Heating medium for heating system

Despite the fact that now has a lot of interesting alternative home heating systems, the water heating circuits still remain 's leaders in terms of punctuality. AND according to all , this trend still soon will change - in the harsh conditions of the Russian climate, when in most of the country the continuous heating season lasts no less than six months, this heat transfer scheme is still optimal and from the point of view of economy, and heating efficiency, and comparative simplicity of control and maintenance of .

heating system However, and have this kind of circuits, and one of the main ones is the probability of liquid freezing in pipes in any extreme situations. Therefore, , although the heating is called "water", very often other heat carriers are used for the heating system. The choice depends on the type of the existing or projected system, the specific models of heating equipment, the purpose and features of the building operation.

What requirements must meet the coolant

Home fluid challenge in the heating system - transfer thermal energy from the boilers to heat points - radiators, convectors, « warm floors".It would seem that any one can approach, but is the amateurish approach of .The is presented to the heat carrier with a number of specific requirements, in order for the heating system to be both efficient and comprehensively safe.

• This liquid must have excellent heat capacity, that is, the ability to maximize the heat from the boiler, for its subsequent recoil on radiators or convectors.
• The coolant must have, if possible, the widest operating temperature range - from the freezing point to the boiling point.
• The chemical composition of the coolant must be inert to the main materials used for sealing in the heating system.
• Liquid should not cause active corrosion in pipes, heating boiler channels, radiators, in elements and devices of connecting, shut-off and special fittings.

• The heat carrier should not give solid sediment or scum on the pipe walls, especially in the boiler heat exchanger.
• Chemical composition of the liquid must be stable, not decompose into components over time or under the influence of temperature changes, the coolant should not change its physical characteristics - density, viscosity, heat capacity and others.
• The heating medium in the operating heating system should not pose a threat to human health - it refers to the release of toxic fumes or high, fire - or even explosive.

And now the natural question is - which coolant will fully meet the for all requirements? The answer, perhaps, someone can and discourage - in nature, there simply is not such an "ideal" chemical composition. Therefore, there is such a difficult problem as selecting for the most optimal coolant for a particular heating system, for the specific features of the its operation, and under what, it is a sin, the financial possibilities of the owner of housing.

Usually the decision to use a heat carrier is taken by the as an at the design stage or reconstruction of the heating system, because its configuration and "hardware filling" very closely connected with the view and performance characteristics of sweaty fluid circuits. That is, it will be necessary to immediately emphasize some of the dominant qualities of the composition planned for use.

If to explain it is easier, the main in questions of a choice - correctly placed priorities. For example, if heating is planned for a house in which tenants will be permanently throughout the year, rather than by weekend visits, then the best solution, and efficiency, and thermal characteristics, will be the use of water.

But here it is necessary to take into account certain nuances. For example, there are inhabited points, in which interruptions with energy supplies are by no means a rarity. And at the peak of winter frosts it is sometimes enough for several hours, so that the water in the idle system begins to crystallize and, accordingly, increase in volume. And is the direct path of to serious accident with a rush of pipes and radiators!

And if a country cottage with a water heating system is not used year-round, or the lifestyle of its inhabitants is such that it is associated with frequent trips and leaving the house without proper supervision, then considerations of "all-season" of the filled coolant should come to the fore. However, this is sure to entail special requirements for the design and tightness of the heating circuits, since almost all non-freezing coolants are more or less toxic, and often and are quite flammable.

From time to time, any coolant needs to be completely replaced, and this, in the case of using antifreeze, can entail enough for serious costs. And still one point - some models of boilers are accompanied by the manufacturer's recommendations for using with certain coolants. The use of other fluids in the system can even easily lead to a loss of rights to warranty service and repair of boiler equipment.

In a word, the choice of coolant is a question that requires certain knowledge from the owner of housing, so it makes sense to get acquainted with the main varieties closer.

