The constant increase in the cost of energy carriers and expensive gas connection requires looking for other types of heating devices for the heating system. An electric or gas heat source is an alternative to a solid fuel boiler. The article introduces the types and characteristics of solid fuel equipment, its pros and cons, methods of protection against overheating.

Solid fuel boilers types and characteristics

Solid fuel boilers are of two types:

  • classical, in them, during the combustion of fuel, heat is released.
  • pyrolysis, with the release of combustible gas when the temperature rises from the combustion of fuel, and its supply to the combustion chamber, where it is burned.

The second type of units is considered more perfect. They have a fairly high efficiency, the fuel burns out almost completely, the power changes in a wide range, there are fewer requirements for the chimney, which ensures the presence of a blower in the design. But their price is much higher, they have more requirements for fuel, its maximum moisture content should not exceed 20%, and for the water temperature in the boiler.


Solid propellant units are cast iron and steel. The hardness of the water is not so important for the first, but they need to ensure the correct temperature of the make-up liquid. The supply line for feeding the heating system must be warm water, not cold tap water. This will protect the heat exchanger from destruction due to temperature changes. Cast iron heat exchangers are heavier than steel, which increases their inertia. They are less frequently cleaned without reducing efficiency, resistant to corrosion, which increases the service life, but also increases the cost.


Boilers can be volatile and non-volatile. The first type is models with an electric control panel and a fan that blows air into the combustion chamber. Usually these are pyrolysis boilers made of steel or cast iron. Sometimes there are non-pyrolysis steel products with a built-in fan that works like a supercharger. Non-volatile equipment also works without electricity, where the heating system has natural circulation. But such models are less comfortable and economical.


The type of fuel affects the power of the equipment. Most often used: brown coal, anthracite, coke, firewood, fuel briquettes, wood chips. The use of low-calorie materials can reduce the boiler output by up to 30%.


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Solid fuel boiler pros and cons

Before you make a decision and buy a solid fuel boiler, you should familiarize yourself with the advantages and disadvantages of the equipment.


The pluses include:

  • high ecological cleanliness;
  • affordable cost;
  • the possibility of using fuel of different fractions and sizes, which allows you to change the power of the boiler and the period of its operation (with a decrease in size, the power increases and the time during which the fuel burns decreases);
  • safety during operation, proper installation ensures energy savings and prevents explosive situations;
  • minimal risk of fire.

The disadvantages of the equipment include the formation of soot on the walls of the boiler, the frequent loading of fuel for continuous operation. It is not always possible to quickly provide the maximum power of the unit.

Protection of a solid fuel boiler against overheating

To avoid troubles that can lead to boiling and explosion of the boiler, it is necessary to ensure its protection against overheating. Its main reason is the high inertia of the unit during fuel combustion. This process cannot be completely stopped until the firewood or coal runs out in the combustion chamber. The fuel will continue to burn in it, therefore, at the outlet of the coolant, the temperature can reach 100°C or more. This will lead to deformation of plastic and metal-plastic pipes and failure of the entire heating system. Special devices are used to protect it.

  1. Heat exchangers for cooling. They are built into the boiler or installed at the outlet of it. A thermal valve is connected to the unit, which is set to 95°C. When a high temperature is reached in the boiler, it opens, and cold water, passing through the heat exchanger for cooling, washed by the hot coolant, begins to cool it until the temperature in the boiler becomes acceptable.
  2. Valves for switching. Its purpose is to block the supply of overheated coolant to the system and supply cold tap water.
  3. Installation of a large capacity storage tank. Such a device allows not to install additional valves.

In the first case, it is necessary that there is a constant supply of water. In the second, the superheated coolant is drained into the sewerage system, and water must be supplied under high pressure.


The best way to protect is to install a solid fuel boiler and a heat-insulated large-volume tank (buffer) with water between the heating system and the boiler.


The correct operation of solid fuel boilers will not be possible without the correct installation of the chimney. At the same time, it is necessary that:

  • was made of heat-resistant materials that can withstand temperatures of at least 500 ° C, resistant to corrosion;
  • had good thermal insulation;
  • was at least 4 m high and over 180 mm in diameter.

But it is impossible to greatly increase the dimensions of the chimney in order to avoid the formation of an air lock that prevents smoke and gas from escaping.


But the main thing is to follow the recommendations of manufacturers and take into account the requirements of building codes during installation. Electric or gas units are an alternative to solid fuel boilers that can be installed as backup heat sources. But it is important to ensure their protection from possible overheating. The use of such modern equipment requires an appropriate acid-resistant chimney. Only the right choice, installation and operation of solid fuel boilers will ensure the safe operation of the entire heating system.


The house insulation program in Ukraine has not started its operation, but it raises many related questions. There are many factors that make the use of allocated funds ineffective.


Literally on December 1, in a message to the Verkhovna Rada, the President of Ukraine announced that the Great Thermal Modernization project would soon be put into operation. The program plans include large-scale insulation of hospitals, educational buildings, apartment buildings, which will make it possible to insure against future price increases set for various energy resources.


To start the comprehensive insulation of houses, the government approved a bill on December 23, according to which many changes were made. From Denys Shmygal, it was said that the process of creating associations of owners of apartment buildings will become much easier, this is due to the simplification of the program itself.


According to plans, in 2022, insulation should take place in at least 5,000 multi-apartment buildings. Rostislav Shurma states that the program plans to carry out the work for 7-10 years. This time will be enough to modernize at least 180,000 houses throughout Ukraine. At the same time, it is planned that the indicators of gas energy consumption will be reduced by about 30-40%.

