How to choose the correct pipe diameter for heating a house? How to calculate what size pipe cross-section is better and more expedient to use for heating a private house. The diameter of the pipe is needed for heating.

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As you know, the energy efficiency of a heating system depends not only on the power of the boiler and the number of radiators. This is enough complex parameter, tied to the climate regime of the region, the materials from which the house is built, the quality and quantity of heating equipment and fittings. AND heating pipes play the role of one of the “first violins” in the thermal system.

What pipe diameter is best to use so that the coolant circulation in the circuit is as efficient as possible? As a rule, they are used for this special programs However, there are alternative concepts that allow you to perform this operation yourself. We will lift the “veil of secrecy” and tell you as simply as possible about complex schemes calculations that allow you to optimize the heating of your home so that it is warm and comfortable without having to throw money away.

Is the pipe diameter really that important? As practice shows, extremely! A number of factors that ensure high efficiency of the entire circuit depend on it:

• Throughput and heat transfer coefficient. Those. the total volume of coolant located in the main during a certain period of time and subject to heating.
• Coolant pressure in the circuit, temperature and speed of its movement.
• Hydraulic losses that occur at the junctions of pipes and elements of different sections. The more such transitions, the greater the losses.
• Noise level of the heating system.

There are several types of diameter:

• External. Takes into account the cross-section of the internal cavity and the thickness of the pipe walls. Used for .
• Interior. Reflects the cross-sectional value of the internal cavity of the pipe. Determines the throughput of the pipeline.
• Nominal (conditional). Represents the average value of internal diameters obtained as a result of calculations.

In order for the heating system to work fully, in addition to the pipe cross-section, a number of other factors should be taken into account:

• Properties of the coolant, which is water, antifreeze or steam.
• The material from which the pipes are made.
• The speed of the coolant.
• Type of heating system: one- or two-pipe.
• Type of circulation: natural or forced.

Pipe material

Before determining what pipe diameter would be better suited To heat a private home, you need to decide what material the pipeline itself will be made of. This allows you to determine the installation method, the cost of the project and predict in advance possible heat losses. First of all, pipes are divided into metal and polymer.

Metal

• Steel (black, stainless, galvanized).

They are characterized by excellent strength and resistance to mechanical damage. Service life – at least 15 years (with anti-corrosion treatment up to 50 years).

Operating temperature - 130⁰C. The maximum pressure in the pipe is up to 30 atmospheres. Not flammable. However, they are heavy, difficult to install (special equipment and significant time costs are required), and are susceptible to corrosion. High ratio heat transfer increases heat loss even at the stage of transporting the coolant to the radiators. Post-installation painting is required. The internal surface is rough, which provokes the accumulation of deposits inside the system.

Stainless steel does not require painting and is not subject to corrosive processes, which significantly extends the life of the pipes themselves and the heating circuit as a whole.

• Copper.

The maximum temperature of the working environment is 250⁰C. Working pressure – 30 atmospheres or more. Service life – more than 100 years. High resistance to media freezing and corrosion.

The latter imposes restrictions on the combined use of copper with other materials (aluminum, steel, stainless steel); Copper is only compatible with brass. Smoothness interior walls prevents the formation of plaque and does not impair the throughput of the pipeline, which reduces hydraulic resistance and makes it possible to use pipes of smaller diameter. Plasticity, light weight and simple technology connections (soldering, fittings). The small thickness of the walls and connecting fittings eliminates hydraulic losses.

The most significant drawback is the extremely high cost, which is 5-7 times higher than the price of plastic analogues. In addition, the softness of the material makes it vulnerable to mechanical particles (impurities) in the heating system, which, as a result of abrasive friction, lead to wear of the pipes from the inside. To extend the life of copper pipes, it is recommended to equip the system with special filters.

The high thermal conductivity of copper requires the installation of insulating sleeves to prevent heat loss, but it also makes it an indispensable material for underfloor heating systems.

Polymer

They can be polyethylene, polypropylene, metal-plastic. Each modification has its own technical characteristics depending on the production technology, additives used and the specific structure.

Service life – 30 years. Carrier temperature - 95⁰C (short-term - 130⁰C); Excessive heating leads to pipe deformation, reducing service life. They are characterized by insufficient resistance to freezing of the coolant, as a result of which they rupture. The smoothness of the internal coating prevents the formation of plaque, thereby improving the hydrodynamic performance of the pipeline.

The plasticity of the material allows pipes to be laid without cutting, thereby reducing the number of fittings. Plastic does not react with concrete and does not rust, which allows you to hide the heating pipe in the floor and install “warm floors”. Special advantage plastic pipes considered to have good sound insulation properties.

Polyethylene pipes under influence high temperatures prone to significant linear expansion, which requires the installation of additional compensation loops and attachment points.

Polypropylene analogues must contain an “anti-diffusion layer” in their structure to prevent airing of the circuit.

The pressure level in the circuit determines not only the diameter of the polymer pipes, but also the wall thickness, which varies in the range from 1.8 to 3 mm. Fitting connections simplify installation of the circuit, but increase hydraulic losses.

When deciding which diameter to choose, you should take into account the specific markings of various pipes:

• plastic and copper are marked by external section;
• steel and metal-plastic - internally;
• often the cross section is indicated in inches; to carry out the calculation they need to be converted into millimeters. 1 inch = 25.4 mm.

To determine the internal diameter of the pipe, knowing the dimensions of the external section and wall thickness, you should subtract twice the wall thickness from the external diameter.

