Which heating system is more efficient: one-pipe or two-pipe? Two-pipe heating system: implementation features The advantage of a two-pipe heating system

Owners of private houses often face the choice of which type of home heating to give preference. There are only two types of heating systems traditionally used in everyday life: one-pipe and two-pipe. Each type has both advantages and disadvantages. The difference between the two systems is in a different way delivery of coolant to heating devices. Which heating structure for own house better, one-pipe or two-pipe - choose directly to the owner of the house, taking into account their own household needs, the estimated heated area and the availability of finances.

In the first version, heat is distributed throughout the house through one pipe, sequentially heating each room of the house. In the second case, the complex is equipped with two pipes. One is a direct supply of coolant to. Another pipe serves to drain the cooled liquid back to the boiler for subsequent heating. A correct assessment of your own financial capabilities, an accurate calculation of the optimal parameters of the coolant in each individual case, will help not only determine the type heating system but also intelligently.

You can understand and figure out what is best for you, a one-pipe or two-pipe heating system, only after a thorough study of the technical nuances.

Single pipe heating system. General representations

A single-pipe heating system can work both with a pump and with natural circulation coolant. Considering the second type, you should delve a little into the existing laws of physics. It is based on the principle of expansion of a liquid when heated. During operation, the heating boiler heats the coolant, which, due to the temperature difference and the pressure created, rises through the riser to the highest point of the system. The movement of the coolant upwards is carried out along one pipe, reaching the expansion tank. Accumulating there, hot water fills all series-connected batteries through a descending pipe.

Accordingly, the first connection points along the coolant will receive maximum warmth, while the radiators located further will already receive partially cooled liquid.

For large, multi-storey buildings, such a scheme is extremely inefficient, although at the cost of installation and maintenance, single pipe system looks attractive. For private one-story houses, residential buildings on two floors, a similar principle of heat distribution is acceptable. Heating residential premises using a single-pipe scheme in a one-story house is quite effective. With a small heated area, the temperature in the radiators is almost the same. The use of the pump in longer systems also has a positive effect on the uniformity of heat distribution.

The quality of heating and the cost of installation in this case may depend on the type of connection. Diagonal connection of radiators gives greater heat transfer, but is used less often, due to the larger number of pipes needed to connect all heating appliances in residential premises.

Scheme with bottom connection radiators looks more economical, due to the lower consumption of materials. From an aesthetic point of view, this type of connection looks preferable.

Advantages of a single-pipe heating system and its disadvantages

For owners of small residential buildings, a single-pipe heating system looks tempting, especially if you pay attention to its following advantages:

• has stable hydrodynamics;
• convenience and ease of design and installation;
• low costs for equipment and materials.

The indirect advantages of a single-pipe system include the safety of the supply of coolant, which diverges through the pipeline through natural circulation.

To the most common problems that owners of a single-pipe heating system have to deal with include the following aspects:

• technical difficulties in eliminating miscalculations in the work made during the design;
• close relationship of all elements;
• high hydrodynamic resistance of the system;
• technological limitations associated with the impossibility self adjustment coolant consumption.

Despite the listed disadvantages of this type of heating, a well-designed heating system will avoid many difficulties even at the installation stage. In view of the listed advantages and the economic component, single-pipe schemes have become quite widespread. Real Benefits have both a single-pipe and another type, a two-pipe heating system. What can you win and what can you lose by choosing one of the types for your home?

Technology for connecting and locating a single-pipe heating system

Single-pipe systems are divided into vertical and horizontal. In most cases, multi-storey buildings are used vertical wiring. In this case, all radiators are connected in series from top to bottom. With horizontal wiring, the batteries are connected one after the other horizontally. The main disadvantage of both options is frequent air congestion due to air accumulation in the radiators. The proposed scheme makes it possible to get an idea of ​​​​some wiring options.

Connection methods in this case are selected at the discretion of the owner. Heating radiators can be connected via side connection, diagonal or bottom connection. The figure shows similar options connections.

For the owner of the house, an important aspect is always economic expediency equipment installed in the house and the resulting effect. Do not underestimate the option with a single-pipe heating system. Today, in practice, there are quite a few effective measures on the improvement of heating schemes of this type.

For example: there is a technical solution that allows you to independently adjust the heating of individual radiators connected to the same line. For this purpose, bypasses are created in the system - a pipe segment that creates a bypass movement of the coolant from a straight pipe to the return, bypassing the circuit of a certain battery.