Using Energy Efficient Billions

About 30 billion hryvnias were allocated from the budget for the current year in the process, like thermal modernization of houses. Their receipt will be realized through the organization “Ukrfinzhitlo”. And if in September about 20 billion hryvnias were sent, then today another 30 billion hryvnias were received due to additional capitalization.


The process of creating the Ukrfinzhitlo organization was organized at the beginning of 2020, when the Affordable Mortgage program appeared. At the end of 2021, a mortgage state institution was additionally connected. If we consider “Ukrfinzhitlo”, then this is an intermediary between a banking institution and a citizen when it is necessary to obtain a mortgage with an interest rate of 7% per annum. More recently, the organization has additionally begun to engage in leasing.


If we evaluate the success of the organization, then they are relative. As soon as the program began, applications were sent for a total amount of about UAH 1.5 billion, and the number of loans concluded was 1245. But the expectations themselves were much higher than they turned out in practice. Now it is planned that Ukrfinzhitlo will be responsible for an equally important program for the state.


If we take the allocated amount of 30 billion and divide it into 5,000 houses, then about 6 million will be directed to each of them. It should be borne in mind that there is a desire to carry out thermal modernization of institutions in the social and budgetary sectors. Therefore, the allocated money will not be enough to carry out high-quality modernization, since the price for 1 square is at least 200-300 euros.


On the part of Oleg Popenko, it was concluded that at least $1 million would be spent on the modernization of one residential building. If we take 5 thousand houses, then the figure will increase to 5 billion. This can be called the possibility of extending the life of a residential building up to 25 years. This will include not only major repairs, but also the renovation of the building with electricity, heat, water and other amenities. It may take about 10 years to implement a process like insulating 5,000 houses. If we evaluate reality, then there are practically no physical opportunities to realize this.


The President of Ukraine claimed that during the first three years, 100 billion will be spent on the process, and about 300 billion on the implementation of the program. There is no information anywhere whether the indicator will be taken into account as an inflationary component. Therefore, the scale of the “Great Thermal Modernization” is artificially inflated, because the program can be partially implemented.

How will the savings

Before large-scale work is implemented, it is imperative to make an audit and decide which of the facilities need urgent thermal modernization, and which can temporarily wait in the wings. Many argue that if money is invested in a house that has not been surveyed, literally in 5 years it will collapse. It is not advisable to modernize all the facilities in a row and it is necessary to fulfill applications not only at will. To do this, it is recommended to perform a comprehensive audit. There is a need to make sure that each of the houses needs modernization. Only then can it contribute to lower prices for expensive communal and housing services.


The indicator, like energy independence, will not be displayed on the actual tariffs, because the consumption of gas by Ukraine and other resources may be reduced. The government has set a goal – to reduce gas consumption by about 30-40%, but within the framework of an optimistic scenario. Not every house will get such an effect, since an important role is given to the use of individual meters and heat points.


Among the arguments responsible for the development of energy sources are political, economic and environmental ones. And, if an exhaustive amount of information has been written about environmental issues, today these arguments are the key factors for the development of renewable energy. There are few of them to support the improvement of the presented sector on the territory of Ukraine. And in most cases this is due to the fact that many people think that it should be cheaper, but not so clean.

Economic Benefits of Renewable Energy Development

There are forecasts that the development of such a direction as renewable energy in Ukraine in the future may contribute to a significant reduction in the cost of electricity for users. Such data appeared several years ago.


On the part of a well-known Swiss company, research is systematically carried out in terms of comparing such an indicator as the cost of electricity in Ukraine, received from completely different sources of generation. Traditional production has been found to increase the price, while renewable energy reduces it.


If we make a comparison, then for wind and solar power plants of an industrial design, it is already significantly cheaper. At the same time, every year this difference in favor of renewable energy only increases.


According to the calculations of a well-known Finnish organization, according to the scenario that provides the most affordable electricity on the territory of Ukraine, the percentage of renewable energy by 2050 should be about 83%. The remaining indicators will be directed to gas generation. But, despite this, in Ukraine over the past few years they have only been saying that renewable energy is expensive, so you should not switch from a traditional source of electricity generation.

Emergency state of power plants and small reserves of coal

In recent years, a hybrid struggle against the use of renewable energy has been carried out on the territory of Ukraine, despite the fact that there is a need to reduce its price. For several years, the question has arisen as to whether the use of renewable energy will be the right decision and whether it will be possible to achieve more affordable prices for heat and light.


During the struggle on the territory of Ukraine, the whole world has fallen into a rather serious crisis situation related to energy. The cost of gas has become 15-20 times higher, and more than once the limit was crossed over $2,000 per 1,000 m3. And recently, more and more often you can hear that in the near future in the winter the price will exceed $ 3,000. As for the cost of coal, during this time period it rose 3 times and already in December 2021 it exceeded $150,000.


Due to the fact that the cost of coal and gas became record high, this led to the fact that tariffs for heat and electricity also increased significantly. As for the solution, the EU argues that it is necessary to deal with the development of renewable energy. Therefore, it is possible to realize the displacement of coal from the electric power sector through the introduction of wind and solar generation. Bioenergy will play a key role in replacing natural gas for the implementation of such a process as the decarbonization of transport.

The Political Virtues of Renewable Energy Development

Considering political issues, the most serious of them is the price of natural gas. Due to the fact that the average import of Ukraine per year is about 10 billion m3, even at the minimum cost, this will amount to more than 10 billion dollars. Coal is imported in the amount of approximately 19 million tons, which in terms of money equivalent will be about $3 billion. If these types of energy generation are replaced by renewable energy, it will be possible to save about $13 billion.

