Double-circuit electric boilers for heating a private house. Double-circuit electric heating boiler

An electric heating boiler is the best alternative to a gas boiler. Reasonable price, low requirements associated with the installation of an electric boiler, make it possible to install equipment in high-rise or private houses. How to choose an electric boiler for home heating, the price of which is best for you? What features of an electric heating boiler are most in demand and what to look for when choosing?

The main parameters to pay attention to are:

• Type of heat carrier heating.
• The number of contours.
• Options for connecting to the electrical network.
• Power.

These four parameters make it possible to accurately select the model of an electric boiler for heating, which will most fully meet the needs of the owners and specifications apartment or private house.

How to choose a double-circuit electric boiler

The choice of an electric boiler for a private house should begin with the choice of the number of circuits. It depends on what the boiler will be used for. Double-circuit devices can simultaneously heat water and coolant. Installing a double-circuit boiler makes it possible to do without already traditional columns, water heaters, etc. When choosing an electric boiler with two circuits, you need pay attention to the following points:

Household double-circuit electric heating boilers are made floor and wall. Some devices low power can be connected to the normal electrical network.

How to choose a single-circuit electric boiler

Unlike double-circuit devices, completely different requirements are imposed on an electric boiler, where one circuit is located. Because electric heating boilers with one circuit not used for DHW heating, the main selection parameters are significantly different.

As a rule, single-circuit electric heating boilers have more power than double-circuit devices, because energy is not spent on heating water.

Flow electric boilers

The method of operation of a flowing electric boiler for heating a private house is based on heating the coolant by passing through special tank where the heating element is located. Flow boilers have an automatic system that prevents overheating in the event of a lack of circulation or air entering the system. The choice of a boiler depends on the following parameters:

There are a number general requirements applied to all flow devices. These are: performance, type of heating of the coolant and the option of connecting to the network, and the number of circuits. These indicators are decisive.

How to determine the performance of an electric boiler

The calculation and selection of the boiler power for a private house according to the area of ​​\u200b\u200bthe building is carried out using a special formula. Calculate performance possible in the following ways:

W=SxWsp / 10 m²

• W is the rated power of the boiler.
• S- total area Houses.
• Wsp - specific power. This indicator depends on the region where the house is located.

Single-phase electric boilers

These are, as a rule, household electric boilers 220 volts. To connect a single-phase boiler, a conventional network of 220 volts is sufficient. The features of these devices are:

• Possibility of operation from a simple network.
• The principle of operation is not much different from some kind of heating device.
• A single-phase boiler has a low power of 6-12 kW, which is enough for heating a 2 or 3-room apartment.
• Many single-phase models work on the principle of indirect heating of the coolant. A heating element is installed as a heat source.
• Installation of a single-phase device does not require permits. It is regarded as a conventional device, the same type as a water heater.

The purchase of an electrical device that operates on 220 volts pays off at a price if it is necessary to heat a building up to 100 square meters in size. m.

Three-phase electric boilers

All boilers with power over 12 kW can be connected to a 380 volt network. These are three-phase devices, characterized by performance and at the same time noiselessness and compactness. Three-phase boilers, as a rule, are made of two types:

Electrode - the heating procedure occurs due to the action of current on the coolant itself. The advantage of this equipment is the speed of heating the coolant.

Induction - heating occurs due to the formation of a magnetic field. The core of the device is a copper winding, like a transformer. But the price of the energy consumption indicator is not the most economical here.

To connect a three-phase device, you need to make a separate line with a current of 380 volts. For a private house, it is very easy to get this permission. It is more difficult to obtain a permit for the conversion of an apartment.

Features of the operation of electric boilers

Water heating electrical equipment continues to be the safest type of heating boiler. Operation risks, as a rule, relate to the use of electricity and are almost minimized due to the installation of special automation. But there are some rules for the safe operation and installation of electric boilers and boiler rooms, which provide for such work when installing devices:

Automatic switches off electricity. The unit must be connected directly to the electricity meter. In the role of an addition, the use of RCD is indispensable. This makes it possible to quickly respond, both to a short circuit in the mains, and to some voltage drops in the network and turn off the power supply of the installed device.

Grounding is required condition for the installation of an electric heating water heater.

Boiler safety group. This safety group includes: air vent (does not allow air to accumulate in the system), pressure gauge (allows you to control pressure indicators), safety valve (used to reduce pressure in the system).

Control system and automation. Control over the operation of an electric boiler is an important component of heating devices, especially for a powerful unit that is used to heat large rooms. The automation of the device controls the temperature mode, gives a signal to turn off the power supply. The performance and efficiency of the unit will depend on the well-functioning operation of automation. Imported manufacturers pay great attention to equipment control and automatic system.

The requirements for the installation and operation of an electric boiler make it possible to use devices for heating an apartment in a multi-storey building. Subject to security measures, the type of heating from electrical devices is not as dangerous as from gas or solid fuel boilers.

Well, in the end, the advantages and disadvantages of electric boilers

The advantages are:

• Autonomy of work. The devices can operate in a completely autonomous mode; control does not require constant human control. Control over the preservation of the temperature mode can be performed using installed temperature sensors. It is also possible to control an electric boiler with a control controller using the Internet.
• Compactness and noiselessness. During operation, electrical devices almost do not emit extraneous noise. Even induction devices very compact and can be installed even in the kitchen.
• Functionality. Some types of boilers can respond to temperature changes environment, set the most optimal heating mode and even connect to the Internet.

There are also some disadvantages. Namely, he alone electricity price. If we calculate the costs associated with paying for public Utilities, it turns out that an electric boiler costs, unlike gas equipment, about 2 times more. But with the condition that it is impossible to conduct gas, nevertheless, an electric boiler is the most acceptable alternative.

