Homeowners who use solid fuel stoves for heating know firsthand such a nuisance as cooling the room after the wood burns out in the stove. This can happen at night or during a long absence of the owners.
In these cases, a combined wood-electricity boiler for heating a private house will help maintain the temperature. Such heat sources are equipped with automation that monitors the system - if the stove goes out and the water in the boiler cools down, it gives a command to turn on the electric heating elements.
Externally, the combined boiler practically does not differ from the standard one. Source: darizz.access.ly
The use of combined boilers
Today, such devices are universal, and at the same time economical devices for autonomous heat supply at home. Their main trump card is that there is no binding to one type of fuel. If such a boiler is powered by electricity, then during a sudden shutdown, you can melt the wood stove to keep the heat in the house and vice versa.
Buying a combined boiler decides immediately multiple tasks:
If there is no main gas pipeline in the village where the house is built, then it is possible to use two alternative types of energy carrier at once - solid fuel and electricity.
If a country house is connected to a weak power line, a combined boiler is almost ideal - you won’t have to freeze if you need to turn on another powerful electrical appliance for a long time.
Excludes cooling of the house when using solid fuel. Such a unit, connected to water heating, helps maintain a constant temperature in the system: in the event of a burnout of the fuel, the boiler will automatically smoothly switch to heating through the heating element. This is especially convenient at night: no need to get up and put firewood in the furnace.
When a conventional boiler cools down, it has to be ignited immediately so as not to lose heat. Source iobogrev.ru
Principle of operation
Combined boiler wood-electricity works according to the following algorithm:
Melting and heating of the unit takes place in the traditional way. During the combustion of solid fuels (wood, coal, briquettes), the water temperature is maintained using a thermostat together with a sensor. Electric heating elements are not working at this moment.
If fuel is not added to the furnace in time, then after it burns out, the water temperature in the system gradually drops to a certain value, after which a sensor is triggered that closes the control contacts and the heating element (one or more) is turned on. From this moment the boiler starts to work from the mains.
After the next loading of fuel, the water in the pipes is heated from the side of the firebox and, upon reaching the set temperature, the sensor is triggered again, but to turn off the heating elements. The electrical part of the boiler is again inactive until the water temperature drops again.
Most often, the electric heater in a combined boiler is designed as an auxiliary heating device, but if desired, it will be possible to choose a boiler model that, if necessary, can work continuously, providing hot water to the house and heating system.
Video description
The principle of operation of the combined boiler is clearly shown in the video:
On our website you can find contacts of construction companies that offer home insulation services. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".
Positive and negative points of combined boilers
When choosing any equipment, you need to focus not only on its positive aspects, but also study the disadvantages in order to understand which characteristics are more important to you.
Advantages
The advantages of wood-electricity devices compared to heating units that operate on only one type of fuel are obvious:
Versatility equipment. Electricity for the boiler can be both the main energy carrier and auxiliary - which in this case will be a priority for you to decide.
autonomy. There is no need for constant monitoring, as the boiler is equipped with automation.
economy. Firewood is one of the most affordable types of fuel in many regions of the country, and it is now almost impossible to find a house without an electrical connection.
Convenient design. Constant maintenance of the set water temperature with minimal energy consumption.
If a two-tariff meter is installed, you can program the boiler to turn on the heating elements only to maintain heat at night, when the billing is much lower and thus save electricity consumption.
With the correct distribution of the load, a two-tariff meter saves from 30 to 65% on electricity bills Source zinoti.lt
Long service life. Such boilers with proper operation work up to 25 years.
The production of models with built-in nozzles for Possibility of connecting the "warm floor" system.
Important! Wood-electricity boilers work effectively even in low-power modes.
Flaws
With all the advantages of such boilers, there are also disadvantages:
Separate room. Units of this type require their own boiler room and an annex for fuel storage.
Big weight. Most often, boilers are made of cast iron and require a solid concrete base for its placement.