Steps to solve the problem

  1. Political recognition of renewable energy in Ukraine.
  2. Development of a special comprehensive program, according to which the transition to “green” energy will be implemented.
  3. Holding tenders for the construction of generating capacities and energy storage.
  4. Regular holding of auctions, according to which quotas will be distributed to support those projects related to the introduction of renewable energy.
  5. Signing of the law on stimulating the process of production of renewable energy without state support and on market terms.
  6. Signing of the law on energy storage devices.


Additionally, it is necessary to introduce those steps that are related to thermal energy and the transport system.


For a long time, Ukraine was tied to Russia by a gas purchase contract. There was a great dependence – 90% of the consumed blue fuel was Russian. In November 2015, thanks to the efforts of the Ukrainian side, this connection was severed. According to the Kremlin’s forecasts, Ukraine could not do without Russian supplies. It was predicted that there would be a gas shortage in the country, which would be especially felt in winter. But Ukraine did not freeze, but became independent and managed to build profitable partnerships with Europe.

Resolution of the conflict between Ukraine and Gazprom

Despite the cessation of purchases in 2015, Ukrainian Naftogaz and Russian Gazprom tied a gas supply contract until 2019. The Russian side put forward a demand: if Ukraine does not buy 52 billion cubic meters every year. fuel, you will have to pay a fine. The price was made similar to the price of oil, which was higher than in the European market.


For Ukraine, these were predatory conditions. Financially and physically, they could not be fulfilled. As a result, Gazprom presented a debt of $ 50 billion for payment. There were also claims from Naftogaz. The conflict was resolved thanks to an appeal to the Stockholm Arbitration Court, which considers international disputes.


The investigation lasted three and a half years. The Ukrainian side brought many arguments and documents in its favor and won. Court decision: Gazprom must pay Naftogaz more than $ 4 billion.This saved the Ukrainian company, since the claims from Gazprom amounted to an unbearable amount of $ 80 billion.

Landmark of Ukraine to Europe

Ukraine began looking for gas suppliers in Europe even before the severance of relations with Gazprom. The search was successful, as a result of which relationships with partners from different countries were established. The conclusion of contracts with European companies allowed Ukraine to purchase gas in 2015 at a price of $ 0.3 per cubic meter. At the same time, Gazprom offered a higher price – $ 0.34. In 2020, Ukraine purchased gas in 13 European countries. The main ones were:

  • Switzerland;
  • Germany;
  • Slovakia.

The Slovak direction is now the most ambitious. Since 2020, gas settlements are being made with neighboring European countries. The fuel is not transported at the same time, which reduces costs.

Own gas production in Ukraine

Ukraine is a country with natural gas reserves. The production is carried out by state and commercial companies. The total annual demand for blue fuel across the country is 30 billion cubic meters, and 20 billion cubic meters are produced. Of these, 14 billion cubic meters. in 2020 accounted for by Ukrgasvydobuvannya (part of the Naftogaz Group). The company keeps all wells in working order and makes sure that gas production does not drop. There are plans to develop the Black Sea shelf.


Our own production allows us to supply gas to the population at a lower price than imported fuel. The minimum cost in November was UAH 7.80. per cubic meter, maximum – UAH 13.50. Enterprises engaged in heating the housing stock purchase gas for the winter at a wholesale price of UAH 7.42. for one cubic meter.

Ukraine’s plans for gas use

Independent gas production and imports from Europe cover Ukraine’s needs for blue fuel, but there is talk of returning cooperation with Russia. The reason is that Russian contracts are long-term, while European contracts are short-term. However, Gazprom approaches pricing from a policy perspective. Taking advantage of his monopoly, he achieved that the price of fuel on European exchanges rose to $ 2 per cubic meter, and gas was supplied to Moldova for $ 0.45.


Ukraine’s gas plans include:

  • drawing attention to the Asian market;
  • introduction of liquefied natural gas;
  • a proposal to transfer for use the existing gas transmission system and gas storage facilities;
  • replacement of natural gas with synthesized and biomethane.

In the future, gas independence of Ukraine should be achieved. There are opportunities in the country to exclude gas imports. To do this, it is necessary to increase our own production and at the same time look for ways to reduce fuel consumption.


Now the country is deciding the issue of replacing coal as an energy source with more environmentally friendly gas, so the demand for blue fuel is growing. But in the future, the entire civilized world is going to refuse from gas. Ukraine supports this direction and plans to develop alternative energy sources.


In Ukraine, not all regions can boast of gasification. In many areas there is no gas pipeline, and electricity is supplied with frequent interruptions. In such conditions, for a comfortable home environment, the optimal solution would be installation of a solid fuel boiler. It is a metal heating device that generates thermal energy by burning solid fuels. Its operation differs from electric and gas boilers:


  1. All standard steel and cast iron boilers with volumetric combustion of fuel provide their passport efficiency in the maximum combustion mode. Since the power of the boiler is selected according to the peak heat losses, and they fall only for an insignificant period of the heating season, we have a situation when the boiler operates in incomplete power mode for most of the heating season. It is not recommended to reduce the power by less than 50-60%, which leads to excessive consumption of fuel, clogging of the furnace and chimney.
  2. The need for periodic reloading of fuel into the boiler. Most standard boilers have small combustion chambers, so the fuel loading (again, it concerns firewood) burns out in 2-3 hours. Bituminous coal burns out much longer, but it is more expensive, so wood is the leader in popularity.
  3. Today, most heating systems are designed closed, with forced circulation of the coolant. The risk of exploitation increases. In case of power outages, the circulation pump may stop or the coolant boil.


