Coolants for heating system
Despite the fact that nowadays there is a lot of interesting alternative home heating systems, water heating circuits still remains the leader in popularity. And apparently, this trend is still not soon change - in the harsh conditions of the Russian climate, when most of the country continuous heating season lasts at least six months, so the heat transfer scheme so far is the best and from the standpoint of economic efficiency, and heating efficiency, and comparative management and ease of maintenance.
Coolants for heating system
However, there is in such a scheme and vulnerabilities, as well one of the main is a risk of freezing in the pipes in any extreme situations. Therefore, although the heating is called the "water" is very often used coolants and other heating systems. The choice depends on the type of existing or planned systems, specific models of heating equipment, the purpose and features of the building.
What requirements must meet the coolant
The main task of the fluid in the heating system - heat transfer from the boilers to the heat exchange points - the radiators, convectors, "warm floors". It would seem, can go either, but it is - an amateurish approach. By coolant presented a number of specific requirements to the heating system was also effective, and comprehensively secure.
- In this fluid must be canceled thermal capacity, i.e. the maximum capacity to store heat transferred from the boiler, for their subsequent return to the radiators or convectors.
- In the coolant should be, if possible, the widest operating temperature range - from the freezing point to the boiling boundary.
- Chemical composition must have coolant inertness to basic materials used for gaskets in the heating system.
- The liquid should not cause active corrosion in pipes, ducts boiler, radiators, in the elements and the connecting devices, valves and special valves.
Traditional &# 171; a scourge&# 187; heating systems &# 8212; overgrown scum pipe.
- The coolant should not produce a solid precipitate or form scale on the walls of pipes, especially - in the heat exchanger of the boiler.
- The chemical composition of the fluid must be stable, does not decompose into components over time or under the influence of changes in temperature, coolant should not change their physical characteristics - density, viscosity, specific heat, and others.
- Heat transfer medium in a running heating system should not pose a threat to human health - it concerns the emission of toxic fumes or elevated fire&# 8212; or even explosive.
Now a natural question - what is the heat transfer fluid will fully meet all the requirements? The answer, perhaps, someone may discourage - in nature simply does not have such an "ideal" chemical composition. Therefore, there is not an easy problem so as to select the most optimal for a particular coolant heating system for the specific features of its operation, and under what must be confessed, the financial capacity of the Host.
Typically, the decision to use one or another heating medium is taken at the design stage or reconstruction of the heating system, as its configuration and the "hardware filling" is closely related to the type and operational characteristics of the circulating fluid circuits sweat. That is, you must be right to focus on this or that dominant quality planned to use composition.
If to explain simply, the most important in the selection - correctly placed priorities. For example, if the heating system is planned for the house where the tenants will be constantly throughout the year, rather than arrivals at the weekend, the best solution, and in terms of efficiency, and heat engineering characteristics, is the use of water.
But here it is necessary to take into account certain nuances. For example, there are villages in which interruptions in energy supplies are by no means uncommon. A peak in winter frosts sometimes just a few hours so that the water in the system is off starts to crystallize and thus increase in volume. And this is - a direct path to a serious accident with impulse pipes and radiators!
And if a country cottage with a water heating system is not used year-round, or the way of life of its inhabitants is such that it is associated with frequent trips and leaving home without appropriate supervision, that the fore considerations should leave "all-season" filled in the coolant. However, this will necessarily entail specific requirements for the construction and sealing of heating circuits, as virtually all antifreeze coolants in varying degrees, toxic, and often - and even quite flammable.
From time to time any coolant needs to be completely replaced, and this, in the case of the use of antifreeze, can cause quite serious charges. And one more thing - some models of boilers are accompanied by the manufacturer's recommendations on the use of certain heat transfer with them. The use of other fluids in the system can even easily lead to a loss of rights for warranty service and repair of boiler equipment.
In short, the choice of coolant - a question that requires some knowledge of the owner of property, so it makes sense to learn the basic species closer.
Water as a coolant heating system
You can just say that about 70% of all heating systems of houses is water is used, it is possible, with certain builders. This is due to several key factors:
- The first, of course, is the universal availability and low cost of such a coolant. In the vast majority of Russian regions with no water no problems, and can be found, or for free, or at such a "ridiculous" prices that absolutely can not be compared with the cost of the special ice-free formulations. And fill the system and refill the coolant in case of any emergencies - will not be difficult and will not cause serious financial expenses.