Optimal size, temperature and pressure

When installing a small heating circuit of a standard type, some recommendations from experts will allow you to do without complex calculations:

• For pipelines with natural circulation carrier, it is recommended to use pipes with an internal cross-section of 30-40 mm. Increasing the parameters threatens with unreasonable coolant consumption, a decrease in the speed of its movement and a drop in intra-circuit pressure.
• Too small a pipe diameter will cause an overload inside the line, which can cause it to break through at the connecting elements.
• To ensure the required speed of movement of the coolant and the required pressure inside the forced circulation circuit, preference is given to pipes with a cross-section of no more than 30 mm. The larger the cross-section of the pipe and the longer the line, the more powerful the circulation pump is selected.

Important! Arrangement of an effective heating system involves the use of pipes of different sections in different sections of the main line.

The operating pressure level of the circuit must not exceed the stability limit:

• heat exchanger built into the boiler (max - 3 atm or 0.3 MPa);
• or 0.6 MPa (with a radiator circuit).

The optimal value for heating systems with a circular pump is considered to be in the range from 1.5 to 2.5 atm. Under natural circulation conditions - from 0.7 to 1.5 atm. Exceeding the standard will inevitably cause an accident. To control the pressure level in heating systems, expansion tanks and pressure gauges are installed.

Autonomous heating allows you to regulate the temperature of the coolant yourself, depending on the season and the individual needs of the residents of the house. The optimal temperature is considered to be in the range from 70 to 80⁰C, in steam heating systems – 120-130⁰C. The best solution would be to use gas or electric boilers, which allow you to control and regulate the heating of the circuit, which cannot be said about solid fuel equipment.

Design features heating systems also determine the characteristics of the temperature regime:

• the maximum heating of the carrier in a single-circuit wiring is 105⁰C, in a double-circuit wiring - 95⁰C.
• in the carrier temperature is limited to 95⁰C, in steel - 130⁰C.

The temperature difference between supply and return is 20⁰C.

Boiler and circuit power

The efficiency of the boiler, which plays one of the key roles in the heating system, is affected not only by the diameter of the pipes, but also by:

• type of fuel used;
• location of the boiler (removing the boiler unit outside the house requires increased power, a larger cross-section and insulation of the main line in the outdoor area);
• level of thermal insulation of the external walls of the house;
• use of a heating circuit for hot water supply.

When choosing a boiler, you should take into account the above factors and reserve power by 1.5-2 times.

Calculation methods

1. According to special tables. However, their use still requires preliminary calculations: the power of the heating system, the speed of movement of the coolant, as well as heat loss along the main line.
2. By thermal power.
3. According to the resistance coefficient.

What you need to know to calculate

To carry out the calculation you will need the following data:

• Heat demand (thermal power) of the entire house and each room separately;
• The total power of the heating devices used (boiler and radiators).
• The total heat loss of the house and each room separately during the coldest winter period.
• Resistance value. It is determined by the wiring diagram, the length of the line, the number and shape of bends, connections, and turns.
• The total volume of coolant loaded into the heating main.
• Flow speed.
• Circulation pump power (for forced heating).
• Line pressure.

Calculation of pipe cross-sections for heating systems with forced air circulation:

Calculation procedure

1. Calculation of required thermal power.
2. Determination of the circulation rate of the carrier in the heating system.
3. Calculation of heating circuit resistance.
4. Calculation of the required pipeline cross-section.
5. Calculation of the optimal diameter of the heating collector (if necessary).

Calculation of system thermal power

Method 1. The simplest way to calculate thermal power is based on the established standard of 100 watts per 1 m² of room. Those. with a house area of ​​180 m², the power of the heating circuit will be 18,000 watts or 18 kW (180 × 100 = 18,000).

Method 2. Below is a formula that allows you to adjust the data taking into account the power reserve in case of severe frosts:

However, these methods are characterized by a number of errors, because does not take into account the range of factors influencing heat loss:

• ceiling height, which can vary in the range from 2 to 4 or more meters, which means that the volume of heated rooms, even with the same area, will not be constant.
• the quality of insulation of the house facade and the percentage of heat loss through external walls, doors and windows, floor and roof;

• thermal conductivity of double-glazed windows and materials from which the house is built.

• Climatic conditions of the regions.

Method 3. The method presented below takes into account all the necessary factors.

1. The volume of the entire house or each room separately is calculated using the formula:

• V – Volume of the heated room.
• h – Ceiling height.
• S – Area of ​​the heated room.

1. The total power of the circuit is calculated:

The following formula is often used:

In this case, the regional correction factor is taken from the following table:

The heat loss correction factor (K) directly depends on the thermal insulation of the building. It is customary to use the following average values:

• With minimal thermal insulation (typical wooden or metal structure made of thin sheets), a coefficient in the range from 3 to 4 is taken into account;
• Single brickwork – 2-2,9;
• Average level of insulation (double brickwork) – 1-1.9;
• High-quality thermal insulation of the facade - 0.6-0.9.

Water speed in pipes

The uniformity of the distribution of thermal energy among the elements of the circuit depends on the speed at which the liquid moves, and the smaller the diameter of the pipeline, the faster it moves. There are speed limits:

• not less than 0.25 m/sec, otherwise air pockets will form in the circuit, preventing the movement of the coolant and causing heat loss. If the pressure is insufficient, the air pockets will not reach the installed Mayevsky valves and air vents, which means they will be useless;
• no more than 1.5 m/sec, otherwise the media circulation is accompanied by noise.

The reference flow rate is from 0.36 to 0.7 m/s.

This should be taken into account when choosing the appropriate pipe section. By installing a circulation pump, it becomes possible to control the circulation of coolant in the circuit without increasing the diameter of the pipeline.

Calculation of heating circuit resistance

When calculating the cross-section of pipes using the resistance coefficient, the first step is to determine the pressure in the pipeline:

Then, by substituting the pipe diameters, the minimum heat loss value is selected. Accordingly, the diameter that will satisfy acceptable resistance conditions will be the desired one.