That is, safe, comfortable and economical operation is what a heat accumulator is needed for in a heating system. A buffer or heat accumulator for a solid fuel boiler is a non-enamelled metal heat-insulated container with connecting pipes for the heating system and boiler circuits.


The buffer tank for a solid fuel boiler at maximum operating power accumulates heat, and then, as required, releases it into the heating system. 1 and 2, the differences in operation are thus completely smoothed out, since no heat is lost and the fuel burns efficiently. It is extremely important to correctly calculate the buffer capacity.


Today you can see many methods for calculating storage tanks. For example, 25 or 50 liters of tank volume per 1 kW of boiler power. However, such calculations do not take into account either the temperature regime of the heating system, or the fuel used in the boilers, and, most importantly, there is no definition of the function of the tank – heat accumulation or other purposes.


So, we have a small residential building with a heated area of ​​150 sq.m. Estimated heat loss 10 kW (insulation according to modern standards). Heating radiator, temperature 70/50. We have a standard solid fuel boiler – cast iron Demrad Solidmaster 5S with a wood-fired thermal power of 23 kW. The volume of the furnace is 70 liters, the amount of loaded firewood, taking into account the density of oak firewood, is 600 kg per 1 cubic meter. and the fuel loading factor of 0.5 is: 70 x 0.6 x 0.5 = 21 kg. The calorific value of wood (dry oak), taking into account the boiler efficiency, is 3 kW per 1 kg. Thus, a one-time fuel loading will give out 21×3 = 63 kW. The fuel bookmark will burn out in 63/23 = 2.7 hours, let’s round up to 3 hours.


With a heat demand of 10 kW (peak heat loss), out of 23 kW of rated power, 10 kW is transferred to the system, and 13 kW must be stored. For 3 hours of bookmark operation, the system will consume 10×3 = 30 kW, and will store 13×3 = 39 kW, which the system will consume after the bookmark burns out for another 39/10 = 3.9, that is, almost 4 hours. When using a heat accumulator, the fuel fill will be enough for 3 + 4 = 7 hours of continuous operation.


To store 39 kW of heat, it is necessary to calculate the volume of the tank, taking into account the temperature regime of the system. The temperature in the heat accumulator cannot exceed + 95C, and the supply temperature to the system + 70C. We have a temperature reserve of 95-70 = 25C.


Heat accumulator volume = 39000 W / (1.163×25) = 1334 liters. This value is the minimum required. It can be rounded up to 1500 liters.


With an increase in the outside temperature and, accordingly, a decrease in heat demand, the operating time from charging the heat accumulator increases. Since at outdoor air temperatures of -22C and 0C, the value of heat loss differs by 2 times, then, accordingly, at a near-zero temperature, the heat supply will be enough for 7×2 = 14 hours.


At zero temperatures, the heat demand will be about 5 kW. Then the tank will store (23-5) x 3 = 54 kW of heat, which is enough to provide heat for 54/5 = 10-11 hours. The stored power increases and the temperature reserve increases.


A heating system with a buffer tank for proper functioning requires:


  1. Calculation of the amount of heat for the power reserve depending on the duration of operation.
  2. Determination of the temperature graph of the heating system.
  3. Determination of the level of heat loss in the room.


Calculate the volume of the buffer tank based on these three points. Because the power of the boiler itself is selected specifically for the volume of the buffer, and not for heat loss. With the correct scheme, the buffer should be charged up to a two-fold power reserve in one or two boiler firing.


In our case, a 23 kW boiler will provide the initial heating of the battery (at room temperature of the coolant) in (1500x (95-20) x1.163) / 23000 = 5.5 hours, that is, in almost 2 heating. In the future, during operation, the lower temperature of the coolant is unlikely to fall below 40C, and therefore the tank will heat up in one or one and a half firing, which fully meets the specified requirements.


Thus, our boiler operates with maximum efficiency throughout the entire heating season and provides quite comfortable operating conditions with a one-time boiler load operating time from 7 to 14 hours. On the face of it, the thermal accumulator performs its functions in full.


The storage tank with the “buffer tank” function means, as a rule, the protection of the solid fuel boiler from accidents associated with the boiling of the coolant. The buffer tank has various options for installation in heating systems.


The appropriate installation option is selected individually, depending on the layout of the house and other factors. It is possible to install a buffer tank in series boiler-tank-heating system as a heat accumulator. It is also possible to connect the boiler directly to the heating system, then the heat will accumulate in the buffer through the switching valves.


The buffers also serve to reduce the frequency of switching on and off (cycle) of the boiler burner.


As for calculating the volume of buffer tanks, you can find 2 options:


  • Just as with heat accumulators, a certain amount of coolant per 1 kW of boiler power.
  • The calculation formula, which is given in the documentation for many foreign boilers:


Buffer volume = 15 х Н х Qк х (1-0,3 х (Qп/Qmin), where:


Н – boiler burning time at rated power, h.

Qк – rated thermal power of the boiler, kW.

Qп – heat loss of the heated room. kW

Qmin – minimum heat output of the boiler. kW


Example. The same solid fuel boiler Demrad Solidmaster 5S with a wood-fired power of 23 kW. Burning time of the bookmark is 3 hours. The minimum boiler power, taking into account the small adjustment range, will be taken as 20 kW. The heat loss of the room is 20 kW, that is, the boiler is matched exactly to the nominal value. We have the following calculation:

Buffer volume = 15 х 3 х 23 х (1-0,3 х (20/20)) = 724 liters. Round up to 750 liters.


