The comfortable existence of the residents of a modern country house is provided by a powerful network of various engineering communications, among which one of the main places is occupied by the system responsible for heat. When planning to mount it on their own, almost every owner wonders what pipe diameter to choose for heating a private house. For many, this becomes a real problem, since both the final cost and the efficiency of the heating system depend on it.
Factors affecting the choice of pipes
The choice of the diameter of pipes for heating a private house plays a really important role, since the throughput of the heating system, as well as its thermal and hydraulic losses, will depend on this parameter. In addition, it is imperative to take into account the scale of the system being installed, namely the number of radiators and rooms that require heating. Many people think that the larger the diameter of the pipe for heating a private house, the greater its throughput, which means that the number of radiators can be increased.
However, it is unlikely that it will be possible to increase efficiency in this way. Not only will the purchase of pipes with an unreasonably large cross section entail additional costs, but there will also be a risk of a pressure drop in the system to a critical value and, as a result, a decrease in efficiency.
Thermal engineering calculation
The calculation of the diameter of heat supply pipes is carried out taking into account the material from which they are made, the length of the circuit, the wiring diagram and the principle of circulation of the coolant. It is quite difficult to independently perform the calculation correctly, especially if there is no experience in such matters. It is best to contact a specialist who can develop a competent heating project for a private house to resolve this issue.
When compiling it, the following parameters of the future heating system must be taken into account:
- wiring diagram, on the basis of which the total length of the pipes is calculated;
- coefficient of resistance of a pipe for a heating system to fluid flow (this indicator is affected by the size, material and smoothness of the inner surface of the product);
- sections of the outlet and inlet pipes of the boiler (usually they are identical);
- the inner diameter of the pipe for heating a private house (the inner section is indicated in millimeters or inches; 1 inch = 25.4 mm);
- coolant cooling level;
- the maximum rate of movement of the coolant;
- the amount of heat that will need to be transferred from the heating boiler to all radiators.
Calculation principle
When drawing up a heating project for a private house, the specialist focuses on the optimal indicators that must be achieved when creating a new system. For example:
- The speed of water movement in the system should not exceed 1.5 m/s. The best option is from 0.3 to 0.7 m / s.
- The degree of cooling of the water coolant (the temperature difference in the water entering the boiler and leaving it) should be in the range of 15-20 degrees.
- The amount of heat required by the system must be equal to the total power of all radiators (the maximum indicator is taken from the passport). For heating 10 sq. meters of area of the insulated room requires 1 kW plus a margin of 15-20%.
Natural circulation systems
The maximum diameter of the pipe for heating a private house equipped with a heating system with natural or combined circulation must correspond to the dimensions of the inlet and outlet pipes of the boiler (most often they are the same). Pipes of this section will be needed to complete the initial and final sections of the circuit.
If we talk about which pipe for heating a private house is better, then we must take into account the type of boiler. So for solid fuel boilers, it is recommended to use metal products. If you plan to use polymer pipes, then a metal pipe should still be used to install the first couple of meters.
The starting diameter is the largest. It is kept until the first branching. Further, the wiring is performed with a gradual decrease in the diameter of the pipes after each branch. At the last point, the diameter should correspond to ½ inch (12.7 mm) or ¾ inch (19 mm). When installing the "return" the same principle applies.
Forced circulation systems
Such systems usually operate on gas or electric boilers. The diameter of the pipes for them should be chosen as small as possible, since the forced circulation is provided by the pump. The expediency of small diameter pipes is explained by the following factors:
- a smaller section (most often these are polymer or metal-plastic pipes) allows minimizing the volume of water in the system and, therefore, accelerating its heating (the inertia of the system decreases);
- installation of thin pipes is much easier, especially if they need to be hidden in the walls (making strobes in the floor or walls requires less labor);
- pipes of small diameters and connecting fittings to them are cheaper, therefore, the total cost of installing the heating system is reduced.
