Greetings, Comes! Do you know which pipe diameter is needed for the heating of a private house? If you are interested in the title of the article, then you probably do not know. I'm going to fix this shortcoming and become acquainted with the extremely simple and understandable schemes for calculating the heating system. So, on the road.

Step by step

To calculate the size of the pipes on different sections of the heating system, you need to know:

1. The need for the warmth of the whole house. It determines the power of the boiler or other heat source and the diameter of bottling at the entrance and output from its heat exchanger;
2. Heat load on separate contour sections. It consists of the total power of the heating devices and is determined by the heat loss of heated room or the room group.

Calculate the power of the boiler

Simple scheme

Soviet Snaps of half a century ago were offered to calculate the thermal power of the heating system, based on the rate of 100 watts per square meter. Let's say, a house of 150 m2 is needed a heat source with a power of 150x100 \u003d 15000 watts, or 15 kW. Point.

The scheme is understandable, simple and ... gives huge errors. The fact is that it completely ignores a number of factors that are very strongly affecting heat loss:

• Height ceiling. In the apartments of the buildings of the 60-90 years of the 20th century, it was typical - 2.5 meters. In the cottages you can find the scatter from 2.4 to 4 or more. Meanwhile, with an increase in the height of the ceiling, the heated volume is increasing, the walls of the walls (through which heat is lost) and, accordingly, the energy costs are growing;

• Quality of insulation walls. The building from aerated concrete with an external insulation of foam or mineral wool will lose much less heat than the country house with the walls in one;

When a SNIP was created, offering to calculate heating at a rate of 100 W / m 2, the standard de facto was typical for houses of Stalinskaya buildings brick walls in 2 bricks thick (taking into account the thickness of the masonry seams - 51-52 centimeters).

• Square and glazing structure. Through the windows in the general case, much more heat is lost than through the walls, therefore, the more of their area - the more heat is needed for heating. At the same time, the windows can vary greatly with thermal conductivity: the triple energy-saving double-glazing passes 8-10 times less heat than solitary glazing;
• Climatic conditions. With the unchanged quality of heat solar, the heat loss is directly proportional to the temperature difference between the house, which we flash, and the outer air. At +20 in the house, heat consumption of 0 ° C and -40 ° C on the street will vary exactly three times. SNiP standards, faithful to the European part of Russia, are equally unsuitable for warm and cold regions.

Accurate scheme

How to take into account all variables when designing the heating system of the cottage?

Very simple. In the calculations you need to consider:

1. Volume heated room. It is equal to the product of the heated area to the height of the ceiling;
2. Quality insulation walls and heat loss through windows;

1. Maximum temperature difference With Street.

The formula for calculation has the form Q \u003d V * K * DT / 860. In it:

• Q - calculated power (kW);
• V is the volume of the house or a separate room, which we have to dash (M3);
• K is the heat dissipation coefficient, determined by the quality of the insulation of the walls and the structure of glazing windows;
• DT is the difference between the temperature in the house (in the calculations, it takes appropriate sanitary standards) and the lower peak of winter temperatures (read - the temperature of the five coldest days of the cold month itself).

I emphasize: the calculations takes into account the temperature of the cold five days, and not the absolute minimum temperature. Extreme frosts occur with periodicity once a few decades, and put them in the project, to put it mildly, considerably.

Where to get the values \u200b\u200bof sanitary standards and winter mounters?

With the first parameter, everything is simple: it is equal to +18 ° C in regions with an average winter temperature above -31 degrees and +20 ° C in a colder climatic zone.

The source of information about the temperatures of the coldest five days for different regions of the country may be SNIP 23-01-99, dedicated to building climatology. If you do not want to rummage in the regulatory documentation - just find your city on the Row map below.

What is the coefficient of heat loss?

It is selected from the following ranges of values:

Picture	Coefficient and Description of the building
	0,6-0,9 : Insulated facade, triple and / or energy-saving windows.
	1-1,9 : Walls in 2 bricks and double double glazing.
	2-2,9 : Walls - 25 cm of brickwork or 10 cm of timber, windows - with single glazing.
	3-4 : Building with metal walls without insulation.

Let's make it possible to calculate the total power of the heating system for the house with an area of \u200b\u200b150 squares, specifying a number of additional parameters:

• The house is located in Sevastopol (the temperature of the coldest five days of winter - -14 degrees);
• Its walls are stacked from an inkerman stone (local sedimentary breed with good thermal insulation qualities) and have a thickness of 40 cm;
• Ceiling height - 3.2 meters;
• Windows - plastic, with single-chamber windows.

We will proceed to the calculation.

Road volume equal to 150x3.2 \u003d 480 cubic meters.

