,22	48,58	0,28	0,261	11,21	25,68	1016,91	0,11	29,79
4-5		10979,75	4,145	0,15	51,46	0,27	0,261	11,88	49,87	2789,63	0,29	29,41
5-6		3857,75	2,105	0,22	48,58	0,28	0,261	11,21	25,68	1016,91	0,11	29,79
6-7		7418,75	3,125	0,17	50,68	0,27	0,261	11,70	37,74	1903,62	0,20	29,60
7-8			3,38	0,17	50,93	0,27	0,261	11,76	40,77	2125,15	0,22	29,55
8-9		2670,75	1,765	0,27	46,79	0,28	0,261	10,80	21,72	720,73	0,08	29,85
9-10		1483,75	1,425	0,39	42,69	0,28	0,313	9,86	17,92	423,17	0,04	29,91
10-11		890,25	1,255	0,57	37,74	0,29	0,313	8,72	16,25	272,45	0,03	29,94

The branch is calculated as transit sections with a given pressure (pressure) drop. When calculating complex branches, first determine the calculated direction as the direction with the minimum specific pressure drop, and then carry out all other operations.

Hydraulic calculation of the heating pipeline branch is shown in table. 5.3.

Table 5.3

Results of hydraulic calculation of branches


№	L,m	δP,Pa	Σξ	A	Rl, Pa/m	d, m	d", m	R", Pa/m	Le, m	δP",Pa	δH", m	ΔH", m
3-3.1			1,34	0,458607	25,36	0,31	0,313	5,86	19,07	229,1455	0,02	29,95
3.1-3.2		593,5	1,17	0,80085	27,35	0,31	0,313	6,32	16,36	166,6545	0,02	29,96
3.1-3.3		2077,25	1,595	1,224859	22,87	0,32	0,313	5,29	23,27	308,2111	0,03	29,94
3.3-3.4		593,5	1,17	0,80085	27,35	0,31	0,313	6,32	16,36	166,6545	0,02	29,96
3.3-3.5		890,25	1,255	0,572688	26,32	0,31	0,313	6,08	17,71	199,023	0,02	29,96
3.5-3.6			2,02	0,230444	19,65	0,33	0,313	4,55	30,55	411,7142	0,04	29,91
3.5-3.7			1,34	0,458607	25,36	0,31	0,313	5,86	19,07	229,1455	0,02	29,95
4-4.1		593,5	1,17	0,80085	27,35	0,31	0,313	6,32	16,36	166,6545	0,02	29,96
5-5.1		890,25	1,255	0,572688	26,32	0,31	0,313	6,08	17,71	199,023	0,02	29,96
6-6.1		593,5	1,17	0,80085	27,35	0,31	0,313	6,32	16,36	166,6545	0,02	29,96
7-7.1		890,25	1,255	0,572688	26,32	0,31	0,313	6,08	17,71	199,023	0,02	29,96
8-8.1		890,25	1,255	0,572688	26,32	0,31	0,313	6,08	17,71	199,023	0,02	29,96
9-9.1		890,25	1,255	0,572688	26,32	0,31	0,313	6,08	17,71	199,023	0,02	29,96
10-10.1		2670,75	1,765	0,268471	21,46	0,32	0,313	4,97	26,14	353,213	0,04	29,93
11-11.1		890,25	1,255	0,572688	26,32	0,31	0,313	6,08	17,71	199,023	0,02	29,96

The piezometric graph is shown in Fig. 5.2.

6.Calculation of insulation thickness

Average annual coolant temperature t 1 =100, t 2 =56.9

Let's define internal d w.e. and external d AD equivalent channel diameters according to the internal (0.9×0.6 m) and external (1.15×0.78 m) dimensions of its cross section:

Let us determine the thermal resistance of the inner surface of the channel

Let us determine the thermal resistance of the channel wall Rк, taking the thermal conductivity coefficient of reinforced concrete λst = 2.04 W/(m deg):

Let us determine, at a pipe axis depth of h = 1.3 m and soil thermal conductivity λgr = 2.0 W/(m deg), the thermal resistance of the soil

Taking the surface temperature of the thermal insulation to be 40 °C, we determine the average temperatures of the thermal insulation layers of the supply t t.p and return t t.o pipelines:

Let us also define using adj. , coefficients

thermal conductivity of thermal insulation (Thermal insulation products

made of polyurethane foam) for the feeder λ k1 and reverse λ k2 pipelines:

λ To 1 = 0,033 + 0,00018 t t.p = 0.033 + 0.00018 ⋅ 70 = 0.0456 W/(m⋅°C);

λ k2 = 0.033 + 0.00018 t t.o = 0.033 + 0.00018 ⋅ 48.45 = 0.042 W/(m⋅ °C).