With all this, the size of the pipes should optimally correspond to the indicators provided for by technological calculations. If these recommendations are not followed, the efficiency of the heating system will decrease and its noise level will increase.
Connecting radiators
With a collector wiring diagram, the boiler and collectors are connected by pipes of a larger cross section (from 19 to 25 mm). Distribution from the manifolds is carried out using thin pipes, the internal diameter of which is 12.7 mm (1/2 in.).
Radiators, as well as additional equipment, in particular, a safety unit, a pumped storage tank, etc., are also connected with half-inch pipes.
Types of radiators
Regarding what kind of heating is better for a private house, the reviews of the owners are quite diverse, but as for radiators, many prefer aluminum models. The fact is that the power of heating batteries depends on the material. They are bimetallic, cast iron and aluminum.
One section of a bimetallic radiator has a standard power of 100-180 W, cast iron - 120-160 W, and aluminum - 180-205 W.
When buying radiators, you need to find out exactly what material they are made of, since this is the indicator that is required for the correct calculation of power.
for heating
Heated water is transported from the boiler to the radiators through pipes, so their quality directly affects the level of heat loss. Three types of pipes are now presented on the building materials market:
- metal;
- copper;
- metal-plastic.
Each species has its own characteristics, which will be discussed below.
metal pipes
This option was previously widely used in heating systems of multi-storey and private houses. Metal pipes are gradually becoming a thing of the past, as they are not characterized from the best side. Their disadvantages include:
- big weight;
- problematic installation (requires professional equipment);
- ability to accumulate static electricity;
- limited service life due to inability to resist rust.
Copper pipes
Such products have a number of advantages, for example:
- the ability to withstand high temperatures (within 200 degrees);
- high strength (maximum pressure - 200 atmospheres);
- durability (not subject to corrosion).
However, copper pipes are not popular, and the reasons for this are as follows:
- complexity of installation (requires professional equipment and special skills);
- for the installation of copper pipes, special brackets are required;
- high price (copper is an expensive material);
- high cost of work due to their labor intensity.
Metal-plastic pipes
This type of pipe is the most popular among consumers. Such products are available in a wide range of sizes and are ideal for the installation of heating systems. They have the following advantages:
- increased strength and durability (aluminum or fiberglass base coated with plastic generally creates a high-strength structure that does not collapse over time and is resistant to mechanical damage);
- resistance to corrosion processes (sealed outer coating does not allow air to pass through);
- minimum hydraulic resistance (such pipes are ideal for heating systems with natural and forced water circulation);
- have antistatic properties;
- simplicity and high speed of installation (installation does not require professional knowledge, it is enough to familiarize yourself with the installation technique on the Internet and purchase a special soldering iron);
- low cost of pipes of any diameters and accessories to them.
Reliable connection of elements is provided by special elements - fittings. If metal-plastic pipes must be connected to metal or stop valves, flanges or adapters for a threaded connection are used.
When installing a heating system from pipes and fittings reinforced with fiberglass, the operation for stripping these elements is not required, which greatly speeds up and simplifies the work.
Thus, metal-plastic pipes are the best option for self-assembly of the heating system. The main thing is to choose the right number and diameter of pipes and accessories (fittings).
Greetings, comrades! Do you know what pipe diameter is needed to heat a private house? If you are interested in the title of the article, then you probably do not know. I am going to correct this defect and introduce you to extremely simple and understandable schemes for calculating the heating system. So, let's go.
Step by step
To calculate the size of pipes in different parts of the heating system, you need to know:
- The heat demand of the whole house. It determines the power of the boiler or other heat source and the filling diameter at the inlet and outlet of its heat exchanger;
- Thermal load on individual sections of the circuit. It consists of the total power of the heating devices and is determined by the heat loss of the heated room or group of rooms.