Insulation coefficient Taking into account the extremely low thermal conductivity of the inkerman stone, we accept an equal unit (1.0).

Delta temperature between house and street equal to 20 - -14 \u003d 34 ° C.

We substitute the values \u200b\u200bin the formula: Q \u003d 480 * 1 * 34/860 \u003d 19 (with rounding) Kilowatt.

Calculate the power of a separate circuit

The heat load on each separate section of the heating circuit is equal to the sum of the power values \u200b\u200bof the heating devices connected to it. If there are two radiator in a room of 1.5 kW each, it creates a load on the contour, equal to 1.5 + 1.5 \u003d 3 kilowatts.

The total power of all heating devices in the house should be equal to the rated power of the boiler or slightly exceed it.

Where to get information about the power of the instruments?

For panel, lamellar radiators and convectors - only in the accompanying documentation or on the official website of the manufacturer.

In the case of sectional radiators, the following power values \u200b\u200bper section can be used in the calculations:

Picture	Radiator type and nominal thermal power section
	Cast-iron: 140-160 W.
	Bimetallic: 180-190 W.
	Aluminum: 200-210 W.

As always, there is a nuance. Manufacturers indicate power for a very specific mode of operation - for the temperature delta between the surface of the radiator and the ambient air in 70 degrees.

In practice, this mode is achieved only in the central heating system and only in the peak of cold weather: at a temperature on the supply of heating 95 ° C close to the elevator node of the battery can be warm up to 90 degrees at air temperature in apartments 20 ° C.

The actual thermal power of the section will decrease in proportion to the temperature difference between the heated room and. At +60 on the surface of the radiator and +25, the temperature delta room will be 35 degrees, and the thermal power of each section will fall relatively nominal smoothly.

The calculation of the diameter of bottling and supplying to radiators is performed for the highest temperature of the coolant, with which it is planned to operate the heating system and the minimum room temperature. In this case, the project is laid as the maximum possible thermal load.

Let's analyze the calculation of the load on a separate heating circuit on the example.

Dano:

• The room is heated with two radiators with a rating capacity of 1.5 kW each;
• The heating system will operate with a flow temperature of 75 degrees;
• The air in the room can cool to +18 ° C.

Delta temperature equal to 75-18 \u003d 57 ° C, or 57/70 \u003d 0.81 from the one at which the radiator gives the nominal power.

Actual power radiators (that is, the maximum thermal load on the contour) is 3 * 0.81 \u003d 2.43.

Calculate the diameter of the pipe

The calculated diameter of pipes for the heating system is influenced by two parameters:

which we just learned to count on;

The speed of the coolant in the circuit. The faster it moves, the more heat is transferred per unit of time with a constant inner section of the pipe.

In a system with a circulation pump, it is more profitable not to increase the diameter of bottling and eyeliner, and speeding up the circulation by putting a more productive pump. The price of the pipe meter of the pipe with a height of the diameter increases nonlinearly, so it is obligated to put thick pipes.

However, there is a limiting factor - hydraulic noise. At a speed of over 0.7 m / s, noise appears on chokes, and at 1.5 m / s and above - on turns and fitting compounds. Therefore, the calculation rate of 0.4-0.6 m / s is laid into calculations.

The inner diameter of the pipe is calculated by the formula d \u003d √354 * (0.86 * q / dt) / v. In it:

• D - the desired diameter (mm);
• DT is the temperature difference at the inlet and outlet of the circuit (° C);

A typical temperature difference between the supply and reverse in the autonomous circuit is 20 degrees.

• V is the speed of the coolant (m / s).

So, with a 12 kW boiler power, a degree of 20 degrees and water velocity in circuit 0.6 m / s Minimum inner pouring diameter is √354 * (0.86 * 12/20) / 0.6 \u003d 17.4 mm.

In the steel pipe, its nominal size (DP, or DN) is approximately equal to the inner diameter. Taking into account the real line of the size of the internal diameter of 17.4 mm corresponds to the water-and-wire pipe Du 20.

For eyeliner to radiators and small heating circuits, it is difficult to calculate the temperature difference between the feed and reverse. In this case, it is easier to choose the sizes of the pipes on the table:

In private houses, the installation of the heating system is more often performed by non-steel pipes, but plastic and metal-plastic. The reason is the lower price of the robust meter of polypropylene or metal-polymer pipes compared to steel. These products use another system designation system: they are specified by the outer diameter.

Only the inner section of the pipe affects the bandwidth of bottling or eyeliner. To calculate the inner diameter, take two wall thicknesses from the outer diameter. Both parameters are always indicated in the marking.

Example: We need a pipe with an inner diameter of 17.4 mm. The wall of the reinforced polypropylene tube size of 25 mm has a thickness of 3.2 mm. The inner diameter of the pipe is 25- (3.2 * 2) \u003d 18.6 mm.