The formula allows you to calculate the protection against boiling, since it takes into account the power of the boiler and the duration of burning the bookmark in the maximum mode.


The examples considered give the definition of the main parameters for choosing the required volume of the tank и объясняют, по каким принципам его рассчитывают. Перед установкой данного типа теплового оборудования следует детально изучить все факторы и условия его эксплуатации.


In the context of annual increases in prices for gas heating, the popularity of solid fuel boilers is growing. They are especially relevant for rural areas, where it is more profitable to heat a room with firewood than to pay exorbitant gas bills.


Produce industrial and household solid fuel boilers. In industrial fuel supply occurs automatically, in household it is done manually.


The choice of heating equipment is approached systematically, three groups of technical factors are taken into account to create the most comfortable atmosphere in the house:

  • The first group is the characteristics of heating boilers, which determine the efficiency of combustion of a certain type of fuel (coal, wood, briquettes, various waste), that is, the efficiency of the boiler, on which the volume of fuel consumption depends.
  • The second group is the boiler design parameters, that is, the quality of the metal or cast iron from which the boiler body and heat exchange surfaces are made (quality of welds, quality of casting of cast iron sections), as well as the presence of certain safety elements (automation, cooling coil).
  • The third group of characteristics of solid fuel boilers is operational parameters, that is, comfort and convenience for the user.

The operating parameters determine how easy it is to set up and control the boiler, to clean it and maintain it. The third group includes the most important factor for household solid fuel boilers: the burning time of the fuel insert, how often it will need to be supplied.


Ideal boilers, that is, having all the above advantages (high efficiency, high-quality layout and ease of use), are very insignificantly represented on the heating market, besides, their cost is often not affordable for most consumers. Therefore, in the process of choosing the required model of a solid fuel boiler, a compromise option is most often chosen, in which the emphasis is precisely on the comfort of operation.


The burning time of a solid fuel boiler is affected by:

  1. Combustion chamber volume. It is quite a logical parameter, since the larger the volume of the furnace, the correspondingly larger the volume of the contained fuel. In addition, the geometrical dimensions of the combustion chamber affect the comfort of use, especially for wood combustion. It is much more practical and faster to serve large logs rather than small pieces of wood. The type of combustion chamber itself is also important: upper, lower or volumetric combustion.
  2. Fuel type and quality. These include: calorific value, humidity, bulk density of each type of fuel. In addition, for coal, the size of the fraction is taken into account, and for firewood, the size of the logs.

Coal fuel has a high calorific value (on average 5500-6000 kcal per kg) and bulk density (800 kg 1 cubic meter). Wood, in turn, has a lower level of heat generation (on average 3500 kcal per 1 kg) and density (550-600 kg per 1 cubic meter). Obviously, the same loading volume holds more coal than firewood, and such coal will burn longer than a similar laying of a tree.


Actually, the duration of fuel burning is calculated simply:

  1. The useful thermal power of the boiler is determined (passport data, taking into account efficiency).
  2. The volume of the loading chamber is determined (a figure from the passport data or the product of the height, width and depth of the furnace).
  3. The type of fuel used is determined and, accordingly, the amount of fuel contained in the combustion chamber (taking into account the fuel density and the fuel stacking factor)
  4. The amount of heat energy that can be “extracted” from the loaded fuel is calculated.
  5. The calculated amount of heat energy from the tab is divided by the rated power of the boiler. The resulting figure is the burning time of the bookmark at rated power.

Example. Solid fuel boiler Kolvi Eurotherm KST-12. Thermal power 12 kW. The type of fuel is dry oak firewood. The volume of the combustion chamber is 33 liters (0.033 cubic meters). The efficiency of this wood boiler is 70%.


The density of dry oak is 650 kg per 1 cbm. Accordingly, with a furnace volume of 0.033 cubic meters, the theoretically possible capacity of the furnace is 650×0.033 = 21 kg of firewood. However, we understand that the actual filling volume will be an order of magnitude less, since the loaded firewood will have a certain amount of gaps between itself and the walls of the firebox. Therefore, for wood, an indicator such as a stacking coefficient is used. This parameter is rather arbitrary and can vary within 0.35-0.5. For this example, let’s take an average of 0.4.

Thus, taking into account the stacking factor, the amount of oak firewood: 21×0.4 = 8 kg, which is a very real indicator.


Next, we calculate the calorific value of the bookmark: 8×4200 kcal = 33600 kcal, or 39 kW. Taking into account the boiler efficiency, this tab will give 39×0.7 = 27 kW.


Now we calculate the burning time of the bookmark: 27 kW/12 kW = 2.25 hours.


All factors cannot be taken into account with absolute precision. This calculation gives approximate values, the formula indicates the nominal power of the boiler with the maximum heat loss.


The heating power level depends on the outside temperature. If you reduce the intensity, the burning time of the fuel tab will increase. It is not recommended to reduce the boiler output by less than half. During smoldering, heat loss occurs, since the fuel does not burn out, condensate forms and the boiler furnace becomes clogged.


The Kolvi Eurotherm KST-12 boiler, depending on the selected power, can operate on dry oak wood for 2 – 4 hours. The operating time of other solid fuel boilers is calculated according to the same principle.


The development of individual construction, the construction of multi-storey residential buildings, various buildings and structures for commercial purposes have led to the need to use transportable boiler installations or stationary boiler houses for heat supply of these objects, operating mainly on natural gas and using modern heating boilers as heat generating installations. But, along with this, on the territory of Ukraine and the countries of the former USSR, a large number of already existing housing stock and industrial enterprises, built in the 50-80s of the last century, use boiler and pumping equipment of an outdated type for heat supply and preparation of hot water.