Water as a coolant for the heating system

It can be said at once that approximately 70% of all heating systems in apartment houses use water, possibly with some or other modifying additives. This is due to several main reasons:

• The first, of course, is the universal availability and cheapness of such a coolant. In the overwhelming majority of Russian regions with water, there are no special problems, and can be found or completely free of charge, or for such "ridiculous" prices that is absolutely incompatible with with the cost of special non-freezing compounds. And to fill the system, and replenish the coolant stock in case of any emergency situations - it will not be difficult and will not cause serious cash outflows.
• In its thermal characteristics, ordinary water leaves far behind all other technical fluids. has excellent heat capacity - about 1kal / g × C ° at high density, which varies slightly from temperature, with average heating in the system to about 70 g / ml or 977 g / dm³ with ° .(liter).So way , with " exemplary return" heat on the radiator - drop, for example, temperature by 20 degrees, from 80 to 60 ° With , each liter of water will transfer to the room of about 20 kcal. With detailed indicators, no other compounds can compare.
• Water is an absolutely harmless product in terms of ecology. The leakage of in the system can only deliver certain household troubles, but will not bear any toxic threat to the health of the inhabitants of the house. Similarly, one can argue about the fire safety of such a heating system.

However, , water is still not the ideal coolant for the series of reasons:

• About the main already mentioned - a sufficiently high freezing point of water. Leave a system filled with a similar coolant, without supervision in the winter time, is strictly prohibited - this can lead to a large-scale accident. All know that freezing water can literally rupture pipes and metal radiators.

• Water itself is a powerful oxidizer, plus oxygen is constantly in dissolved in state, and this is always an increased corrosion hazard for pipes, radiators and other metallic elements of the heating system.
• Usual water almost always in its composition has a lot of dissolved salts that are able to form deposits on the inner surface of the pipes, and reducing the patency in them, and significantly worsening heat exchange, including on TANs electric boilers. And this necessarily entails reduction in heating efficiency, as a result, an increase in operating costs for energy carriers, the output of heating elements .
• Water more often than other coolants requires a complete replacement of the volume filled in the circuit - usually this is performed by the annually.

If it is impossible to do something essential with the freezing point of water, the remaining negative water qualities in the of a particular degree can be eliminated or significantly reduced.

The concentration of salts in water can be reduced by carrying out the procedure for its softening. There are several ways, different in their effectiveness.

So, even conventional boiling of water is able to remove of from a number of unstable carbonate compounds - they decompose on solid sediment( scum) and carbon dioxide output. For boiling it is better to take a large bowl with a large area of ​​contact its surface with water - it is at these points is the bulk of the process.

Boiling will help " alleviate " water only from bicarbonate calcium and magnesium salts, but dissolved salts with other bases require a different approach. Good results are shown by chemical softening using calcined soda, lime solution or sodium orthophosphate. However, it must be remembered that for quality water treatment without loss of its basic thermal properties and without giving her any qualities to activate corrosion processes, it is required to observe the exact dosage of components so that there is no excess of reagents introduced in the water. Ideally, all salts present in the water should fall into the solid precipitate, which is then removed by filtration.

Perhaps the simpler solution will be the use of technical distilled water - its can always be purchased in specialized building stores. Of course, this is much more expensive than the water from the tap, but the hassle with the heating system will be significantly less. So can be worth about 15 ÷ 20 rubles per liter, and are not afraid that pipes, radiators and heat exchangers in the boiler will quickly overgrow with scum? Water is sold in a variety of packages - from m scarlet bottles of 0.5 liters to the huge plastic cubes that contain a ton of liquid. It is always possible, knowing volume of its heating system, to purchase the right amount, especially because usually with this wholesale discounts.

Sometimes "conditionally" distilled water hosts houses are collected independently. Speech goes about rain or melt water - it has already passed through the process ss pr of the original distillation. However, to talk about its purity can only partly - it probably already had time to be saturated with pollutants contained in the atmosphere. However , it is always much softer than the one goes from the cranes or is taken from underground sources - wells or wells.