Verdict: Suitable.

A special case

The gravitational heating system has a couple of features:

• Overpressure in the system is missing. The outline communicates with the atmosphere through an open expansion tank;
• Instead of pump, the coolant is driven by natural convection: The water heated with a boiler is displaced in the upper point of heating bottling and returns to the boiler through the bottling of gravity, along the way, giving heat batteries.

The advantages of the gravitational heating scheme are complete non-volatility and absolute safety. Water boiling in the heat exchanger Water will not cause his explosion: couple will leave the contour through an open expansion tank.

The reverse side of the advantages of natural circulation is the minimum hydraulic pressure in the circuit. The consequences of low pressure are slow water circulation and uneven heating of radiators.

To compensate for low pressure, you need to reduce the hydraulic resistance of bottling to a minimum.

How to do it?

The instruction is obvious: it is necessary to increase its diameter. The pressure loss in the pipe is inversely proportional to its internal cross section.

The inner diameter of the heating bottling in the gravitational system should not be less than 32-40 millimeters.

Conclusion

I hope that this material will help the reader in the design of its own heating system. Learn more about the methods of calculating heating you will help you video in this article. Waiting for your additions to her. Successes, Camrads!

16709 3 10

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

Greetings, Comes! This article is about which diameter of the pipe to choose for heating. In it, I will talk about the methods of calculating the passability and section, give a number of practical recommendations for the selection of sizes and will explain the difference between different types of pipes. So, on the road.

Method of calculation

Reference data

There is a simple and understandable dependence between the heat load, the pipeline cross-section and the speed of the coolant movement: the number of pumping thermal energy can be increased by making the pipeline thicker or forcing water to move faster.

With the cross section, everything is clear: the thicker the pipe, the more expensive it is. Why can not be significantly increased by the rate of coolant pumping? Because when it is raised to 1.5 m / s, noticeable hydraulic noises occur, which make the stay in the heated room frankly uncomfortable.

Typically, the calculation of the filling section is performed for a flow rate of 0.4 - 0.6 m / s. The reduction in speed to 0.25 m / s and below will not only affect the effectiveness of heating, but also will not allow the coolant to squeeze the air traffic jams to the aircraft or the crane of Maevsky.

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

Inner diameter, mm	Heat flux (kW) at the speed of flow, 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 pipe diameter for heating, guided by this table? Very simple:

1. Choose the most appropriate thermal load from the second - fourth columns;
2. Take the corresponding value from the first column.

What kind of beast is the thermal load? How do you calculate it with your own hands?

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

• For eyeliner to a separate heating device, the thermal load is equal to its passport power adjusted to the real temperature mode. As a rule, manufacturers indicate power for ideal conditions - the temperature delta between the coolant and the air of the heated room at 70 degrees (that is, with +20 in the room, the battery should be heated to 90 s).
  In practice, in the autonomal circuit, 70 - 75 degrees are maintained on the supply and 50 - 55 on the return on the return, which, with a comfortable +25, the house will give a temperature delta at 30 - 50 C. When delta at 50 degrees, the thermal capacity of the battery will decrease and will be 50/70 \u003d 0.714 from passport value;

• For separate sections of the circuit, the heat load is equal to the total power of the connected heating devices. Let's say if there are two batteries of 1.2 kW in the room, it will be 1.2 * 2 \u003d 2.4 kW.

Where to take data on the thermal power of the batteries? In general, from the accompanying documentation or from the manufacturer's website. Rough calculation can be performed based on the following values:

• The cast-iron section in ideal conditions gives 140 - 160 W heat;
• Bimetallic -180 W;
• Aluminum - 200 W.

I led data for standard size radiators, with an inter-axis distance of a 500 mm leash. In the rules of many producers there are batteries with a smaller and large size of sections.

How to determine the heat load, if you plan to use weld registers of non-standard sizes as heating devices?

For the first section of the register (bottom pipe), the formula has the form Q \u003d 3.14 * D * L * K * DT, where:

• Q - cherished thermal power in watts;
• D - the outer 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 air indoor.

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

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

• It consists of four identical sections;

I consciously neglect the heat transfer of the jumpers between sections and the ends of the sections. It is insignificant against the background of the total 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 up to 23.

Initially, calculate the power of the first section. It is equal to 3.14 * 0.108 * 2 * 11.63 * (60-23) \u003d 292 watts (with rounding to the whole value).

Then we find the thermal power of the second and subsequent sections. It will be equal to 292 * 0.9 \u003d 263 watts (again with rounding).

The last step is to calculate the total power of all sections. 292 + 263 * 3 \u003d 1081 watts.