According to the Ministry of Energy and Coal Industry of Ukraine, as of March 2021, at least 21% of old boilers should be modernized or boilers replaced. At the same time, at least 25% of boiler equipment in Ukraine has been in operation for more than 30 years. The efficiency of many of these boilers does not exceed 60-70%. Here we note the critical degree of physical deterioration of heating networks (according to the Ministry of Energy and the Association “Ukrteplokommunenergo”, as of March 2021, at least 35% of all trunk pipelines in Ukraine are in emergency condition, and the value of heat losses in them ranges from 15 to 30% ) Of course, the solution to these problems should be carried out in a complex, however, in this article we will consider issues relating specifically to heat-generating boiler equipment.


On the territory of Ukraine, as in the countries of the former USSR, there are 2 main types of industrial gas (and solid fuel) boilers, characterized by the method of washing heating surfaces with fuel combustion products: fire-tube and water-tube boilers. In turn, these boilers are divided into hot water boilers (heating the coolant according to different temperature graphs, for example, 95/70 С, 115/70 С, 150/70 ˚С1) and steam boilers used to produce saturated or superheated steam …


Fire-tube heating boilers are a cylindrical combustion chamber (fire tube), with smoke tubes located around the chamber, through which combustion products circulate, providing convective heat exchange. The “water jacket” of the boiler is located in the space between the fire tubes.


Types of fire tube boilers


There are 2 main types of fire tube boilers:


  1. 1) Two-pass boilers, or boilers with a reversible combustion chamber, in which the first passage of the combustion products circulation is the combustion chamber itself, and the second passage is a bundle of smoke tubes.
  2. 2) Three-pass boilers – boilers in which the first pass is the combustion chamber, and the second and third are 2 channels of smoke tubes. Three-pass boilers, due to the larger area of convective heat exchange surfaces, have a higher level of cooling intensity of combustion products.


Fire tube boilers of modern type have a number of indisputable advantages, such as:


  • • Compact design due to more intense heat flow.
  • • Delivery of a complete boiler in the form of a single monoblock.
  • • The minimum hydraulic resistance (measured in millibars), due to which relatively low-power pumping equipment is used to circulate the coolant through the boiler.
  • • The tightness of the combustion chamber, which allows the use of blast burners and, as a result, does not make the use of smoke exhausters mandatory.
  • • Small inertia – quick response to changes in heat load, which simplifies and optimizes the automation of these boilers.
  • • Less, in contrast to water-tube boilers, labor costs for the manufacture of boilers.
  • • No need for additional lining.
  • • General simplification of construction and installation work.


The experience of developing fire-tube boilers in the USSR showed, along with advantages, a number of significant disadvantages, mainly due to design errors, which became the reason for the decision to abandon their production in favor of water-tube boilers. The first developed fire-tube models had a low value of efficiency, high metal consumption, limitation in heat and steam production. The flame tubes were not very reliable. As practice has shown, the use of the Normative Method of Thermal Calculation of a Boiler Heating Unit, which is relevant for water-tube equipment, for the design of fire-tube boilers in many cases was incorrect.


Water tube steam and hot water boilers were the main type of boilers manufactured in the USSR. These boilers, depending on the modification, were intended for burning natural gas or solid fuel (mainly coal). Structurally, water-tube boilers are a bundle of a large number of pipes that are reduced to one or more drums that serve as reservoirs for water or steam. A tube bundle with a drum is placed above the combustion chamber. A coolant circulates inside the tube bundle. Partitions installed in the combustion chamber provide multiple passage of fuel combustion products through tube bundles, which ensures high-quality heat transfer from combustion products to the coolant.


Also, in many models of water-tube steam boilers, heating surfaces such as radiation tube screens are provided, through which heat exchange is carried out not by convection, but by radiation. The coolant passing through a large number of wall tubes is converted into steam.


Advantages of water tube heating boilers


Water tube boilers have a number of advantages, such as:


  • • The circulation rate of the coolant in the tube bundles is at least 1 m/s, which protects the boiler tubes from possible boiling of the coolant and sludge deposition.
  • • Lack of stringent requirements for the quality of the coolant.
  • • Possibility of normal long-term operation in forced mode.
  • • The speed of the boiler operation to the nominal mode.
  • • Complete explosion safety.
  • • Durability of operation.


However, in addition to the positive characteristics, water-tube boilers also have a number of disadvantages.:


  • • The above-mentioned high speed of the heat carrier leads to a high hydraulic resistance of these boilers, which requires significantly higher consumption of electrical energy for the operation of the boiler circulation pumps.
  • • The complexity of the design of boilers, a large number of various units that complicate their transportation, installation and repair work.


The mass production of water-tube boilers in the USSR led to the fact that a large number of boilers such as NIISTU, DKVR, PTVM, KVGM and other similar ones, which are morally and physically obsolete and require modernization, function in Ukraine. Of course, these boilers were once manufactured in accordance with the strict requirements of the then GOST and many of the operating boilers are distinguished by the high quality of the boiler pipes and welds. However, their long service life requires constant repair of these boilers, replacement of tube bundles, screens, and lining work.


Modernization of water tube boilers

If we talk specifically about the modernization of water-tube boilers, then here, first of all, the question of the characteristics and safety of operation of gas-burning devices of these boilers is raised, the degree of their automation and, as a result, the environmental parameters for emissions of harmful substances do not correspond to modern standards. A fairly common practice today is to replace obsolete burners with modern European-made gas burners. The group of companies “Ukrainian Energy Industrial Group” has experience in implementing similar solutions based on Italian-made CIBITAL UNIGAS burner equipment.