Device complexity. This factor affects the price of the boiler: it is 20-30% higher than the cost of units operating on the same fuel.
On a note! The electrical heating elements of most combi boilers are mainly designed to support heat. In winter, when the external temperature is below -5 °C, they cannot completely replace the combustion of solid fuel due to low power. If long-term use of electric heaters is expected, it is necessary to look for boiler models that operate on three-phase power (if this is carried out to the house).
With the correct “distribution of duties” between a wood-burning stove and an electric heater, the use of heating boilers for a private house on wood and electricity is not only convenient, but also profitable. And in regions where there is no gas pipeline, it is quite difficult to find a worthy alternative to such a device.
Today, the market offers a wide range of universal boilers, which differ in power, performance, design and configuration. But before you buy such a unit, you need to weigh the pros and cons, and it is also useful to listen to the recommendations of professionals in this matter.
When buying a boiler, consider the following:
Power. It depends on the fuel that will be a priority.
The volume of one bookmark of fuel and the size of the combustion chamber. The duration of burning firewood depends on this parameter.
Firebox material. These parts are made of cast iron and steel. It is preferable to choose chambers made of cast iron, since they are not subject to deformation when heated, they retain heat longer, unlike a steel exchanger.
Grids. Two types are used: standard cast iron and the same, but coated with ceramics. The latter are used mainly for bulk materials, which consume more oxygen during combustion, respectively, and the temperature is created higher.
Weight and size. Typically, the body of such boilers is made of cast iron, which makes them much heavier than their "brothers".
Advice! Buy a heating device, you need to be consistent with the area of \u200b\u200bthe house. You should not purchase a boiler "with a power reserve", as this will entail an overpayment - both upon purchase and during operation.
Installation Requirements
Combined boilers according to SNiP 41-01-2003 must meet the requirements. At the same time, they have their own characteristics during installation and operation, distinguishing them from a number of similar units operating on a single fuel.
Requirements for the premises
Boilers for wood and electricity for home heating are produced only in the floor version and are installed in a boiler room with ventilation, and in accordance with other requirements of SNiP:
The walls in the room are made of non-combustible material.
The equipment in the boiler room is installed no closer than 300 mm from the walls.
The boiler room must be dry and moisture-proof.
Since the boiler is heavy, the platform under it is reinforced with a concrete screed.
Also, the room must comply with fire safety standards: there are no flammable objects or flammable liquids near the boiler; a sheet of iron is installed in front of the firebox to prevent fire from falling coal or sparks from the firebox.
Chimney
When installing an electric wood-burning boiler, an indispensable condition is the presence of a chimney like a unit with solid fuel. For the uninterrupted operation of the installation, good traction is needed, for which the pipe must rise above the ridge of the roof of the house and have an internal diameter not less than the boiler nozzle.
The chimney pipe must be without mechanical damage, and have a tight joint. During the operation of heating elements, it is recommended to make a view to preserve heat in the chimney. It is also desirable to insulate the pipe so that condensation does not form in sub-zero weather.
A high-quality chimney is the key to the smooth operation of the heating boiler Source kakpostroit.su
Electrical Requirements
When installing an electric wood-burning boiler, they do not currently ask permission from Gorenergo. But in any case, it is necessary to have a power supply capable of withstanding the operation of heating elements without the occurrence of overloads.
For example, if the boiler is supposed to be used by connecting heating elements over 6 kW, then the voltage should be 380 volts.
In any case, the connection of the device must be strictly according to the instructions. Wherein:
It is not allowed to install a combined boiler in a room where there is high humidity or where the electrical part of the equipment is likely to come into contact with water.
The temperature range in the room should be between 0 and +45 °C.
The cross section of the wire is calculated and corresponds to the required power and current strength.
Despite such seemingly simple requirements, the installation and connection of the combined boiler must be carried out by certified specialists. In this case, in addition to the quality of the work performed, you get the right to a free warranty repair of the boiler if the breakdown occurred due to a defect in the equipment.