And now let's find out which diameter of the pipe is needed for heating when connecting this register. How to easily notice, the minimum value in the above table overlaps its power to three more 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

The theory is worth it if it is not supported by practice. Here is the instructions for choosing sizes based on my many years of practical experience.

• Any heating device can be safely connected by a pipe diameter 15 (1/2 inches). The restriction is one thing: in the system of the Central Union of the apartment building, the eyeliner must be equipped with a jumper, a diameter of the non-inferior riser (as a rule, Du 20 - DU25). When changing the configuration, a decrease in the diameter of the riser is unacceptable;

• In a system with forced circulation, a pipe size can be used as a filling. or, with some increase in the flow rate, Du 20;

In the photo - the heating layout site in my basement. Used polypropylene tube with a size of 25 mm.

In new houses with the TsO, the heating is bursting exactly the pipe DU 20. In a ten-story house, 20 radiators are mounted on the pair of risers of this diameter or.

Heating riser in an apartment building. Pipe size - Du 20.

• In the gravitational (samotane) heating system, the hydraulic diameter increases to DU 32 - DU 50. The fact is that an increase in the inner cross section of the pipe allows you to drastically reduce its hydraulic resistance - the most important parameter in the circuit, the circulation in which is only provided by the difference in hot and cold water density. .

Such different diameters

Due to the difference in the system names of pipes from different materials in the head of a potential buyer, some confusion emerges inevitably. I will try to clarify this question.

• Steel pipe is marked with conditional passage, or Du. It is approximately equal to the inner diameter; Small deviations of the actual size from the Du are due to the scattering of the thickness of the walls of ordinary, lungs and reinforced water-gas pipes;

• DN marking indicates the same Du (conditional pass). However, DN is often indicated in inches. Inch is 2.54 centimeters; Only here the marking in inches is traditionally rounded up to several integers and fractional values, which aggravates the confusion. For the convenience of the reader, I will give a table of matching the size of steel pipes in millimeters and inches;

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

• Stitched and conventional polyethylene pipes, polypropylene and metal-polymer products are marked outdoor diameter. On average, their diameter per step is larger than the internal section: a pipe with a size of 25 mm has the same inner cross section as steel Du 20, 32 mm corresponds to 25 and so on;

• All polymeric products are lower than steel, hydraulic resistance due to the minimum roofing of the walls. In addition, they overgrow with rust and lime deposits, therefore their diameter is selected without stock. But the steel pipes for the system of the CO is better to buy with these factors, rounding the calculated diameter of the pipes in the biggest.

Conclusion

I hope that I managed to comprehensively answer the questions accumulated from the respected reader. As always, additional materials can be studied by reviewing the video in this article. I will be grateful for your additions and comments. Successes, Camrads!

The efficiency of the heating line depends on the power of the boiler, radiators, valve parameters. The appropriate diameter of pipes for heating is determined by online programs or independent calculations, as well as technical indicators and material. Knowing all the nuances, the owner of the house may pick up high-quality and reliable products.

The difficulty of selecting the diameter of the pipeline

When choosing pipes, the internal and external diameter is taken into account, as well as the manufacturer

The main complexity of the diameter selection is in the features of the planning of the highway. Considered:

• outdoor indicator (copper and plastic) - the surface of the reinforcement can give heat streams into the room;
• the inner diameter (steel and cast iron) - allows you to calculate the capacity of the individual section;
• conditional parameters - rounded value in inches, need for theoretical counts.

To determine the section, take into account that 100 W energy is spent on 1 m2 of the premises.

Dependence of size from the coolant speed

The selection of the diameter indicator will determine the capacity of the highway, taking into account the recommended speed of 0.4-0.6 m / s. It takes into account that at a speed of less than 0.2 m / s, air traffic jams are formed, and at a speed of more than 0.7 m / s there is a risk of increasing the pressure of the coolant.

To exclude heat loss and increasing the coolant speed of the coolant

How evenly the thermal energy along the contour is distributed and the diameter of the nozzles is determined. What he is less, the faster the water moves, but the high-speed indicators have a limit:

• up to 0.25 m / s - otherwise there are risks of the appearance of air traffic jams and the impossibility of their removal removal, heat loss in the room;
• no more than 1.5 m / s - the coolant in the circulation process will be noise;
• 0.36-0.7 m / s - the reference amount of the coolant speed.

To control the intensity of circulation without increasing the diameter of nozzles, a circulation pump is used.

The volume parameters of the coolant

For systems with natural circulation, it is better to choose fittings with an enlarged diameter. This will reduce heat loss in the process of friction of water about the inner surface. When using this reception, it should be noted that with an increase in the volume of water increases the cost of energy on its heating.

