Review of ionic boilers – we heat water with electric current

Recommendation points

• The history and principle of operation of the ion (electrode) boiler
• Characteristics of ion (electrode) boilers
• Device and installation of the electrode boiler
• Ion boiler – prices and manufacturers
• At the end

In this article: an electrode boiler – the brainchild of defense enterprises; how an ionic boiler works; is it possible to heat water without a heat source; lower ohmic resistance – add salt to water; pros and cons of ion boilers; electrode boiler device; how to properly install the electrode boiler; which heating devices can be used in a circuit with an ionic boiler and which cannot; manufacturers and prices; at the end – the nuances of installing ion boilers.

How many ways to heat your home with electricity do you know? Most often, a boiler with a water heater comes to mind – having a high resistance, the nichrome thread inside such a heater heats up, transferring heat to the tube filler, then to the metal shell and, finally, to water. Why not simplify the task and not heat the coolant without going through an intermediary, because you can do this using primitive electrodes from two razor blades, connecting wires to them and connecting them to the power supply? It was from this logic that the creators of the first models of ion (electrode) boilers, originally developed for the needs of the USSR Navy, proceeded.

The history and principle of operation of the ion (electrode) boiler

This type of heating boilers was created in the middle of the last century by enterprises of the defense complex for the needs of the USSR submarine fleet, in particular, for heating the compartments of submarines with diesel engines. The electrode boiler fully complied with the conditions for ordering submariners – it had extremely small dimensions for conventional heating boilers, did not need an exhaust hood, did not create noise during operation, effectively heated the coolant, which was most suitable for ordinary seawater.

By the 90s, orders for the defense industry had sharply decreased in volume, along with this, the needs of the navy for ion boilers were reduced to zero. The first “civil” version of the electrode boiler was created by engineers A.P. Ilyin and D.N. Kunkov, who received the corresponding patent for their invention in 1995.

The principle of operation of the ion boiler is based on the direct interaction of the coolant, which occupies the space between the anode and cathode, with an electric current. The passage of an electric current through the coolant causes a chaotic movement of positive and negative ions: the former move towards a negatively charged electrode; the second – to the positively charged. The constant movement of ions in a medium that resists this movement causes a rapid heating of the coolant, which is especially facilitated by the change of roles at the electrodes – every second their polarity changes 50 times, i.e. each of the electrodes within one second will be the anode 25 times and the cathode 25 times, since they are connected to a 50 Hz AC source. It should be noted that it is precisely such a frequent change of charge at the electrodes that does not allow water to decompose into oxygen and hydrogen – a constant electric current is required for electrolysis. As the temperature rises in the boiler, the pressure rises, causing the circulation of the coolant along the heating circuit.

Thus, the electrodes installed in the tank of the ion boiler do not directly participate in heating the water and do not heat up themselves – positively and negatively charged ions, split under the influence of electric current from water molecules, are responsible for the increase in the water temperature..

An important condition for the effective operation of an ion boiler is the presence of an ohmic resistance of water at a level of not more than 3000 Ohm at 15 ° C, for which this coolant must contain a certain amount of salts – initially, electrode boilers were created under sea water. That is, if you pour distilled water into the heating system and try to heat it with an ion boiler, there will be no heating, since there are no salts in such water, which means that there will be no electrical circuit between the electrodes.

Characteristics of ion (electrode) boilers

Possessing the positive characteristics inherent in electric boilers, this type of boilers also has a number of its own. I will note all the advantages:

• high efficiency, close to 100% (however, any electric heater has an efficiency of at least 96%);
• extremely small dimensions with high power, compared to any other boilers;
• no chimney required;
• able to independently raise the pressure in the heating circuit;
• unlike boilers with heating elements, there is no danger of an accident at an insufficient level of the coolant in the boiler tank – a lack of coolant will only lead to the termination of the boiler operation, since there will be no electrical circuit between the electrodes;
• extremely low inertia allows you to effectively control temperature conditions during boiler operation using automation, as a result, the least energy-consuming operation of the heating system is achieved – the temperature in the heated rooms will always be at the level that is set to the automatic controller;
• voltage drops in the power grid do not harm the ion boiler – only its power changes, the work does not stop;
• installation as an additional source of thermal energy, installation of several ion boilers at the same time is allowed;
• there is absolutely no negative impact on the environment.