Video description
Combined boilers are also called such devices that were originally designed to work on solid fuels, but they also provide the ability to connect electric heaters separately:
Conclusion
Today, electricity and solid fuels are the most popular and affordable energy sources for heating boilers. Boilers that can heat a house by burning wood or using electricity are an efficient solution, moreover, no different from conventional devices in terms of reliability.
Our units run on solid fuel and are designed for wood heating of cottages and low-rise private country houses. The area of premises heated by firewood is from 80 to 320 squares.
The design of the wood burning apparatus allows additional use of electric heating of the coolant. To do this, a threaded sleeve for the heating element is provided on the rear or side wall of the housing.
This is a useful option for wood-fired boilers, which allows you to avoid temperature fluctuations in the heating system between fires. When water is used as the heating medium, the electric heating will protect the system from freezing in the event of prolonged downtime during the cold season.
A tubular electric heater with a control panel will automate the process of controlling the unit and expand the functionality of a simple wood-fired boiler.
Heating element installation
The heating element is not included in the sale of the wood-burning boiler, but is an option that must be purchased separately. For combi wood boilers of low power up to 18 kW, a tubular electric heater of 1-3 kW is suitable; for devices of 18-32 kW, a heater with a rated power of 6 to 9 kW is recommended.
The control panel with a thermostat automatically maintains the temperature within the specified range by turning the electric heater on and off. The block is equipped with protection against boiling and a light signal.
Heating elements with a power of 1 to 3 kW are single-phase and are powered by a household electrical network with a voltage of 220 V, and heating elements with a power of 6 to 9 kW are three-phase and are powered by a network of 220/380 V. When installing the unit, connect the ground.
If there is no gas in the house, then this is not a problem - you can heat it with firewood bought or chopped in the forest. In addition, solid fuel boilers can operate on other types of solid fuels. Also on sale are combined units connected to the mains. Heating boilers for a private house on wood and electricity are more convenient to operate than their traditional counterparts. Let's take a look at what kind of equipment it is, how it works and what its advantages are.
Features of boilers for wood and electricity
A traditional solid fuel boiler is a wood-burning stove with a built-in heat exchanger that provides the heating system with a hot coolant. Firewood is placed in its firebox, burning merrily and generating thermal energy absorbed by the coil. And in order for the house to always be warm, it is necessary to throw all new logs into the firebox - even at night. That is, instead of sleeping, you will have to get up and stomp to the insatiable unit.
Wood-fired heating boilers cause inconvenience even during the day. The logs in them burn out very quickly. If you do not follow the level of the flame, the heating will cool down, the house will become noticeably cooler. This problem is solved in the following ways:
- Purchase of pyrolysis units and models with large fireboxes;
- Purchase of pellet boilers with automatic fuel supply;
- Installation of a boiler that runs on wood and electricity.
The last option is the cheapest. Pyrolysis units are complex and expensive, the same drawbacks are inherent in pellet samples. But boilers and stoves on wood and electricity have an affordable price.
An electric wood-burning boiler is a conventional solid fuel appliance that runs on wood. But as soon as the firewood in its interior runs out, and the temperature of the coolant drops below a predetermined level, the heating element (or several heating elements at once) is turned on. It maintains the temperature in the circuit, preventing it from cooling down quickly.
Heating elements are responsible precisely for maintaining the temperature, they are not able to warm houses only due to their power. They also allow a gradual cooling of the coolant, but they are enough for several hours.
Temperature control can be built-in or external - some models are equipped with built-in thermostats.
Solid fuel combined boilers are equipped with one or two heating elements of limited power. Single-phase and three-phase networks (more often single-phase) act as a power source for them.
Advantages and disadvantages of wood-fired boilers and electricity
Boilers for heating on wood and electricity are characterized by the following advantages:
- The presence of support for the temperature regime - will prevent the coolant from cooling too quickly;
- Balanced cost - equipment is distinguished by its low cost, which will be discussed in our review;
- No additional maintenance is required, as required by combined devices with liquid and gas burners.