CIBITAL UNIGAS has developed special models of gas burners for water tube boilers. One of the features of such boilers is the shallow depth and significant volume of the furnace space, which requires a short torch for the burners. Therefore, it was decided to manufacture these burners not with one nozzle, as in standard burners, but with four short flame nozzles. Such a technical solution ensured high-quality preparation and combustion of the gas-air mixture, simplified commissioning, and, most importantly, provided complete automation of the boilers and modulation of their power in a wide range. As a result, the efficiency of the boilers increased by at least 10-15%. Optionally, UNIGAS burner models are available with frequency control of engine speed (to save energy) and control of the oxygen content in flue gases (to further save gas and reduce harmful emissions).


It should be noted that the installation of modern gas burner devices is relevant not only in terms of replacing outdated burners, but also when converting water-tube boilers operating on coal. Depending on the current physical state of the heat exchange surfaces of such boilers, their conversion to gas fuel entails an increase in the efficiency of a gas boiler by 5-15%.


As for fire-tube boilers, this type of boiler equipment began to be massively introduced for heat supply to housing and communal services and industry from the late 1990s – early 2000s as part of the implementation of projects for the decentralization of heat supply systems. Fire tube boilers of both Ukrainian and foreign production, which began to be introduced, no longer had the above disadvantages, since their designs were developed by each manufacturer on the basis of modern computer programs. Almost each of the major manufacturers of fire tube boilers already had their own research organizations, the main task of which was the issue of modernizing the design of boilers at the stage of their design, as well as developing recommendations and requirements for the operation of boilers. This includes:


  1. 1) Increasing the efficiency of boilers – choosing the optimal area of the heating surfaces of boilers, researching the operation of boilers with additional heat exchangers (economizers) from combustion products, as well as determining the economic efficiency and payback period for the introduction of economizers.
  2. 2) Reduction of emissions of harmful substances in combustion products – calculation of the design of fire-tube boilers, use of special burners with low NOx emissions.
  3. 3) Ensuring the maximum service life of boilers and equipment operation, preserving the integrity of the fire-tube monoblock structures – using water treatment plants in boiler plants (removal of hardness salts, iron), sludge and microbubble separators, removal of dissolved oxygen, increasing the pH of the coolant, etc. Plus regular maintenance.
  4. 4) Optimization of the overall dimensions of boilers as a whole and of individual units, as well as their material consumption. This includes the economic aspect, namely, reducing the cost of manufacturing boilers while maintaining high quality parameters of equipment.
  5. 5) The choice of the optimal solution for the use of gas burners – selection and determination of standard sizes of burners, their thermophysical characteristics, their cycle of operation and the necessary functions. Modern gas burners, with the right choice, have a long service life, and their maintenance costs are relatively low.
  6. 6) Maximum automation of equipment operation. This includes, first of all, the use of the most modern means of automation and visualization of the operation of boilers and auxiliary equipment – boiler controllers that control the operation of boilers and burners with control of the operating parameters of the equipment (temperature and pressure of the coolant, control of the rarefaction of flue gases and their temperature, control of the circulation of the coolant, automatic stopping the operation of boilers in emergency situations, etc.) Boiler automation contributes to saving energy resources, since with its help a modern heating boiler releases exactly the amount of thermal energy that is needed in a specific time period.
  7. 7) Maximum safety of the equipment. This task is closely related to the issue of automating the operation of boilers, since it is the control systems for the operation of boiler equipment that are responsible for the safety of the operation of boiler units, monitoring the parameters given in the previous paragraph. Modern fire tube boilers are equipped with a complete set of functional devices necessary for safe operation.


Thus, today it is fire tube boilers that occupy the main niche in the line of industrial boiler equipment with a capacity of up to 30 MW. In Ukraine, among the national manufacturers of such boilers, the main niche is occupied by KOLVI boiler equipment, on the basis of which many construction projects have been implemented. As an example, the most ambitious project of such a plan was implemented on the basis of KOLVI equipment in the resort town of Truskavets, where in 2001-2011. 21 boiler houses with a total capacity of 51 MW were built or reconstructed, which heat 158 ​​objects for various purposes. Since 2019, the Ukrainian Energy Industrial Group Group of Companies has begun implementing a large project for the construction of 17 modular transportable boiler houses with KOLVI gas fire tube boilers.


After analyzing all of the above, we can draw conclusions about the following three aspects of the relevance of the service modernization of heating boilers:


  • • The economic aspect is a reduction in the cost of energy resources (gas, solid fuel, electricity), the cost of maintenance and repair of boilers.
  • • Environmental aspect – reduction of emissions of pollutants into the atmosphere.
  • • The safety aspect is ensuring uninterrupted and trouble-free heat supply during the heating season.

At the end of May 2021, the Minister for the Development of Communities and Territories of Ukraine presented a draft law for consideration, the main goal of which is to introduce effective measures to reduce energy consumption in buildings by thermal modernization. The details of the presentation are reported by the press service of the Ministry of Regional Development.


At this stage, the priority task in the work of the Ministry is to improve the energy efficiency of buildings. Minister A. Chernyshev noted that the introduction of this law will provide an opportunity not only to save energy resources, but also to significantly reduce the numbers in the “payments” of citizens of Ukraine. In his report, he focused on the fact that the right measures in the development of energy efficiency will lead to significant economic growth in the country. The adoption of this bill will bring Ukraine even closer to the European Green Deal.