Valves and valves are placed on the bypasses, blocking the flow of the coolant. You can install thermostats on radiators that allow you to control the heating temperature in each radiator or throughout the system as a whole. A competent specialist will be able to calculate and install bypasses to achieve maximum efficiency. In the diagram you can see the principle of operation of bypasses.

Two-pipe heating system. Operating principle

Having become acquainted with the first type of heating system, a single-pipe, it's time to deal with the features and principle of operation of a two-pipe heating scheme. Thorough analysis of technological and technical parameters heating of this type allows consumers to make independent choice- which heating is more efficient in a particular case, one-pipe or two-pipe.

The basic principle is the presence of two circuits along which the coolant diverges through the system. One pipe provides the coolant supply to the heating radiators. The second branch is designed so that the already cooled coolant, after passing through the radiator, returns back to the boiler. And so constantly, in a circle, while the heating is on. At first glance, the very presence of two pipelines in the scheme can repel consumers. The long length of highways, the complexity of wiring are factors that often scare owners of private houses away from a two-pipe heating system.

This is at first glance. Like single-pipe systems, two-pipe systems are divided into closed and open. The difference in this case lies in the design of the expansion tank.

Closed with a membrane expansion tank are the most practical, convenient and safe to use. The obvious benefits are confirmed by:

• even at the design stage, it is possible to equip heating devices with thermostats;
• parallel, independent connection of radiators;
• the technical possibility of adding heating devices after the installation is completed;
• ease of use of hidden gaskets;
• the ability to turn off individual radiators or branches;
• ease of adjustment of the system.

Based on the foregoing, one unambiguous conclusion can be drawn. Two-pipe system heating, much more flexible and more technologically advanced single-pipe.

For comparison, the following diagram is presented:

The two-pipe System is very convenient for operation in a house in which it is planned to increase the living space, extension options are possible, both up and along the perimeter of the building. Already at the stage of work, technical errors made during the design can be easily eliminated. Such a scheme is more stable and reliable than a single-pipe one.

With all the obvious advantages, before choosing this type of heating, it is appropriate to recall the disadvantages of a two-pipe system.

It's important to know! The system is characterized by a higher complexity and cost of installation and rather cumbersome connection options.

If you have a competent specialist at hand, the necessary technical calculations have been carried out, then the listed disadvantages are easily compensated by the advantages of a two-pipe heating scheme.

As in the case of a one-pipe system, the two-pipe option involves the use of a vertical or horizontal arrangement pipelines. Vertical system - radiators are connected to a vertical riser. This type is convenient for two-story private houses and cottages. Air congestion is not terrible for you. In case of horizontal option- the radiators in each room or room are connected to a horizontal piping. Two-pipe horizontal heating schemes are mainly designed for heating one-story buildings and large residential buildings with the need for floor-by-floor adjustment. Arising air jams are easily eliminated by installing Mayevsky cranes on radiators.

The figure shows a vertical two-pipe heating system. Below you can see what a two-pipe horizontal type system looks like.

Traditionally, radiators can be connected using bottom and top wiring. Depending on the specifications and the project - the choice of wiring option depends on the owner of the house. The top wiring is more convenient. All highways can be hidden in the attic space. The system creates the circulation necessary for a good distribution of the coolant. The main disadvantage of a two-pipe heating scheme with an upper wiring option is the need to install a membrane tank outside the heated premises. The top wiring does not allow to make a fence technical water for household needs, as well as connect expansion tank with domestic hot water tank. This scheme is not suitable for flat-roofed residential properties.

Summary

The selected type of heating for a private house should provide all the inhabitants of the residential building with the necessary comfort. Save on heating is not worth it. By installing a heating system in your house that does not meet the parameters of a residential facility and domestic needs, you run the risk of spending a lot of money on refurbishment in the future.

Two-pipe or one-pipe heating system - the choice should always be justified, both from a technical point of view and from an economic one.

Among the countless options for distributing heating systems, the most common is the scheme of a two-pipe heating system with lower wiring and forced circulation of the coolant. It can be assembled independently, provided that it is designed and calculated correctly. But not every homeowner understands these issues, and even if it is decided to hire specialists for design and installation, their work must be checked. This is possible only if you figure out what a two-pipe heating system of a private house is and how to install it correctly. Our article is just to help such homeowners.

Types of two-pipe heating systems

Our topic is entirely devoted to these systems, since they have a number of advantages over single-pipe ones. It makes no sense to list them all, it is worth noting only the main thing: a two-pipe system works in such a way that a coolant of almost the same temperature enters all radiators.

The word "almost" means that there are exceptions to this rule, these are circuits assembled from steel, copper and stainless corrugated pipes not covered with an insulating layer.