Heating manifold calculation

If the heating system provides for the arrangement distribution manifold, then the determination of its diameter is based on calculating the cross-sections of the pipelines connected to it:

The distance between the collector pipes should be equal to triple their diameter.

Examples

Let's look at examples.

Calculation for a two-pipe circuit

• Two-storey house with an area of ​​340 m².
• The building material is Inkerman stone (natural limestone), characterized by low thermal conductivity. → House insulation coefficient = 1.
• Wall thickness – 40 cm.
• The windows are plastic, single-chamber.
• Heat loss on the 1st floor – 20 kW; the second - 18 kW.
• Two-pipe circuit with a separate wing on each floor.
• Pipe material is polypropylene.
• Serving temperature - 80⁰C.
• Outlet temperature - 60⁰C.
• Temperature delta - 20⁰C.
• Ceiling height – 3 m.
• Region – Crimea (south).
• The average temperature of the five coldest days of winter is (-12⁰C).

1. 340×3=1020 (m³) – volume of the room;
2. 20- (-12) = 32 (⁰C) – temperature difference (delta) between indoors and outdoors;
3. 1020×1×32/860≈38 (kW) – heating circuit power;
4. Determination of the pipe cross-section in the first section from the boiler to the branch. According to the table below, pipes with a cross-section of 50, 63 or 75 mm are suitable for transmitting thermal power of 38 kW. The first option is preferable, because provides the highest speed of movement of the carrier.
5. To distribute the media flow to the first and second floors, reference books prescribe pipes with a diameter of 32 mm and 40 mm for powers of 18 and 20 kW, respectively.
6. On each floor, the circuit is divided into two mains with an equivalent load of 10 and 9 kW, respectively, and a cross-section of 25 mm.
7. As the load decreases due to cooling of the coolant, the diameter of the pipes should be reduced to 20 mm (on the first floor - after the second radiator, on the second - after the third).
8. Reverse wiring is carried out in the same sequence.

To calculate using the formula D = √354x(0.86xQ/∆t)/V, we take the carrier speed to be 0.6 m/s. We obtain the following data √354x(0.86×38/20)/0.6≈31 mm. This is the nominal diameter of the pipeline. For implementation in practice, it is necessary to select different pipe diameters in different sections of the pipeline, which on average will be reduced to the calculated data according to the algorithm described in paragraphs 4-7.

Determination of pipe diameter for a single-pipe system with forced circulation

As in the previous case, the calculation is made according to the indicated scheme. The only exception is in the action pumping equipment, increasing the speed of the carrier and ensuring uniformity of its temperature in the circuit.

1. A significant reduction in power (up to 8.5 kW) occurs only on the fourth radiator, where the transition to a diameter of 15 mm is made.
2. After the fifth radiator there is a transition to a cross section of 12 mm.

Important! The use of pipes made of a different material will make adjustments to the calculation, because... Each material has a different level of thermal conductivity. It is especially important to take into account the heat loss of a metal pipeline.

Features of calculating the cross-section of metal pipes

Heating systems made of metal pipes must take into account the coefficient of heat loss through the walls. This is especially important with a significant length of the pipeline, when heat loss on each linear meter can have catastrophic consequences for the final radiators.

By adding a power reserve to the power system and choosing the correct pipe diameter, it is possible to prevent significant heat leaks.

How to choose the diameter of a heating pipe

The calculations made make it possible to determine the cross-section of the pipeline in specific (approximate) values. In addition to complex formulas, there are special tables that simplify determining the required cross-section if you know the basic parameters of the heating system.

Using the table and values ​​of thermal power, flow and return temperatures, as well as reasonable coolant speed (highlighted pink), the required pipe diameter is selected.

From the correctly calculated pipe diameter depends on the heat and heating costs of the house.

An adequately selected option will not require extra costs to heat the liquid and allow the coolant to pass through the system at a good speed.

What pipe diameter is needed for heating a private house?

Pipe specifications include three types of diameters:

• external— diameter taking into account wall thickness, taken into account when calculating mounting fasteners, required area, thermal insulation, etc.;
• interior- presenter technical parameter element, shows the size of the lumen, calculated for bandwidth systems taking into account physical qualities coolant;
• conditional- the average value of the internal clearance, rounded up or down to millimeters or inches of the standard value, approximately equal to the internal diameter, marked as DN (formerly DU).

Reference. The conditional diameter is calculated to determine the throughput capabilities of the pipeline.

When choosing the required section, the following parameters are taken into account:

• hydrodynamics systems - with an increase in the volume of passing coolant, the efficiency of the system decreases, so choosing a larger pipe diameter entails a decrease in the efficiency of the system;
• pressure inside systems - if the cross-section is large, then the speed of passage of the coolant along the circuit is low. This increases heat loss and the risk of liquid boiling in the heating boiler during natural circulation.

Attention! If the pipes have a smaller diameter, this also leads to a loss of fluid velocity, since the resistance inside the system increases and the coolant does not pass through. This is fraught with loss of temperature and noise during operation batteries

• heating boiler power- the stronger the boiler, the larger diameter can be used;

• length of the system- affects the capacity of the circuit, for example, a pipe in 25 millimeters may skip about thirty liters of water per minute;
• liquid circulation method— for forced circulation it is permissible to take a smaller cross-section compared to natural circulation;
• coolant cooling rate— a correctly selected diameter will ensure adequate speed of coolant passage through all rooms;
• room area— cross-section is one of the heat transfer parameters per square meter;
• Number of sweeps and turns— reduces the rate of passage of coolant and pressure in the system;
• material- influence physical characteristics material on the coolant throughput and heat transfer at a certain speed of the energy carrier.