The document was developed in the Ministry of Regional Development under the leadership of partners from foreign countries, together with deputies and experts in this area. The order of institutional conditions for the widespread thermal modernization of houses was jointly created.


The bill also implies amending the existing laws of Ukraine, which at this stage regulate the issues of energy saving. They must influence questions like this:


• simplification of the system for providing support from the state and its adaptation to the needs of co-owners of residential buildings;

• creation of systemic advancement in the field of formation and implementation of political activities in the issue of reducing energy losses in structures;

• implementation of phased implementation of programs for deep thermal modernization of houses, while using clear criteria for the effectiveness of indicators of rational use of energy;

• introduction of all existing modern methods and tools to reduce energy consumption in buildings;

• implementation of the introduction of a special resource with information on the volumes, characteristics and amount of energy consumed by buildings in Ukraine.


Immediately after the presentation of the bill on the website of the Ministry of Regional Development, it was discussed online, in which experts in this area took part.


Shortly before the presentation, Alexey Chernyshev had already spoken about increasing investments in the construction industry next year. This is another successful step in the reform implemented by the Ministry.


Also, to save consumed energy resources and reduce the amount in “payment” will help heat supply from the EPG-KOLVI Group of Companies.


Photo: РБК-Украина


On May 1, 2021, the legislation of Ukraine provides for new annual gas tariffs for the population.


According to the terms of the relevant tariffs, consumers of natural gas will rise in price. As expected, the price of a cubic meter of gas for Ukrainians will be higher than UAH 6.99 set by our government at the beginning of the year.


From now on, the price range will be from 7.88 to 13.5 UAH per m³ of gas. This figure is lower than what is expected on the market at the beginning of the next heating season.


Despite the fact that the Law determines market prices for gas fuel, consumers in Kiev and other settlements of the country will be able to buy it at a fixed cost – within a year, that is, until the end of April next year, it will not increase.

Features of gas contracts

Gas contracts, which will be concluded for a period of one year, imply the possibility of changing the cost of fuel solely downward. The legislation prohibits increasing the price indicator.


The consumer retains the right to change the supplier if the level or cost of the service does not suit the user. In this case, the consumer will need to notify the new organization dealing with gas supply. All powers and technical issues regarding the termination of the contractual relationship of a new customer with his former supplier fall within the competence of the new supplier.


The company change procedure provided for by the Law can be carried out online.


Suppliers now have the ability to offer customers commercial contracts that differ from the baseline. Let’s try to understand the differences between these two types of contracts.

The essence of basic contracts

The period of validity of the basic annual offer is from the beginning of May of the current year to April 30, 2022, regardless of the date when the gas supply contract was signed by the consumer.


During this period, the supplier is deprived of the right to increase the price – the cost of gas fuel remains fixed until the 12-month term of the base contract expires.


In the case of choosing a basic contract, the monthly payment for the supplier’s services must be made no later than the 25th day of the next month. But the conclusion of an annual contract with one company does not deprive the consumer of changing the supplier until the end of the contract.

On the specifics of commercial contracts

Consumers looking to enter into commercial contracts should be aware that such transactions have several features.:


• if the consumer decides to change the supplier, he does it openly, using the website or call center of the relevant organization;

• communication with customer service is provided by a personal account on the website;

• when renewing a contract with a company, the user will not need to re-submit documents;

• the consumer has the right to demand confirmation by the supplier, receiving his application within 15 days;

• the supplier should notify the client about the refusal to switch to another contract no later than 10 days after the date of receipt of the request from him;

• the supplier can waive a certain commercial rate, but he must inform the consumer about this at least one month in advance;

• if the commercial conditions change, the supplier must notify the consumer in advance.


It is worth knowing that the change in the cost of gas is not included in the category of these conditions. The supplier company is obliged to keep the information on the terms of the contracts of the basic and commercial companies on the official website for three years. All data on changes in contracts should be reflected in payment receipts and in the personal accounts of users.


If the apartment is heated incorrectly, much more energy is spent, and, accordingly, money. This article provides tips on how to stay warm and save money during the heating season.

1. Do not cover the battery

Any object can become an obstacle to warm air. Furniture, curtains, appliances. They absorb heat into themselves and prevent hot air from the battery from heating the room. Place furniture and other items in your home away from the heater.

2. Do not set 0 on the thermostat

Do not set the thermostat temperature to 0 when there is no one in the house. During this time, rooms can cool down and have to be warmed up again. Which will require a lot of resources.

3. Do not set the maximum temperature when heating the room from scratch

The opinion that the maximum temperature on the thermostat will warm up the room faster from zero is erroneous.


There is a great desire to immediately unscrew the thermostat to the maximum, but you should not do this. The battery does not heat up faster, if it is at the maximum, everything will warm up gradually.

4. Do not put the maximum value on the thermostat

Of course, you should not sit in the cold, but the temperature in the room will not be much lower if 4 is set on the thermostat, and not 5. But the difference in the amount of money paid for a communal apartment will be significant.

5. Don’t forget to ventilate the room

Ventilate the apartment daily. The rooms will cool slightly and the air will become fresher. It is worth noting that it is best to ventilate with the windows wide open in the morning, then not only the temperature will drop, but air circulation in the room will also occur.

6. Avoid using batteries as dryers

Of course the laundry dries faster on the battery. But this has its own characteristic disadvantages. A significant part of the heat accumulates under wet clothes, thus not getting into the room and not warming it up. Also, wet laundry increases the humidity in the room, which can lead to mold growth.

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Адреса Україна, Київська обл.,
с. Софіївська Борщагівка, вул. Горького, 1