In the vast majority of autonomous heating systems (CO) of private houses, ordinary water is used as a coolant, which has sufficient heat capacity, optimal density for circulation, and low cost. But under certain conditions, its use is difficult or impossible. Therefore, homeowners use various non-freezing liquids for the heating system of a private house. About the types of antifreeze, the advantages and disadvantages and the independent manufacture of “non-freezing” for the heating system at home and will be discussed in this publication.
Purpose and composition of antifreeze
The main reason for using non-freezing liquid in heating systems is the possibility of negative temperatures affecting the coolant. In addition, the use of water in a heating circuit made of metal pipes sooner or later leads to the formation of scale and corrosion of the latter.
Any non-freezing liquid for the heating system consists of:
- Basics. All antifreezes are water or alcohol based.
- The active component, the purpose of which is to reduce the threshold of water crystallization.
- Additives that are responsible for giving the composition the necessary properties and performance characteristics.
- Inhibitors that reduce the corrosive effects of the composition on CO materials.
As the main component of most antifreezes present on the domestic market today, we can distinguish:
- propylene glycol. The composition includes: distilled water 50%; main component 46%; additives and inhibitors 4%. It can be used both in open and closed high-temperature CO with solid fuel boiler equipment.
Ethylene glycol. This antifreeze in the home heating system has the following composition: water 31%; main component 63%; additives and inhibitors 6%.
Important! Due to its high toxicity (in the vapor state), ethylene glycol is allowed for use only in closed COs.
Glycerol. “Nezzamerzayka” based on glycerin is not hazardous to human health, fireproof and can be used in any CO. The technical characteristics of glycerin formulations are significantly lower than those of glycolic ones.
Important! The compositions of non-freezing glycol and glycerin coolants for CO are known, but it is quite difficult to make them yourself due to problems with the correct dosage and selection of the necessary additives. Failure to comply with the proportions and production technology leads to an increase in foaming during heating of the “non-freeze” and a decrease in the heat transfer of a home-made coolant.
Features of the use of antifreeze liquids
Glycol antifreezes for the heating system of a country house are the most common in the domestic market. Before pouring the finished mixture into CO at home, some points should be considered, namely:
- All water-glycol formulations have greater (than water) ductility. To compensate for the increased hydraulic resistance, it is necessary to use more powerful pumping equipment or make the pump rotate faster.
- Experts note that glycerin and glycol “non-freezes” have a significantly higher expansion coefficient when heated. If you decide to switch from water to antifreeze, then you should provide for a larger expansion tank.
- All glycol and glycerin antifreezes have a lower heat capacity. In other words, they bring heat to heating devices by 15–20%. If you want the efficiency of the heating system not to decrease during the transition to “anti-freeze”, then radiators of higher power should be provided.
Tip: There is an option that does not require an increase in battery power: it is necessary to increase the speed of the coolant in the circuit.
Limitation of the use of antifreeze liquids in heating systems
This publication will not consider the positive aspects of glycol antifreeze. Manufacturers and marketers have taken great care of this. In fact, not all non-freezing coolants are suitable for a certain type of boiler equipment. Incorrect selection can lead to failure of the heat generator heat exchanger.
Important! Most models of double-circuit heating boilers cannot work with antifreezes due to the possible ingress of coolant (in an emergency) into the domestic hot water system.
- The use of ethylene glycol in open COs is prohibited.
- The use of glycol antifreezes in CO with galvanized piping is not recommended. When interacting, the protective layer of zinc is destroyed, which can lead to failure of the heating circuit section.
- Water-glycol “anti-freeze” negatively affects rubber seals. The only option to avoid an accident in such a situation is to replace the rubber gaskets with paronite ones.
Important! Glycerin antifreeze, along with low cost, has one significant advantage — a beneficial effect on the condition of sealing rubber gaskets.
Good do-it-yourself anti-freeze
So, what to do if it is impossible to use water as a CO coolant, and there is no technical possibility to switch to purchased antifreeze? There is a way out: independent production of a non-freezing coolant, which, in terms of its technical and operational characteristics, will be as close as possible to water, but will not freeze. To make such a mixture is quite simple: you need to mix distilled water with ethyl alcohol. Such a home-made “non-freezing” has the following characteristics:
- Viscosity and density are slightly higher than purified water, but significantly lower than glycol antifreezes.
- The fluidity of a water-alcohol solution is much lower than that of glycol and glycerin heat transfer fluids.
- Alcohol prevents corrosion. It becomes possible to use aluminum and steel heating radiators for cottages with antifreeze from alcohol and distilled water.
- The water-alcohol solution does not affect the rubber seals.
- Alcohol in the composition of the coolant reduces the formation of scale, which inevitably appears when using hard water.
- The boiling point of a water-alcohol solution is approximately equal to the boiling point of water.
To make an alcohol “anti-freeze”, one should proceed from the temperature characteristics of the composition. The proportions are as follows:
- 20% percentage solution withstands temperatures of ‑10°C.
- 33% alcohol coolant remains in a liquid state at ‑23°C.
- 40% percentage solution does not freeze at ‑29°C.
Tip: To create this coolant yourself, it is very important to correctly calculate the dosage of alcohol (usually 96%) and water. The most common water-alcohol solution contains 33% alcohol. For the calculation you need 96/33= 2.9. In other words, for 1 liter of 96% alcohol you need 2.9 liters. distilled water.