Power calculation

First of all, the power of the entire heating system is calculated. The calculation is made using the formula:

Qt= V*∆t*K/860

Wherein:

• Qt— heat power, kW.
• V— size of the heated room, m³.
• ∆t- the difference between the temperature inside the home and the temperature outside the home in winter.
• TO— coefficient showing the heat loss of the building.

For standard buildings, average values ​​are used.

Calculation principle

The general starting point for determining the required cross-section is the quadrature of the heated room - 10 sq. m. require 1 kW heat, which means the room is in 30 sq. m.

with a ceiling height of about three meters should get 3 kW.

Having this data, calculate the diameter using the formula:

D= √(354*(0.86*Q/∆t)/V),

V— coolant speed in the system (meters per second);

Q— required volume of heat for heating (kW);

∆t— difference between feeds (reverse and forward) (C);

D— cross-section (in millimeters).

Determining the appropriate pipe size for heating systems

The size of the pipes depends on the type of heating system in a private home.

With natural circulation

The first and last pipes that are installed with the heating boiler must correspond to the diameter of its pipe from 25 to 50 mm.

Photo 1. Diagram of a heating system with natural circulation. The numbers indicate the components of the structure.

It is advisable to choose the maximum permissible diameter, since in the future it will decrease to increase the pressure in the system (branching with a cross-section of an inch is carried out with a pipe in 3/4 inch, next part - half-inch).

Reference. The first reduction is made after the first branching. At the end point the minimum diameter corresponds to the recommended one ( 12.7 or 19 mm).

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With forced circulation

For systems with forced circulation it is permissible to take narrower pipes than for gravity flow, since the pressure in the system is provided by a pump.

Section depends on the connection diagram and wiring and varies in the system from less to more and vice versa or remains unchanged(at single pipe system heating).

With beam distribution cross-section of the pipe extending from the boiler to the collector - 19 mm, to the radiators the pipes go to the radiators 12.7 mm.

Types of radiators

Batteries are used for space heating:

• cast iron― durable, insensitive to coolant and pressure, able to withstand water hammer;
• aluminum- average service life 15 years, good heat transfer, quite fragile, cannot withstand high pressure and dirty coolant;
• bimetallic- serve 25 years, give off heat well, are resistant to water hammer, and are insensitive to energy;
• steel- are used for 10 years, good heat transfer, withstand medium pressure, capricious to the coolant;
• copper― durable, insensitive to the type and quality of the liquid, withstands pressure and pressure changes well.

Connection

Two popular types battery connections:

• single-pipe— both the supply of hot coolant and the return of cooled coolant occur through one pipe;

Photo 2. Single-pipe scheme connecting radiators according to the top-down (top) and bottom-type (bottom) principle.

• two-pipe— the heated liquid is supplied through one pipe, the cold liquid through the second.

Reference. The third type is not the most popular collector type, in which pipes go from one collector to each radiator. The method is good for heating, but expensive in terms of equipment costs.

In each type, the circuit can go:

• vertically— from the upper floors to the lower, often used in gravity systems;
• horizontally— the pipe connects all radiators in series and is used in both natural and forced circulation.

Radiator connections can be top, bottom, or diagonal. The type of connection affects the diameter of the connected pipes and their number.

Types of heating pipes

For heating systems they are used different kinds pipes

Metal

The most popular type produced made of two types of steel:

1. carbon:

• little subject to expansion;
• low price;
• insensitive to mechanical influences;
• highly susceptible to corrosion.

1. stainless:

• not subject to mechanical stress;
• less susceptible to corrosion;
• slight expansion;
• higher price compared to carbon.

Metal pipes are manufactured:

• welding (suture)- seams can be straight or spiral; in heating systems, circuits with a spiral seam are used, since the straight line can diverge due to the influence of temperature;
• rolling— in terms of technical characteristics and durability, they are superior to suture ones (insensitive to temperature and pressure), but are more expensive in price.

Positive properties include:

• slight expansion;
• Possibility of installation on any surface except drywall;
• resistance to water hammer;
• temperature limit up to 1500 degrees.

Among the shortcomings, we only note:

• susceptibility to corrosion;
• inconvenient installation;
• heavy weight.

Important! Regardless of what kind of pipes the system is equipped with, it is recommended to install the first links of the outlet and return from the heating boiler only metal parts.

Copper

The most expensive, but also exceptional in quality. Produced from:

• copper High Quality;
• mixtures of copper and zinc;
• copper coated with a layer of polyvinyl chloride or polyethylene.

Reference. For heating systems, you must choose pipes marked EN 1057, indicating the treatment of copper with phosphorus, which further increases its resistance to water.

According to the manufacturing method, pipes are divided into:

• annealed- more elastic and soft;
• not annealed- hard.

During installation they are connected by hard soldering.

Among the advantages noted:

• large temperature range ( from -100 °C to +250 °C);
• slight expansion;
• life time up to one hundred years;
• ecologically pure material;
• resistance to high pressure.

Photo 3. Copper pipes connected to heating radiators. Such designs last a very long time.

The disadvantages include:

• undesirability of using copper with other metals - chemical reactions, occurring during interaction, can lead to corrosion;
• stray currents negatively affect operational life.

Metal-plastic

Metal-polymer (metal-plastic) pipes - five layer construction: cross-linked (modified) polyethylene, adhesive layer, thin aluminum, glue and a protective layer of polyethylene inside. The tube is stitched with an overlap (ultrasound) or a joining seam (laser).

Contours made of metalpropylene are used in:

• water supply and heating;
• transmission liquefied gases;
• hot air supply;
• as a protection screen for cables.