The fact is that the heating system of a private house, made by hand from non-insulated metal pipes, will give off heat to the premises not only through radiators. The metal has a high thermal conductivity, so the coolant flowing in such a line will cool slightly as it moves away from the boiler. Although the temperature drop compared to single-pipe wiring is insignificant, it still needs to be taken into account.

Note. Many supporters of single-pipe schemes such as Leningradka say that they are cheaper, since the material will take half as much. But at the same time, they forget about the drop in water temperature, as a result of which it is necessary to increase the capacity of the radiators, that is, add sections. These are additional funds, and considerable ones.

According to the orientation of the risers in space, vertical and horizontal views systems, and they can have top, bottom and combined wiring. With a vertical scheme, one or more risers are located in the building, powered by a heat source located in the basement or first floor. Radiators are connected directly to vertical risers, as shown in the figure:

This is a circuit with a bottom wiring, since main pipelines the coolant is supplied to the risers from below. A vertical system with top filling means they are laid from above, with combined version only the supply horizontal collector runs under the ceiling, and the return one runs from below. Usually, the lines laid from above are placed in the attic space, and in its absence - under the ceiling last floor. Which is not very good in terms of aesthetics.

Horizontal systems

This is a closed two-pipe system in which horizontal branches are laid instead of vertical risers, and a certain number of heating appliances. As in the previous case, branches can have top, bottom and combined wiring, only now this happens within the same floor, as shown in the diagrams:

As you can see in the figure, a top-wiring system requires pipes to be laid under the ceiling of the premises or in the attic and will hardly fit into the interior, not to mention the consumption of materials. For these reasons, the circuit is used infrequently, for example, for heating basements or in the case when the boiler room is located on the roof of the building. But if the right choice circulation pump and the system has been set up, then it is better to let it go down from the roof boiler pipe, any homeowner will agree with this.

Combined wiring is indispensable when you need to install a two-pipe gravity system, where the coolant moves naturally due to convection. Such schemes are still relevant in areas with unreliable power supply and in houses of small area and number of storeys. Its disadvantages are that many pipes of large diameter pass through all the rooms, it is very difficult to hide them. Plus the high material consumption of the project.

And finally, a horizontal system with a lower wiring. It is no coincidence that it is the most popular, because the scheme combines a lot of advantages and has almost no drawbacks. The connections to the radiators are short, the pipes can always be hidden behind a decorative screen or cast into a floor screed. At the same time, the consumption of materials is acceptable, and from the point of view of work efficiency, it is difficult to find a better option. Especially when a more advanced associated system is used, as shown in the diagram below:

Its main advantage is that the water in the supply and return pipes runs the same distance and flows in the same direction. Therefore, hydraulically, this is the most stable and reliable scheme, provided that all calculations are carried out correctly and installation features are taken into account. By the way, the nuances of systems with a passing movement of the coolant lie in the complexity of the arrangement of ring circuits. Pipes often need to cross doorways and other obstacles, which can increase the cost of the project.

Conclusion. For a private house the best option is a two-pipe horizontal heating system with lower wiring, but only in conjunction with artificial circulation of the coolant. If you want to ensure energy-independent operation thermal equipment and networks, it is recommended to take one of the combined gravity systems - horizontal or vertical. The latter will be appropriate in a house with two floors.

Forced circulation heating system

So, the wiring diagram is selected, further actions the following:

• draw it in the form of a sketch, or even better - a three-dimensional model (axonometry);
• calculate and select pipe diameters in all branches and sections;
• pick up all necessary elements two-pipe system: batteries, pump, expansion tank, filter, fittings and other parts of the boiler and radiator piping;
• purchase equipment and materials, perform installation work;
• test, balance (if necessary) and put the system into operation.

On the sketch in the form of an axonometric view, it is necessary to draw lines, arrange radiators and stop valves, mark the heights, taking the surface of the first floor screed as a reference point. Subsequently, after completing the calculation, it will be necessary to put down the dimensions and sections of the pipes on the drawing. An example of how a two-pipe system with forced circulation is installed is shown in the drawing:

Important. The finished sketch will allow you to better understand all the nuances of the future system, up to the number and types of fittings made of polypropylene, metal-plastic or other material. It is especially convenient when a house plan is attached to a three-dimensional image.

Selection of pipe diameter

This calculation consists in determining the flow rate of the coolant from the thermal power necessary for heating the room, and from it the diameter of the pipes for a two-pipe heating system. In simple words, the flow area of ​​the pipe should be enough for delivery to each room right amount heat along with hot water.