Hydraulic losses

The phenomenon occurs if the pipeline is made of plastic products of different diameters. The reason is the difference in pressures in the fields of joints and an increase in hydraulic losses.

Main diameter calculation formula

The correct definition of the diameter of the pipe used for the highway heating of an apartment or private home is made on the basis of the table and formula. When working with the table, you need to focus on green cells - they indicate the optimal pressure rate of the coolant.

The calculation is made by the formula D \u003d √ (354 * (0.86 * Q / Δt) / V)Where:

• V.- fluid speed in the pipe (m / s);
• Q.- the right amount of heat for heating (kW);
• Δt.- the difference between the reverse and direct feed (s);
• D. - Pipe diameter (mm).

In the system with natural circulation, the diameter of the pipes choose more

As an example, you can consider a two-storey house with four wings (2 to the floor), connected to a two-pipe system with a total heat loss 36 kW, 20 kW of which are heated on the 1st floor, 16 kW - second. Polypropylene was used for communications, they operate in 80/60 mode at a temperature of 10 degrees.

Counting algorithm:

1. The entire volume of water falls on the plot of the first branch of the boiler. This is the total amount of heat equal to 38 kW.
2. The table needs to find this line and the corresponding green cells. With these parameters, the required diameter is 40 and 50 mm. The choice is made in favor of the smaller.
3. For the development you can see the amount of heat on the first (20 kW) and the second (16 kW) floors. The cross section of tubular reinforcement on the table - 32 mm.
4. Since on each floor 2 wings, the contour is divided into two branches. For the first floor 20/2 \u003d 10 kW on the wing, for the second - 16/2 \u003d 8 kW on the wing.
5. The table determines the diameter - 25 mm, used until the load drop to 5 kW, then 20 mm.

The calculations for the return is not needed - pipes are used with similar parameters.

Important technical specifications

High-quality room heating is impossible without taking into account the technical characteristics of the equipment. They can be considered on the example of standard products from polypropylene of the RN 20 and 30 brand.

With a heat carrier at a rate of 0.4 m / s, it is necessary to take into account the thermal power of products of various diameters. With external parameters, 20 mm produced 4.1 kW, at 25 mm - 6.3 kW, at 32 mm - 11.5 kW, at 40 mm - 17 kW.

The procedure for calculating the reservoir of heating and assembly sleeves

The sleeves on the heating manifold are installed after selecting the pipe diameter

The heating manifold is equipped with an apartment or a private house. The device provides a layer of coolant for several branches. The collector's calculation is made together with the pipe cross section along the outer or internal size on the basis of the principle of "three diameters" - pipes on the track are removed from each other by 6 radii each. The diameter of the collector is also equal to this magnitude.

The parameters of the sleeves are calculated after the trigger cross section is established. The elements are selected taking into account the material of the wall and reinforcement, the degree of expansion during heating. For example, the diameter of the plastic tube is 20 mm, the sleeve is 24 mm.

Sequence of calculating the section of heating highways

For communications with circulation pumps, you will need to take into account the volume of the coolant in the system, the total length of the heating main, the reference flow rate, heat transfer, the power of the equipment, the resistance value and pressure without the pump.

To find out the size of the products, you will need to make a correction to the reduction of the efficiency - the resistance of turns, bends and fittings. Calculations can be carried out by the formula H \u003d λ (L / D) (V2 / 2G)Where:

• N. - the height of the zero pressure without pressure in m;
• λ - pipe resistance coefficient;
• L. - Length of the highway;
• D. - the inner diameter of the pipe in mm;
• V. - flow rate in m / s;
• g. - Acceleration of free incidence, equal to 9.81 m / s2.

In the process of calculating the minimum heat loss, it is necessary to check several variants of diameters for minimum resistance.

Characteristics of materials for the manufacture of pipes

Table of diameters of plastic pipes for heating

Manufacturers produce pipelines from several types of materials.

Polymer

Products for which plastic material is used is stitched or ordinary polyethylene. After calculations, it is possible to establish which diameter of propylene pipes is needed for heating a private house depending on the type of equipment:

• one or two batteries - 16 mm;
• radiator or group of radiators with a capacity of 1-2 kW (standard), up to 5 batteries with a capacity of up to 7 kW - 20 mm;
• shoulder dead-end layout (wing at home), radiators up to 8 pcs. with a total capacity of up to 11 kW - for heating it is better to use propylene tubes with a diameter of 25 mm;
• one floor (up to 12 radiators with a total capacity of up to 19 kW) - 32 mm;
• mainstroke of 20 radiators up to 30 kW with a capacity of 40 mm.

The thickness of the walls of polymeric products is selected by the parameters of the pressure on the network and is 1.8-3 mm.