And more better, just to choose distilled technical water for heating, enriched with special additives. Speech goes about inhibitors - special chemical components that sharply reduce the corrosive qualities of water.

In addition, special additives - surface active substances( surfactants) are introduced into the composition of this water coolant. This gives liquid a number of positive properties - the formation of sediment on the walls of pipes and radiators is practically reduced to zero, and already existing deposits will gradually peel and leave, lingering in the filters-sedimentation tanks. Moreover, the internal surfaces acquire pronounced hydrophobic properties, which means a sharp decrease in hydraulic resistance of the liquid in the heating circuit and, as consequence, a reduction in energy consumption. Such water will not have a negative effect on gaskets - gaskets and gaskets will last longer their functionality.

Such distilled water with surfactants and inhibitors costs a little more expensive - it will cost approximately in 22 - 25 rubles per liter.

Antifreezes in the role of coolants

Even distilled, with the corresponding improving additives, water does not solve the main problem of this liquid - freezing at a relatively high temperature( about 0 degrees Celsius), accompanied by a significant volume expansion. Since winter temperatures in most cases are negative, it is very risky to use water in heating systems in cases where constant monitoring of their work is impossible. Hence, will fill the circuit with special non-freezing liquids - antifreeze.

Under this single name( ANTI - "against" , "freeze" from English - "freeze", otherwise in Russian in everyday use - " non-frost-free ") several types of chemical liquid compositions are combined, which have very low initial crystallization temperatures. This allows them to be used in house heating systems, and they are more familiar to motorists, as the main material of engine cooling system or washer liquid for glasses.

The temperature drop affects most antifreezes slightly differently than ordinary water. So, such a substance, even in severe frost, will never turn into a completely solid substance. Even at the lowest limit of its operating temperature, it will become gel-like, lose its fluidity, but, with , this will not be accompanied by an increase in volume of and not will cause to deform pipes or rupture of radiators. But a rise in temperature will cause liquefactiongel-like structure of the antifreeze, returning it to its normal state without any loss of performance.

Most industrial-produced antifreezes in pure, concentrated form are able to operate normally at temperatures up to up to - 65 ° With .As the rule, in most of Russia such qualities are excessive, so the compositions are often diluted with distilled water to working solutions with a minimum threshold in - 30 ÷ 35 ° With - this is quite enough.

Chemical components that form part of the antifreeze and determine their performance characteristics have a good level of stability. Usually a quality non-freezing liquid factory-made can serve faithfully for at least 5 years. True, then it needs a one-time complete replacement.

Convenient? Of course yes, but, as they say, "everything must be paid for."Conversation about the fact that similar qualities of antifreeze have been achieved for account of some negative features of this coolant, distinguishing it from water to a bad side:

• According to its heat capacity , that is, by functional heat transfer, none of the antifreezes can compare with water- as a rule, it is 15 percent less. The efficiency of the heating system from this is also significantly reduced. To ensure a normal temperature regime, in addition, it is necessary to significantly increase the number of sections of radiators in the premises, and this is quite a tangible additional costs.
• Antifreezes always have a greater viscosity than water. To ensure the normal movement of this type of coolant through pipes and radiators, powerful pumps will be required. For a system with natural circulation, most non-freezing coolants simply do not use the - for the same reason.
• Paradox, but along with increased viscosity, such coolants have a very special "penetrating power".Those seals, which suffices with the use of water, sometimes becomes insufficient when using antifreeze - on the joints nodes leakage begins. So, we need a special approach when assembling the heating circuit elements, using special reliable gaskets for sealing. This is especially true still and because some antifreezes belong to the category of extremely aggressive substances that can erode rubber, so for seals it is necessary to use either special its varieties, or paronite.
• Some antifreezes, as already mentioned, are made on the basis of toxic substances, which are dangerous for human health. This means that when installing the heating system, even the slightest leakage or penetration of the coolant vapors should be completely ruled out. In addition, it is strictly forbidden to use antifreezes in the two-circuit heating systems, where the probability of entering the hot water supply system falls.

