Everyone is familiar with natural selection, and this is also true in relation to numerous inventions of mankind. Over time, something similar they also pass. Some technologies will sink into the abyss, remaining forever forgotten, while others become classics that are immortal and out of competition. As for the latter, this also includes a heating system with natural circulation (CO with EC). Despite the availability of more advanced and functional solutions, the technology is still in demand, it has successfully passed the test of time.
Features of natural circulation
This system has other names: thermosyphon, gravity, gravity.
It includes several components:
- Heat generator (boiler, stove or fireplace with watershirt).
- Closed loop - pipes, radiators filled with liquid heat carrier (water, oil, antifreeze).
- Expansion tank.
- Shutoff and control valves.
- Instruments.
Heated coolant from the furnace or boiler moves in a closed circuit, heating the radiators. And those, in turn, transfer energy to the surrounding air in the room. The main feature of this system lies in the special way that ensures the movement of the coolant.
It is noticeably easier for residents of residential buildings, since central heating has been established in the apartments. Owners of private real estate have to establish water heating with natural circulation for their homes on their own. But how does the system in question work? This is discussed below.
Operation principle
As we know from school, if a medium is heated, its volume will increase according to the known laws of physics. Moreover, from the side of the colder area, the Archimedes force begins to act on it, forcing it to rise.
This phenomenon also has its own name - convection. It is it that acts as a "power unit" of the coolant, where the concept of "natural circulation" appears. And since convection is closely related to gravity, the system is also called gravitational.
The power of the convection flow largely depends on the temperature difference between the coolant heated in the boiler or furnace and in the area of the incoming medium (return). How can you understandpumping of the working medium is carried out without the use of a pump. And this implies that the heating system of a one-story house with natural circulation does not need electricity, that is, it is non-volatile. And since there is no electrical appliance, the savings are obvious.
In other words, when heated, water (usually it is used as a heat carrier) loses its density and rises along the central riser, pushed by a cold stream that returns to the boiler. After that, hot water is sent to the radiators through the supply pipes. Giving off heat, it cools and by gravity goes back to the heat generator (return) and the cycle repeats countless times.
Besides, since there is no pump, there will be no excess pressure. Therefore, an open container is sufficient as an expansion tank. Its presence is due to the fact that a constant pressure is maintained in the heating system.
Significant Factors
But what affects the speed of water in the natural circulation heating system of a one-story house? This is usually due to the following factors:
- The value of the circulation pressure - the more it is, the better.
- Diameter of pipelines - a small section will create more resistance to water flow than a larger diameter. In this regard, the dimensions for wiring are usually from 32 to 40 mm.
- Material for the manufacture of pipelines - modern polypropylene solutions are lessresistance when compared to metal pipes.
- Contour turns - ideally when the pipeline is straight.
- The number of fittings, adapters, retaining washers - there are limitations here, since each valve reduces the degree of pressure.
To create the optimal pressure in the heating system with EC, the boiler must be placed as low as possible below the circuit system. As a rule, this is the basement. For obvious reasons, the expansion tank is installed as high as possible and in most cases located in the attic.
It should be taken into account that the heating system of a house with natural circulation has an inert character, which means it flows rather slowly. The duration from the kindling of the boiler to the complete stabilization of the temperature regime takes several hours.
Coolant options
As a rule, it is customary to use water or antifreeze as a coolant. But since the latter has a higher density and low heat transfer, it will take much more time to heat it, and hence the fuel. In this regard, it is much more profitable to use water.
In addition, when antifreeze is heated, it expands much more. As a result, when choosing this coolant, the expansion tank must be even larger than with water.
Advantages of EC heating system
The key benefits of natural circulation home heating are:
- Low cost effectno expensive circulation pump.
- No noise. Even the most modern pumps produce a quiet hum - during the day it is not heard against the background of ambient noise, but at night the hum can be heard, which causes discomfort.
- Pump malfunctions result in additional costs.
- The number of breakdowns is minimal - there is practically nothing to break here, except for the boiler. Leaks are rare and can be easily repaired by yourself.
But the main advantage of the EC heating system lies precisely in its energy independence. In areas where there are constant power outages, this is the best option.
Obvious cons
Yes, and such a seemingly perfect heating system of a one-story house with natural circulation, operating according to all the laws of physics, has a number of drawbacks.
Obvious disadvantages include:
- Short range of coolant.
- The inability to regulate the temperature in each room individually.
- Water circulates through the circuit under slight pressure, which causes a noticeable decrease in temperature - the farther the radiator is from the boiler, the lower it is.
- Long period for the system to enter full operation mode.
- Since the expansion tank is located in a cold attic room (which is often not heated), there is a possibility of the coolant freezing.
Despite all these downsides,heating with EC is still relevant. Perhaps this is due to the fact that for many people the benefits outweigh all of the above disadvantages.
Varieties of heating circuits
A water heating system with natural circulation can be made according to one of several schemes:
- one-pipe;
- two-pipe;
- beam.
At the same time, general parameters such as the length of the circuit, the number of batteries and a number of others do not play a special role. However, there may be many more specific schemes. However, below we will consider only the simplest of them.
Single-pipe line
This is the simplest scheme, where one pipe is used to supply water to the radiators. However, in some cases, you can do without them, since heat is provided by the area of the pipelines themselves.