Steel

Different with durability and good heat transfer, but are complex in terms of installation. The surface of the reinforcement from the stainless steel is not corrosion, is characterized by smoothness. Steel heating reinforcement according to GOST 3262-75 is classified according to the outer diameter, on which the wall thickness depends. Data is shown in the table.

Standard and light modifications are used to organize apartment or home heating.

Calculate the optimal cross-section of the pipeline with a professional is easy. Practical experience + Special Tables - all this is enough to take a right decision. But how to be an ordinary owner of the dwelling? After all, many prefer to mount the heating contour on their own, but at the same time they do not have a profile engineering education. This article will be a good tip for those who need to decide on the diameter of the pipe heating of a private house.

There are several nuances to be paid attention to:

• First, all data obtained on the basis of computations by formulas is approximate. Various roundings of values, averaged coefficients - all this makes a number of amendments to the end result.
• Secondly, the specificity of the operation of any heating circuit has its own characteristics, so any calculations give only approximate data, "for all cases".
• Thirdly, pipe products are available in a specific assortment. The same applies to diameters. The corresponding values \u200b\u200bare located in a certain row, with gradation by values. Therefore, you will have to pick up the nominal closest to the calculated one.

Based on the foregoing, it is advisable to take advantage of the practical recommendations of professionals.

All do - in "mm". In brackets - for systems with natural circulation of the coolant.

• Total line pipe - 20 (25).
• Taps to batteries - 15 (20).
• When - diameter 25 (32).

But these are common circuit parameters that do not take into account its specifics. More accurate values \u200b\u200bare reflected in the table.

What is taken into account when choosing a pipe diameter

The power of the heat generator. It takes the basis and is determined individually for each structure. What is the owner, acquiring the boiler? On the cumulative area of \u200b\u200ball heated premises. That is what will definitely clarify the manager at the point of sale, if the buyer has questions about this item.

On a note! It is believed that in order to ensure high-quality heating of the house, it is necessary to adhere to the following relationship - 1 m2 / 0.1 kW. But if you consider the features of the climate, gentle the mode of operation of the unit (so as not to "drive" it at the limit), then add about 30%. It turns out - 1 / 1.3.

The speed of the coolant. If it is less than 0.25 m / s, that is, the risk of enhancing the system, the formation of traffic jams on the track. Excess 1.5 value is fraught with "noises" in the highway. This is especially noticeable when metal pipes, and are also laid in an open way. But in any case, the movement of the coolant on the track will be well listening.

The practice is proved that for a private structure (with an autonomous heating circuit), it is necessary to focus on the indicator ranging from 0.3 to 0.7. This is the optimal value for any system.

Contour configuration. In private houses, when it is installed, as a rule (regardless of the scheme), all "threads" are at the collector. Each of them is "loaded" to a certain number of radiators. It makes no sense to acquire pipes of the same diameter for all lines, if we consider that the larger the cross section of the workpiece, the higher the price of 1 p.m.

Pipe diameter. The external special role does not play, as products from various materials have differences in the wall thickness. This parameter testifies only to the convenience of fastening the product. Inner diameter - about the bandwidth of the track. It is he and is determining.

On a note! It is customary to operate with averaged value of the size of the section (diameter of the conditional pass). This parameter is applied in the calculations.

The diameters of the pipes are made in inches. For us, this is unusual (not metric) system, so you should know the rules for the translation of values. The ratio of inches to centimeter is ½, 54 (or 25.4 mm). Pipe material - metalplastic, steel, PP, PE.

The specificity of the structure. First of all, this refers to the effectiveness of its thermal insulation - from which materials it is mounted, for which technique, and so on.

• The wrong choice of diameters of products is fraught with many troubles: leaks (due to hydrodynamic shocks or excess pressure in the highway), an increased consumption of EL / Energy (fuel) due to the low efficiency of the system and a number of others. Therefore, they should not mount it according to the principle of "like a neighbor (Cuma)".
• If the outline consists of heterogeneous pipes, it will have to do special calculations for each site (line) of the track. Separately - for plastic, metal (steel, copper), apply various coefficients and so on. Only a specialist can solve such a task. In such situations, it is not necessary to deal with the calculations, since the error can be quite significant. Professional services will cost much cheaper than the subsequent alteration of communications, and even in the heating season.
• Connecting all devices (expansion tank, batteries and other) contour is carried out by pipes of one section.

To eliminate the formation of air traffic jams (in the case of some errors in the calculations), the so-called air vent should be installed on each line.

For systems with forced circulation, a properly chosen pipeline is of great importance. If errors will be made in the calculation of the diameter of pipes for heating, it will affect the effectiveness of the heating of the house.

What is needed for this

1. Total heat loss housing.
2. What power is heating radiators separately in each room.
3. The total length of the contour pipes.
4. How diluted system.