Let us determine the thermal resistance of the surface of the heat-insulating layer:

Let's take it by adj. normalized linear heat flux densities for supply ql1 = 45 W/m and return ql2 = 18 W/m pipelines. Let us determine the total thermal resistances for the supply Rtot1 and return Rtot2 pipelines at K1 = 0.9:

Let us determine the coefficients of mutual influence of the temperature fields of the supply ϕ1 and return ϕ2 pipelines:

Let us determine the required thermal resistances of the layers for the supply Rk.p and return Rk.o pipelines, m ⋅°C/W:

R k.p = R tot1 − R p.c − (1+ϕ 1)( R p.k + R k + R gr)=

2.37− 0.1433− (1+ 0.4)(0.055 + 0.02+ 0.138) =1.929 m⋅ °C /W;

R k.o = R tot2 − R p.c − (1+ϕ 1)( R p.k + R k + R gr)=

3.27− 0.1433− (1+ 2.5)(0.055 + 0.02 + 0.138) = 2.381 m ⋅ °C /W.

Let us determine the values of B for the supply and return pipelines:

Let us determine the required thicknesses of thermal insulation layers for the supply δk1 and return δk2 pipelines:

We accept the thickness of the main insulation layer for supply mm, return pipelines mm.

Compensator calculation

Compensators are designed to compensate for thermal expansion and deformation to prevent pipeline destruction. Compensators are located between fixed supports.

Calculation of compensator for the 3rd section.

Taking the coefficient of thermal elongation α=1.25 10⋅ − 2 mm/(m ⋅°С), using the data in table. 14.2 adj. 14, we determine the maximum length of the section over which one bellows compensator can provide compensation:

Here λ is the amplitude of the axial stroke, mm, λ = 60mm

Required number of compensators n in the calculated area will be

Let us assume equal spans between fixed supports

83/2= L f = 41.5m.

Let us determine the actual amplitude of the compensator λ f with the span length between fixed supports L f = 41.5 m .

R s. k, taking equal spans between fixed supports L= 41.5 m:

R c.k = R f + R r,

Where R– axial reaction arising due to the rigidity of the axial stroke is determined by formula (1.85)

R = WITH λ λ f = 278 36.31 =10094.2 N

Where WITHλ – wave stiffness, N/mm, ( WITH λ = 278 N/mm);

R p– axial reaction from internal pressure, N, defined

Let's determine the response of the compensator R s. To

R c.k = R f + R r = 10094.2+ 17708 = 27802.2 N.

In the heat supply system, the heating point connecting the heating network with the heat consumer occupies an important place. By means of a heat point (TS), local consumption systems (heating, hot water supply, ventilation) are controlled; it also transforms the parameters of the coolant (temperature, pressure, maintaining a constant flow rate, heat metering, etc.). At the same time, at the heating point the network itself is controlled, since it distributes the coolant in relation to the heating network and controls its parameters

We are carrying out a heating substation project for a 5-storey building connected to plot 6.

The diagram of an individual heating point is shown

Selection of mixing pumps

The pump flow is determined according to SP 41-101-95 using the formula:

where is the calculated maximum water consumption for heating from the heating network kg/s;

u– mixing coefficient, determined by the formula:

where is the water temperature in the supply pipeline of the heating network at the design temperature of the outside air for heating design t n.o., °C;

– also, in the supply pipeline of the heating system, °C;

– the same, in the return pipeline from the heating system, °C;

;

The pressure of the mixing pump with such installation schemes is determined depending on the pressure in the heating network, as well as the required pressure in the heating system and is taken with a margin of 2-3 m.

We choose circulation pumps WiloStratos ECO 30/1-5-BMS. These are standard pumps with a wet rotor and flange connection. The pumps are intended for use in heating systems, industrial circulation systems, water supply and air conditioning systems.

WiloStratos ECO are successfully used in systems where the temperature of the pumped liquid is within a wide range: from -20 to +130°C. A multi-stage (2, 3) speed switch allows the equipment to adapt to the current conditions of the heating system.

We install 2 pumps from Wilo brand ECO 30/1-5-BMS with a flow of 3 m^3/h, a pressure of 6 m. One of the pumps is in reserve.

Selection of circulation pump

We choose a GrundfosComfort type circulation pump. These pumps circulate water in the DHW system. This ensures that hot water flows immediately after the tap is opened. This pump is equipped with a built-in thermostat that automatically maintains the set water temperature in the range from 35 to 65 °C. This is a pump with a “wet rotor”, but due to its spherical shape, it is almost impossible to block the impeller due to contamination of the pump with impurities contained in the water. We choose a Grundfos UP 15-14 B pump with a flow of 0.8 m 3 /hour, a head of 1.2 m, and a power of 25 W.

Selection of Magnetic Flange Filters

Magnetic filters are designed to capture persistent mechanical impurities (including ferromagnetic materials) in non-aggressive liquids with temperatures up to 150 °C and a pressure of 1.6 MPa (16 kgf/cm2). They are installed in front of cold and hot water meters. We accept the FMF filter.