Note. By default, it is assumed that the calculation of the heat losses of the building has already been completed and the amount of heat for all rooms is known.

To carry out the selection of the diameter of the pipes, they begin from the very end of the system, from the last battery. First, the coolant flow rate for heating this room is calculated according to the formula:

G = 3600Q/(c∆t), where:

• G - the required consumption of hot water for the room, kg / h;
• Q - the amount of heat for heating this room, kW;
• c is the heat capacity of water, taken as 4.187 kJ/kg ºС;
• Δt - the calculated temperature difference in the supply and return manifolds, usually take 20 ºС.

For example, 3 kW of heat is needed to heat a room. Then the flow rate of the coolant will be equal to:

3600 x 3 / 4.187 x 20 = 129 kg / h, in volume it will be 0.127 m3 / h.

To balance a two-pipe water heating system initially, it is necessary to choose the diameter as accurately as possible. Based on the volumetric flow, we find the flow area using the formula:

S=GV/3600v, where:

• S - area cross section pipes, m2;
• GV- volume flow coolant, m3/h;
• v is the water flow velocity, taken in the range from 0.3 to 0.7 m/s.

Note. If the heating system one-story house- gravitational, then the minimum speed should be taken - 0.3 m / s.

In our example, let's take a speed of 0.5 m / s, find the cross section and, using the formula for the area of ​​​​a circle - the diameter, it will be equal to 0.1 m. The polypropylene pipe closest in assortment has inner size 15 mm, and put it on the drawing. By the way, connecting radiators to a two-pipe system is usually carried out with just such a pipe - 15 mm. Next, go to the next room, count and summarize with the previous result, and so on until the boiler itself.

Connecting radiators to a two-pipe system

Installed batteries are connected to the lines during installation, correct connection heating radiators with a two-pipe system - it is lateral or diagonal. All existing methods shown in the figure:

What temperature balance does the bottom connection of the radiator to a two-pipe system lead to is well illustrated by the figures:

Batteries used in a vertical circuit usually have a side connection (method No. 3). In horizontal systems, the diagonal connection scheme (method No. 1) is most preferable, due to this, the maximum heat transfer of the heater is achieved, which is shown below in the image:

Balancing

The meaning of this operation is to balance all branches of the system and regulate the flow of water in each of them. To do this, each branch must be correctly connected to the mains, that is, install special balancing valves. Also, control valves or thermostatic valves are installed on the connections to all radiators.

It is not so easy to carry out accurate balancing with your own hands, you need to have the appropriate instruments (at least a pressure gauge to measure the pressure drop across the balance valve) and perform pressure loss calculations. If none of this is present, then after testing it is necessary to fill the system, bleed air and turn on the boiler. Further, the balancing of the two-pipe system is done by touch, according to the degree of heating of all batteries. Appliances located near the heat generator must be “pressed” so that more heat goes to the distant ones. The same is true for entire branches of the system.

Conclusion

It is noteworthy that it is much easier to install a two-pipe heating system than to develop it, calculate it, and then balance it. So that this stage you can go through on your own, and it is advisable to coordinate all the rest with specialists.

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Heating systems: one-pipe, two-pipe.

Nowadays, 2 different systems heating: one-pipe or two-pipe. Each has its own design features. Two-pipe heating systems are the most popular.

Nowadays, 2 different heating systems are installed in houses: one-pipe or two-pipe, and each has its own characteristics.

Single pipe heating system

In order to understand what it looks like, look at the ring with a stone. In the heating system, the boiler plays the role of a stone. As for the ring, these are pipes of a specific diameter that run along the perimeter of the entire building. Radiators are connected to them. The coolant is often water and sometimes antifreeze. The functionality of a single-pipe heating system is based on the gradual release of heat by water. After passing through the ring, the water returns to the boiler with a lower temperature.

This scheme usually has a natural circulation of the coolant. Hot water first served on the top floor. And then, passing through the radiators, the part of the heat that has been given off descends to the boiler, having carried out full circulation. A single-pipe heating system can be supplemented with elements:

• thermostatic valves;
• radiator regulators;
• balancing valves;
• ball valves.

Thanks to them, it becomes more balanced and it becomes possible to change the temperature in certain radiators.

Distinctive features of the heating system

The biggest plus is electrical independence, and the minus is pipes, in which large diameter and the wiring is sloping.

Compared to the two-pipe option, there are quite a few advantages:

• pipes can be diverted to the “warm floor” system or heating radiators can be connected;
• it can be carried out regardless of the layout of the room;
• it covers the entire perimeter with a closed ring;
• it is less material-intensive and has a lower cost.

