Open heating system

construction of a private house, and especially if it is carried out on their own - it's a long series of solutions for the various problems.And one of the most important - is to ensure future building the most optimal living conditions at any time of the year (of course, if the house is not only planned as a summer dacha).

And in this regard the creation of the desired indoor climate will be the most difficult task of the proper calculation and mounting reliable heating system.Despite the emergence of modern systems of electric heating the house leader for on popularity of and demand remains water heating - it is more familiar, time-tested, technology its installation and debugging worked out to the smallest detail.Master of the house, which has chosen water heating, remains to be defined with a specific kind of - closing or open heating system, with its «hardware filling" and distributing pipe system in the house. Then there are the stages of careful design and installation.

Among the numerous publications on this subject, placed on the Internet, you can find a lot of these, which state that an open heating system - the device is extremely simple and it can be installed in just a single day.If the reader comes across such "art" - can be read without any regret to interrupt and close the page - the author clearly has no idea , or about heating general , or about open system - in particular.Any system must be properly designed with accounting m m nogochislennyh nuanced, well-balanced, reliable mounted - and these problems did absolutely easily and quickly by not called .

What is an open system heating

First of all, you need to immediately make one important remark.Very often, describing an open heating system, the authors of all the facts, "interfere in a heap", presenting her necessarily as heating with natural circulation of coolant.Nothing like this!An open system can be both with natural and forced circulation of fluid, and with proper performance from the hosts in in Always have the ability to easily and quickly switch from one mode to another.

main feature of an open system - in absence of its loop of whatever artificially created excess pressure, as it is directly connected with the atmosphere.The system is mounted on a mandatory basis the expansion tank, the free volume which is designed to compensate for the heat transfer fluid extensions at higher temperatures.This tank is always positioned in the highest points throughout the pipe layout of the heating circuit.Thus, it has falls function bleed - all gas accumulation in the pipes should come out here.Serves he kind of water seal - layer of liquid coolant, which necessarily always have to be in the expansion tank prevents air from entering the system from outside.

worth considering such a system more:

1 - a source of thermal energy, boiler that runs on certain as fuel ( solid , liquid, gas) or is used to heatelectrical energy.

2 - upward of boiler standpipe that rises to the highest point of the system and very often in this place finishes expansion tank.There may, however, be other layout options - this will be discussed later.The main thing - it always used the riser pipe of the largest diameter in the system - it helps to provide the necessary pressure difference in the flow return pipe.

3 - Open the expansion tank (atmospheric) type.In this position it can be used as industrial enterprises produced a special tank and, as principle, any suitable volume for capacity . example, often use the converted metal drums, cans dairy , gas cylinders and etc .

4 - to the expansion tank does not happen overflow in it always do on certain level drainer access to the pipe, which will take excess water to drain or just outside,on the ground.In principle, a good "mood" of the heating system, such play - a rarity . and often this outlet will be used for controlling the filling of the entire system, and the primary relief.

5 - trumpet, the feed to the coolant heaters (radiators).In systems such as open , even if in their capacity for the pump, the pipes must be defined slope to ensure natural circulation of fluid.Wiring pipes may be different - this will be discussed below.

6 - heaters located in areas of the house - heating radiators.Convectors or, for example, the "warm floor" is not commonly used in an open system.The scheme of installation of radiators can be different - it linked with certain system wiring pipes.

7 - Reverse pipeline - providing coolant flow to the radiator to the boiler for further circulation.

8 - circulation pump.The system can do without it, working on the principle of natural circulation, but pump sharply raises the heating efficiency, reduces the consumption of energy.

9 - tap (faucet) for priming and periodic replenishment of the heating system from the mains (10).In the normal position, it is always in the closed state.

11 - valve (valve) to drain coolant from the heating system, for example, to carry out any repairs or maintenance work.

• Now, after the open heating device in more detail - about the principles of its action.

If the system pump is embedded, the particular issues and there is no - it creates forced circulation of coolant through the pipes.But as the heat exchange occurs in the circuit, not equipped with a pump, or same in the absence of electricity when switched node on natural circulation?

here in full force come into effect the laws of thermodynamics.Consider a simple example - why pond water is always warmer than the surface, and much colder - with increasing depth?The answer is simple - and with gases and liquids occurring about the same phenomenon - the increase in their temperature (in a free volume) leads to a decrease in their density, and therefore - and the total weight.In short, the heated fluid or gas is always easier to cool.