• All heat transfer fluids use for thermal expansion - much higher than for water. This will require installing a much larger volumetric expansion tank, more capacious radiators. The expansion tank of the open type in the in this case is not is suitable - it will evaporation of the antifreeze into the atmosphere.

Modern antifreezes that are used for domestic heating systems can be divided into three main groups: those based on ethylene glycol, propylene glycol-based and glycerin.

Ethylene glycol antifreeze coolants

Antifreezes on ethylene glycol based so far that still prevail over other, more advanced compositions. They are simple in industrial production, and therefore relatively inexpensive, which predetermines their rather high popularity among consumers.

Such coolants are generally sold in two versions - a concentrate with a freezing point - 65 ° With , or a ready-to-use solution with a lower boundary in - 30 ° C .By adapting to local climatic conditions, it is possible, by changing the concentration of ethylene glycol in the solution, to bring it through distilled water to the correct proportion. The approximate data on the dependence of the freezing point on the solution concentration are given in the table.

Concentration of ethylene glycol in the coolant, % of total	Lower temperature limit for operating the heating system ( crystallization point), ° C
10%	- 3.5
20%	-8.0
25%	-11.0
30%	-15.0
35%	-18.5
40%	-24.0
50%	-34.0
55%	-41.0
60%	-55.0
64%	-65,0
80%	-47,0
85%	-40,0
90%	-30,0
95%	-19,0 ​​
100%	-13,0

An interesting feature of ethylene glycol- with an increase in its concentration from above65% the reverse process is observed - the freezing point begins to increase rapidly. Thus, the antifreeze realized with the freezing point in 65 ° With - is the maximum capability of this composition.

Special components are added to the component composition of ethylene glycol antifreezes - their content is usually not less than 4% of the total volume .The fact is that at high temperatures, ethylene glycol has a tendency to actively foaming, and this leads to " air-blasting " of the system. Therefore, the additives that are added include antifoaming ingredients and, optionally, inhibitors that prevent corrosion of the metal parts of the system. But even the presence of such additives does not completely remove the activity of ethylene glycol to zinc. If the galvanized pipes or other parts and devices with such anti-corrosion coating are used in the heating system, it can be assured that for even one season the antifreeze will completely "eat" this layer

The huge disadvantage of ethylene glycol antifreezes is their high toxicity. Even accidental ingestion of ethylene glycol in the liquid or vapor state can lead to serious health disorders, and at high concentrations - even to a lethal outcome. Moreover, even getting it on the skin can be very unsafe. Working with such an antifreeze requires special precautions, and the heating system - exclusively reliable sealing. Absolutely not allowed application of such a coolant in double-circuit boilers!

Another one "weak spot" ethylene glycol antifreeze - the need careful control over the boiler's temperature regime. The point is that when a high temperature is reached close to the boiling point of the coolant, even for a short time, it begins to actively decompose with the precipitation of solid precipitate and active acids. Insoluble substances are capable of clogging or narrowing the channels of fluid movement, creating build-ups on the heating elements or heat exchangers - and this leads to more more overheating with still large with the decomposition of antifreeze. A formed acids cause the activation of corrosion of metal parts and components of the system. In addition, all this is accompanied by a rapid foaming with the ingress of gases into the heating circuits. In addition, all the stabilizing drawdowns also lose their properties, and this is usually accompanied by the appearance of m m of the numbered leakage on the seals of the connecting units.

So, this antifreeze can only be used in for those conditions , where it is possible to provide very accurate maintenance of the heating temperature. However, not all boilers are equipped with such capabilities, and this is necessarily taken into account when selecting a coolant.