In use, it may sometimes be difficult to circulate through the pipes, but this is easily solved by installing pump equipment. It produces competent circulation of the coolant through the pipes.

The vertical single pipe scheme is a popular example of wiring in apartment buildings.

And the horizontal one is used mainly for heating huge rooms and is used very rarely in private buildings (mainly in small one-story houses). Here the supply pipe bypasses the heaters, which are on the same level. The water in each radiator cools down and, approaching the last heating devices, it becomes already significantly cooled. This scheme will help reduce installation and piping costs, but has two drawbacks.

Firstly, this is a problem with heat regulation in any heating device. You can not increase heat transfer, reduce it, turn off the radiator. In installation practice, there is a jumper - a bypass, which allows you to turn off the radiator without shutting down the system. Heating of the room is carried out indirectly by means of a riser or supply pipes. Another drawback - you need to use radiators of the most different sizes. In order for the heat transfer to be the same, the first heater must be very small, and the last one must be large. A horizontal single-pipe heating scheme is also used.

Two pipe system

There are several types of it. The principle of operation is the same and consists in the following. Hot water rises through the riser and from it enters the radiators. And from them, through highways and return lines, it enters the pipeline, then into heating device. With this system, the radiator is served by two pipes at the same time: return and supply, therefore it is called two-pipe. Water in this system is supplied directly from the water supply. She needs an expansion tank, which can be either simple or with water circulation.

The composition of the simple includes a container with 2 pipes. One is a water supply riser, and the second is used to drain excess liquid.

More complex structure has 4 pipes. 2 pipes provide circulation, and 2 others are needed for control and overflow, they also monitor the water level in the tank.

Two-pipe systems can be operated using a circulation pump. Depending on the circulation method, it can be co-current or dead-end. In the second movement warm water completely opposite to the direction of the already cooled. Such a scheme is characterized by the length of the circulation rings, which depends on the distance of the heater to the boiler. Circulation rings have equal length in systems with one-way water flow, all devices and risers work under equal conditions.

A two-pipe heating system has a large set of advantages compared to a single-pipe:

• the possibility of distributing the heat supply in different rooms;
• can be used on one floor;
• locking systems of the return and supply risers are located in the basement - this significantly saves the area of ​​\u200b\u200bliving premises;
• minimizing heat loss.

The only drawback is the considerable consumption of materials: you need 2 times more pipes than for a single-pipe connection. Also, the disadvantage is the low water pressure in the supply line: taps will be needed to bleed air.

The horizontal closed two-pipe scheme comes with a lower and upper wiring. The advantage of the lower wiring: sections of the system can be put into operation gradually, as the floors are built. The vertical two-pipe scheme can be used in houses with variable number of floors. Any of the varieties of two-pipe schemes is more expensive than one-pipe horizontal wiring, for the sake of comfort and design, a two-pipe scheme should be preferred.

One-pipe and two-pipe systems: comparison

Single-pipe systems, unlike two-pipe systems, do not have return risers. The heat carrier from the boiler, under the action of the circulation pressure or the pump, enters the upper heating devices. Cooling, he returns back to the supply riser and goes down. The lower radiators receive a mixture of coolant from the riser and from the upper radiators. Passing through all radiators and other heat consumers, the coolant returns to the boiler, where the process is repeated again. The temperature of the coolant decreases when passing in a circle, and therefore the lower the radiator is, the larger the heating surface should be.

For one-pipe systems, there are 2 schemes. This is a flow and mixed scheme. The flow circuit has a feature - the complete absence of jumpers between the supply and exit from the radiator. These schemes are almost never used in the installation of heating systems due to their impracticality. One battery breaks, and the riser needs to be turned off, because there is no way to turn on the coolant bypassing it. The advantage of single-pipe systems is the lower cost of building materials and ease of installation. Installation of single-pipe systems requires top wiring.

A two-pipe heating system can be operated in any houses: multi-storey, one-story, etc. A two-pipe heating system is easy to implement with normal circulation, since its configuration makes it possible to organize a circulation pressure, do not forget that the boiler must be installed below the level of the radiators. You can organize a heating system with forced circulation by simply placing a circulation pump in the circuit.

If it is possible to implement ring scheme, then you have to do it. A two-pipe system usually needs to be installed where there are difficulties with gas, power outages, etc. For this system, a solid fuel boiler and pipes with a larger diameter are enough. Bring firewood or coal, and do not worry about frost.

Methods for installing heating systems

Mounting methods depend on the characteristics of the system.

Price installation work heating is determined by the characteristics of a particular project, and only specialists with experience in such work can calculate everything.