The use of electricity as a source of energy for the heating system at home is not always justified due to the high cost of operating costs. But if the main gas pipeline does not pass nearby, then the choice, as a rule, is made in favor of electric boilers. Enough for sale a large assortment products, but experts recommend paying attention to a double-circuit electric boiler. Its capabilities allow not only to heat the room, but also to provide households with hot water.

Advantages of electric boilers and their disadvantages

Ease of installation and ease of use of an electric heating unit, its compactness and aesthetics, and most importantly, safety, attract consumers, despite the costs associated with the use of electricity. But by taking some steps, you can achieve real decrease material costs for utilities.

For the possibility of saving the consumed electricity, there is the possibility of stepwise adjustment of the power of the heating boiler.

At night, in many regions of the country there are reduced tariffs. A zealous owner will program a more intense heating mode for this period than during the daytime, when all household members go about their business. For a double-circuit electric heating boiler, it would not be superfluous to calculate the time the boiler is turned on in such a way that, firstly, by the time it wakes up, there is hot water in it. And secondly, the period of water heating would fall at a lower daily rate for paying for electricity.

It will help to reduce the cost of heating a house by almost 30% by installing a temperature controller on each heating battery. In this case, in each room you can set your own thermal regime.

Advantages of heating electric boilers:

• simple management;
• high efficiency;
• noiselessness and vibrationlessness;
• the most complete automation of processes (without human presence);
• the ability to set the most favorable temperature conditions;
• no need for separately located rooms (for installing a boiler with a boiler and storing fuel), as well as in a chimney;
• easy maintenance (cleaning of the burners is not required);
• low fire hazard (no source of open fire);
• environmental friendliness - no carbon monoxide;
• facilitated installation;
• variety of design and size range;
• affordable price and low maintenance costs.

Electrical double-circuit boilers not only as an independent unit. Often they are built into combined heating systems paired with gas boiler, solar systems, or with solid fuel equipment. In this case, they perform the function of the main or backup boiler.

But despite all the advantages, install a double-circuit electric boiler in houses large area Not recommended - high price on electricity makes this option unprofitable. A more correct solution would be to choose a universal multi-fuel model of the unit.

But the disadvantages don't end there. A common problem is power outages and power surges. This is especially acute away from the city, when, due to snowfall or slush, it can be difficult for emergency services to quickly reach the place of a wire break. To avoid hypothermia at home during the cold season, the installation of a combined modern boiler or additional solid fuel equipment will help.

Another unpleasant nuance that a homeowner may face. This is a small cross section of the supply or internal wiring cable. At best, insufficient power will limit the ability of the boiler to work, and at worst, it can lead to a fire or blackout of several houses. In this situation, you should either abandon the electric boiler, or change the cables, or run a separate power wire to the equipment.

Design features

The double-circuit type heating boiler is different simple device, although it performs the function of a mini-boiler room. Both of its circuits can work both separately and in pairs, heating the house and providing hot water at the same time. The considered equipment consists of the following components:

• heat exchanger;
• boiler;
• heating elements;
• expansion tank;
• circulation pump;
• air vent;
• safety valve;
• automation;
• control unit.

Electric double-circuit differ from single-circuit models by the presence of a built-in boiler in the design.

By appearance and main design features models of electric boilers can be:

• wall-mounted - compact and relatively light;
• floor - massive, with a high power index (more than 60 kW).

As the name suggests, heating equipment the first group is mounted on walls or on specially installed metal frames. The second group of boilers is placed directly on the floor in a specially designated place. It should be noted that modern electric boilers are quite aesthetic and in no way can spoil the interior of the room.

According to the method of heating can be divided into three groups:

• TENovye - highly reliable, having one or more heating elements inside the tank in the form of a metal tube;
• electrode (or ion) - heating the coolant in the process of passing through a liquid medium alternating current. They have the ability to turn off automatically when short circuit, the maximum increase in temperature and a decrease in the volume of water to a critical level;
• induction - functioning thanks to inductors. They are energy saving devices.

The first option refers to indirect heating of the coolant, and the second is considered as direct heating.

By power, electric boilers intended for heating needs can be:

• single-phase (up to 12 kW);
• three-phase (more than 12 kW).

It is recommended to select power with the help of specialists, since only they are able to make a competent calculation. The method of choosing a boiler according to the area of ​​\u200b\u200bthe house is incorrect, since in addition to this parameter, a number of others are taken into account (wall thickness, number of openings, orientation to the cardinal points, etc.).

As a rule, household heating units operate from a 220V network.

Principle of operation

Double-circuit electric boiler for heating a house works on the principle of converting electrical energy into thermal energy. This process takes place with the help of heating elements, which are one of the main components of the equipment. They are responsible for heating water for household needs and coolant.

The circulation of water through the pipes is carried out due to the operation of the pump or natural way, and automatic controls the situation.

The heating system has a regulator temperature regime, which gives the appropriate signals:

• upon reaching required indicators- to turn off the heating;
• when the temperature drops to the programmed values ​​- to turn on.

Some types of programmers allow you to set the necessary heating modes, depending not only on the temperature of the indoor, but also the outdoor air. With their help, self-regulation boiler operation in autonomous mode.

Control over the operation of the heating boiler is carried out using the built-in control unit.

Any modern electric heating boiler is equipped with safety system, which, as a rule, is not reflected in the price. When the coolant overheats, the maximum allowable indicator of its pressure is exceeded, after which the safety valve is activated. The control function is performed by a thermal switch.

TENovye electric boilers

The principle of operation of this type of heating equipment resembles the operation of boilers or electric kettle. As a heating element, one or more heating elements are installed inside each container (designation of a tubular heating element). Their number depends on the power characteristics of the boiler. The coolant, in this case, is heated in flow mode, which contributes to its natural circulation inside the heat pipe.

