The theoretical efficiency of all modern electric boilers is approximately 99%, that is, at maximum load, a boiler producing 9 kW of thermal energy will consume 9.091 kW of electricity. However, the efficiency, for example, of heating elements of electric boilers depends on the hardness of the water and the formation of scale on the heating element, so over time it can drop to 90, 80 or even 70%. Then more electricity will be required to heat the water to the same operating temperature.
Therefore, the efficiency of the electric boiler, first of all, depends on the principle of its operation, as well as the functionality of the electric boiler control: modulated power, scheduling modes, the ability to set up work for a period of cheaper nightly tariffs.
Description and principle of operation of heating electric boilers
Gas boilers are popular because of the cheapness of fuel, but it is not always possible to connect them because of the complexity of the procedure, the need to coordinate with government agencies. Energy sources for solid fuel units are even cheaper, but there are much more disadvantages — they pollute, require the removal of combustion products, fuel loading, and storage space.
The listed disadvantages are absent for electric boilers, which are sometimes the only option for heating if it is not possible to supply gas. Moreover, electrical devices are considered not only as additional or emergency sources, but also as the main devices for preparing the coolant. With them, you do not have to worry about ignition and other inconvenient moments associated with fuel combustion.
The most economical electric boiler should be chosen from energy-saving induction and electrode models. But it must be taken into account that in any case, his work will cost more than gas units by about 2.5 times, at best 1.5 times. Savings here are considered for situations where there are no other alternatives to electricity or if this type of energy is cheap (there are alternative sources — solar collectors, etc.).
How electric boilers work
The general principle of operation of electric boilers for heating: the coolant (water) circulates by means of a pump along the circuit of the heating system, through the boiler (inner chamber, flask, coil) and is heated there by heating elements, heat exchangers with electrodes, induction coils.
The main parts of the electric boiler: a body with heaters, a circulation pump, a power supply, an expansion tank, a control and safety system (pressure gauge, check valve and for releasing excessive pressure).
Economical electric boilers are required in such conditions:
- if it is not possible to use gas;
- a unit is required that is easier to maintain than fuel-powered appliances;
- preference is given to a cleaner source of energy;
- an additional heater is required in case the main unit is switched off.
Positive features of EPO-9.45/220V
Economical electric boilers have many advantages over more powerful equipment. For example, they are easy to operate, because they have a control panel. This makes the device safe and easy to use. The boiler body is durable, because in the conditions of the factory it is coated with a composition that prevents the formation of corrosion and provides protection for the components, as well as a long service life of the unit itself. Such economical electric boilers can be used without making additional expenses. After all, you do not have to clean the chimney, as well as unload and load fuel.
Installation and maintenance are not accompanied by difficulties: the chimney does not have to be installed, as well as the coal bunker, as well as the fuel tank. During operation, the device is silent and environmentally friendly. Its work does not depend on external factors, and the functioning will be carried out automatically. There is no need for constant monitoring, as well as in the boiler room.
Types of electric boilers for home heating
There are several types of electric boilers according to the principle of using electricity and functioning. Traditional and familiar to everyone — heating elements. More innovative and energy-saving — induction (vortex) and ionic (electrode), they are more expensive, but the cost pays off with extreme efficiency and efficiency, which slightly or does not decrease over time.
The efficiency of all electric boilers is the same — 94-99%, but some types are more efficient due to the organization of the design and method of operation. And also over time, due to scale, this characteristic decreases by 10–20% for heating element boilers, but this is not typical for induction and ionic products.
Types of electric boilers:
- with heating elements;
- ionic (heating by electrodes);
- induction (vortex).
TENovye electric boilers
Boilers for heating with heating elements can only be classified as economical: different models may have more efficient heating elements, programming options, power settings.
Inside the device there is a tubular electric heater — a copper or stainless steel tube (there may be sand or oil inside) with an incandescent filament (nichrome). The principle of operation is similar to that of a conventional boiler or heater: the spiral inside the shell heats up and transfers heat through the tube in which it is enclosed to the water entering the chamber (flask) with a heating element.
When choosing electric heating for a home with a special emphasis on economy, units with heating elements should not be seriously considered. You can choose a high-quality device with a larger or smaller amount of energy consumption, but it will still be more voracious than induction and ion boilers. On the other hand, the cost savings can be compared to some extent, since the boiler with a heating element is cheap to maintain.
Advantages and disadvantages of electric heating elements
Advantages of heaters for heating with heating elements:
- cheap and convenient repair (the case is easily disassembled, parts are replaceable);
- advanced functionality: power setting, programmability, the ability to connect a thermostat;
- is usually produced in a monoblock compact case (there are convenient wall-mounted sizes) ready for operation, including a safety group, an expansion tank, a pump. There is no need to buy and install these elements separately, you only need to connect the device to the input and output of the heating system.