If it is necessary to install heating with normal circulation, the installation of a system with a top spill will be effective. The water circulates through the pipes itself. Bottom spill systems do not work effectively without a circulation pump.

Scheme of the collector (beam) wiring of the heating system.

Installation methods are also classified:

• by type of wiring (collector, beam);
• by the number of risers;
• by type of pipe connection (side or bottom).

Heating installation with bottom pipe connection is the most popular. It becomes possible not to run the pipeline directly along the walls, but to hide it under the floor or baseboard. Achieved aesthetic appearance premises.

The main classification of mounting methods is carried out in complete dependence on the scheme. You can install a two-pipe heating system or install a single-pipe heating system. In the second case, the water flows through the pipeline through the radiators, cooling along the way. The last radiator will be colder than the first. With a two-pipe system, 2 pipes are connected to the radiators: return and direct. This allows you to create the same temperature of the radiators. The first option is the simplest and cheapest, due to the low cost of materials. But it is only effective in small houses. If your house is over 100 square meters or it has more than 1 floor, it is better to install two-pipe heating.

The two-pipe system gives great choice ways of mounting radiators:

• serial connection;
• parallel connection;
• lateral one-way connection;
• diagonal connection.

Depending on the location of the supply risers, there are certain ways to install autonomous heating:

1. Heating with horizontal wiring.
2. Heating with vertical wiring.
3. Heating without risers with supply and return lines.

A single pipe system is cheaper. If you care about the quality of the heating system, there is no need to spare money for a two-pipe wiring, because we get the opportunity to control the heat in the rooms.

When developing a heating system for our home, we certainly think about the scheme for laying pipes and connecting radiators. Most often, when creating projects, common schemes are used with two pipes laid through heated rooms. A two-pipe heating system is more difficult to install, but it has many undeniable advantages - this is what we will talk about in our review. We will also look at:

• Structural features of two-pipe heating systems;
• Their main disadvantages;
• Varieties of two-pipe systems.

At the very end, we will talk about the most effective ways connecting batteries to heating systems.

Features of two-pipe heating systems

A two-pipe heating system is the most common laying scheme. heating pipes and radiator connections. It provides for the use of two pipes - one is used to supply hot coolant, and the second it is diverted to the heating boiler. This scheme is different high efficiency and provides uniform distribution heat in all heated rooms.

Single-pipe heating systems, unlike two-pipe ones, have a number of disadvantages:

The difference in the operation of single-pipe and two-pipe heating systems is well illustrated by this picture.

• More limited contour length;
• Uneven distribution of heat over heated rooms - the very last rooms suffer;
• It is difficult to heat multi-storey buildings;
• Increased hydrodynamic resistance in the heating system;
• Lack of separate adjustment of the heating temperature in different rooms;
• Difficulties in repair - you can not remove a faulty battery without stopping the entire system.

Some of the above problems are partially solved using the Leningradka scheme, but this is not a full-fledged way out of the situation.

A two-pipe heating system provides for the laying of two parallel pipes to which radiators are connected. The coolant from the supply pipe enters the heating devices, after which it is sent to the return pipe (return). Despite the more impressive financial and labor costs, the finished system is more functional in operation and easy to repair.

Two-pipe heating is actively used for space and building heating for various purposes. These include one-story private houses and cottages, multi-storey apartment buildings, as well as industrial and administrative buildings. In other words, the scope of its application is distinguished by its breadth.

Advantages and disadvantages of two-pipe heating systems

Two-pipe heating is distinguished by its versatility. It works equally well in both small buildings and multi-storey buildings, including high-rise buildings. residential buildings. Let's look at the main advantages of two-pipe systems:

When using two-pipe heating, even the most distant batteries in the house will be able to provide heat at an acceptable level.

• The increased length of one line (circuit) is relevant when heating elongated buildings, for example, hospital or hotel buildings;
• Uniform supply of heat to the premises - unlike single-pipe systems, it will be warm even in the rooms farthest from the boiler;
• Two-pipe heating makes it easy to organize separate temperature control in individual rooms and premises - for this, thermostatic heads are placed on each battery;
• The possibility of dismantling batteries and convectors without stopping the entire heating system is an important advantage that manifests itself in large buildings;
• Two-pipe heating is the best suited for heating large buildings - for a more even distribution of heat, certain piping schemes and connection of heating devices are used.

Unfortunately, there are some downsides:

• High costs for the purchase of equipment - compared to single-pipe heating systems, two-pipe systems require an increased number of pipes;
• Difficulty in installation - an increase in the number of nodes and the need for optimal distribution of the coolant over the heated premises affects.