We calculate the boiler power
simple circuit
Soviet SNiPs of half a century ago proposed to calculate the thermal power of the heating system, based on the norm of 100 watts per square meter. Let's say a house with an area of 150 m2 needs a heat source with a power of 150x100=15000 watts, or 15 kW. Dot.
The scheme is clear, simple and ... gives huge errors. The fact is that it completely ignores a number of factors that greatly affect heat loss:
- ceiling height. In apartments of houses built in the 60-90s of the 20th century, it was typical - 2.5 meters. In cottages, you can find a spread from 2.4 to 4 meters or more. Meanwhile, with an increase in the height of the ceiling, the heated volume, the area of \u200b\u200bthe walls (through which heat is lost) increase and, accordingly, the energy costs for heating increase;
- Wall insulation quality. A building made of aerated concrete with external insulation with foam or mineral wool will lose much less heat than a country house with walls in one;
When SNiP was created, proposing to calculate heating at a rate of 100 W / m 2, the de facto standard was 2-brick-thick brick walls typical of Stalin-era houses (taking into account the thickness of masonry joints - 51-52 centimeters).
- Glazing area and structure. In general, much more heat is lost through windows than through walls, therefore, the larger their area, the more heat is needed for heating. At the same time, windows can vary greatly in thermal conductivity: triple energy-saving double-glazed windows transmit 8-10 times less heat than single glazing;
- Climatic conditions. With the same quality of insulation, heat loss is directly proportional to the temperature difference between the house we heat and the outside air. At +20 in the house, the heat consumption at 0 ° C and -40 ° C on the street will differ exactly three times. The norms of SNiP, true for the European part of Russia, are equally unsuitable for warm and cold regions.
Exact scheme
How to take into account all the variables when designing a cottage heating system?
Very simple. In the calculations you need to take into account:
- Volume heated room. It is equal to the product of the heated area and the height of the ceiling;
- Quality of insulation walls and heat loss through windows;
- Maximum temperature difference with the street.
The formula for calculation is Q=V*K*Dt/860. In it:
- Q - calculated power (kW);
- V is the volume of the house or a separate room that we have to heat (m3);
- K - coefficient of heat dissipation, determined by the quality of wall insulation and the structure of window glazing;
- Dt is the difference between the temperature in the house (in calculations it is taken to comply with sanitary standards) and the lower peak of winter temperatures (read - the temperature of the five coldest days of the coldest month).
I emphasize: the calculations take into account the temperature of the coldest five-day period, and not the absolute minimum temperature. Extreme frosts happen every few decades, and putting them into the project, to put it mildly, is expensive.
Where can I get the values \u200b\u200bof sanitary standards and winter temperature minimums?
Everything is simple with the first parameter: it is equal to +18 ° С in regions with an average minimum winter temperature above -31 degrees and +20 ° С in a colder climatic zone.
SNiP 23-01-99, dedicated to building climatology, can become a source of information about the temperatures of the coldest five-day days for different regions of the country. If you do not want to rummage through the regulatory documentation - just find your city on the map in the line below.
What is the heat loss coefficient?
It is selected from the following ranges of values:
| Image | 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 glazing. |
 |
2-2,9 : walls - 25 cm of brickwork or 10 cm of timber, windows - with single glazing. |
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3-4 : building with metal walls without insulation. |
Let's once again calculate the total power of the heating system for a house with an area of 150 square meters with our own hands, specifying a number of additional parameters:
- The house is located in Sevastopol (the temperature of the coldest five days of winter is -14 degrees);
- Its walls are made of Inkerman stone (local sedimentary rock with good heat-insulating qualities) and are 40 cm thick;
- Ceiling height - 3.2 meters;
- Windows - plastic, with single-chamber double-glazed windows.
Let's start with the calculation.
Room volume equal to 150x3.2 = 480 cubic meters.
Insulation coefficient taking into account the extremely low thermal conductivity of the Inkerman stone, we take it equal to unity (1.0).
Temperature delta between indoor and outdoor equal to 20 - -14 \u003d 34 ° С.