By installing a heating boiler on wood and electricity in your house, you will not jump up at night to lay a portion of firewood.
Not without traditional disadvantages - this is high power consumption and the need for hardy electrical wiring.
Popular Models
Let's see how to choose a combined wood-electric heating boiler for home heating. The main parameter here is the power of the device. Usually 10 sq. m. heated area requires 1 kW of thermal energy. Also, do not forget about 15-20% of the reserve in case of cold winters.
Heating elements in wood and electricity boilers can be optional or built-in. In the first case, they will have to be purchased separately, and in the second they are supplied in the original configuration. It would be nice if there was already a thermostat on board to maintain the temperature - then you do not have to buy it separately. You should also evaluate the power of the heating element used, since samples with a power of 8-9 kW and above operate from three-phase networks.
Before us is a typical boiler on wood and electricity for heating a large house - up to 200 square meters. m. It is non-volatile, but comes with a pre-installed block of heating elements, the power of which is 9 kW. The model is single-circuit, designed for traditional floor installation. The combustion chamber is open, it burns briquetted fuel, coal, firewood and other types of solid fuel.
If you are going to buy this boiler, you will make a bargain. After all, it can work not only on wood and electricity, but also on gas - for this, a connected gas burner is bought in addition to it. The cost of this model in online stores varies between 22-28 thousand rubles.
Electric wood-burning stoves for a house with water heating are in demand among those who are tired of freezing when the fire is attenuated in the furnace. Using the ZOTA Poplar M20 model, you will have at your disposal a powerful heating device from a well-known brand. Its power is 20 kW, efficiency - 75%, control - mechanical. It is possible to work from electricity, but for this you will have to buy a block of heating elements for it. The boiler is omnivorous, it burns wood, coal and anthracite. Estimated cost in the Russian market is about 36,000 rubles.
The GEFEST company produces not only gas and electric stoves known throughout Russia, but also heating boilers for a private house using wood and electricity. A typical example of this is the above model. It is made in a simple rectangular case, devoid of any hint of design. The power of the sample is 25 kW, the heated area is up to 250 square meters. m. The efficiency is up to 82%, this is a fairly high figure.
Despite the apparent simplicity, the GEFEST VPR KSTGV-25 boiler on wood and electricity is not at all as simple as it seems. The thing is that it is a double-circuit - it gives heat and hot water. The capacity of the DHW circuit is 8.5 l / min at a temperature change of 35 degrees. The primary heat exchanger is made of steel, the secondary heat exchanger is made of copper. As soon as you get tired of spending firewood and electricity, the device can be switched to gas by purchasing a burner for it.
Those who know how to make good boilers that work equally well on wood and electricity are Siberian manufacturers. The presented model has a power of up to 12 kW and can heat an area of up to 100 square meters. m, consuming up to 3.2 kg of fuel per hour. As soon as the wood in the firebox comes to an end, the electric heater will turn on - it will maintain the temperature in the heating circuit and will not let it cool down until the next fuel load.
The boiler for wood and electricity Sibenergoterm Prometheus 12M-5 12 kW works not only on wood, but also on other types of fuel - coal and coal briquettes. Moreover, coal acts as a fuel recommended for this model. Separately, the high efficiency of the model, which is 84 kW, pleases. It also includes an air vent and safety valve. Heating elements for operation from the mains are purchased separately.
This boiler, which can work on electricity and wood, is combined, because a gas burner is also connected to it. The power of the device is 16 kW, which is enough to heat houses up to 160 square meters. m. The fuel for this model is traditional firewood, coal and wood briquettes, as well as coal.. The block of heating elements is already pre-installed, you do not need to purchase anything additionally. The device is one of the most affordable, its average cost is about 24 thousand rubles. For this money, consumers receive almost omnivorous equipment.
The combined solid fuel boiler is considered the most common type of universal equipment. Below we will talk about all types of combinations of fuel use.
