Heat transfer to the heating system

Although nowadays there are many interesting alternative home heating systems, water heating circuits still remain leaders on on popularity of. And judging by around , this trend is more long time 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 circuit is what isoptimal and from the point of view of efficiency, and heating efficiency, and comparative ease of management and maintenance .

, however, have similar schemes s and yazvimye places, and one of the principal is a risk of freezing in the pipes in any extreme situations.Therefore , although heating is called the "water" is very often used coolants and other heating systems.The choice depends on the type of existing or projected systems, specific models of heating equipment, purpose and features of the building.

What requirements must meet the coolant

main task of the liquid in the heating system - heat transfer energy from the boilers to heat points - radiators, convectors, « warm sexes."It would seem, can go either, but it - amateurish approach .By coolant presented a number of specific requirements to ensure that the heating system was also effective, and fully secure.

• In this fluid should be repealed heat capacity, ie the ability to accumulate the maximum heat transferred from the boiler, for its subsequent impact on the radiators or convectors.
• have the coolant should be, on features the widest operating temperature range - from the freezing point to the boiling boundary.
• chemical composition of the coolant must have inertia to the main materials used for seals in the heating system.
• liquid should not cause active corrosion in pipes, ducts of the heating boiler, radiators, in the elements and connecting devices, valves and special valves.

• The coolant should not give solid precipitate or form a scum on the walls of pipes - especially in the heat exchanger of the boiler.
• chemical composition of the fluid must be stable, does not decompose into components over time or under the influence of changes in temperature, the coolant should not change their physical characteristics - density, viscosity, heat capacity and others.
• coolant in operating the heating system must not pose a threat to human health - it concerns the emission of toxic fumes or elevated, fire - or even explosive.

Now a natural question - what is the heat transfer fluid will fully meet all requirements?The answer, perhaps, some people may be discouraged - in nature simply does not have such an "ideal" chemical composition.That is why there is so not an easy problem, as the selection of the optimal coolant to specific heating system to the specific characteristics its operation, and under what must be confessed, the financial capacity of the Host.

Typically, the decision to use one or another coolant is taken still on design stage or reconstruction of the heating system, as its configuration and "hardware filling" very closely linked overlooking and performance circulating sweat contours of liquid.That is, you must be right to focus on this or that dominant quality planned to use composition.If

explain simply, the main in the selection - correctly placed priorities.For example, if the heating system is planned for the house where the tenants will be constant throughout the year, rather than arrivals at the weekend, the best solution, and economy, and heat engineering characteristics, is the use of water.

But here it is necessary to take into account certain nuances.For example, there are populated points at which disruptions in energy supplies are by no means uncommon.And at the height of winter frosts sometimes just a few hours, the water in the system is off start to crystallize and, accordingly, increase in volume.A is - a direct path to the a serious accident with a gust 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 home without appropriate supervision, that the fore considerations should leave "all-season" filled in the coolant.However, this necessarily entails specific requirements for the construction and sealing of heating circuits, as virtually all non-freezing heat transfer fluids in varying degrees, are toxic and often - still and quite flammable.

from time to time any coolant needs to be completely replaced, and this, in the case of using antifreeze, can cause quite serious costs.And even one moment - some models of boiler are accompanied by the manufacturer's recommendations on the use of them certain coolants.The use of other liquids in 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 the owner of property of certain knowledge, so it makes sense to learn the basic varieties closer.

water as heating

coolant system can immediately say that about 70% of all heating systems of houses is water used, perhaps with some or other builders.This is due to several main reasons:

• first, of course, is the universal availability and low cost of such a coolant.The overwhelming majority of Russian regions with water no special problems are not present, and can be found for free or, or same for such a "ridiculous" prices that absolutely not comparable with the cost of special ice-trains.And to complete the system and refill the coolant in case of any emergency - would not be difficult and will not cause serious monetary expenditure.
• According to its thermo-technical characteristics of ordinary water leaves far behind all the other technical liquids.In her excellent heat capacity - about 1kal / g × ° C at a high density, which is slightly varies from the temperature at an average heating system up to 70 ° With - about 0.977 g /ml or 977 g / dm³ (liter).So way, when « exemplary impact" of heat to the heat sink - fall, for example, a temperature of 20 degrees, from 80 to 60 ° With , 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 a certain 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.