Cons of the electrode boiler:

• consumes only alternating current, with direct current electrolysis of water will occur;
• high requirements for the electrolytic characteristics of the coolant, when they change, the quality of work (heat production) decreases sharply. Control over the electrical conductivity of the coolant is required;
• requires mandatory grounding (however, like any heating device with a water heater). At the same time, the risks of electric shock in case of insulation breakdown are higher than that of heating elements;
• the heating temperature of the coolant should not exceed 75 ° C, otherwise the boiler’s energy consumption will seriously increase;
• the formation of scale on the electrodes reduces the power of the boiler, since it prevents the ionization of the coolant;
• high requirements for the quality characteristics of heating devices;
• the need to equip the heating system with a circulation pump;
• wear of electrodes caused by alternating voltage, requiring periodic replacement;
• in an air-conditioned heating circuit containing a coolant-electrolyte, corrosion processes will be accelerated many times over;
• in a single-circuit system, the use of heated water for domestic needs is unacceptable;
• commissioning work requires the involvement of specialists – it is practically impossible to independently lower the ohmic resistance of water with an increase in its conductivity to the optimal level;
• the electrical conductivity of the coolant changes during operation, it is necessary to control it, and therefore, have the appropriate knowledge and equipment.

Device and installation of the electrode boiler

It has a rather simple design, in which special attention is paid to protection against electric leakage: a solid-drawn steel pipe as a body, on top of it is covered with an electrical insulating layer of polyamide; coolant inlet and outlet pipes; terminals for power supply to the case and ground; a special alloy electrode (three-phase boilers are equipped with three electrodes), insulated with polyamide nuts; additional insulation with rubber gaskets at the connectors.

Externally, a household ion boiler has a cylindrical shape, its diameter usually does not exceed 320 mm, length – 600 mm, and weight – 12 kg. The smallest power – 2 kW (for space heating about 80 m³), maximum – 50 kW (space heating about 1600 m³). Single-phase boilers have a power from 2 to 6 kW, three-phase boilers from 9 to 50 kW. The energy consumption of the boiler reaches the nominal level (the power declared by the manufacturer in kilowatts) when the temperature inside it reaches 75 ° C – at lower temperatures, the energy consumption is lower, since the current conductivity is lower in a colder coolant. It should be noted that the temperature of 75 ° C is optimal for ion boilers, since with the development of a higher temperature, the energy consumption of the boilers will exceed that stated in the data sheet..

An automatic control system (controller) is included with the electrode boiler, which includes an electronic thermostat, automatic protection against power surges in the mains and a starter unit. Some models of controllers allow both direct control and remote control via gsm channels. It is the controller that provides the electricity savings declared by the manufacturers of ion boilers – unlike heating water with the help of heating elements, electrode heating allows you to change the temperature of the coolant in a shorter time, because has low inertia.

In an open heating system with natural circulation of the coolant, the latter moves up the pipes due to thermal expansion and pressure in the ion boiler, enters the radiators and cools down, then returns through the return pipe to the boiler, where it heats up and repeats the cycle again. The closed heating system is additionally equipped with an expansion tank-expansomat and a circulation pump required at the initial stage of heating the coolant.

When installing an electrode boiler, a mandatory requirement is to equip the heating circuit at its highest point with a safety group – an automatic air vent, a pressure gauge, an explosive (back-safety) valve. In open systems, control or shut-off valves should only be installed after the expansion tank, i.e. the pipe section between the boiler outlet and up to the expansion tank must not contain any shut-off valves! In closed-type systems, shut-off valves are installed on a section of the pipeline after the expansion tank and before entering the boiler. If, however, immediately after leaving the boiler, a safety group is installed, then the shut-off valves can be installed before the expansomat – in this case, the expansion tank must be installed in the return section.

Ionic boilers of any model are installed in the heating system strictly vertically, with their own fastening to the wall. The first 1200 mm of piping on the coolant supply to the boiler are made of a metal non-galvanized pipe, then the use of metal-plastic pipes is allowed.