now focus on the scheme:

in the heating system, by and large account , two types of heating appliances, working in opposition to each other. boiler (. Item 1) is the first accurate heat exchanges - converts energy from an external source into heat - heats the water.Then ide t t Transporting coolant to the second main point of heat - the heat sink (item 3). It is clear that in the supply line (in the figure - the red area item 2.) Water density Rgor - significantly lower than the opposite side (blue area poses 4.).The higher density of the liquid Rochl means its «predominance" in terms of gravitational processes - it is simply a much denser and heavier.If properly positioned the two main points of heat transfer relative to each other - namely, heat transfer devices place higher boiler certain height h , make sure you will create a natural circulation fluid flow.On the lower part of the circuit is clearly visible.The area with the coolant low density conditionally "removed" (it can not prevail over the more dense).It turns out the two communicating vessels, one of which is higher than the other.Water tends to equilibrium, and constantly flows from the radiator to the boiler.

So, to create a natural movement of the coolant, boiler must be located below the lowest of the radiator in the house.This value h may be different (the higher it is, the more will be the movement of the liquid), but it should not exceed 3 meters.In most cases, if there is such a possibility, a boiler room in the basement or on the ground floor - it is the most convenient, as fully provides the required excess of the radiators in the rooms of the first floor above the boiler.

If the basement in a private home is not, then we have to make the boiler room in the annexe, a few recessed floor in the boiler installation point.If this is not possible, the creation of an open heating system and need not take - it will not work in the mode of natural circulation, and will be much more logical to use the right scheme with accumulation tank receiver.

• may be noted still an important property of an open heating system, operating mode natural circulation. it is about a kind of self-regulation of the coolant flow rate in the pipes. Unlike from from opleniya forced circulation, speed of fluid flowing through the pipes is very unstable .

When running the boiler and the heating of a certain amount of liquid, it begins natural current through the pipes.Characteristically, in order, to such a movement began , boiler must be run briefly to power close to the maximum - to overcome the inertia of the water and the existing flow resistance in the pipes.

the area is warmed up, the amplitude of the temperature in the boiler and the output of radiators - maximum.Consequently, the most important is the difference in coolant density, and hence , as we have seen - and the intensity of fluid movement along the contour.As warm, this difference begins to decrease.That is gradually falling and speed of the coolant.

As a result, at a certain stabilize water flow system is quite slow - but this is enough to maintain a comfortable temperature in the right places (usually - a certain accuracy exposed user share in the boiler controls).However, with a sharp decrease in temperature in the room, for example, with the windows open or when cold weather outside, fluid flow spontaneously accelerate - the system will seek to achieve a balance.

Advantages and disadvantages of open heating system type

open type of heating system is definitely not a "self perfection", and it many serious shortcomings. However, some owners housing choose exactly such a scheme, explaining his decision its advantages:

• Reliability - probably the main advantage of such a heating system.Driving thoroughly tested, it has passed every conceivable test in a variety of environments and fully proved its effectiveness.By and large account , in a system with natural circulation is simply nothing to break down (if not to take into account itself, boiler).The term of such heating "life" is determined solely by the operational life of pipes and radiators - with proper selection of components it will be many tens of years.
• scheme - is quite simple to install, it does not have a particularly complex parts.
• Such a system does not require any specific debugging and tuning.Just fill the water system and include boiler.Princi- pp growth - boiler included - the system works, off - the current stopped.
• When operating without a pump - the lack of any kind was characteristic vibrations and noise.
• Nothing prevents complement circulating pump system - then it will receive the full versatility.With the pump of course, a loss on heating will be less, but in case of lack of electricity or when exiting from the pump system simply by switching valves heating completely converted into a non-volatile mode.

The diagram shows the position of the cranes at work in forced circulation mode - both the valves Pos.1 open, and standing on the main pipe (item 2). - Closed.To switch modes simply change the position of the crane on the opposite.

• already mentioned property of the system of self-regulation allows to maintain stable indoor microclimate is given without any complicated additional control devices.

Now - about open heating system deficiencies:

• Such a system simply can not be put in a very large house. When distance of 30m from the boiler (horizontal) flow resistance in the pipes can exceed the pressure created in a natural way, and static equilibrium is created in the circuit - it is unacceptable for heating.
• system - is very inert, that is long enough to include in the operation.This is due to the need to create a natural flow of water, and a very large volume of water in the heating circuit.
• There some difficulty with the acquisition of material - will need reflux Pipes of different diameters and adapters for them and etc .A large diameter pipe - is another and a lot of money.
• When installing the system must be set up on the slope of pipe sections - from the supply and return line to , without exception.This should be taken into consideration in the design and preparation of installation drawings.