The cost of ethylene glycol antifreeze is relatively low - about 50 rubles. for ready-to-use solution( - 30 ° with ), or in the area 70 rub. - concentrate( - 65 ° with ).

Propylene glycol coolants

This type of antifreeze is a more modern product, with the development and production of which it was possible to get rid of many disadvantages of ethylene glycol.

• Firstly , propylene glycol is not toxic - many of its varieties( for example, E1520) are raw materials for the production of food products. Thus, it is quite applicable in two-circuit circuits, since even accidental addition of it to the water does not bring any trouble. Do not pose health hazards and leakage propylene glycol coolant in case of contact with the skin or inhalation of fumes.
• Secondly, the thermal qualities of propylene glycol antifreeze - much higher.
• And thirdly, these coolants have special properties - they have a peculiar lubricating effect on all internal cavities of the heating system. This significantly reduces the hydraulic resistance in pipelines and reinforcing elements, and as a result leads to reduce unnecessary energy losses.

A very significant disadvantage of such antifreezes is, in spite of on , the special additives, their "dislike" for zinc, is similar to , which is also possessed by ethylene glycol. Well, the second disadvantage, probably, will be their high price. So, a modern coolant with a service life of up to 10 years can cost 120 - 130 rubles per liter.

Glycerin antifreeze

Glycerin also refers to the glycol group of organic compounds( alcohols).Heat carriers on its basis in various sources of information are called close to ideal for household use, then subject to severe criticism.

Without claiming to be a connoisseur or arbitrator on this issue, just you can list all "pro" and " contra " similar antifreeze that occur in Internet publications:

Supporters of glycerinThe coolants are told about their following advantages:

• The basic substance is absolutely safe from an ecological point of view.
• The glycerin coolant has a very wide range of operating temperatures, from minus 30 to plus 100 ° C .When freezing it does not give a bulk expansion, after thawing it completely restores its properties.
• Do not act destructively on galvanized surfaces( especially important for our conditions, where galvanized pipes have been used practically everywhere ).
• Does not decompose seal materials.
• When pouring the system, it does not require any special cleaning or flushing.
• Glycerin is not flammable and is explosion-proof .
• The lifetime of such antifreeze is estimated at 7 ÷ 10 years.
• Small in than yielding to the performance characteristics propylene glycol antifreeze, glycerin is cheaper than them. A liter of such coolant costs approximately 70 - 90 rubles.

And now - the arguments of those who oppose the use of glycerine antifreeze:

• The weight of the glycerin coolant due to its high density is much higher than that of the propylene glycol , which means increased loads of the and on the pipe system, and on the on the pine equipment.
• Due to the increased viscosity of glycerin, especially with a decrease in temperature, there is a rapid wear of boiler equipment.
• The heat capacity of glycerin antifreeze is lower than that of propylene glycol .
• Glycerin is not thermally stable. At a temperature near 90 ° With , can begin its decomposition into insoluble components deposited on pipes and heat exchangers, and on volatile substances. One of them is acrolein, , not only does have an unpleasant smell, but it also has and carcinogenic properties.
• Glycerin has a very pronounced foaming with increasing temperature - special additives are required to reduce this phenomenon.
• After overheating and evaporation of water, such antifreeze completely loses its validity - the products formed after decomposition under such conditions of begin to pass into a solid or gelatinous state even at positive temperatures of the order of + 15 ° C .
• Glycerin was actively used as antifreeze for in the first half of the 20th century, until it was found to be a worthy substitute in the form of other glycol compounds. So from this point of view, these coolants are a "step back".
• There are no rigid standards for similar antifreezes - each manufacturer installs its TU .By the way, glycerol is actively used by manufacturers of counterfeit - it is introduced into coolants in as specified by , as a substitute for a more expensive and effective propylene glycol.

By the way, in some European countries where the production and use of ethylene glycol antifreeze is simply forbidden, glycerol coolants are not produced - they are not considered practical and effective.