- According to its thermo-technical characteristics of ordinary water leaves far behind all the other technical liquids. It has excellent thermal capacity - about 1kal / g × ° C at a high density, which varies somewhat from the temperature at an average heating of the system up to 70 ° C - about 0.977 g / ml or 977 g / dm³ (liter). Thus, if the "model returns" heat on the heat sink - the fall, for example, temperatures of 20 degrees, from 80 to 60 ° C, each liter of water to give about 20 kcal room. The detailed figures can not match any other compositions.
- Water - absolutely safe product from the point of view of ecology. Leakage in the system can only deliver some domestic troubles, but will have no toxic threat to health inhabitants of the house. Similarly, we can argue about fire safety and a heating system.
However, the water is still not an ideal coolant for many reasons:
- About main mentioned - a sufficiently high temperature of freezing water. Leave the system filled with coolant such unattended in winter is strictly forbidden - it can lead to a large-scale accident. Everyone knows that the freezing water can literally rip the metal pipe and heating radiators.
Water during freezing has terrible destructive power!
- Water itself is a powerful oxidizing agent, plus it is constantly in dissolved oxygen, and it is - is always an increased risk of corrosion to pipes, radiators and other heating metal elements.
- Plain water is almost always in its composition has a lot of dissolved salts, which can form deposits on the inside of the pipes, and reducing permeability in them, and significantly degrading the heat exchange, including on TENah electric boilers. This necessarily entails reduction of the heating efficiency, as a consequence, increase operating costs for energy, the output of the heating elements of the system.
- Water more often than other coolants requires complete replacement of all poured into the volume circuit - usually held annually.
If the freezing point of water to do anything significant impossible, the other negative qualities of water to a certain extent you can eliminate or significantly reduce.
Reduce the concentration of salts in the water as possible, spending its softening procedure. There are several ways that differ in their effectiveness.
Thus, even the conventional boiling water is able to deduce from it a number of unstable composition carbonate compounds - they decompose into solid (scum) and leaving the carbon dioxide. To better take boiling volumetric dishes with a large area of contact with the surface of the water - in these points there is the main part of the process.
sodium orthophosphate &# 8212; effective means for water softening
Boiling help to "alleviate" water only bicarbonate from calcium and magnesium salts, salts with dissolved but other bases require a different approach. Good results shows chemical softening using soda ash, lime or sodium orthophosphate solution. However, we must remember that for the quality of water purification without loss of its basic thermal properties and without giving it any qualities activate corrosion processes is required to follow the exact dosage of ingredients, so that the water does not remain excess reactants introduced. Ideally, all the salts contained in the water must drop a solid precipitate which is then removed by filtration.
Heating systems can acquire distilled water
Possibly the easiest solution would be to use technical distilled water - it can always be purchased at specialty stores building. Of course, it is much more expensive than tap water, but then the trouble with the heating system will be significantly less. So maybe it's worth to pay about 15 ÷ 20 cents per liter, and are not afraid of the pipes, radiators and heat exchangers in the boiler quickly overgrown scum? The water is realized in the most diverse packaging &# 8212; from small bottles of 0.5 liters to large plastic cubes enclosing a ton of liquid. It is always possible, knowing the extent of their heating system, purchase the right amount, moreover, that usually operate at the same volume discounts.
Sometimes "conditionally" householders distilled water is collected independently. We are talking about rain and melt water - it has already passed the natural process of distillation. However, one can only speak in part about its cleanliness - it certainly has already fed contained in air pollution. Nevertheless, it is always much softer than the one that comes from the taps or taken from underground sources - wells or boreholes.
So it is possible to organize the collection of rain water
Better still, immediately choose technical distilled water for heating enriched special additives. We are inhibitors - special chemical components that dramatically reduce the corrosive quality of water.
surfactants (tensides) - In addition, special additives are introduced into the composition of the aqueous fluid. This gives the liquid a number of positive properties - almost reduced to zero fouling on the walls of pipes and radiators, and existing deposits will gradually peel off and go, lingering in the settling filter. Moreover, the inner surface becomes pronounced hydrophobic properties, which means a sharp decline in the hydraulic fluid resistance in the heating circuit and, as a consequence, reduction of energy consumption. This water will have no negative impact on seals - gaskets and seals retain their functionality longer.