Choosing a Mudman

Mud collectors are designed to purify water in heating systems from suspended particles of dirt, sand and other impurities.

We install a mud trap of the Du65 Ru25 T34.01 series s.4.903-10 on the supply pipeline when entering the heating point.

Selection of flow and pressure regulator

The regulator is used as a direct-acting regulator to automate subscriber inputs in residential buildings. It is selected according to the valve capacity coefficient:

where D R= 0.03…0.05 MPa – pressure drop across the valve, take D R= 0.04 MPa.

m 3 / h.

Selecting a Danfoss AVP flow and pressure regulator with a nominal diameter, D y – 65 mm, - 2 m 3 / h

Selecting a thermostat

Designed for automatic temperature control in open hot water systems. The regulator is equipped with a locking device that protects the heating system from emptying during peak DHW load hours and in emergency situations.

We choose a DanfossAVT/VG thermostat with a nominal diameter, D y – 65 mm, - 2 m 3 / h.

Selection of check valves

Check valves are shut-off valves. They prevent backflow of water.

Check valves type 402 from Danfoss are installed on the pipeline after the RR, on the jumper after the pumps, after the circulation pump, on the DHW pipeline.

Safety valve selection

Safety valves are a type of pipeline fittings designed to automatically protect a technological system and pipelines from an unacceptable increase in pressure of the working medium by partially releasing it from the protected system. The most common are spring safety valves, in which the pressure of the working medium is counteracted by the force of a compressed spring. The direction of supply of the working medium is under the spool. The safety valve is most often connected to the pipeline using a flange, with the cap facing up.

Select a spring safety valve without manual release 17nzh21nzh (SPK4) with D y = 65 mm.

Selection of ball valves

On the supply pipeline from the heating network, as well as on the return line, on the pipelines to the thermostat and after it, we install ball valves, made of carbon steel (ball - stainless steel), welded, with a handle, flanged, ( R y = 2.5 MPa) type Jip, Danfoss, with D y = 65 mm. On the circulation pipeline of the hot water supply line before and after the circulation pump, we install ball valves with D y = 65 mm. Before the heating system flow and after the return line, ball valves with D y = 65 mm and c D y = 65 mm. On the jumper of the mixing pumps we install ball valves with D y = 65 mm.

Selecting a heat meter

Heat meters for closed heat supply systems are designed to measure the total amount of thermal energy and the total volumetric amount of coolant. We install the Logic 9943-U4 heat calculator with a SONO 2500 CT flow meter; Dу= 32 mm.

The heat meter is designed to operate in open and closed water heating systems from 0 to 175 ºС and pressure up to 1.6 MPa. The difference in water temperatures in the supply and return pipelines of the system is from 2 to 175 ºС. The device provides connection of two identical platinum resistance thermal converters and one or two flow meters. Provides registration of parameter readings in an electronic archive. The device generates monthly and daily reports, where all the necessary information about the consumption of thermal energy and coolant is presented in tabular form.

The platinum set of thermal converters KTPTR-01-1-80 is designed to measure the temperature difference in the supply and return pipelines of heat supply systems. Used as part of heat meters. The operating principle of the set is based on a proportional change in the electrical resistance of two thermal converters selected for resistance and temperature coefficient, depending on the measured temperature. Temperature measurement range from 0 to 180 o C.

Conclusion

The goal of the work was to develop a heat supply system for a residential neighborhood. The district consists of thirteen buildings, eleven residential, one kindergarten and one school, the location of the district is Omsk.

The heat supply system being developed is closed with central quality control with a temperature schedule of 130/70. The type of heat supply is two-stage - buildings are directly connected to the heating network through automated heating substations; there are no central heating substations.

When developing the heating network, the following necessary calculations were performed:

Thermal loads for heating, ventilation and domestic hot water supply of all subscribers are determined. As a method for determining heating and ventilation loads, the method based on aggregated indicators was used. Based on the type and volume of the building, the specific heat losses of the building were specified. The calculated temperatures are taken according to the outside temperature according to SNiP “Building Climatology”. Temperature inside the room according to reference data according to SanPiN based on the purpose of the room. The load on the hot water supply was determined by the standard consumption of hot water per person according to reference data based on the type of building.

Calculated schedule of central quality regulation

The estimated costs of network water (subscribers) have been determined

A hydraulic diagram of the heating network has been developed and a hydraulic calculation has been performed, the purpose of which is to determine the diameters of pipelines and the pressure drop in sections of the heating network

Thermal calculations of heat pipes have been completed, i.e. calculation of insulation to reduce heat loss in the network. The calculation was performed using the method of not exceeding normalized heat losses. A pre-insulated pipe with polyurethane foam insulation was chosen as the heat pipes. Ductless pipeline laying method

A selection of compensators was carried out to compensate for the elongation of pipelines due to thermal expansion. Bellows expansion joints are used as compensators.

- a diagram of an individual heating point was developed and the main elements were selected, i.e. pumps, control valves, thermostats, etc.

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