Antifreeze for electrode boilers

If electrode boilers are installed in the heating system, they need a special type of coolant. The fact is that the heating to the desired temperature occurs behind the account of the passing through it an alternating current with the ionization of the solution. Accordingly, the coolant, in addition to its basic qualities, which has already been mentioned many times in the article, must have a specially selected chemical composition that provides the necessary ionization and necessary electrical conductivity and electrical resistance.

Generally, electrode cat manufacturers give direct recommendations for the use of certain coolants. Moreover, most of the development companies have mastered the production of the necessary antifreezes, which are optimally combined with the produced boiler equipment.

. In any case, if an electrical heating system with ionic( electrode) boilers is planned to be installed at home, special care must be taken to select the necessary coolant. It is not excluded that the manufacturer will give a warranty for his products only with the changing the strictly limited list of antifreezes.

The main conclusions and recommendations for the selection of coolants

So, sum up the main results in the selection of the required coolant.

In case the accommodation conditions ensure that the positive temperature of the is always maintained under any circumstances, is without any doubt it is better to use water - ideally, distilled with surfactants and the corresponding additive inhibitors .If distilled - expensive, means with ordinary water, it is necessary to carry out a complex of preparation( softening).

If the use of antifreeze is planned, the conditions under which they are completely excluded are to be taken into account:

• The heating system is constructed in an open type - the inevitable evaporation of both water and the organic base will quickly change the chemical composition of the coolant and its performance characteristics. In addition, the evaporation of ethylene glycol poses a danger to human health.
• The heating system uses pipes, stop valves, other elements with a galvanized surface.
• When installing the system used seals made of linen winding with oil paint - the glycol base necessarily and very quickly "will" paint, and the formation of leaks - is inevitable.
• Heating boiler not is equipped with precise temperature control. Heating almost any of the antifreezes to temperatures above 70 degrees leads to the onset of destructive chemical processes.

In order to use antifreeze coolants, a number of specific rules must be observed:

• With the calculation of the heating system, consider that a more powerful circulating pump and more volumetric membrane expansion tank will be required. Usually the volume of of such a tank is twice as much as in a system using water.
• Pipes and radiators should also have larger dimensions - the diameter and internal volume of .
• Automatic air deflectors are not designed to work with antifreezes. To ensure the yield of accumulated gases, it is better to use manual valves , type of the Mayevsky crane.
• When installing radiators, they must be sorted out so that the is guaranteed by the to install gaskets from a resistant material - paronite or Teflon. The same applies to other detachable connections.
• In threaded joints it is recommended to use linseed cotton with a special sealing paste.

• sealing paste. The antifreeze should only be poured into the heating system after a thorough of its rinsing. It is best to its using special formulations.

• special formulations are used for flushing heating circuits. If is purchased with concentrate, dilute it to the desired concentration with only distilled water. Even melt and well-kept water for these purposes is not suitable for .
• It is very important to observe the correct proportion when diluted. Even if the region of residence does not differ in the severity of winters, all equals to bring the concentration to the pour point above minus 20 ° With - is strictly prohibited. The fact is that excess water will disturb the balance of the chemical composition of glycol, reduce the effectiveness of the action of additives. This can result in the sudden appearance of foci of corrosion or the formation of scale.
• After filling the system and start the boiler can not immediately output it at full capacity. This should be done stepwise, to allow the antifreeze to expand normally, enter the working state.
• In order to ensure the safety of their household, it is still necessary to purchase a coolant based on propylene glycol. Yes, it is, of course, more expensive, but to save on one's own health is not the smartest step.

Video : several recommendations on the choice of coolant for heating

And, in conclusion article, one interesting fact. It can be regarded with as a certain share of humor, and you can take and seriously - all that will be said is the pure truth !

Almost ideal heat carriers for domestic heating systems can become . .. ordinary vodka.