To begin with, we note that universal boilers can have two circuits:
- One circuit - designed for space heating.
- Two circuits - the ability to provide the room with heat and hot water in flow mode.
As well as other units, universal boilers are floor and wall. Unlike a boiler with a steel heat exchanger, equipment equipped with a cast iron heat exchanger has more weight and, accordingly, a floor modification. However, cast iron is a much more durable material and increases the life of the boiler. The average service life of such a device is 30 years, subject to all the necessary rules for tying such equipment.
Universal heating boilers
Undoubtedly, the combined boiler has a large number of positive characteristics. The main advantages are, of course, its versatility and practicality.
Before you buy a universal heating boiler for your home, we recommend that you familiarize yourself with all the variations offered to the consumer. By the number of burners used, such boilers are divided into:
- Multi-fuel - used from three types of fuel.
- Bi-fuel - it is possible to use two types of fuel.
For universal boilers for heating a private house, prices are higher than for conventional boilers operating on the same type of fuel. However, such equipment is a great opportunity to use all available resources.
The owners of universal equipment claim that it was the right decision to buy a double-circuit combined boiler for heating a private house, since such a device is very economical and efficient.
Gas boilers with combined fuels
Universal equipment has many combinations of fuel use.
Multifuel:
- Are used:
- firewood
- electricity
- Are used:
- firewood coal pellets
- electricity
Bifuel:
- gas electricity
- gas diesel
- gas wood coal pellets
Coal gas heating boilers are very popular.
Boilers for heating on wood and electricity
Electric wood heating boiler is ideal for rooms that are not connected to the main gas. Basically, such equipment can operate on different types of fuel. For a combined heating boiler for firewood and electricity, the price, as well as for other similar units, depends on the power of the equipment. Other technical characteristics of the equipment also affect pricing. A universal boiler that works according to the firewood electricity scheme is easy to manage. Usually the design of such a boiler is as follows: a solid fuel steel boiler is combined with an electric heating element of various capacities. It can be either initially built-in or built-in if necessary. Electricity is used to maintain the temperature of the coolant after the firewood has burned out. As a standard, an electric heating element is selected based on the power of a solid fuel boiler in a ratio of 1:2. Equipment that uses solid fuel, wood, coal, electricity, is considered highly efficient and economical. A solid fuel boiler with an electric heating element is the most profitable combined heating equipment. Like any other solid fuel unit, such boilers require a stainless steel chimney with thermal insulation and the presence of mandatory ventilation in the room where it is installed.
Heating boilers combined with solid and diesel fuel
The boiler for liquid and solid fuels can run on diesel and wood (coal, pellets). Various modifications of such boilers are presented in the range. It is advisable to install a universal boiler for wood and diesel fuel in a separate room. Installation is recommended to be entrusted to specialists. The combination of two types of fuel (diesel firewood) is the most cost-effective for the consumer.
Combined solid fuel boilers
Solid fuels can be combined in various variations:
- wood pellets;
- wood pellets;
- coal pellets;
Be sure to read the instructions that came with the equipment. The manufacturer indicates which type of fuel can be used in the operation of this particular boiler.
Autonomous heating is becoming more and more popular among private property owners. The ability to heat a house and even an apartment at any convenient time, and not with the start of the heating season, provides huge advantages. And if in apartments the choice of energy is limited (electricity or gas), then in a private house you can install both a solid fuel and a combined boiler (wood-electricity).
Combined boiler in the most successful way combines the uninterrupted equipment and its versatility. Depending on the availability of a particular type of fuel, you can select the appropriate mode, each of which will be equally effective.
The design of the unit is quite practical, which leads to a reduction in heat loss and economical fuel consumption. During the day, it is advisable to heat the house with coal and/or wood, and at night to maintain the temperature with electricity. At the same time, there is no need to monitor the availability of firewood in the furnace, and the nightly electricity tariff is 15-35% lower than the daytime one.