Boilers with heating elements are currently the most common and in demand in relation to other models. They are relatively inexpensive and attractive in design. Water or antifreeze can be used as a coolant. Depending on the model, TENovye boilers are equipped with different temperature sensors, which make it possible to maintain the thermal regime of the room, depending on the temperature of the coolant or ambient air. The second version of the sensor is more accurate, but its location must be outside the boiler.

Electric boilers with heating elements are easily regulated, you just need to turn it on or off required amount heating elements.

Among the disadvantages of this unit, one can name the formation of scale on the surface of the heating element, which gradually leads to a decrease in heat transfer, and its burnout over time. Similar problems lead to the replacement of the heating element.

Water softeners, which are added to the coolant, help extend the life of the heating element. But this measure will be temporary anyway.

They differ in their way of heating the coolant. The role of the heating element here is played by the electrodes, although they do not bring the water to a hot state. The liquid medium is transferred electricity, and the water is heated due to its own resistance arising in the process of further reactions.

At the moment of exposure to current, water molecules are split, resulting in ionization. Charged particles begin their movement towards electrodes of different polarity, and meanwhile the coolant heats up, and instantly. An interesting fact is that the deposition of sediments and scale, in this case, does not occur.

Ionic electric boilers are much more economical than heating elements, and small chambers are quite enough for the ionization process.

Electrode boilers have compact dimensions and relatively low cost. When the coolant evaporates or leaks from the system, the equipment stops its operation. This provides a high degree of security. But the disadvantages of ion boilers speak for themselves:

• The water must be treated appropriately to meet regulatory requirements. It is almost impossible to do this on your own;
• in case of a decrease in the rate of water circulation in the system, the liquid will boil, and if the coolant moves too quickly, the boiler will not even be able to start working;
• antifreeze is not allowed;
• electrodes require periodic replacement due to the fact that during operation they begin to dissolve.

Induction boilers

Many claim that they are an innovative development. But the physical phenomenon called induction was discovered in the first half of the 19th century.

Electric energy in an induction boiler is converted into heat thanks to an inductor. Schematically, this process can be described in the following way. Under the action of magnetic induction, energy is transferred from the primary winding of the coil to the secondary, where it is converted into thermal energy. The coolant, circulating inside the welded housing of a complex configuration, is heated from the metal walls, which hermetically surround the inductor. Having passed through the entire "maze", the coolant becomes hot and enters the heating system.

The main advantage of this type of boilers is the absence of direct contact of the heating element with water, which eliminates any damage during operation. Also, there is no appearance of a large amount of scale and leaks, due to the fact that there are simply no detachable connections in the design.

Induction boilers are not limited in choosing the type of coolant and have high level electrical safety.

Of the shortcomings, it should be noted high cost, as well as large, in comparison with the above-mentioned boilers, dimensions.

Equipment selection

Manufacturers offer electric boilers in a huge range, their prices also have a wide range. Much depends on the brand, additional features and equipment. But this is not the most important thing.

When buying any boiler, the consumer, first of all, will pay attention to its power, which is responsible for the consumption of electricity and, accordingly, the efficiency of the unit. You should not purchase a boiler that has a power rating much higher than necessary, even if a huge discount on the product is offered. Subsequently, you will have to pay much more for the consumed electricity.

If an electric double-circuit boiler is chosen as a backup, then it will be more profitable to look at cheaper models. But if it is intended for the role of the main heating and water heating equipment, then you should not skimp.

The more desired functions will be in the automation of the boiler, the more economical its operation can be.

When buying an electric boiler, you should pay attention to its noise level during operation. Quality equipment should be practically silent, although it should be borne in mind that the pump will be a little audible. Heaters, depending on the price, may have a built-in stabilizer. Experts recommend choosing just such models so that power surges in the network do not damage the equipment.

It is desirable that the electric boiler be equipped with such useful feature like self-diagnosis. It will help to find out the cause of the problem without the presence of a specialist. Often the unit needs to be simply restarted, and not repaired.

On the market there are floor and wall-mounted electric boiler models of domestic and foreign manufacturers. Their choice is huge, and it is not always possible to cope with the task on your own. In this case, you should contact the specialists of specialized companies who will individually help you choose a boiler.

Will an electric boiler for heating and water supply be more profitable than central heating and centralized hot water supply? What are the so-called economical electric boilers?

Is it possible to reduce the cost of hot water preparation and heating by using electrical heating equipment? Today we will try to answer these questions.

The device of a heating element electric boiler

How are heating elements (that is, heating elements used for heating water - tubular electric heaters) Electric heating and hot water boilers?

• Actually, the heating element is a heating coil in a ceramic insulator, placed in a tube made of corrosion-resistant metal;
• The boiler is equipped with several heating elements and a thermostat that regulates their power in steps depending on the current temperature of the coolant and hot water;
• Heat exchange between heating elements and water takes place in heat-insulated containers with minimal heat dissipation.

Please note: the vast majority of currently sold electric boilers are heating elements. They are inexpensive, structurally simple and extremely maintainable. As a rule, the repair comes down to replacing a defective heating element and takes no more than 15-30 minutes.

A bit of physics

Now we allow ourselves to switch from the device of heating electrical equipment to ... the basics of a school physics course. Specifically - on the law of conservation of energy, formulated more than two and a half centuries ago. According to the classical formulation, energy does not come from anywhere and does not disappear into nowhere, but only passes from one state to another.

And now let's see what happens to the electricity in an electric boiler and in general in any heating device.

She can transform into the following types energy:

Note: electric boilers for heating and water supply, even with an abundance of conductive circuits near their location, lose a fraction of a percent of power due to the effect of electromagnetic induction. Not only that: taking into account the non-zero resistance of the conductors, this energy ultimately turns into heating the wires - into the heat that remains in the heated house.

The heating element does not perform mechanical work (that is, the movement of an object with mass in the direction opposite to the gravitational vector). Oh yes, circulation pump... do not flatter yourself: all the electricity spent by him will eventually also be converted into heating pipes due to the friction of the moving coolant on them.