- the most uneconomical type of electric boilers, especially if two heating elements are used;
- scale and plaque form on the heating element, which requires its periodic cleaning and replacement. A hard crust reduces efficiency by 10-20%. This statement is controversial, since the water of the heating system is not prone to intense scale formation, but you should not ignore it.
Types of induction boilers for home heating (sometimes they are perceived as brand names):
- VIN — «vortex induction heaters», more innovative with a ferromagnetic housing. Smaller and 1.5-2 times more expensive than SAV, but more efficient;
- SAV — the principle is the same, but they are positioned as less advanced.
The second heating with vortex boilers is “inverter”. The product includes a current converter from DC to AC — «inverter» (as in welding machines).
Immediately after the introduction to the market, induction heaters for heating were positioned as the most advanced and efficient, but application experience showed more disadvantages than expected.
The principle of operation of vortex SAV and VIN electric boilers
How an induction SAV boiler works:
- A high-frequency alternating current (from 50 Hz) is supplied to a metal coil (inductor) — a rod (its role can be played by the pipe itself with a coolant) with coils of wire. A magnetic field is generated.
- The polarity and the magnetic field vector change at a high frequency.
- An object located close to the described phenomenon is permeated with constantly changing fluxes of magnetic induction. Foucault eddy currents arise, turning the electrics into heat, which heats the water.
The principle of heat transfer in induction boilers is non-contact — the heating of the object is carried out by electromagnetic fields, and instantly. There is no need for physical contact with the inductor, which improves efficiency.
The electromagnetic principle is used in industry to melt metals. Even a small home-made induction device with a coil with a dozen turns and dimensions of several cm² is able to heat metal to red in a few seconds, which illustrates the power and efficiency of a vortex boiler for heating.
Advantages of induction boilers for heating
Advantages of SAV boilers:
- heating is powerful, almost instantaneous;
- microvibrations repel dirt, so there is no scale and plaque on the parts in contact with water, cleaning is not required;
- economy, the highest efficiency among electric boilers.
Induction boilers are best for preparing water as it flows through the machine, as they heat up extremely quickly. At the same time, heat losses are zero, which favorably distinguishes VIN from heating elements. Despite the disadvantages, if we consider purely the efficiency of using electricity, induction boilers are the most economical type of electric heaters.
Disadvantages of vortex boilers for heating, expediency of use
Many sources list many advantages of VIN and SAV, but in reality the picture is somewhat different, many shortcomings were found:
- most sizes have significant dimensions;
- more expensive than heating elements and electrode units;
- the heating is extremely powerful, so if the auto-shutdown system breaks down, there is an increased risk of an explosion;
- the electromagnetic field is harmful, electrochemical processes provoke corrosion;
- complex repair. It would seem that the device is extremely simple — the coil and the body — but usually the cylinder of SAV boilers is securely sealed, it is extremely difficult to disassemble it. The composition contains electronic circuits of the control unit, which complicates the repair. The coil may burn out, and the cost of a new one is higher than, for example, a new heating element;
- if the SAV is not in a compact package, and most of them are, then a large control unit, a separate expansion tank, a pump, a safety group will be required;
- in most cases, they are not equipped with a soft start — when turned on and even when switching modes, there is a sharp increase in the load on the network, which is fraught with voltage drops (flashing lights and similar effects).
Still, despite the listed disadvantages, a vortex energy-saving electric heating boiler should be considered as a heater for heating a house due to the high level of economy (30% more efficient than heating elements). Some of the listed disadvantages are relative, for example, there are small and compact sizes, similar to products with heating elements. This is the only type of heater whose efficiency does not decrease over time.
Ionic (electrode) boilers
Ionic (electrode) energy-saving boilers for heating must be distinguished from induction units, despite the fact that they also use the properties of alternating current. The organization of the use of energy is different. The body of the device contains a sealed chamber with a coolant and electrodes located in it with a certain gap.
With a direct current, the cathode attracts water ions with a positive charge, and the anode attracts negative ones, but if you change the characteristic to a variable one (starting from 50 Hz), then there will be a constant movement of these particles. The medium has resistance, so the kinetic energy of moving ions (cations and anions) is transformed into thermal energy, the electrolyte is heated.
In the ion boiler, a special electrolyte solution circulating in the pipes of the heating system is heated, in certain cases it can be water. In fact, such a boiler is a simple heat exchanger.