Photo 4. Metal-plastic pipes for heating systems. In the middle part of the products there is a layer of aluminum.

The use is due to the large number of advantages of this type:

• immune to aggressive environments;
• resistant to corrosion;
• economical in installation;
• There are practically no leaks;
• do not become overgrown;
• do not require welding with press fittings;
• impermeable to gases;
• resistant to biodeposits and rust;
• flexibility, keep their shape well;
• low thermal conductivity;
• withstand thermal load up to +110 degrees;
• are not prone to condensation;
• ease.

Disadvantages include:

• by linear expansion 2.5 times exceed metal pipes;
• subject to mechanical stress;
• with long-term influence sun rays, electromagnetic fields wear out quickly;
• break due to improper installation or exceeding the bending angle;
• weak when exposed to organic acids;
• The crimp connections must be tightened.

Pipes are used for heating installation at 16 and 20 millimeters.

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Design and - difficult task. When solving it, it is important to take into account all the existing nuances. First of all, you need to decide on the diameter of private houses or apartments. This is important for both one-pipe and two-pipe systems.

Selecting the diameter of pipes, what happens if you choose the wrong one?

While designing heating circuit, it is necessary to reduce possible heat losses as much as possible in order to reduce energy costs. An incorrectly created system does not work efficiently. The room temperature will not increase, and energy costs will be excessive.

When taking into account not only Chemical properties materials for making channels, but also an indicator of their diameter. This indicator plays vital role. It determines how efficiently the system will work. The cross section of the channels greatly influences the hydrodynamics. You need to pay enough attention to his choice.

There is an opinion that the larger the cross-section of the channels, the better the carrier circulates in them. However, this is absolutely not true. Excessive diameter of pipes connected to gas or electric boilers, leads to a decrease in pressure in the system. As a result, the radiators do not receive enough heat.

If you need to install a heating circuit in a private home, you need to decide on the type of media supply. If the building is connected to the municipal heating main, the design and installation process will be similar to installing the system in an apartment.

An autonomous heating system can have different schemes. The choice of channel cross-section indicator directly depends on them. Dimensions of structures for systems with natural type Media circulation differs between options based on the application of pumps.

Main characteristics of pipes

All existing channels have several cross-section parameters. You need to understand this. Otherwise, you may make a mistake and purchase exactly the designs that you need.

The following structural cross-section parameters exist:

• internal;
• external;
• conditional.

The key parameter is the internal diameter of the channel. Based on it, the design capacity indicator is calculated. The external cross-section is also taken into account when planning the contour. It is very important when installing the system. The conditional section is the rounded diameter indicator. As a rule, it is indicated in inches.

When choosing channels to create a heating circuit, you need to understand that different measuring systems are used for products made from different materials. For example, structures are marked exclusively according to the indicator internal section, and and - along the outer diameter.

In addition, plastic channels come in various types.

Today the following types of polymer pipes are produced:

Plastic structures can have different technical characteristics. The most convenient for creating a heating system are pipes made of reinforced polypropylene. But metal-plastic and polyethylene structures are also used to solve this problem. Before making a choice in favor of one or another product, study its features in detail. This is the only way to choose the most best option.

Below, see the table of correspondence between the diameters of pipes made from different materials. She will help you do right choice.

Correspondence table for outer diameters and nominal bores of steel and polymer pipes

Most often, the cross-sectional indicator is indicated in inches. This applies to all types of channels. Remember that one inch is 25.4 mm.

How to calculate?

To carry out correct calculations, you need to take into account the magnitude of the thermal load. It is believed that one hundred watts per square meter is enough to create a normal temperature in a room. This is true for rooms with a ceiling height of two and a half meters.

Thus, for heating rooms measuring twenty-five square meters you need 2.5 kW of thermal energy. Channel selection can be done using the table below.

Based on the tabular data, to heat rooms measuring twenty-five square meters, you need to use half-inch structures.

Pressure and temperature in the heating system

When creating autonomous systems, you yourself determine the required temperature of the medium in the circuit. There is no approved standard. This indicator depends not only on conditions environment and your own preferences, but also on the value of the heat transfer coefficient of the batteries. This parameter is the lowest. Bimetallic products are characterized by an average coefficient value. The highest parameters are for batteries made of aluminum.

In principle, the specified temperature regime- optimal. But if conditions change external environment, it needs to be changed up or down. Depending on the circumstances. Adjusting the temperature will allow you to create more comfortable conditions indoors and reduce energy costs.

If you choose polypropylene channels to create a heating circuit, keep in mind that the temperature inside them should not exceed ninety-five degrees.

To make the system more efficient, it is better to increase the number of batteries or sections in them rather than increasing the temperature of the media above the specified mark.

To ensure normal functioning of the circuit, monitor the pressure indicator. For autonomous systems, its value should be from 1.5 to 2 atmospheres. If the pressure rises higher, this may lead to an emergency. As a result, channels and other equipment will fail.

To monitor the pressure indicator, you need to use a pressure gauge. Expansion tanks will allow you to avoid the occurrence of unacceptable pressure in the system.

Installation and wiring of the system - installation

To construct a heating circuit in a private house, you need to take into account some details. Exist different schemes system wiring. It is important to choose and design the most optimal option. The circulation of the carrier can be natural or forced. In some cases, the first option is convenient, in others, the second.

Natural circulation occurs due to changes in liquid density. A hot carrier is characterized by a lower density. The water going the other way is denser. Thus, the heated liquid rises along the riser and moves along horizontal lines. They are mounted at a slight angle of no more than five degrees. The slope allows the carrier to move by gravity.