Plugging in the values into the formula: Q \u003d 480 * 1 * 34 / 860 \u003d 19 (rounded) kilowatts.
We calculate the power of a separate circuit
The heat load in each individual section of the heating circuit is equal to the sum of the power values of the heating devices connected to it. If there are two radiators of 1.5 kW each in the room, then it creates a load on the circuit equal to 1.5 + 1.5 = 3 kilowatts.
The total power of all heating appliances in the house should be equal to the rated power of the boiler or slightly exceed it.
Where can I get information about the power of devices?
For panel, plate 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 per section can be used in the calculations:
| Image | Type of radiator and rated heat output of the section |
 |
cast iron: 140-160W. |
 |
Bimetallic: 180-190W. |
 |
Aluminum: 200-210W. |
As always, there is a nuance. Manufacturers indicate power for a very specific mode of operation - for a temperature delta between the radiator surface and ambient air of 70 degrees.
In practice, this mode is achievable only in the central heating system and only at the peak of cold weather: at a heating supply temperature of 95 ° C, the batteries closest to the elevator unit can heat up to 90 degrees at an air temperature in apartments of 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 in the room, the temperature delta will be equal to 35 degrees, and the thermal power of each section will drop exactly by half relative to the nominal.
The calculation of the filling diameter and connections to radiators is carried out for the highest coolant temperature with which it is planned to operate the heating system, and the minimum temperature in the room. In this case, the maximum possible thermal load is included in the project.
Let's analyze the calculation of the load on a separate heating circuit using an example.
Given:
- The room is heated by two radiators with a nominal power of 1.5 kW each;
- The heating system will operate with a supply temperature of 75 degrees;
- The air in the room can cool down to +18 °C.
temperature delta equal to 75-18=57 °C, or 57/70=0.81 of the one at which the radiator delivers its rated power.
Actual power radiators (that is, the maximum thermal load on the circuit) is 3 * 0.81 = 2.43.
Calculate the diameter of the pipe
The design diameter of pipes for a heating system is influenced by two parameters:
, which we have just learned to calculate;
In a system with a circulation pump, it is more profitable not to increase the diameter of the filling and connections, but to speed up the circulation by installing a more efficient pump. The price of a running meter of a pipe increases non-linearly with an increase in diameter, so it is unprofitable to install thick pipes.
However, there is a limiting factor here - hydraulic noise. At speeds above 0.7 m/s, noise appears at the throttles, and at 1.5 m/s and above, at turns and fittings. Therefore, the calculations include a circulation velocity of 0.4-0.6 m/s.
The inner diameter of the pipe is calculated by the formula D=√354*(0.86*Q/Dt)/V. In it:
- D - desired diameter (mm);
- Dt - temperature difference at the inlet and outlet of the circuit (°C);
A typical temperature difference between supply and return in an autonomous circuit is 20 degrees.
- V - coolant velocity (m/s).
So, with a boiler power of 12 kW, a temperature delta of 20 degrees and a water velocity in the circuit of 0.6 m / s, the minimum inner filling diameter is √354 * (0.86 * 12/20) / 0.6 \u003d 17.4 mm.
For a steel pipe, its nominal size (DU, or DN) is approximately equal to the inner diameter. Taking into account the actual range of sizes, an internal diameter of 17.4 mm corresponds to a water and gas pipe DN 20.
For radiator connections and small heating circuits, it is difficult to calculate the temperature difference between flow and return. In this case, it is easier to choose the dimensions of the pipes according to the table:
In private houses, the installation of a heating system is often carried out not with steel pipes, but with plastic and metal-plastic ones. The reason is the lower price per linear meter of polypropylene or metal-polymer pipes compared to steel pipes. These products use a different size designation system: they indicate the outer diameter.
Only the inner section of the pipe affects the capacity of the filling or supply. To calculate the inside diameter, subtract two wall thicknesses from the outside diameter. Both parameters are always indicated in the marking.