Total: A heating element for heating and water supply almost completely converts all consumed electricity into heat. His thermal power can be considered equal to the rated electric power.

But excuse me, why do manufacturers always indicate for heating equipment an efficiency close to 100%, but not equal to them?

Everything is very simple: electric boilers for heating and hot water dissipate part of the heat in the surrounding space, without giving it to the coolant or water in the hot water system. The thermal insulation of the heat exchanger tanks and the housing is not completely effective. But it is still incorrect to talk about power losses here: the dissipated heat is also spent on heating the house.

Comparison of heat sources

What heat sources can the heating and water supply system for cottages use to heat water?

Here is a list of popular solutions:

• Gas (main, in gas tanks and in cylinders);
• Firewood;
• Coal;
• Pellets (granulated sawdust);

• Diesel fuel;
• Electricity.

Economy

From the point of view of efficiency (that is, the minimum cost per kilowatt-hour of heat), at the moment (mid-2017) they are arranged in the following order:

Please note: prices are approximate and may vary significantly depending on the region of the country. Say, in Sevastopol, a ton of pellets costs 15,000 rubles, and in the Moscow region - 7-8 thousand.

Convenience

However, the list of criteria for evaluating heating equipment does not end with efficiency. The boiler should be not only economical, but also as autonomous as possible, that is, if possible, not requiring the attention of the owner and maintaining the set temperature in the house on its own.

Here is what our ranking table looks like when compared by this parameter:

Image	Type of heating equipment
	The electric boiler for hot water supply and heating is the undisputed leader. It works without attention from the owner indefinitely, does not require the removal of combustion products and, as a rule, is compatible with external thermostats, Wi-Fi and GSM control systems.
	are inferior to electric ones only in that they require installation near the ventilation duct (if there is atmospheric burner) or on a common wall with the street (turbocharged, with a coaxial chimney).
	Diesel heating equipment operates autonomously until the fuel supply runs out. However, their disadvantages include a noisy burner and the need to store several hundred or even thousands of liters of diesel fuel.
	Pellet and automatic coal boilers provide autonomy up to a week. The battery life of the equipment is limited by the size of the fuel tank.
	Classic ones require kindling every few hours. The autonomy record belongs to upper combustion boilers and is only 31 hours.

Output: gas boilers combine minimal operating costs with ease of use. Electric heating equipment will make home heating and hot water preparation much more expensive, but it will provide the owner with maximum comfort.

Electric heating versus central heating

What is more profitable - an electric boiler or central heating?

First - input data on the example of the city of Chelyabinsk:

• The cost of heating one square meter of living space in January-April 2017 amounted to 44 (rounded) rubles per month;
• A kilowatt-hour of electricity at a one-rate tariff costs the consumer about 3 rubles;
• For heating one square meter of housing with an average ceiling height of 2.5 meters and high-quality external insulation, the house needs about 100 watts of heat.

1. Hourly electricity consumption for heating one square of living space will be 0.1 kWh, daily - 24 x 0.1 = 2.4 kWh, monthly - 2.4 x 30 = 72 kWh;
2. Electric heating costs per month will be 72 x 3 = 216 rubles per square meter, or almost five times more than with central heating.

Conclusion: the transition from central to electric heating is extremely unprofitable.

Electric boiler versus centralized DHW supply

Now let's compare in terms of costs an electric boiler for hot water supply with a centralized supply of hot water. Let's start again with the statistics for the same Chelyabinsk.

• A cubic meter of hot water costs 56 rubles;
• Cold water together with drainage costs 34 rubles;
• It takes 58 kilowatt-hours of heat to heat a cubic meter of water by 50 degrees (from +10°C typical for a cold water main in winter to +60°C stipulated by SNiPs).

Conclusion: it is definitely not worth refusing the services of a centralized hot water supply to switch to an electric boiler for water supply.

Economic boilers

On sale you can find two types of electric boilers, which are positioned by manufacturers and sellers as economical:

Image	Description
	Induction: a core placed in a dielectric shell is heated by eddy currents induced by an external winding.
	Electrode: Water is heated by current flowing through it between two electrodes.

More about boilers in the video:

The key features of both boilers follow directly from their design:

• The advantage of an induction boiler is its extreme fault tolerance and the ability to operate indefinitely without maintenance. It has no wear or degrading nodes during operation;
• Advantages of the electrode boiler - maximum power at minimum sizes and absolute security. When the circuit is depressurized and the electrodes dry, the water heating will stop not due to the operation of the boiler's security systems, but simply due to the physical principle of its operation.

Electrode "Galan Ochag" with a power of 3 kW (bottom left)

It is useful for a potential buyer to know two features of electrode boilers:

• They work only with water, and only with a certain mineral composition;
• The electrodes gradually dissolve and need to be replaced periodically.

Can these electric boilers for water supply and heating be more economical than heating elements?

No. These are classic direct heating appliances: electricity is almost completely converted into heat in them. They do not have and cannot have additional sources of thermal energy. Nobody canceled the law of conservation of energy specifically for these two devices.

Not only that: the winding of the induction boiler will heat up when high currents pass and dissipate in the surrounding space more heat than heating elements in a heat-insulated heat exchanger.

Conclusion: the so-called economical electric boilers exist only in the imagination of sellers and marketers.

Real Savings

Is it possible to reduce the cost of electric heating and domestic hot water preparation using electricity?

Yes. Key words - "night rate".

The generation capacity in the energy system of the country and individual regions changes slightly during the day, but energy consumption at night drops significantly. Accumulate a large number of electricity at the current technological level is impossible.

To give the consumer an incentive to use appliances with high electricity consumption at night, during periods of low loads, energy companies introduce separate billing:

• During the day, a kilowatt-hour costs more;
• At night, the cost of electricity is reduced by 1.5-3 times.