A heating scheme based on natural circulation is considered the simplest. To perform its installation you do not need to have high qualifications. But it is only suitable for buildings not large area. The length of the highway in this case should not exceed thirty meters. The disadvantages of this scheme include low pressure inside the system and the need to use channels of large cross-section.

Forced circulation implies the presence of a special circulation pump. Its function is to ensure the movement of media along the highway. When implementing a scheme with forced fluid movement, there is no need to create an inclination of the contour. One of its disadvantages is the energy dependence of the system. If there is a power outage, the movement of media in the system will be difficult. Therefore, it is advisable that the house have its own generator.

The wiring happens:

• Single-pipe.
• Two-pipe.

The first option is implemented through sequential flow of the medium through all radiators. This scheme is economical. To implement it, a minimum number of pipes and fittings for them will be required.

The single-pipe scheme has a number of disadvantages. You will not be able to adjust the media feed for each battery. As you move away from the boiler, the radiators will become less warm. It is possible to overcome these defects.

To do this, you need to use the so-called “Leningrad” wiring diagram.

It involves installing bypass pipes and shut-off valves on each radiator. This principle allows for uninterrupted circulation of the carrier when any battery is cut off.

Installing a two-pipe heating circuit in a private house involves connecting reverse and forward current to each radiator. This approximately doubles the channel consumption. But the implementation of this option allows you to regulate the heat transfer in each battery. Thus, it will be possible to adjust the temperature in each individual room.

There are several types of two-pipe wiring:

• lower vertical;
• top vertical;
• horizontal.

Lower vertical wiring involves running a supply circuit along the floor of the lower floor of a building or its basement. Then, from the main line through the risers, the carrier goes up and enters the radiators. From each device there is a “return”, delivering the cooled liquid to the boiler. When implementing this scheme, you need to install expansion tank. There is also a need to install Mayevsky taps on all heating devices located on the upper floors.

The upper vertical wiring is arranged differently. Fluid from the heating unit goes into the attic. The carrier then moves down through several risers. It goes through all the radiators and returns to the unit along the main circuit. To remove air from this system, an expansion tank is needed. This scheme is more effective than the previous one. Because there is a higher pressure inside the system.

The horizontal two-pipe type wiring diagram with forced circulation is the most popular.

It comes in three varieties:

• with radial distribution (1);
• with associated movement of liquid (2);
• dead-end (3).

The radial distribution option consists of connecting each battery to a boiler. This operating principle is the most convenient. Heat is distributed evenly in all rooms.

Option with passing traffic The liquid is quite convenient. All lines going to the radiators are of equal length. Adjustment of such a system is quite simple and convenient. To install this wiring you need to purchase a significant number of channels.

The last option is implemented by using a small number of channels. The downside is the significant length of the circuit from the distant battery, which complicates the adjustment of the functioning of the system.

How to hide pipes

During construction heating circuits Many owners are thinking about how to hide heating pipes in a private house. This problem can be solved in different ways.

Most often for hidden installation channels resort to:

• the use of decorated structures;
• closing channels under drywall;
• hiding products under suspended ceiling panels;
• installation under a false floor;
• hiding structures in the walls of a building.

The choice of method depends on many factors. It is advisable to consult with specialists to solve this problem. There are many details to consider. Including the materials from which the building is made. It could be brick, aerated concrete, etc.

conclusions

When designing and installing heating systems, every detail must be taken into account. In this matter, there are no little things that you can turn a blind eye to. Mistakes made at the planning stage will lead to serious consequences. As a result, you will have to redesign the circuit, dismantle the old system, and install a new one. The design phase must be carried out by a competent and experienced person.

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Thick and thin: how to calculate the diameter of a heating pipe

Greetings, comrades! This article is about what pipe diameter to choose for heating. In it I will talk about methods for calculating patency and cross-section, I will give a number practical recommendations on sizing and explain the difference between different types pipes So, let's go.

Calculation method

Reference data

There is a simple and understandable relationship between the thermal load, the cross-section of the pipeline and the speed of movement of the coolant: the amount of pumped thermal energy can be increased by making the pipeline thicker or making the water move faster.

Everything is clear with the cross-section: the thicker the pipe, the more expensive it is. Why can’t we significantly increase the coolant pumping speed? Because when it increases to 1.5 m/s, noticeable hydraulic noise arises, making staying in a heated room downright uncomfortable.

Typically, the calculation of the filling cross-section is performed for a flow speed of 0.4 - 0.6 m/s. Reducing the speed to 0.25 m/s and below will not only affect the heating efficiency, but will also not allow the coolant to squeeze out air plugs to the air vent or Mayevsky tap.

Here is a table that allows you to calculate the internal diameter of a pipeline with a minimum amount of time with a known thermal load on it.

Inner diameter, mm	Heat flow (kW) at flow speed, m/s
	0,4	0,5	0,6
12	3,7	4,6	5,5
15	5,75	7,2	8,6
20	10,2	12,8	15,3
25	16	20	24
32	26,2	32,7	39,2
40	40,9	51,1	61,3
50	63,9	79,8	95,8

How to choose the diameter of heating pipes based on this table? Very simple:

1. Select the heat load that best suits your conditions from the second to fourth columns;
2. Take the corresponding value from the first column.

What kind of beast is heat load? How to calculate it with your own hands?

• For bottling in a private house, it is taken equal to the peak power of the heating boiler, heat pump or other heat source;

• For supply to a separate heating device, the thermal load is equal to its rated power, adjusted for the actual temperature conditions. As a rule, manufacturers indicate power for ideal conditions - the temperature delta between the coolant and the air of the heated room is 70 degrees (that is, at +20 in the room the battery should be heated to 90 C).
  In practice, the autonomous circuit maintains 70 - 75 degrees on the supply and 50 - 55 on the return, which at a comfortable +25 in the house will give a temperature delta of 30 - 50 C. With a delta of 50 degrees, the thermal power of the battery will decrease and will be 50/70 =0.714 from the passport value;

• For individual sections of the circuit, the thermal load is equal to the total power of the connected heating devices. Let's say, if two 1.2 kW batteries are installed in a room, it will be equal to 1.2 * 2 = 2.4 kW.