Nevertheless , the water is still not an ideal coolant for a number of reasons:

• About main already 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 freezing water can literally break the pipe and metal radiators.

• Water by itself is a powerful oxidizing agent, plus it is constantly in dissolved oxygen condition, and it is - is always an increased risk of corrosion to pipes, radiators and other heating metal elements.
• Normal water almost always in his structure has a lot of dissolved salts, which are capable of forming deposits on the inner surface of the pipe, and reducing permeability in them, and significantly worsening the heat exchange, including on TENah electric boilers.This necessarily entails decrease in heating efficiency, as a consequence, the growth of operating costs for energy, the output of the heating elements fail .
• water more frequently than other coolants requires a complete replacement of all poured into volume circuit - usually held annually.

If the freezing point of water to do anything significant impossible, the other negative qualities of water in certain extent you can eliminate or significantly reduce.

reduce the concentration of salt in the water can be, having spent her procedures softening.There are several methods differ in their effectiveness.

So even ordinary boiling water is able to deduce from its composition a number unstable carbonate compounds - they decompose on solid precipitate (scale) and carbon dioxide coming out.To take better volumetric boiling pans with a large area of ​​contact its surface with water - it is at these points there is the main part of the process.

Boiling help « facilitate » water only from bicarbonate salts of calcium and magnesium, but dissolved salts with other bases require a different approach.Good results show the chemical softening using soda ash, lime or sodium orthophosphate solution.However, we must remember that for quality water treatment without losing its basic thermal properties and without give her any qualities activate corrosion processes is required to comply with an exact dosage of the components, so that the water does not remain made excess reagents.Ideally, all the salts present in water should fall in solid precipitate which is then removed by filtration.

Perhaps a simpler solution would be the use of 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 rubles per liter, and are not afraid that the pipes, radiators and heat exchangers in the boiler quickly overgrown scum?The water is realized in the most diverse packaging - m from Scarlet bottles of 0.5 liters up huge plastic cubes enclosing a ton of liquid.You can always knowing volume its heating system, purchase the right amount, especially since usually at the same time act wholesale discounts.

Sometimes "conditionally» owners distilled water houses are collected independently.It is of rain or melt water - it has already passed proce ss etc. irodnoy distillation.However, to talk about her purity can only partly - she probably had already fed contained in the polluted atmosphere. Nevertheless, it is always much softer than the one that comes of cranes or taken from underground sources - wells or boreholes.

A even better to choose the right technical, distilled water for heating, enriched with special additives.It is inhibitors of - special chemical components that dramatically reduce the corrosive quality of water.surface active agents (surfactants) -

In addition, special additives are introduced into the composition of the water coolant.This gives liquid a number of positive properties - almost reduced to zero fouling on the walls of the pipes and radiators, and existing deposits will gradually peel off and out, lingering in the sump filters.Moreover, the internal hydrophobic surface properties become pronounced, which means drastic reduction of the hydraulic fluid in the circuit resistance heating and as a consequence, reduction in energy consumption.This water will have no negative impact on seals - gaskets and seals retain their functionality longer.

worth like distilled water with surfactants and inhibitors of several more expensive - it cost approximately 22 - 25 rubles per liter.

Antifreeze as coolants

Even distilled, with appropriate additives uluchayuschimi water does not solve the main problem of this liquid - freezing at relatively high temperature (about 0 degrees Celsius), accompanied by a significant volume extension.Since winter temperatures in most cases - negative, to use water in heating systems where continuous monitoring of their operation is not possible, it is very risky.So, have fill outline special antifreeze - antifreeze.

under this single name ( « ANTI » - «against» , «freeze» from English - the "freezing", or in Russian in everyday life - «nezamerzayku ») combined several types of chemical compositions of liquids which have very low temperature crystallization starts.This allows their use in home heating systems, as they are more familiar to motorists as the basic material for engine cooling system or a liquid for washing of glasses .

Lowering the temperature effect on the majority of anti-freeze a little differently than ordinary water.So, like substance even during a hard frost will never turn into a completely solid substance.Even at the lower limit of the operating temperature, it becomes a gel, loses its fluidity, but, however, it is not accompanied by an increase in volume not lead to deformation or rupture of the pipe radiator. But the rise in temperature will cause a dilution of the gel-like structure of antifreeze, return it to its normal state without any loss was performance.

Most antifreeze produced commercially in the pure, concentrated form can normally "work" at temperatures of up to - 65 ° With .