Reliable grounding of the ion boiler is imperative, since in the event of a leakage of currents, this problem cannot be solved using an RCD. The grounding copper wire must have a cross section of 4 to 6 mm, its resistance must not be more than 4 ohms – the conductor is connected to the zero terminal located in the lower part of the boiler body. Grounding must meet the requirements of the PUE.

Ideally, it is planned to install an electrode boiler in a new heating system, pre-washed with clean water. When inserting a boiler into an existing circuit, it must be thoroughly flushed with water with special agents added to it – their list and proportions are described in the technical passport for the boiler, each manufacturer insists on the use of certain inhibitors. If this condition is not met, salt deposits (scale) will interfere with the precise adjustment of the ohmic resistance of the coolant..

When choosing heating radiators for a system with an ionic boiler, pay close attention to their consumption of coolant in liters – you need to find out how many liters one radiator consumes, then calculate the total displacement based on the required number of radiators. It should be noted that especially spacious heating devices are not suitable, because Such a heating system will consume more than 10 liters of coolant per kilowatt of installed boiler capacity, which will force it to work non-stop, and this is not profitable from the standpoint of electricity consumption. Ideally, the total displacement of the heating system should be about 8 liters per kilowatt of power..

According to the material of manufacture, bimetallic and aluminum radiators are most suitable for heating systems with an electrode boiler. When choosing aluminum heating devices, an important criterion is the origin of aluminum – whether it is primary (i.e. obtained from natural materials – bauxite, alunite, nepheline, etc.) or secondary, remelted from recycled materials. The problem is that cheaper radiators made of secondary aluminum are made of an alloy with a high content of impurities that increase the ohmic resistance of the coolant..

In open heating systems, it will be correct to install heating devices made of aluminum with an internal polymer coating that reduces corrosion; in closed systems, such radiators are not needed – corrosion processes are activated when there is air in the volume of the coolant, i.e. its salt content does not cause corrosion.

Cast iron radiators for heating systems with heating the coolant from an electrode boiler are the least suitable, since they are heavily contaminated from the inside and dirt particles will affect the current conductivity. In addition, cast-iron radiators consume a significant amount of coolant, which may exceed the installed capacity of this ion boiler model – its more powerful models will be required. Manufacturers of electrode boilers allow the use of cast iron radiators subject to the following conditions: they are produced according to the European standard (i.e. in Turkey or Czechoslovakia); on the return line, before entering the boiler, mud collectors (sludge catchers) and coarse filters are installed in the pipeline.

Ion boiler – prices and manufacturers

Electrode boilers of the following manufacturers are represented in Russia and the CIS countries – the Russian CJSC “Firm” Galan “(the brand of the same name), the Latvian LLC” Stafor EKO “(the same brand) and the Ukrainian SPD-FO Goncharenko O.A. (brand “EOU” (energy-saving heating installation)).

The cost of an electrode boiler depends on its power – a boiler with a capacity of 2 kW will cost the buyer on average 3000 rubles. It should be borne in mind that the set of necessary automation is sold, as a rule, separately – its cost will be about 6500 rubles, i.e. twice as expensive as the boiler itself.

The warranty period for an electrode boiler, depending on the manufacturer, ranges from one year to two years. The average service life of such boilers is about 10 years, subject to compliance with the operating requirements for the coolant and timely replacement of electrodes (approximately every 2-4 years).

At the end

When creating a heating system based on heating the coolant from an electrode boiler, the following nuances must be observed:

• the electricity consumption of the boiler is significantly higher if installed in a previously used heating circuit. It is better to install the ion boiler in a circuit specially created for it;
• when using antifreeze as a coolant, special attention should be paid to detachable connections, since its fluidity is higher than that of water;
• all pipes that form the heating circuit should be wrapped with a layer of thermal insulation – this measure will facilitate the boiler’s task of reaching the optimal operating mode;
• if the groups of heating radiators are located at different levels (floors) of the building, then it will be more efficient, albeit less profitable economically, to install independent ion boilers of the required power for each group.

Ionic (electrode) boilers are not suitable for heating systems like “warm floor” or “warm plinth”, since the temperature of the coolant circulating in them should not exceed 45 ° C – the boiler will not be able to reach the required operating temperature.