Advantages of ionic (electrode) boilers for heating systems
Advantages and features of ion boilers for heating:
- extremely compact: low-power models only slightly exceed the diameter of the pipes. This is a small cylinder that cuts into the wiring. They do not require space around, so they can be installed literally anywhere;
- the cheapest — 4-9 thousand rubles. (A heating element costs about 15–30 thousand), but if you have to buy an expansion tank, a thermostat, safety valves, a pump, then this is another 10–12 thousand;
- scale does not form — this is prevented by electromagnetic processes;
- the service life before the first breakdown is 12–15 years. According to this characteristic, electrode heaters are comparable to induction devices;
- maintainability. The design is simple and disassembled without much difficulty. Parts are replaceable and cheap;
- the safest: if induction or heating elements in the event of a breakdown of the auto-shutdown (protection against overheating and dry operation) continue to heat up to an explosion or fire, then ionic boilers will simply stop working without any intervention if the coolant leaks;
- no electromagnetic field.
Disadvantages of Electrode Heaters
The installation of the electrode apparatus itself is simple, but it is somewhat complicated by the need to install a pump, a safety group, and an expander. There are also products with the last two elements on the body or in the form of a monoblock ready to work, but this arrangement is less common. In this aspect, TEN boilers have an advantage, since they are more often produced in standard sizes with everything you need in one case.
- there are devices with a heat exchanger and an expansion tank on the case, but in most cases an additional purchase of these elements is required, as well as a pump, a safety group;
- scale and plaque do not form, but electrical processes increase the corrosion of the metal of the heating system circuit. In this aspect, there is a similarity with SAV boilers;
- pipeline water can act as an electrolyte, but usually special solutions from manufacturers of such boilers are always used. The mixture must be undistilled, unfiltered. Special substances are the most effective. Use propylene glycol, ethylene glycol. It is impossible to use antifreeze, oil, distilled water;
- requires replacement of the coolant every 3-4 years.
Electrode boilers consume 20-30% less electricity than heating elements, but they are slightly less energy efficient than induction models. That is, in the rating of economy, given the convenience, low cost of products and services, they are in the middle.
Landmarks and what to consider when choosing an economical heating electric boiler
An economical electric boiler must have programmable operation, the ability to connect a rheostat for on / off. during the period of low tariffs or when a certain temperature is reached, as well as to regulate the heating. At a minimum, there should be at least a three-stage power switch.
Ideal if the device has smooth adjustment and factory economy modes. The product must be suitable for connection to room rheostats, which have many fine settings and respond to the air temperature in the room.
Single and double circuit electric boilers
If it is required to provide hot water at the same time as heating, then double-circuit electric boilers are chosen. Moreover, the consumption of electricity in such products practically does not differ from single-circuit ones. DHW water is heated by washing the heat exchanger in the heating circuit of the boiler, without mixing with its coolant. Such heating does not require additional power, although there are models with increased energy consumption for greater efficiency.
Disadvantages of electric boilers
An ideal heating system, as well as a way to supply energy for heating, cannot be found, since each case has its drawbacks. Electric boilers are no exception, since these devices also have their drawbacks:
- If there is a power failure, the equipment will not work, which can lead to freezing pipes. As a rule, the lack of electricity is associated with emergency situations that the relevant services eliminate in a short time, and during such a period the heating system does not have time to cool down to deep freezing, especially if cast-iron radiators are installed in the house.
- Energy costs are the biggest disadvantage. If you use separate electricity metering, then at night, when the tariffs are lower, you can set more power, and set it to a minimum during the day.
It should be noted that the more expensive the electric boiler, the less electricity it consumes. Therefore, when choosing a suitable device, you should not start only from the price. An expensive boiler will save you money on electricity bills later.
Calculation of power for the area of u200bu200bthe house
We give a simplified calculation of power, since this issue is a topic for a separate article. Approximate calculation usually always gives results as close as possible to real needs.
If the electric boiler performs an auxiliary heating function in addition to the main gas or other unit, to the fireplace, then 3-6 kW will be enough for 120–150 m².
Comparative table of average statistical electricity consumption by electric boilers
|Boiler power||Heating area, m²||Consumption, kV/h||Boiler power||Heating area, m²||Consumption kV/h|
|3 kV 1 phase||fifty||0.5–0.6||3 kV 1 phase||thirty||1.5–1.8|
|5 kV 1 phase||80||0.9–1.2||5 kV 1 phase||fifty||2.0–2.5|
|9 kV 3-phase||120||1.8–2.3||9 kV 3-phase||90||3.6–4.2|
|25 kV 3 phase||350||4.5–5.5||25 kV 3 phase||240||9.5–11.0|
If an energy-saving boiler is the main source of heat, then it is necessary to carry out a calculation taking into account heat losses, which for an average private housing with two-brick masonry and 2.7 m ceilings in the climate of the Moscow region is 1 kW / h. It is recommended to select power with a margin of 10-20%, and for heating elements — by 20-30%, since their efficiency decreases due to scale. For 80 m², you will need a 9.6–10 kW electric boiler (8 kW + 20%).