But excuse me, can an electric boiler for hot water supply and heating be used only at night?

It is possible if the circuit is supplemented with a heat accumulator and an indirect heating boiler. A heat accumulator is a water tank with a volume of 300-3000 liters with external thermal insulation and several outlets for connecting water supply and heating circuits.

With a volume of 3 cubic meters, it is able to store almost 200 kilowatt-hours of heat, which is enough to heat a house with an area of ​​about 100 square meters during the day. At night, the boiler, operating at full capacity, heats the water in the tank, and during the day the accumulated energy is used to maintain the temperature of the heating devices.

An indirect heating boiler makes it possible to use the heat of the heat carrier from the heating system for heating domestic hot water. In summer, when the heating is turned off, the coolant circulates between it and the boiler or heat accumulator.

Connection

How to connect an electric boiler to heating and water supply systems with your own hands?

Here are some possible schemes:

At the montage modern electric boilers for heating needs, there are a couple of subtleties:

• Wall-mounted heating elements are usually completed with a safety group, a circulation pump and an expansion tank located in the device case. This equipment turns the boiler into a full-fledged boiler room: it is connected directly to the heating outlet;

• Compact boilers (induction and electrode) supplied without additional equipment. Their harness should include:

Image	Description
	Expansion tank. It accommodates the excess volume of the coolant when it thermal expansion, preventing pressure buildup in closed circuit. The volume of the tank is usually taken equal to 1/10 of the volume of the coolant in the circuit.
	A safety valve that releases excess coolant in the event of a dangerous increase in pressure.
	Manometer for pressure control.
	Automatic air vent that removes air that prevents circulation.
	Circulation pump that ensures the movement of the coolant.

Where are the strapping elements mounted:

1. Security group (air vent, safety valve and pressure gauge) - at the boiler outlet. The instruction is related to the fact that it is there that when the circulation stops in the circuit, the pressure increases most rapidly;
2. Expansion tank - at any point in the circuit at a distance from the circulation pump;
3. The pump is on the return line in front of the boiler, where the coolant temperature is minimal. The lower the temperature, the longer the rubber seals will last and plastic parts device.

Conclusion

We hope that we have managed to dispel some of the misconceptions associated with electric boilers. To learn more about how heating and hot water boilers work and how they are installed, the video in this article will allow you. Good luck!

An electric boiler effectively solves the issue of autonomous heating of an apartment or a private house. But, in most cases, the consumer needs not only heat, but also hot water. A double-circuit electric boiler simultaneously solves two issues: heating residential premises and ensuring the need for hot water.

How does a double-circuit electric boiler work

In the device of a double-circuit electric boiler, two heating elements are provided that do not touch each other. The design feature is that the boiler simultaneously heats hot water and coolant.

The principle of operation of a double-circuit electric heating and hot water boiler can be described as follows:

• The housing contains a tubular heating element (TEH). With the passage of an electric current, the inner spiral heats up. The heat obtained as a result of heating is transferred to the heating surface in contact with the coolant.
• The transfer of heat from the surface of the heating element to the heat carrier is carried out by means of natural or forced circulation of the liquid in the heating system. The coolant enters a container with an electric heater, passing through which it comes into contact with a heated surface and accumulates heat.
• The heated liquid enters the heating system, giving off heat through radiators or underfloor heating.

The DHW and heating circuits work in an almost identical way. When the hot water tap is opened, the heating element turns on and begins to heat the liquid in a flowing way.

Double-circuit energy-saving electric heating boilers have a built-in storage tank - a boiler. Heated water is stored in the accumulator, with heat loss not exceeding 1°C in a few hours. After opening the tap, hot water is immediately supplied to the consumer. The savings achieved due to the built-in storage capacity reaches 10-15%.

Modern household double-circuit electric boilers of many European companies are created taking into account the connection to low-temperature heating systems - "warm floors", without the need to install additional equipment.

Electric boilers are available in wall and floor (stationary) versions.

Mounted 2-circuit electric boilers

Double-circuit wall-mounted electric heating boiler, optimal solution heating the apartment, due to the following advantages:

• Small footprint - wall-mounted boilers are distinguished by small dimensions. If necessary, the electric boiler can be built into the cabinet.
• Lack of excess power - generated thermal energy is enough to heat the apartment.
• Functionality - double-circuit models, come with a built-in boiler, microprocessor-controlled automation.
  Some boilers are designed to be connected to low-temperature heating systems, without the need to install additional equipment: a hydraulic switch and a mixing unit.

Double-circuit wall-mounted electric boilers, the optimal solution for heating an apartment in a multi-storey building.

Floor electric boilers with two circuits

The installation of a double-circuit boiler in the floor version is justified to provide heat to a private house or cottage. More powerful devices than mounted counterparts do a good job of heating residential premises and preparing hot water in sufficient quantities.

Double-circuit floor electric boilers occupy a lot of usable space. They are produced with a minimum performance of 10-18 kW (depending on the selected manufacturer), therefore, they are mainly used in private houses or cottages.

High performance in the design of floor boilers, combined with a built-in storage tank (not present in all models), automation and high throughput of hot water. Solutions with an additional connection of an external heat accumulator are popular, which allows saving at least 25-30% on electricity.

The essence of the solution boils down to the fact that a connection is made to a three-tariff meter. The boiler is fully operational only at night, when electricity is provided at a reduced price. During this time, the heated water enters the heat accumulator. During the daytime, the boiler is turned off.

The coolant is heated by the previously stored heat. The solution is optimally suited for low-temperature heating systems.

The choice of a double-circuit electric boiler

As already noted, modern electric double-circuit boilers for heating and hot water are made in wall and floor versions. First of all, when choosing, they are determined precisely with the type of installation of the boiler. In addition, pay attention to the following specifications:

• Heating area - heat engineering calculations will be required.
• DHW throughput and operating parameters. The documentation describes the technical characteristics of the device: the maximum and minimum heating of water, the volume of liquid that the electric boiler can heat within a certain time period.
• Additional functions - the boilers are equipped with a remote control, a GSM warning unit, weather-dependent automation.