To be able to calculate the diameter of the pipes, it is necessary to determine in advance the general loss of heat, the power of the boiler equipment and batteries for each room. A considerable value also has what method will be selected for pipe wiring. Having all these parameters on the hands, the scheme of the future calculation is drawn up.

It is also important to remember some specific labeling of various pipes. Thus, on polypropylene pipes for the heating of a private house, the diameter indicates the outer (the same applies to copper products). To calculate the internal parameter, the wall thickness of the walls take place from this indicator. Steel and metal-plastic pipes are marked with internal cross section.

Choosing a suitable diameter of pipes for heating

It is almost impossible to carry out the accurate calculation of the section of the pipeline. For these purposes, several methods are used, with an approximate identity of the final result. As is known, the main task of the system is to delivery on the battery of the required volume of heat to achieve maximum uniformity of heating the heating device.

In forced circuits, the pipeline, coolant and circulation pump are used for these purposes. With this set of devices, it is necessary to submit the desired portion of the coolant for a fixed time. There are two ways to implement this problem - the use of pipes of a smaller diameter in combination with a greater speed of water movement, or the use of a system with a large cross section in which the intensity of movement will be less.

The reasons for the popularity of the first option:

1. Ligger price for thinner pipes.
2. Big ease of installation.
3. In open areas, such systems are less noticeable. If they are placed in the floor or walls, landing spaces are required smaller.
4. In narrow pipelines there are less fluid. This leads to a decrease in the inertia of the system and to fuel economy.

Due to the set of typical diameters and the fixed amount of heat transported on them, there is no need for the same calculations. For these purposes, special tables were compiled: they allow, having data on the hands of the desired amount of heat, water supply speeds and the operating temperature of the contour, calculate the desired dimensions. To determine which pipe diameters are for heating, you need to find the desired table.

To calculate the diameter of the heating pipes, the following formula is used: d \u003d √354x (0.86x Q / ΔT) / V, where D is the desired diameter of the pipeline (mm), Δt ° is the temperature delta (the difference in feed and returns), q - load To this section of the system, kW is a certain amount of heat required for the heating of the room, V is the speed of the coolant (m / s).

Autonomous systems usually possess the speed of the coolant at the level of 0.2 - 1.5 m / s. As practical experience shows, the most optimal rate in such cases is 0.3 m / s - 0.7 m / s. With a decrease in this indicator, there is a real threat to the appearance of air traffic jams, with an increase - the coolant when moving begins to noise much.

To select the optimal value and there are tables. They contain data for pipes from different material - metal, polypropylene, metalplastic, copper. When determining the diameter of the heating pipes, as a rule, the emphasis was applied to standard operating modes with high and medium temperatures. Some examples will understand the essence of the procedure.

Calculation of two-pipe systems

It will be about a two-storey house with a two-pipe heating system for two wings on each floor. Polypropylene tubes are used to improve the system. Mode of operation - 80/60, temperatures delta - 20 degrees. The heat loss level is 38 kW of thermal energy (the first floor is 20 kW, the second is 18 kW).

Calculation procedure:

1. First you need to decide on which pipe to issue a plot between the boiler and the first branching. It is transported by the entire volume of the coolant transmitting heat to 38 kW. Reference data indicate two suitable parameters - 40 and 50 mm. It is more profitable to stop at a smaller diameter of 40 mm.
2. In the place of separation of the flow of 20 kW is sent to the first floor, and 18 kW - to the second. According to the directory, the section is determined. In this case, for each direction the optimal diameter is 32 mm.
3. In turn, each contour includes two lines with an equivalent load. On the first floor, both parties are 10 kW (20 kW / 2 \u003d 10 kW), on the second - 9 kW (18 kW / 2) \u003d 9 kW). Suitable values \u200b\u200bfor these branches will be 25 mm. This parameter is more reasonable to use until the load reduction to 5 kW. After that, go to the diameter of 20 mm. The first floor is translated by 20 mm immediately at the second radiator. The second floor usually goes after the third instrument. As practice shows, this transition is best carried out with a load of 3 kW.

Thus, the diameter of polypropylene pipes for a two-pipe system is calculated. It makes no sense to determine the size of the feed pipe: they are taken the same as for the feed. This procedure is simple: the main thing is to have all the source data. If the organization of the system is assumed to organize a system of other type, it is necessary to use data for a specific manufacturing material. Calculation of pipe diameter Heating with natural circulation is somewhat different.

Calculation of a single-tube system of forced type

The principle applies the same as in the previous case, but the algorithm of action is changing. For example, it is possible to calculate the internal diameter of a simple single-tube heating system in a single-storey building. There are six radiators with a serial connection in the circuit.