If the scheme still implies the presence of radiators, then it is necessary to make the correct calculations for the number of batteries (sections). The optimal amount is no more than 5. After all, as the water passes through each point, it cools down. In addition, in the heating system in a private house with natural circulation, as few shutoff valves as possible should be used. At the same time, the length of the contour itself does not need to be greatly reduced.
The ideal option in this case is a diagonal arrangement. In other words, the coolant will enter the radiators from above, redirecting to each point. After the last battery, the cooled water will be returned back toboiler through the outlet pipe called the return pipe. At the same time, the entire pipeline is the same, which is actually the whole essence of a single-pipe line.
Two-pipe system
This scheme is a little more complicated, but it also has its advantages. Here, the hot coolant is carried through the batteries through one pipeline, and in a cooled state returns to the boiler through another line. As a result, the efficiency of heat transfer from the batteries connected to one horizontal leg is improved. As a rule, the supply line runs along the ceiling or is located in the attic. As for the return line, it is above the floor.
Despite the obvious advantage of a single line (minimum materials, therefore, minimum costs), a two-pipe heating system with natural circulation of a two-story house (or one-story) will still be the best solution. Moreover, it is divided into two branches with an identical number of radiators.
At the same time, each battery receives a coolant with the same temperature, which is already a plus, and a very important one! In addition, it is possible to automatically regulate it, since the devices do not depend on each other. Based on the mentioned advantage of a single-pipe scheme, the disadvantage of a two-pipe system follows - an increased consumption of materials. This is especially true for two-story houses.
Features of the ray scheme
In this case, the inlet and outlet lines are connected to a special manifold. In fact, this is a distribution comb, in which each outlet is equipped with a choke. However, for each batterytwo pipes are supplied.
Judging from the point of view of temperature control, such a heating system with natural circulation is the most convenient. At the same time, the installation work here is more complicated, since too many pipes are used. Therefore, in order not to spoil the appearance of the room, they are removed to the floor or hide behind false walls. And this already leads to a significant increase in the cost of work.
Features of building CO with EC
Since the operation of the CO with the EC is based on natural physical laws (a heated environment creates an upward flow), the batteries must be located above the level of the boiler. The optimal location is the basement or basement. If neither one nor the other is available, then a recess of the appropriate size is made in the floor for installing a heat generator.
And this is true not only for a private house, but also for apartments with autonomous heating. A small section of the floor is cut off along with a screed so that a natural circulation heating boiler can be placed directly on the floor slab.
For better natural circulation of the coolant, an accelerating collector or a vertical pipe section is required, which originates from the boiler and rises to the very ceiling. Subsequently, the premises are descended from the main highway to the radiators.
The minimum height of the boost manifold must be at least 1,500 mm, while it should be borne in mind that there must be free space between the upper line and the ceilingspace for an expansion tank. And as we know, this is an indispensable element of the entire heating system. If the house has low ceilings, then the tank is just removed to the attic, and these rooms need to be insulated. You can make a closed-type heating system using a membrane expansion tank, which can be placed in any convenient place.
It is worth noting that a closed heating system with natural circulation has its advantages:
- Heat loss is largely reduced through the expansion tank.
- Closed system does not require regular venting.
- The volume of the expansion tank is also reduced, the same applies to the thermal inertia of the system.
As you can understand, the presence of a second floor in the house significantly increases the efficiency of the accelerating collector.
For this reason, it is much easier to organize natural circulation of the coolant in a two-story mansion than in a one-story house.
Rules for installing a heating system with EC
If there is a desire or need to organize a heating system with EC, then a number of rules should be taken into account:
- Horizontal branches of the pipelines of the circuit must necessarily be sloped in the direction of movement of the coolant. Up to 10 mm on long lines and up to 50 mm on short sections per meter.
- In the course of creating a natural circulation heating system with your own hands, you should use all possible waystry to reduce the hydraulic resistance of the circuit. This rule should be followed when choosing batteries - cast iron radiators are the best choice due to their small clearance.
- Polymer pipes have the lowest degree of hydraulic resistance. In addition, they do not overgrow with scale. But it is better not to use metal-plastic options, since the flow area is noticeably reduced due to the fittings. The best choice is polypropylene pipes, their operating temperature is 70 °. Cross-linked polyethylene options are even more preferable - their temperature threshold is 95 ° C.
- If there are branches in the heating circuit, then after each of them the pipe diameter is selected one size smaller. For the return, the opposite is true - the size increases.
Since the concept of a heating system with natural circulation implies the absence of the use of electricity, the boiler must also be non-volatile. And such models are made by many manufacturers.
Among foreign companies are Bertta, Stropuva, Buderus. But Russian companies can also offer good options - Energia, Ogonyok, Conord.
Conclusion
As you can see, the heating system with EC coolant has its advantages and disadvantages. Someone will like this option, and they will want to implement it. Others see only cons in it. In any case, such a heating scheme with natural circulation suits manyhomeowners.
At the same time, most of them put a circulation pump on the return pipeline to improve the efficiency of the heating system. Only it is located on the bypass. Such a measure allows you to transfer the circuit to gravity by opening a special tap when the power is turned off.