To select a boiler suitable for technical specifications at home and corresponding to the needs of the owners, determine the required power, brand of the manufacturer, after which they choose boiler equipment in an affordable price range.

What power do you need a boiler - we make a calculation

The procedure for calculating an electric double-circuit boiler includes the need to calculate total power, sufficient separately for heating and hot water:

• The performance of a 2-circuit heating electric boiler, sufficient for heating residential premises, is calculated by the formula 1 kW = 10 m2. To the result obtained, add about 15% of the stock.
• Next, the calculation of hot water is carried out - for classic double-circuit electric mounted boilers for heating and hot water supply, operating in the mode of instantaneous heating of water, about 15-20% are added to the calculated power + margin.
• When calculating a boiler with a built-in boiler, they are guided by the manufacturer's recommendations and the power indicators indicated by him, sufficient for heating water and heating.

The calculations affect another area related to the amount of electricity consumed. Manufacturers, depending on energy consumption, produce two basic models of electric heaters: single-phase and three-phase.

The first, single-phase, are produced with a power of up to 8 kW and are connected to a 220V network. IN technical documentation, single-phase boilers, are classified as conventional water heaters (boilers), therefore, when connected, they do not require additional permits and the allocation of a separate voltage branch.

If the power consumption exceeds 8 kW, a three-phase boiler is installed. Connection to the mains is carried out through a separate branch of 380V. If the line is not connected to the house, a request for an increase in energy consumption is submitted.

The main manufacturers - who to choose

European companies remain leaders in the production of double-circuit boilers. The models offered by the concerns are distinguished by high efficiency, safety and reliability of assembly. In the design, apply the latest technology, providing protection of the heater from scale, preventing failure during power surges.

Deserve special mention, domestic electric boilers with two circuits. The products of Russian companies are fully adapted to the operating conditions. Although the boilers are inferior to foreign analogues in terms of functionality, they are not inferior in terms of reliability and performance, and in some cases even surpass the latter.

There are several models that are in constant consumer demand:

• Russia - EVAN Ecowatti, ThermoStyle EPN, Savitr Premium.
• Europe - ACV E-tech S, Wespe Heizung Kombi, Jaspi FIL-B.
• Ukraine - ROSS AOE.

Most of these models are presented in the premium class and use energy-saving technologies in their work.

Prices for electric boilers with two circuits

The cost of a 2-circuit electric boiler depends on several factors:

1. Options.
2. Manufacturer and place of assembly.
3. performance.

Domestic premium class electric boiler is offered starting from 20 thousand rubles. The basic model of a European brand will cost 1.5-2 times more. Prices start from 30 thousand rubles. and higher.

Pros and cons of double-circuit electric boilers

In fact, the main difference between single-circuit and double-circuit boilers is the number of heating elements located in the body. In the model with two heating circuits, two heating elements are provided. It is in this feature that all the advantages and disadvantages lie:

• Advantages - double-circuit boilers, work both for heating water and for heating the coolant. Accordingly, there is no need for additional installation boiler or water heater.
• Disadvantages - flow heating of water using a heating element, not the best design solution for several reasons. Two heating elements operate simultaneously, which creates a peak load on the power grid. Even with the use energy saving technologies, electricity costs are significant.

When it is not possible to bring gas into the house, solve the problem with independent heating and domestic hot water is accounted for by alternative energy sources. You can install solar generators, heat with wood or pellets, but if you are used to not only living in warmth and comfort, but also spending a minimum of effort on this, a double-circuit electric boiler can be the solution.

He is able to heat the house and provide the necessary amount of hot water.

The design of a double-circuit boiler provides for the placement of two heating elements in one device for heating water and a coolant. The system works by converting electric current into thermal energy.

Design features of a double-circuit boiler

To heat the room, a closed-type heating circuit is connected to the boiler, through which the coolant moves. The second pipeline is designed to supply hot water, which is heated in a built-in storage tank or according to the flow principle.

In the warm season, heating can be turned off and the boiler can only be used as a boiler.

Two circuits of an electric boiler can function both independently of each other and simultaneously, heating the house and heating water

The device consists of the following main elements:

• buildings with thermal insulation, inlet and outlet fittings;
• a heat exchanger through which the coolant circulates;
• control system and an automation unit that allows you to install temperature parameters and turn off/on the device;
• heating device;
• expansion tank for pressure relief;
• safety valve;
• air vent (automated or manual) to remove air pockets;
• circular pumps for hot water and heating systems;
• safety groups with temperature sensors and relays.

The principle of operation of the electric boiler is heat exchange: a circular pump pumps water into the tank, which is heated to a certain temperature by a thermoelement and output either to the heating circuit or to the DHW system. In fact, a double-circuit electrical appliance, like its gas counterpart, can perform the function of both a house boiler room and a flowing water heater.

Advantages and disadvantages of electrical equipment

Electric heating is an environmentally friendly heating method, because it does not pollute the air with smoke and soot like solid fuel boiler, carbon monoxide and other harmful "work-outs", such as gas equipment. In addition, the peculiarity of the operation of boilers on an electrician practically eliminates emergency force majeure in case of water leakage - if there is no coolant in the system, the equipment automatically turns off.