However, the pros completely outweigh the above cons.

Varieties of two-pipe heating systems

We have already familiarized ourselves with the advantages and disadvantages of two-pipe heating systems, as well as their distinctive features. It remains to talk about their varieties.

Forced or natural circulation

The natural circulation of the coolant provides for the absence of a circulation pump. Heated water circulates through the pipes independently, obeying the forces of gravity. True, this requires pipes of increased diameter - two-pipe heating with thin plastic pipes will not be able to provide independent circulation, which is associated with a large hydrostatic pressure in the system. Heating with natural circulation is simple and cheap, but you need to remember about the limited length of the circuit - it is not recommended to make it longer than 30 meters.

The scheme of a two-pipe heating system with forced circulation involves the use of a circulation pump. It is installed next to the heating boiler and provides a quick run of the coolant through the pipes. Due to this, the warm-up time is reduced, the length of the heating circuit is increased, and the distribution of thermal energy is noticeably improved. Two-pipe scheme heating with forced circulation allows you to heat buildings of any number of storeys - you just need to choose a productive pump.

Disadvantages of two-pipe heating systems with circulation pumps:

• Installation cost increase good pump it is expensive, while buying a cheap one does not make sense due to its reduced service life;
• Possible noises - cheap pumps sooner or later begin to vibrate, the sounds from their work are carried through the pipes even to the farthest rooms. The higher the speed of rotation of the pump shaft, the stronger the noise;
• Energy dependence of the heating system - when the power is turned off, the circulation of the coolant stops.

For the correct operation of a two-pipe heating system with a circulation pump, it is necessary to provide a backup power supply, otherwise the heating boiler may break down.

It should be noted that cheap circulation pumps are noisy even at the very beginning of operation. The increased noise level is most noticeable in heating with metal pipes. And if any section of the pipe gets into resonance, the sound will only increase.

You should also pay attention to the method of laying pipes - in two-pipe heating systems with natural circulation, a slope is provided, which ensures the normal movement of the coolant. In circuits with forced circulation, no slopes are needed. For the same reason, pipes can be bent as many times as you like, bypassing obstacles - in circuits with natural movement of the coolant, the pipes should be as straight as possible so as not to create excessive hydrodynamic resistance.

Open and closed schemes

Two-pipe heating scheme open type involves the use of a traditional expansion tank, which is mounted in the high point contour. The pressure here is minimal, the coolant is in contact with the atmosphere. In case of excessive expansion, the water goes into a special branch pipe that extends from the tank. The undoubted advantage of open circuits is the ease of air removal - it exits through the expansion tank on its own. Only now, together with the departure of air, the evaporation of the coolant is observed, so its level must be constantly monitored.

With insufficient water in open two-pipe heating systems, water gurgling is heard in the radiators.

Closed heating systems include sealed expansion tanks of membrane type. The coolant circulates here in a closed space, so it has nowhere to evaporate. If necessary, antifreeze ethylene glycol can be poured here. In order to prevent airing of the circuit, air vents are placed in it - automatic or manual.

AT closed systems heating, a circulation pump is necessarily installed, while in open ones its presence is not mandatory.

Vertical and horizontal two-pipe heating systems

A two-pipe horizontal heating system is relevant in one-story houses. Two pipes are laid across the premises, parallel to which radiators are connected. If a household or building includes 2-3 floors, then a separate horizontal circuit is created on each floor, connected to vertical risers. Such a connection scheme ensures uniform distribution of the coolant over all floors and rooms.

Vertical systems are most often mounted in apartment buildings. Here are mounted two vertical pipes from top to bottom floor. Hot coolant is supplied through one, and through the other it goes back to the boiler room. Radiators are connected to both pipes. Most often, the scheme looks like this, that separate risers serve all the radiators in the kitchens, others - in the bedrooms, halls and other rooms.

Also, mixed systems are laid in buildings, which include both vertical and horizontal sections.

Top and bottom wiring

There are two-pipe heating systems with upper and lower piping. The upper wiring implies that the coolant first rises to the highest point of the circuit, and from there it is distributed to individual vertical sections. Two-pipe heating with bottom wiring provides that both pipes pass below (near the floor or under it), and branches go up from them, to radiators and individual radiator cascades.

The upper wiring is focused on the creation of two-pipe heating systems with independent movement of the coolant. The pipe from the boiler rises to the upper point of the system, from where the horizontal section begins - it is made at a slope. A similar shift is made in return pipe so that the coolant flows independently towards the boiler, obeying the pressure in the circuit and gravity.

