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Which coolant to choose for heating system - water or antifreeze
For heating, as a coolant, in the climate of Russia, it is customary to consider antifreeze a panacea for all ills. Is it so? Consider the advantages and disadvantages of water and antifreeze as a coolant.
Content
Water - coolant
Filling the heat supply system with water, the owner should provide for possible negative consequences.
Under normal conditions, the liquid in the heating system is practically not consumed, but here the quality of the water comes to the fore.
advantages of water as a coolant
Water itself is not an aggressive element.
If the water contains few salts and other impurities, and before filling the system, water is passed through a filter, to remove the above impurities, this is an excellent coolant.
If the owners live in the house permanently, they can monitor the condition of the heating system - they will not allow the thermal system to freeze.
If the boiler has an open system and is not dependent on energy supply, a power outage does not affect the operation of the gas boiler.
The best option is to constantly fill the system with water, even in the summer the system must be constantly filled - this will prevent corrosion and other problems.
shortcomings of water as a coolant
If the water contains salt and other impurities, then when heated, all these salts will settle on the internal elements of the heating system - this will reduce heat transfer.
If the boiler is used periodically, residents in the cold season move to the city - the coolant in the form of water is drained, the system is preserved.
As a result, new water is poured every season - the amount of scale increases.
All this gradually reduces heat transfer and increases gas consumption.
Antifreeze - coolant
Antifreeze is an artificially created chemical coolant.
The basis of antifreeze is an aqueous solution of salts, alcohols, ethylene glycol with additives.
These additives are able to adjust the physical properties of the solution.
In Russia, ethylene glycol-based antifreezes are most common.
advantages of antifreeze as a coolant
The main advantage of antifreeze is its low freezing temperature, up to -68 * С.
At the same time, changing the ratio of concentrate and water, the freezing temperature also changes from -10 * С to -68 * С.
With a decrease in antifreeze temperature in the range from -20 * С to -30 * С - 35%, the concentration of ethylene glycol acquires a sludge state.
The use of various additives in antifreeze allows you to protect metal from corrosion, dissolves and removes the resulting scale, prevents the destruction of seals in threaded joints.
But this is ideal. But in fact, all European manufacturers of heating boilers do not recommend using antifreeze as a coolant.
Manufacturers in passports always emphasize that the coolant is only water.
Many sellers simply ignore this problem, and the buyer reads the passport after the boiler is purchased.
Why not recommend antifreeze as a coolant?
disadvantages of antifreeze as a coolant
The heat capacity of antifreeze is less than the heat capacity of water by 15-20%.
The viscosity of antifreeze is 2-3 times higher than the viscosity of water.
Volumetric expansion is 40-60% more. Many other characteristics differ.
In practice, it turns out that if you decide to use antifreeze in the heating system, you must make changes to the design of the heating system in advance.
Namely: it is necessary to purchase larger batteries, a more powerful circulation pump, and a storage tank must be larger.
And most importantly, you need to purchase a more powerful boiler.
Accordingly, the power of the entire system increases, gas consumption increases and, accordingly, the charge for it.
In addition to the above, ethylene glycol-based antifreeze is not stable during overheating, since thermal decomposition of the antifreeze into components will occur, acids will form and solid precipitates will form.
Carbon deposits form on the heating elements of the boiler - this further leads to the destruction of the heat exchanger.
Acid provokes metal corrosion, gaskets corrode at threaded joints, leaks appear at joints.
When overheating, the antifreeze begins to foam, the system becomes airy.
Overheating for ethylene glycol antifreeze is a very big danger.
Antifreeze has an increased property of permeability or fluidity.
When the heating system is off, when cooling, leaks often appear at the junction points.
Ethylene glycol based antifreeze is a toxic material, therefore it is not recommended to be used for double-circuit boilers in the hot water supply system.
If the heat exchangers are not tight, there is a danger of the antifreeze getting into hot water.
New Generation Antifreeze
At present, in Russia, a new generation of antifreezes has become more widespread, in Europe they have become widespread in the late 90s of the last century.
The basis of these antifreezes is food-grade propylene glycol - it is an environmentally friendly substance.
Such antifreeze is absolutely harmless, it is allowed to use dual-circuit heating systems.
Although the thermal and hydraulic characteristics are equivalent to the characteristics of antifreeze based on ethylene glycol - they are less aggressive towards metals and materials in heating systems.
Many leading manufacturers of gas boilers allow the use of propylene glycol antifreeze in their boilers.
The price of the new antifreeze is quite high.
Dispute Results
Does it make sense to increase the cost of the entire heating system - a question that does not have a clear answer.
With the correct operation of any boiler, freezing of the coolant is simply impossible, since there is an automatic heating mode, almost all wall-mounted boilers.
If the boilers are non-volatile - the best coolant is water.
If you have a backup power source - it will be able to ensure the efficiency of the heating system.
But if your house is in a clean field, powered by a single cable, and power outages are long - pour antifreeze.
When pouring antifreeze, check if it precipitates when interacting with water.
In case of precipitation, add distilled water.
Do not dilute antifreeze more than 50%.
Do not pour antifreeze into galvanized pipes, as this will form a huge precipitate - the heating system will fail.
After 4-5 years, antifreeze is changed, as it ages.