The electric boiler has an excellent efficiency indicator - 95-99%, but even such a high heat transfer does not compensate for the high electricity consumption, therefore, in comparison with a gas boiler, the appliance loses

Also, the general advantages of electrical equipment include:

• Easy installation– there is no need to equip a chimney, a system forced ventilation, supply a gas pipeline and issue a bunch of permits, as when installing a gas boiler.
• Security– the probability of leakage or boiling of the electric boiler is very small, in addition, the design of the device does not provide for the use of an open flame, flammable materials and explosive gas.
• Compact dimensions – important point for small spaces. In addition, the device can be installed not only in places specially provided for by the project (like gas equipment), but in any convenient place where it is possible to connect to the mains and heating system.
• Noiselessness- the electric boiler works without vibrations, "exhausts" and other sounds that solid fuel and gas appliances sin.
• Affordable cost both the device itself and its installation, maintenance.

As for the shortcomings, one of the most significant - cost of consumed energy. If we are talking about heating and hot water for a large cottage, the amounts will be impressive, so it would not be superfluous to make at least an approximate calculation of consumption before buying, after analyzing the information about the area, water consumption and power of the device. And then decide whether the "game" is worth such costs.

The installation of special controllers, storage devices and differentiated meters operating in the "day-night" mode will help to significantly reduce costs.

Other cons:

• Dependence on energy supply- in an area with constant interruptions in electricity, the installation of such a heater loses its meaning. However, if blackouts are random, and not the norm, buying a generator that stores energy will help solve the problem.
• Power surges have a detrimental effect on the sensitive automation of the boiler, therefore, before installing the equipment, it is worth purchasing good energy stabilizers.
• Since DHW is used running water, heating elements gradually are covered with scale to be removed from the equipment. The solution may be to install filters at the entrance cold water and regular service.

In addition, before installing an electric boiler, you should find out if your home network is designed for such a load. For example, for an area of ​​200 squares, at least 16-20 kW will be required. And this is only for heating, excluding other electrical appliances. And if in new cottage settlements such power is provided for by connecting to a three-phase network, then no more than 10 kW is usually allocated for a summer cottage.

Types of electric boilers

Modern electric boilers are equipped with heaters with different operating principles. But at the same time only devices with a heating element design can be used for both heating and hot water supply.

Connecting an electric boiler to a heating and hot water system most often involves installing a boiler with a heat exchanger or a tank for accumulating hot water

Other types of equipment can only be used for hot water if an indirect heating boiler is connected to the heating circuit.

Electrical appliances with heating elements

The most common models of electric boilers have built-in heating elements - heating elements, which are made of ceramic or metal, have the form of rods, a spiral or a hollow rod bent by an arc, inside which a thread of a certain resistance is placed. They act as "intermediaries", heating up during the passage of an electric current and transferring heat to the water.

Scheme of the device of a double-circuit electric boiler. The number of elements depends on the power of the device and its internal volume, but additional heating elements not only increase the heating rate, but also the cost of electricity and maintenance

The main disadvantage of the device is the rapid formation of scale on the heating elements, which impairs its performance. For example, with a thickness limescale only 0.5 mm, the efficiency of the device is reduced by 10% of the nominal, and at 2 mm - by 35-40%!

As a result, the device heats the water more slowly, so the electricity consumption increases. Therefore, the boiler needs constant cleaning and periodic replacement of failed heating elements.

In addition, boilers with heating elements require regular maintenance, because we are talking about the safe use of equipment. The heating element wears out over time and may burn out.

If this happens with depressurization of the hull, it's not so bad. In this case, heated nichrome will simply crumble from contact with water and does not pose a danger to humans. But if the disconnected element remains in the undamaged case and continues to work, the entire metal case will be energized due to the conductor-water.

Induction heating equipment

The operation of an induction boiler is based on magnetic induction, which allows you to convert electricity into heat energy. Inside the case there is a primary circuit with an inductive coil, which, when voltage is applied, creates an alternating magnetic field. As a result, the so-called Foucault currents (or eddy currents) arise, which heat the metal, and it transfers its heat to the circulating carrier.

Time-tested heating elements can be safely installed even in a living room, but for induction devices it is better to provide a separate room - despite the manufacturers' advertising statements, medicine has not confirmed the harmlessness of electromagnetic fields for humans

Advantages of induction boilers compared to heating elements:

• The highest level of efficiency is 98-99%.
• Large heating area and therefore faster heat transfer.
• On the heating element scale does not form.
• Completely autonomous and do not require service.
• In addition to water, oil products and oil can be used as a heat carrier.

The main disadvantage of such devices is the high price and the need to connect an indirect heating boiler or storage tank to provide the house with hot water. Therefore, despite a number of advantages of induction equipment, double-circuit heating boilers firmly hold the palm of leadership in consumer demand.

Boilers with electrode heaters

The operation of the electrode boiler is based on high rates thermal conductivity of water. Inside the housing, there are negative and positive electrodes that generate electric current, a coolant circulates between them.

Heating occurs due to the energy that is released during the splitting of molecules into charged ions, and their movement to the electrode of the corresponding polarity. Due to this, the heating of water in the boiler chamber occurs almost instantly.

A prerequisite for an electrode boiler is good grounding, since the devices are potentially dangerous devices and the case can “break through” with a strong current charge

Advantages of electrode boilers compared to heating elements:

• They heat water 10 times faster.
• They use 20-30% less electricity.
• They have compact dimensions even with high productivity (most often the models are presented in wall-mounted versions).
• Do not fail during power surges.

But because of significant shortcomings electrode boilers have not yet been widely adopted. They are mainly used for heating, but it is possible to organize a second circuit for hot water supply provided that the system is equipped with an indirect heating boiler.

These devices are very demanding on the composition of the liquid, which is the coolant. Ordinary tap water is excluded, it is recommended to use a special liquid with a balanced salt composition. In addition, the electrodes gradually dissolve during operation and require replacement.

Electrode boilers are very compact, but do not have high power, therefore, for heating large areas, modules with several devices connected in series are provided.

For safe use, it is recommended to equip the electrode boiler with an additional automation kit, which is sold separately and often costs more than the device itself. First of all, it is a circulation pump and an electronic temperature controller that controls the heating temperature. A current controller is also needed to regulate the current strength, with the ability to turn off the equipment in order to prevent the water from boiling.