The second scheme (bottom) is optimal where you need to hide all the pipes. In this case, a two-pipe heating system with a lower polypropylene wiring is hidden in the floors or behind the ceilings, only radiators and convectors are visible in the rooms.

Connecting radiators

We introduced you to the main varieties of two-pipe heating systems. Now you know that the coolant is supplied here through one pipe and removed through the other. This ensures uniform heat distribution even in the largest buildings. Let's see how best we can connect the radiators. There are three possible schemes connections:

• Lateral connection - the supply and return pipes approach the heater from the side. Accordingly, the areas located on only one edge will be as warm as possible;
• Bottom connection - the supply and return pipes go to the lower edges of radiators and convectors. Heat losses in such a scheme will be maximum, since the coolant tends to pass through the internal volume "through", along the most direct section;
• Diagonal - the most optimal connection scheme, providing uniform heat distribution throughout the internal volume of radiators. For example, the supply pipe goes to the upper left inlet, and the outlet pipe goes to the lower right (or vice versa). In this case, the coolant will heat the entire area of ​​\u200b\u200bheaters as evenly as possible.

The choice of a suitable scheme depends on the design of the heating system and the number of sections in the radiators. When creating two-pipe heating, we recommend making a choice in favor of a diagonal and lateral connection.

Video

When designing a heating system, the question arises: “What kind of heating system will we make? One-pipe or two-pipe? In this article we will understand what these systems are and how they differ. To make things clear, let's start with definitions.

Definitions of one-pipe and two-pipe systems.

• Single-pipe - (abbreviated as OSO) is a system in which all heating devices (radiators, convectors, and so on, we will abbreviate them as software) are connected to the boiler in series using one pipe.
• Two-pipe - (abbreviated as DSO) is a system in which two pipes are supplied to each PO. According to one of them, the coolant is supplied from the boiler to the software (it is called the supply), and through the other, the cooled coolant is diverted back to the boiler (it is called the "return").

For the sake of completeness, we add two more definitions. According to these definitions, there is a division according to the principle of laying the supply line:

• With upper wiring - the hot coolant is first supplied from the boiler to the highest point of the system, and from there the coolant is supplied to the software.
• With lower wiring - the hot coolant is first discharged horizontally from the boiler, and then rises up the risers to the software.

Single pipe heating system.

There are two types of OSS:

1. OSO, in which heating devices are installed on the "bypass" (bypass jumper).
2. Flow OCO - all devices are connected in series without jumpers.

The second type is unpopular due to the difficulty of regulating the temperature in radiators, which is caused by the fact that it is impossible to use special fittings (thermostatic valves). Since when closing or reducing the flow through one radiator, the flow through the entire riser decreases. The main advantage of OCO is the lower cost of components and easier installation. The most popular version of a single-pipe system is Leningradka.

What is "Leningrad".

According to legend, this system got its name from the city where it was first applied. But of course, it is impossible to confirm this reliably, and I don’t really want to. So, "Leningradka" is a one-pipe heating system in which the software is installed on the "bypass". This allows you to regulate the temperature of individual radiators or convectors or turn them off altogether, if necessary. All the advantages and disadvantages of a single-pipe system are inherent in Leningrad, therefore, for distant radiators, it is necessary to increase the number of sections. Possible various options pipe layouts:

• Horizontal - the pipe lies in a horizontal plane and radiators are already installed on it.
• Vertical - the pipe runs vertically through the floors and radiators are connected to it.

OSO of the "Leningradka" type is best used for small private houses, where the number of floors does not exceed two. For large cottages with extended heating systems, such a "Leningrad" is not suitable.

Two-pipe heating system.

The main advantage of DSO is that the coolant comes to all software equally hot. This allows not to increase the number of sections on the "distant" radiators. That is, the most effective use heating appliances. The presence of two separate pipes for supply and return makes the installation of such a system more expensive. For such systems, both top and bottom piping and horizontal or vertical piping are possible.

In addition, DSO may differ in the direction of the coolant flow:

• Dead-end systems - water in the supply and return pipes flows in different directions.
• Flow systems - water in the supply and return pipes flows in the same direction.

Summary of the article.

The question of choosing the type of heating system depends on several factors:

• your budget
• area of ​​your home.
• Features of the internal structure of the house. For example, the number of floors
• The number of heating devices.

Most often for small country houses(no more than 2 floors) a one-pipe system is better suited, and for large cottages (with a floor number of 2 or more floors and a large length of pipelines), a two-pipe heating system will be more efficient. Specific features of the implementation of a particular system are best discussed with a professional designer.