For SAV boilers, a power of 2.5 kW is 2100 kcal / h, which is enough to heat 25–30 m². The required temperature affects the calculation. If it is necessary to maintain 15–20 degrees in a room of 120 m², then a 6 kW unit will suffice.
An economical electric boiler for heating of an ionic type with a power of 3 kW is suitable for heating 50 m². The same product with a heating element will heat 30 m².
Estimated energy consumption
Is it worth using an electric boiler for heating at all, or is it better to purchase a more economical type of equipment? The fact that the efficiency of such devices is close to unity does not mean a profitable solution to the heating problem. The price of electricity is rather high, and your boiler will “eat” it all season long.
First, make an approximate calculation for your home according to the following scheme:
1. Required performance in kilowatts — the area of u200bu200bheated premises divided by 10.
2. The value of heat is the power obtained in paragraph 1, multiplied by the total time of operation of the device per day. Here you already need to know whether the heating of a private house with an electric boiler will be “main” or backup. For the first option, you can take 12 hours as a minimum, in the case of a combined system, subtract the operating time of the main equipment.
3. It is more convenient to immediately translate the daily value into indicators for the month — we multiply by 30. To reach the annual figure — by another 7 (the cold season usually lasts this long).
Having calculated the energy consumption in this way, do not rush to get scared — the result still needs to be divided by 2 in order to bring it closer to the actual operating mode of the heating system. At maximum power, it is operated on the strength of 2-3 months. The rest of the time, the temperature outside the window is not -20, which means that energy consumption will be regulated downward.
What to choose: comparison of consumption, cost, ease of operation
If we focus on ease of installation, ease of use, average price, then the first place in the ranking is occupied by boilers with heating elements. As a standard, they are carried out in a monoblock case, completely ready for operation after installation — it already has a safety group, an expansion tank, a circulation pump and other elements. It is enough to connect to the input and output of the heating system. But they are in last place in terms of economy and energy-saving they cannot be called.
If we consider the question of which electric boiler is the most economical and with the best energy saving, then induction and ionic units should be considered.
Vortex heaters are in the first place in terms of economy, but they have a number of disadvantages that slightly offset this advantage: price, difficulty in repair, large dimensions. These are the most expensive and inconvenient electric boilers considered: the cost of such a product for 25 kW is 86 thousand rubles. (A heating element for 24 kW can be bought for 46 thousand).
Below is a table comparing different types of electric boilers. But the data in it should not be unconditionally trusted — manufacturers are trying to show their products in a favorable light. For example, in other sources, ion boilers are shown to be much more economical and efficient than heating elements.
|Loss in power after 12 months of use||twenty %||fifteen %||0%|
|Max pressure||3 atm||3 atm||6 atm|
|Heating temperature||Up to 90 degrees||Up to 85 degrees||Up to 115 degrees|
|Life time||3–7 years||10–12 years old||30–60 years old|
|Probability of rejection within 12 months||15–20%||15-35%||0%|
Another disadvantage of SAV and VIN is the large dimensions of the body itself and individual elements, which include the control cabinet. A product with a tubular electric heater contains everything you need in a compact package, and an ion boiler generally resembles a thick water pipe. The weight of an induction boiler for 25 kW is 80 kg, a heating element of the same power is 40 kg.
Vortex boilers are increasingly chosen for private homes. Although such devices are the most energy-efficient, they are more often used where induction heating is indispensable — in an industrial, production environment, in chemical plants.
Economics of using VIN
|The name of a room||Heated area/volume||VIN model||power, kWt||Cost of kWh, rub.||Monthly payment, rub./month||Payment for the heating period, rub.|
|1-room apartment||50 m²||VIN-3||3||2.0||1227.6||9147.6|
|garage box||450 m³||VIN-10||ten||3.2||5952||45888|
Ionic (electrode) boilers are the best choice in the economy class in all respects, especially in terms of cost, if you need an energy-saving heater for heating a private house. Their economy and efficiency may be somewhat lower than that of induction and heating elements, but this is offset by ease of maintenance, small size. An important fact in favor of ion boilers is the price — these are the cheapest energy-saving heaters for heating (4-5 thousand rubles).
Ionic boilers are a good option as an additional source of heating. If you use them as the main devices, then you can embed several of these cylinders for greater efficiency.
The best known manufacturers and models: features and prices
|A photo||Manufacturer and model||power, kWt||Mains voltage||Peculiarities||price, rub.|
|Alternative energy WIN 3||3||single-phase||To date, the only worthy candidate among vortex induction electric boilers. The boiler is carried out through the control panel with many fine settings, including temperature. As a coolant, you can use not only water, but also antifreeze, oil, glycerin, ethylene glycol-based coolants.||34 000|
Poll: what type of electric boilers did you choose?