The procedure for calculating the diameter of the heating heating pipeline:

1. The boiler passes to the beginning of the system of 15 kW heat. According to reference data, this site can be equipped with pipes 25 mm and 20 mm. As in the first example, it is better to choose 20 mm.
2. Inside the first battery there is a decrease in thermal load to 12 kW. This does not affect the cross section of the outgoing pipe: it remains in the same value of 20 mm.
3. The third radiator reduces the load to 10.5 kW. In this case, the cross section remains the same - all the same 20 mm.
4. The transition to a smaller diameter of 15 mm occurs after the fourth battery, since the load decreases to 8.5 kW.
5. By the fifth device, the coolant is transported by a pipe of 15 mm, and after it takes place by 12 mm.

At first glance it may seem that the calculation of pipe diameters for the heating system is easy and simple. Indeed, when polypropylene or metal-plastic products are used to organize contour, it usually does not occur complexity. This is due to their low thermal conductivity and small leaks of heat through the walls (they can not be taken into account). It is different in a different way with metal products. If the steel, copper or stainless pipeline has a decent length, a lot of thermal energy will be treated through its surface.

How to calculate metal pipes

Large heating systems equipped with metal pipes require metering heat loss through the walls. Although on average, these indicators are quite low, but on very long branches the total value of lost energy is quite high. Often because of this, the latter batteries in the heating circuit are not well heated. The reason here is one - the diameter of the pipes was incorrectly selected.

An example will be determined by the loss of steel pipe 40 mm, with a thickness of the walls of 1.4 mm. For calculation, the formula Q \u003d kx3.14x (TB-TP) is used, where q is thermal losses of the pipe meter, K -Line coefficient of heat transfer (in this case, it corresponds to 0.272 W * m / s), TB - water temperature inside (+80 degrees), TP - air temperature in the room (+22 degrees).

To obtain the result, it is necessary to substitute the necessary values \u200b\u200bin the formula:

q \u003d 0.272x3.15x (80-22) \u003d 49 W / s

This picture is evaporated that each meter of the pipe loses heat in the amount of almost 50 W. On very long pipelines, total losses can be simply catastrophic. In this case, the volumes of leaks directly depend on the cross section of the contour. To account for such losses to the indicator of the heat load on the battery, you must add a similar indicator on the pipeline. The determination of the optimal diameter of the pipeline is carried out with regard to the total value of leaks.

Usually in autonomous heating systems, these indicators are not critical. In addition, during the procedure for determining the heat loss and power of boilers, the data obtained is usually rounded upwards. This creates a safety margin that exempted from compound computing.

Search for relevant data

As for the search for optimal reference data, almost all the sites of manufacturers of component heating systems provide this information. In cases where suitable values \u200b\u200bwere not found, there is a special selection system of diameters. This technique is based on calculations, and not on the averaged laws built on the processing of data on the huge amount of heating systems. The calculation of the coolant for the pipe cross section is designed by plumbing with practical experience of installation work, and is used to arrange small contours inside the dwellings.

In the overwhelming majority of cases, heating boilers are equipped with two sizes of feed and reverse pipes: ¾ and ½ inches. This size is based on the layout to the first branching. In the future, each new branching serves as a reason to reduce the diameter by one position. This method allows you to calculate the cross section of pipes in the apartment. We are talking about small systems in 3-8 radiators. Typically, such schemes consist of two or three lines with 1-2 batteries. Similarly, small private cottages can be calculated. If there are two or more floors, you have to use reference data.

Method of equiation

Although pipes from different materials are marked with different values \u200b\u200b(internal or external), in some cases their equalization is allowed. This concerns situations when it is not possible to find data on a specific pipe: in such a situation, you can use information on a similar section of the product from another material.

Suppose it is necessary to calculate which diameter of the metal-plastic pipe is needed for heating, and the necessary information was found in this material were not found. Alternatively, a coolant rate table in the heating system for polypropylene products is used. Using the appropriate dimensions, select the appropriate parameters for the metal-plastic pipe. Without inaccuracies, in this case, it fails, but in contours of forced type, they are not critical.

Output

Using for the organization of heating of their home is not a very complex and branched scheme, the calculation of the optimal diameter of the pipeline can be implemented on its own. To do this, it is necessary to arm yourself with information on the heat loss of the home and the power of each battery. Further, using special tables and reference books, they select the optimal value of the cross section of pipes, which can ensure the transportation of the desired volume of thermal energy into each of the rooms.

If complex schemes are used with a plurality of elements, it is desirable to invite a professional plumber to calculate them. In the presence of confidence in our own power, it is recommended to consult with a specialist. There are cases when due to the mistakes admitted, it is necessary to engage in expensive reconstruction of the entire contour.