Example A: We need a pipe with an inner diameter of 17.4mm. The wall of the reinforced polypropylene pipe with a size of 25 mm has a thickness of 3.2 mm. The inner diameter of the pipe is 25-(3.2*2)=18.6 mm.
Verdict: fits.
A special case
The gravity heating system has a couple of features:
- There is no excess pressure in the system. The circuit communicates with the atmosphere through an open expansion tank;
- Instead of a pump, the coolant is driven by natural convection: the water heated by the boiler is forced out to the upper point of the heating outlet and returns to the boiler through the outlet by gravity, giving off heat to the batteries along the way.
The advantages of the gravitational heating scheme are complete energy independence and absolute safety. Boiled water in the boiler heat exchanger will not cause it to explode: the steam will leave the circuit through the open expansion tank.
The reverse side of the advantages of natural circulation is the minimum hydraulic head in the circuit. The consequences of low pressure are slow water circulation and uneven heating of radiators.
In order to compensate for the low pressure, it is necessary to reduce the hydraulic resistance of the filling to a minimum.
How to do it?
The instruction is obvious: it is necessary to increase its diameter. The pressure loss in a pipe is inversely proportional to its internal section.
The inner diameter of the heating filling in the gravity system should not be less than 32-40 millimeters.
Conclusion
I hope that this material will help the reader in designing his own heating system. The video in this article will help you learn more about methods for calculating heating. I look forward to your additions to it. Good luck, comrades!
When choosing pipes, it is necessary to take into account a large number of their features. For example, in addition to taking into account the physico-chemical properties, it is necessary to take into account what their length and diameter will be. It turns out that the hydrodynamics of the entire heating system directly depends on the diameter. The most commonly used and used for private houses are pipes with a diameter of approximately 16-40 mm.
Scheme of the device of a polypropylene pipe.
Pipes of this size are able to withstand the pressure in the heating system, in addition, they are convenient to use in work, they will not create problems during the installation process. Using them, it is possible to ensure the wiring of the pipeline of a hidden nature.
What diameter of polypropylene pipes is used for heating
To correctly select the size, the internal diameter of the pipes is calculated using the following formula:
d = √(4-U-1000/πL),
where U is a value that is equal to the total water consumption in the house, which will fall on this water supply,
L is the speed of water flow, for pipes of large diameter it is considered to be equal to 1.5-2 m / s, for a small one - 0.7-1.2 m / s.
Scheme of the heating system of the house.
Polypropylene materials for heating are used in a diameter of approximately 20-32 mm. For mounting a warm floor, plastic with a diameter of 16 mm is most often used. It is important at the beginning of work to assess all its complexity and select the necessary material. Given the various factors in the heating system, you need to correctly calculate the cross section of the pipe. Many things are important here: carrier temperature, flow velocity, pipeline length, pipe diameter and hot water pressure.
It is believed that only a correctly calculated size of the required diameter of polypropylene pipes for heating will help make the entire system reliable and efficient. In cases of an incorrectly selected size, some shortcomings in the operation of the system are possible. For example, if the diameter is larger than necessary, then the pressure in the heating system will become lower than necessary, which will lead to disturbances in the circulation of water throughout all apartments in a large house. And only the repair work carried out, which involves the replacement of pipes with pipes of the correct size, will be able to establish the operation of the system.
How to choose the right pipe diameter
In cases where heating is carried out in a private house or cottage, the pipes must be selected taking into account the fact that the diameter will not change only when there is a direct connection to the central heating system. In the case of an autonomous pipe system, any size (different diameter and length) can be used, depending on the preferences of the owner of the house.
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When choosing the necessary blanks, it is necessary to take into account all the features, especially when it comes to a natural heating system, where the ratio of the cross section to the pump power will not be a primary feature. This fact is attributed to the advantages of this heating system.
Pipe installation scheme.