It should be similar to distilled water with surfactants and inhibitors of several more expensive - it cost about 22 - 25 cents per liter.
Antifreeze as coolant
Even distilled, with appropriate additives Uluchay water does not solve the main problem of the liquid - freezing at a relatively high temperature (about 0 degrees Celsius), accompanied by significant volume expansion. Since winter temperatures in most cases - negative, use water in heating systems in cases where continuous monitoring of their work is not possible, it is very risky. Hence, it is necessary to fill the outline of the special anti-freeze fluids - antifreeze.
A variety of anti-freeze &# 8212; very large
By that single name ( 'anti' - "against", "the freeze" from English - the "freezing", or in Russian in everyday life - "nezamerzayku") combined several types of chemical compositions of liquids, which have a very low temperature crystallization starts. This allows their use in home heating systems, and they are more familiar to motorists as the base material for engine cooling system or a liquid for washing glasses.
Lowering the temperature effect on the majority of anti-freeze a little differently than ordinary water. Thus, a similar substance, even during a hard frost will never turn into a completely solid. Even at the lower limit of the operating temperature, it becomes a gel, it loses its fluidity, but at the same time, it is not accompanied by an increase in volume and will not lead to deformation or rupture of the pipe radiators. But the temperature increase would cause dilution of the gel-like structure of antifreeze, return it to its normal state without any whatsoever loss performance.
Most commercially produced antifreeze in a clean, concentrated form capable normal "run" at temperatures up to &# 8212; 65 ° C. Usually, in most of the Russian such qualities are redundant, therefore formulations often diluted with distilled water to working solutions with a minimum threshold in &# 8212; 30 ÷ 35 ° C - this is quite enough.
DEVICES OR SYSTEMS HEAT
Collapsible, sectional radiators
Sealed radiators and convectorsWarm floor
HEATING TUBE CIRCUIT (feed + return)
ADDITIONAL DEVICES AND HEATING SYSTEMS UNIT (heat accumulator, gidrostrelka collector, teplobomennik and others)
Several necessary explanations:
- The volume of the heat exchanger of the boiler - it is characteristic of the passport, and it is easy to learn.
- Similarly - and with an expansion tank. The program of calculation takes into account that when filling the coolant system expansion tank is filled incompletely.
- Next - heat transfer equipment:
&# 8212; For collapsible radiators base value for the calculation is the volume of one section. The calculator presents the most common types of collapsible radiators, and the values of their volume is already included in the calculation of the program - will only have to specify the total number of sections.
&# 8212; For non-separable radiators or convectors amount placed in them coolant - passport value.
&# 8212; Somewhat more complicated with the contours of a warm floor (if available). It is necessary to specify the type and diameter of the pipes and the total contour length. The database program parameters made most often used for water underfloor plastic pipes and unreinforced XLPE - PE-X, with diameters for those and other - 16 to 25 mm.
- Reached the supply pipe and return circuits. Measure their length - Easy, as well as to define the outer diameter.
There are some nuances - in the heating system, especially to create for a long time, it can be used various types of pipes. For example, the case that kept the old steel-beds collectors from pipes VGP, and then go to the transitions of metal and plastic or polypropylene wiring of risers and further - on the radiators.
But the fact that the entire similarity of external diameters, wall thickness, and hence the nominal diameter of the pipes in different manufacturing material varies considerably. About it should not be forgotten, as the filling volume and meter site will also be uneven.
Do not worry - the program provides an opportunity to take into account this circumstance. It is enough to select those types of pipes, which are present in the system - and for each of them there will be lists of diameters with sliders to enter the land length. That is, all will be considered in detail.
- Finally, the system is often worth the extra instruments and devices - buffer tanks, hydraulic arrow, prefabricated collectors, boilers of indirect heating, heated towel rails and other elements. If such equipment is installed in the general scheme of the heating system, the last of the emerging data entry window will be prompted to specify the value of the volume of passport.
After that, click on the "Calculate" button once will result in a ready-accurate results.
Now, probably, all gaps are eliminated, and the reader full information picture should appear - on which it is suitable coolant at the optimum level, to calculate precisely the amount that will be required to purchase or prepare.