Where can I get data on the thermal power of batteries? In general, from the accompanying documentation or from the manufacturer’s website. A rough calculation can be made based on following values:

• Cast iron section in ideal conditions gives off 140 - 160 W of heat;
• Bimetallic -180 W;
• Aluminum - 200 W.

I provided data for radiators standard size, With center distance leash 500 mm. Many manufacturers have batteries with smaller and large size sections.

How to determine the thermal load if you plan to use welded registers of non-standard sizes as heating devices?

For the first section of the register (lower pipe), the formula is Q=3.14*D*L*k*Dt, where:

• Q is the cherished thermal power in watts;
• D— outside diameter in meters;
• L - length (again in meters);
• k is the heat transfer coefficient, determined by the thermal conductivity of the material and the thickness of the pipe walls. For a steel register, the coefficient is taken equal to 11.63 W/m2*C;
• Dt is the same temperature delta between the coolant and the air in the room.

The second and subsequent sections of the register are in the upstream warm air from the first section, which reduces their heat transfer. For them, power is calculated with a coefficient of 0.9.

Let's, as an example, calculate the thermal power of the register for the following conditions:

• It consists of four identical sections;

I deliberately neglect the heat transfer of the jumpers between the sections and the ends of the sections. It is insignificant compared to the overall power of the device.

• Each section has an outer diameter of 108 mm (0.108 meters) and a length of 2 meters;
• The register is heated to 60 degrees, and the air in the room is heated to 23.

First, we calculate the power of the first section. It is equal to 3.14*0.108*2*11.63*(60-23)=292 watts (rounded to the nearest whole value).

Then we find the thermal power of the second and subsequent sections. It will be equal to 292 * 0.9 = 263 watts (again, rounded).

The last stage is calculating the total power of all sections. 292+263*3=1081 watts.

Now let's find out what pipe diameter is needed for heating when connecting this register. As is easy to see, the minimum value in the table above exceeds its power by more than three times. Therefore, a liner with an internal size of 12 mm will not limit the heat transfer of the register at any reasonable flow rate.

Practice

Theory is worth little if it is not supported by practice. Here's a sizing guide based on my years of hands-on experience.

• Any heating device can be safely connected with a pipe with a diameter of DN 15 (1/2 inch). There is only one limitation: in the central heating system apartment building The supply line must be equipped with a jumper with a diameter not inferior to the riser (as a rule, DN 20 - DN 25). When changing the configuration, reducing the diameter of the riser is unacceptable;

• In a system with forced circulation, a pipe of size DN 25 can be used as filling or, with a slight increase in flow speed, DN 20;

The photo shows the heating distribution area in my basement. A polypropylene pipe measuring 25 mm was used.

In new houses with central heating, the heating risers are routed using a DN 20 pipe. In a ten-story building, 20 radiators or 20 are installed on paired risers of this diameter.

Heating riser in apartment building. Pipe size - DN 20.

• In a gravity (gravity) heating system, the filling diameter increases to DN 32 - DN 50. The fact is that increasing the internal cross-section of the pipe allows you to sharply reduce its hydraulic resistance - the most important parameter in the circuit, circulation in which is ensured only by the difference in the density of hot and cold water .

Such different diameters

Due to the difference in the naming system of pipes made from different materials in the head potential buyer There is bound to be some confusion. I will try to clarify this issue.

• The steel pipe is marked with a conditional bore, or DN. It is approximately equal to the internal diameter; small deviations of the actual size from the DU are due to the variation in the wall thickness of ordinary, light and reinforced water and gas pipes;

• The DN marking indicates the same DN (conditional bore). However, DN is often specified in inches. An inch is 2.54 centimeters; only markings in inches are traditionally rounded to several whole and fractional values, which aggravates the confusion. For the convenience of the reader, I will provide a table of correspondence between the sizes of steel pipes in millimeters and inches;

DU	Size in inches
15	1/2
20	3/4
25	1
32	1 1/4
40	1 1/2
50	2

• Pipes made of cross-linked and ordinary polyethylene, polypropylene and metal polymer products are marked outer diameter. On average, their diameter is one step larger than the internal section: a pipe measuring 25 mm has the same internal cross-section as a steel pipe DN 20, 32 mm corresponds to DN 25, and so on;

• All polymer products have lower hydraulic resistance than steel due to minimal wall roughness. In addition, they do not become overgrown with rust and lime deposits over time, so their diameter is selected without reserve. And here steel pipes for a central heating system, it is better to buy taking these factors into account, rounding the calculated pipe diameter up.

Conclusion

I hope that I was able to comprehensively answer the questions that the respected reader has accumulated. As always, Additional materials can be learned by watching the video in this article. I would appreciate your additions and comments. Good luck, comrades!

For cold water supply, polypropylene pipes with a uniform wall are used. Reinforced products are used for hot water supply systems and heating circuits, since the inclusion of an aluminum shell in the wall structure of a polypropylene pipe significantly increases the strength of the pipe material and reduces the amount of thermal expansion.

What diameters are polypropylene pipe materials produced?

When choosing components for a heating and water supply system, the decisive factors are the temperature of the liquid, its flow rate and pressure. The required cross-sectional area of ​​the water supply system is determined by calculations made in accordance with the scope of application and operating conditions of the equipment.