The disadvantage of such a system is the small radius of action and the high cost of the large-sized elements used in this case.
To ensure the efficiency of the system, it is necessary to maintain a certain level of pressure in it, allowing the water moving inside to overcome all obstacles in its path. Resistance (obstacles) can be in the form of friction of water against the walls, a tap or a tap and a heating device. The most interesting thing is that the resistance and speed at which water will flow depends on the length and diameter of the pipeline pipes. With a high water velocity, a small cross section and a long pipeline, the level of resistance in the path of water increases.
Which pipes are suitable for the heating system
Any heating system involves drawing up a project scheme. After that, it is necessary to prepare and select everything you need in advance (materials and tools for installation work): pipes, fittings and the necessary tools. And only after that you can proceed with the installation of polypropylene pipes.
Elements are selected for a particular room, taking into account all its features and type of heating. It is important at the preparation stage to determine your strengths and understand what the work will be like. After all, installation is not always easy to do with your own hands, sometimes you have to turn to professionals for help.
For heating systems, it is possible to use polypropylene, metal and metal-plastic materials. All of these materials have their own advantages and disadvantages, which must be considered when selecting for your system. Polypropylene is considered the best material for heating system elements. In turn, metal ones are more expensive, and also difficult to use, they are unstable to corrosion, which leads to a decrease in their service life. Metal-plastic materials are cheaper, easy to use, but their reliability and durability leaves much to be desired, so it is better not to consider this option for installing a heating system.
Scheme of heating from polypropylene reinforced pipes.
From this we can conclude that polypropylene is best suited for a heating system, as it serves as a good option for installing water pipes. It is important to know and be able to separate different types of polypropylene pipes that are designed for hot or cold water. You need to use materials only for a certain type of work. For example, pipes for heating, where hot water will flow, should not be used for pipelines with cold water, since the temperature regime will be different and various violations and malfunctions in the system are possible.
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For the installation of a warm floor or a heating system, you can safely choose polypropylene elements that have a large number of positive characteristics, among which the following points are worth noting:
- Reliability.
- Durability (exploited for 100 years).
- Corrosion resistant.
- No mineral deposits.
- High level of chemical resistance.
- Ease of mounting.
- Possibility of carrying out repair work in cases of malfunction or breakdown.
- Price availability.
The only, but the main drawback of this type of material is flammability and instability to high temperatures.
For heating systems, you need the right choice, which depends on the right diameter.
The diameter of the pipes should not be very small, but not large either, so as not to affect the cost of the system and the water pressure in it.
Installation of a heating system using polypropylene pipes
Installation of the heating system involves the correct choice of the scheme of work. For example, the use of polypropylene pipes provides for several options for work:
Scheme of installation of hot water pipes.
- Gravity circulation of water in the system. In this case, there is no need to install a circulation pump, since the movement of water will be independent. This option is suitable for rooms where there are frequent chances of problems with power outages, which will lead to the impossibility of using the pump.
- Bottom spill system in heating. This system has a radial wiring, which involves the presence of a pump used to increase the water pressure, which requires a smaller diameter.
- It is possible to use one- and two-pipe systems with connection to the radiator using a side or bottom type of connection.
Installation of a heating system from polypropylene pipes
Installation of polypropylene elements can be easily done with your own hands, and it is not necessary to trust this work process to the masters. During installation, welding (soldering) is used, in no case should threaded connections be used for pipes made of polypropylene.
Before welding, the workpieces are cut into segments of the desired length using special scissors so that the edges are smooth, without burrs, and all this is done very quickly. The welding process is carried out using a special apparatus designed for this purpose. For welding, it is necessary to insert the pipe into the nozzle of the correct diameter (the diameter must match the nozzle) and heat it to a temperature of 260 degrees. The heating time of the pipe depends on its diameter, for example, a 20 mm pipe will heat up for 5 seconds, but a pipe with a diameter of 50 mm will heat up for 18 seconds.