Video 1 Combined boiler device in a private house
Design features
The main difference between combined equipment and solid fuel equipment is the presence of a thermoelectric heater in the heat exchanger tank. The heating element turns on automatically at the moment when the power of the combusted fuel is not enough to ensure the optimum temperature of the coolant. In other words, the heating element starts up when firewood or coal burns out, the heat subsides and there is a need to heat the coolant. All processes are fully automated and do not require human intervention, with the exception, perhaps, of laying firewood in the firebox.
In order to quickly and efficiently heat up the premises, different boilers have from 1 to 4 combustion chambers, each of which is connected to a separate thermoelectric heater.
The boiler for heating a private house combined wood / electricity has only 1 combustion chamber and 1 thermoelectric heater, and the water is heated by analogy with a storage water heater (boiler).
Video 2 Single-circuit boiler on wood and electricity
Why buy
- A wide range of fuels used - it can be not only coal or firewood, but also briquettes, pellets, wood waste, etc.;
- Autonomous operation - the combined boiler in the "electricity" mode works for an unlimited amount of time without human intervention. The restriction in heating can only be due to the lack of electricity. The operation of the equipment is absolutely safe;
- Convenient maintenance - if necessary, the boiler can be converted into mono-fuel. When using a predominantly electric mode, cleaning of the boiler and chimney is not required; with regular use of solid fuel, it is necessary to clean the boiler as often as a standard solid fuel boiler - once a week the furnace and 1 time in 3-5 months the chimney.
Price is hard to include as an advantage. Compared to mono-fuel boilers, combined boilers are much more expensive, depending on the brand and the number of combustion chambers.
How to choose
Heating equipment can be used both for heating the residential sector, and industrial and industrial premises. To select the appropriate model that will be suitable for power and efficiency, you should focus on the number of circuits, performance and performance.
When purchasing a combined electricity / firewood boiler for heating a private house, consider the following indicators:
- equipment - as a cheaper alternative, some manufacturers offer a boiler where the coolant heats only the heating element. This design is irrational, since the voltage in the network is not always stable, and electricity is sometimes turned off;
- dimensions of the equipment - in the presence of several combustion chambers, which, as a rule, are made of cast iron alloy, the weight of the equipment can reach 500 or more kilograms, which will require a special base and a separate room. Also pay attention to the size of the firebox, since the frequency of laying firewood depends on this parameter.
Cast iron retains heat much longer than ceramics and is suitable for all types of solid fuels.
- power is a parameter that directly depends on the type of fuel - electricity or firewood. Taking into account which type of fuel will be a priority, you should focus on the power of the boiler.
In order for heating to be efficient, the boiler output must always exceed the actual need for it.
- the presence of a water heating circuit, which provides hot water at the points of water intake.
Installation Features
Combined equipment will require a separate room. Here it is necessary to provide the following mandatory installation elements:
- foundation - a low reinforced concrete layer that compensates for the dimensions of the boiler;
- arrangement of the chimney - the principle is in many respects similar to the chimney on a solid fuel boiler, where high-quality draft is provided
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Photo 4 Plan-scheme of the heating system for a combined boiler
The traction power depends on the height of the pipe head. Its optimal height above the ridge is from 50 cm.
Once the boiler has been installed, the chimney must be carefully insulated. This will avoid the appearance of condensate and ice in the pipe, which prevents smoke from escaping.
- a ventilation system that will allow timely removal of combustion products and carbon monoxide when it appears.
- connection to the mains - a heating element that maintains and heats the coolant to a certain temperature, operates exclusively from the mains 220 volts.
To connect the equipment, a 380 volt line and 3 phases is required. In this case, it is necessary to ensure the correct connection of the input and grounding to the circuit. You should not take risks and make grounding to zero a simple break in the circuit, the automation simply will not have time to do the skew.
The popularity of combo boilers wood / electricity is due to the fact that both types of energy are the most accessible to the population. At the same time, all processes in the heating equipment are fully automated, and heat losses are minimized. The overpayment in price is compensated during the first 2-3 years of operation.