Based on the configuration of the pipe section (round ring), its geometric parameters are determined by the outer and inner diameters. The current classification of polypropylene pipes clearly defines standard sizes each type of pipe products used for installation.

Today, both domestic and foreign manufacturing companies produce components for pipelines in standard versions. Taking into account practical application, standard engineering solutions have been developed that make it possible to determine the optimal passage in products for home heating and other water communications. Based on the data in the table, you can make the correct choice of equipment and components for the heating main without resorting to hydraulic calculations.

As a rule, the marking contains one of the following outer diameter values:

16, 20,25, 32 and 40 mm,

which correspond to the internal diameters of polypropylene pipes grade PN25:

10.6; 13.2; 16.6; 21.2; 26.6 mm.

For ease of use, the correspondence of diameters and wall thicknesses of polypropylene pipes used in heating and water supply systems are summarized in the table:

Table with data on the diameters and wall thickness of polypropylene pipes used in everyday life

A reasonable question. Why are external parameters marked on finished products if the size of the internal passage of the pipeline is so important for functionality? The thing is that the outer diameter indicates the appropriate type of connection.

Potential for using polypropylene pipes of various outer diameters at a coolant flow rate in the pipeline of 0.7 m/sec:

• a pipe with a diameter of 16 mm is designed to connect one or two heating radiators;
• a value of 20 mm corresponds to connecting up to 5 radiators with a total power of up to 7000 watts);
• for a larger number of radiators (total power up to 11 kW), propylene polymer pipes with an outer diameter of 25 mm are used;
• polypropylene pipe material with an outer size of 32 mm is designed to equip a whole house or one floor with a heating system of 10-12 kW of total power (maximum 19 kW);
• products with a diameter of 40 mm are used for laying main pipelines in large residential areas. Usually these are cottages and country houses, in which the number of heating devices reaches 20 pieces, and the total power of all connection points is approximately 30 kilowatts.

The influence of pipe diameter on the performance characteristics of the heating system

The rate of coolant supply and the volume of transferred thermal energy directly depends on the internal cross-section of polypropylene pipelines. To make this statement clearer, the dependence of the provision of thermal energy on the intensity of coolant supply and the values ​​of pipeline diameters is summarized in the table:

Table for selecting polypropylene pipe material depending on the intensity of coolant supply and the need for thermal energy

Thermal power indicated in W, coolant supply intensity in kg/sec. The calculated data are based on average temperatures: supply coolant at 80 0 C, return at 60 0 C, air in the room +20 0 C.

For example: at a flow speed of 0.4 m/s the following amount of thermal energy will be transferred in the pipeline:

• for a line with an outer size of 20 (internal cross-section 13.2 mm) the amount of heat is 4.1 kW;
• for propylene products Ø 25 and 16.6, respectively, the amount of heat will be 6.3 kW;
• propylene pipelines with outer and inner diameters of 32 and 21.2, respectively, have a thermal energy supply of 11.5 kW;
• pipe materials of 40 millimeters (internal clearance size 26.6 mm) will provide a heat supply of 17 kW.

When the fluid flow rate increases to 0.7 m/sec, the coolant supply intensity will immediately increase by 70-80%.

Important! The practical purpose of the above table is to recommend, based on the required amount of thermal energy, the required pipe diameter when selecting pipe materials for a residential heating system.

Let's look at an illustrative example:

Available standard house usable area 250 m2. The building is sufficiently insulated to create normal conditions residence needs heating at the rate of 1 kW per 10 sq. m, that is, to create comfortable temperature 25,000 watts of thermal energy (maximum) will be enough in the house.

On a note: the first floor always requires more heat - approximately 2/3 of the total amount consumed.

Thus, out of 25 kW, heating the first floor will require 15 kW, the second - 10 kW.

The house is equipped with an autonomous heating system based on a double-circuit boiler. The radiators installed in the rooms are connected in parallel. The house has wiring for two wings, with equal thermal power. On the ground floor, the power for each wing is 7500 watts. For the second floor, both wings require 5000 watts.

Two-story house with a water heating system based on an autonomous boiler - cross-section

The boiler produces 25 kilowatts of thermal energy to heat the house. This means that for the heating main you need to use polypropylene pipes and fittings with an internal diameter of 26.6 mm (at a feed speed of 0.6 m/s). This value corresponds to an outer pipe diameter of 40 millimeters.

To supply the branches on the first floor, 1500 watts of heat will be required. Using the data from the table, we get the following:

• at a flow speed of 0.6 m/sec, the optimal diameter of the internal lumen of polypropylene pipes will be 21.2 mm - the identical external parameter corresponding to this value, according to the table, is 30 mm;
• for each wing suitable pipe material with internal diameter 16.6 mm, which corresponds to Ø 25 mm of the external contour of the cross-section of polypropylene pipes.

Now let's look at the procedure for connecting heating devices.

Water heating radiators have an average power of 2 kilowatts, so theoretically, pipes with minimum value outer diameter - 16 mm (PN16). However, in practice, it is recommended to use polypropylene products with an internal section size of 13.2 mm and an outer diameter of 20 mm (PN20), since the use of PN16 polymer pipes is considered inappropriate due to low manufacturability.

The second floor is equipped with a pipeline with a cross-section of 32 mm. For each wing, pipes and connecting fittings Ø25 mm are used. The situation with radiators is the same as on the first floor - the batteries are connected using PN20 pipes.

Conclusion

Based on the above example, for each section of the pipeline in the heating system, you can select components of the required diameter - the efficiency of the heating equipment will also depend on this.

It should be remembered that the materials for the pipeline in the heating system are selected to comply with the maximum technical characteristics of an autonomous boiler, despite the fact that in most cases the unit will operate as normal - in accordance with the specified operating parameters.