What to look for when buying

When you figured out what type of device you want to buy, it's time to think about its dimensions and technical parameters. Most often, electric boilers are installed in the kitchen, but you can also equip a mini-boiler room, which will allow you to hide unattractive communications and additional equipment (storage tank, indirect heating boiler, etc.).

Choice of device according to the method of installation

Regardless of the type of construction, all double-circuit boilers can be divided into two large groups- wall and floor. The dimensions and choice of model directly depend on the area that you need to heat, and even on the amount of free space for the device itself.

A wall-mounted boiler differs from a floor-standing one in its small size - if necessary, it can be hidden in a hanging cabinet or cabinet, but even an unmasked appliance does not look bulky and harmonizes perfectly with other household appliances

Attached appliances are designed to heat relatively small areas - up to 100 m2, so they are most often installed in apartments or small country houses. They are mounted on special brackets to any vertical surface that can withstand such a load.

Floor boilers are rather bulky devices, but they can provide a house with an area of ​​​​up to 200 m2 with heat and uninterrupted water supply, and storage tanks can either be built into the device itself (which significantly increases its dimensions), or mounted separately

If the quadrature of the cottage exceeds 200 m2, you can equip a boiler room with several electric boilers or use additional sources of heating - solid fuel equipment or solar panels.

How to calculate the required power

The easiest way is to divide the heated area by 10. It is believed that heating 10 m2 will consume 1 kW, but the resulting figure will be very conditional, because such a calculation makes sense only for rooms with a height of no more than 3 meters. In addition, heat costs largely depend on the availability of insulation, the quality of windows and their sizes, the climatic features of the area and the materials used in the construction of the house.

If in the house high ceilings, you must first determine the volume of the room (multiply the area by the height). Then already calculate the required power on the basis that 35 watts will be required per 1 m3.

When buying, consider models whose power is 15-20% higher than yours calculated indicators- it is better to set the boiler to a weaker mode than to freeze in the cold winter when the equipment is working at the limit

To the result you need to add "reserve":

• 10% - with a large glazing area (panoramic windows, veranda, etc.).
• 15% - in the absence of house insulation.
• 10-15% - for areas with cold winters.
• 20% - for additional load at DHW operation in continuous heating mode.

When calculating the required power for boilers with built-in storage, you need to focus on the data specified by the manufacturer in the technical documentation.

The way it is fed also depends on the technical parameters of the boiler. Appliances up to 10 kW can be connected to a conventional 220 V network, and more powerful boilers to a three-phase network (moreover, this may require permission from local power networks if a 380 V line is not connected to the house).

Other important nuances

According to the principle of water heating, double-circuit electric boilers can be divided into flow and storage. First - a good option for small house and families, he will be able to safely serve 1-2 points of water intake in addition to heating. But, despite the compactness and comfort in operation, the 2 in 1 device has a significant drawback - a high load on the power grid.

But the storage unit takes up much more space due to the additional tank in which the supply of hot water is stored. The advantage of this type of equipment is that it can supply water to large quantities and allows you to save up to 10% on electricity, because it does not spend energy on constant heating, but only maintains its temperature.

Thanks to the insulating casing, the heat loss of water in the tank per hour will be no more than 0.5 degrees.

The technical data sheet of a device intended for connection to the DHW system must indicate its throughput - the temperature minimum and maximum, the volume of water and the required time for its heating.

Modern electric boilers allow you to control the device and control the temperature of the heating in the room using smartphones or the smart home system

Additionally, the boiler can be equipped with:

• Automation unit for remote control remote control or network.
• Frost protection, which will allow you to maintain a minimum temperature in the system, which is important for country and country houses where there are no permanent residents.
• Sensors that track changes in the weather turn on the device when temperatures drop and turn it off during sunny hours.
• Equipment that lowers the water temperature for connection to the "warm floor" system.
• Sensors with the ability to program the microclimate in the entire room or separate rooms at your discretion.

Of course, the "bonuses" from the manufacturer increase the cost of the device, but with their help it is much more comfortable to operate the boiler.

Ways to save money during operation

To reduce energy costs when using an electric boiler as a heating device and water heater, you need to reduce the overall heat loss of the house.

First of all, it is worth replacing the old wooden frames modern windows with 2-3 air chambers and take care of wall insulation (best external) with foam, mineral wool or other materials with low thermal conductivity

Other savings options:

1. Additional connection or separate devices running on alternative energy(solar panels, wind turbines, wood burning fireplace) will significantly reduce electricity consumption.
2. A multi-tariff meter will allow you to pay less for night heating, and for the period of morning and evening "peak hours" the device can be turned off (the most expensive is electricity consumed between 8.00 - 11.00 and 20.00 - 22.00). And if you supplement the system with an external heat accumulator, you can accumulate “cheap” energy at night in order to spend it during the day.
3. Recuperator in ventilation system will help keep the heated air inside the house.
4. The weekly programmer will collect system operation data for a specified period of time in order to select the most comfortable and economical mode of operation with minimal energy consumption.
5. Room thermostats will monitor changes in the microclimate of the house and transmit data to a sensor built into the boiler, which will turn off / turn on the heating, protecting it from overheating and unnecessary heat loss.

With the proper organization of the operation of an electric boiler, you can reduce electricity consumption and related costs by up to 40%.

Conclusions and useful video on the topic

Nuances electric heating- boilers and other electric heaters, calculation of equipment power and costs for the heating season:

Although double-circuit electric boilers seem very comfortable to use, before you go shopping, calculate the electricity costs for cold period years or contact a heating specialist.

Perhaps they will advise you on a more economical system with a single-circuit boiler with an indirect heating boiler or design combined heating, where the "gluttony" of the electrical appliance will be compensated by additional sources of energy.