Efficiency of a gas boiler - what it depends on and how to increase it

The efficiency (coefficient of performance) of a heating boiler is the ratio of the volume of fuel consumed to the volume of heat generated. The efficiency of even the most efficient modern models of hot water boilers cannot be 100% due to heat loss inside the boiler, insufficient thermal conductivity of metals, or imperfections in the operating principle. In addition, the efficiency of the same gas boiler model also depends on the load: the efficiency indicated in the passport is not real in the entire range of heating output.

In the article we will look at how to correctly calculate efficiency, what it depends on and how to increase the efficiency of an already purchased boiler on your own.

Incorrect air supply

The work of the flame greatly depends on how much oxygen enters the firebox. In order for fuel to burn normally and give off the maximum amount of heat, it needs a strictly defined amount of air - no more, no less. If there is not enough air, the hydrocarbons released during combustion will be poorly oxidized, which means less heat will be released. If a lot of air comes in, and it usually comes in cooled, the temperature of the released gases decreases and they do not have time to burn (again settling as soot on the pipes) and thereby release useful heat. It is worth noting that the air contains moisture, the evaporation of which also wastes heat (instead of heating the house).

Most solid fuel boilers offered on the market operate on the following principle. They have a thermostat installed that regulates the temperature of the water circulating through the heating system of the house to warm it. If the water becomes too hot, the thermostat reduces the air supply to the boiler (this is how the power of a solid fuel boiler is regulated). It turns out that at the moment when the fuel flared up and the efficiency with the power of the solid fuel boiler became maximum, which means the flame began to need more oxygen, the thermostat artificially reduces the efficiency, limiting the air supply.

After the temperature has dropped, the thermostat starts supplying air again. But by that time the fuel is already burning down and it doesn’t need as much oxygen. The heating efficiency is again reduced due to the cooling of the released gases, as mentioned earlier.

It turns out that the operating principle of most solid fuel boilers absolutely contradicts the concept of high efficiency.

Conclusions and useful video on the topic

The first video will help you understand how to clean the boiler heat exchanger, which will help to significantly increase its efficiency.

The following video will give you an opportunity to understand how to clean a gas burner in order to increase the efficiency of the boiler.

Experience shows that maximum efficiency from a boiler can be achieved with its systematic maintenance with timely cleaning of burners and heat exchanger from combustion products and dirt. And also with proper placement and use of radiators. In addition, only modern high-tech equipment can be highly efficient.

Have you noticed a discrepancy or want to supplement our material with useful recommendations for increasing the efficiency of the boiler? Leave your comments, participate in the discussion and ask your questions to our experts - the feedback form is located below.

Economical gas boiler with high efficiency

As practice shows, as well as technical documentation, boilers from foreign manufacturers have a higher efficiency. European organizations are focusing their efforts on improving energy-saving technologies. Foreign gas boilers are characterized by high performance because their design implies:

Modulation burner. Boilers from popular companies are distinguished by two-stage or modulating burners, which boast automatic adaptation to the actual operating parameters of the heating system. There is a minimum amount of residue at the exit.
Heating the liquid. A good boiler is equipment that heats the coolant to a maximum of 70 °C, while the exhaust gases heat up to no more than 110 °C, this gives the best heat output. However, when heating a liquid at low temperatures, there are some disadvantages, such as low draft and active formation of condensation. Heat exchangers in high-performance gas units are made of high-quality stainless steel and have a special condenser unit, which is necessary to extract energy from the condensate.
Heating of the supply gas and air that enters the burner device. Closed type units are connected to a coaxial chimney. The air circulates into the combustion chamber through the outer cavity of a pipe with two cavities, before being heated, which helps reduce the required heat costs by a couple of percent. Burner devices with preliminary production of a gas-air mixture also heat the gas before supplying it to the burner.
Installation of a waste gas recirculation system. In this case, the smoke does not immediately enter the combustion chamber, but circulates through the chimney, mixes with clean air and ends up back in the burner.

The highest efficiency is observed when heating the formation of condensation or “dew point”. Units operating at low temperature heating are called condensing units. Their difference is in the small amount of gas consumed and high thermal efficiency, which is very visible when connected to equipment from gas cylinders and a gas holder.

There are many brands of condensing units, the most popular of which are just a few. You can choose from the following brands of high-efficiency gas boilers for your home:

Wissman;
Buderus;
Vaillant;
Baxi;
De Dietrich.

Safety measures for increasing efficiency

Just 20-30 years ago, the price of energy resources in the post-Soviet space was low, so no one paid attention to such a parameter as efficiency. After all, performance could decide everything. But when gas began to rise in price, and modern technologies were still unavailable, craftsmen began to modernize gas boilers in order to increase efficiency, using accessible methods.

When performing any work with gas equipment, it is necessary to observe safety measures and possess special skills and tools. And also you should not use methods prohibited by law to increase efficiency.

For example, attaching copper and aluminum plates to heat exchangers to improve heat transfer. Heat loss from structural elements of heating devices was reduced by welding third-party elements. The automation and heat exchangers were changed. Other similar methods were also used. Efficiency increased, but the state and the gas service did not react to the “creativity” of the craftsmen.

Now everything is different and relevant laws prohibit changing the design of gas boilers, which must be certified, like all their individual elements. As a result, it is impossible to increase efficiency by replacing mechanical, electrical and other components of heating devices with third-party ones.

Violation of these requirements may result in:

Administrative responsibility . If Gorgaz employees detect tampering with the boiler design, but there were no incidents, they will have to pay a fine of 10-15 thousand rubles. This is indicated by Article 7.19 of the Administrative Code . In severe cases, the gas service has the right to even terminate the service contract and stop supplying fuel.
Criminal liability . As evidenced by Federal Law No. 229-FZ of July 29, 2018 “On amendments to Article 215.3 of the Criminal Code of the Russian Federation and Articles 150 and 151 of the Code of Criminal Procedure of the Russian Federation .” These standards will come into force if design changes lead to serious consequences.

That is, it’s not worth risking people’s lives to increase the efficiency of the boiler by a few percent.

How to calculate the efficiency of a heating boiler

Values can be calculated in several ways. In European countries, it is customary to calculate the efficiency of a heating boiler based on the temperature of the exhaust gases (direct balance method), that is, knowing the difference between the ambient temperature and the actual temperature of the gases exiting through the chimney. The formula is quite simple:

ηbr = (Qir/Q1) 100%, where

ηbr (read “this”) – boiler efficiency “gross”;
Qir(MJ/kg) – the total amount of heat released during fuel combustion;
Q1 (MJ/kg) – the amount of heat that was accumulated, i.e. used for heating the house.

The direct balance method does not take into account the heat loss of the boiler itself, underburning of fuel, deviations in operation and other features, so a fundamentally different, more accurate calculation method was invented - the “reverse balance method”. The equation used is:

ηbr = 100 – (q2 + q3 + q4 + q5 + q6), where

q2 – heat loss with exhaust gases;
q3 – heat loss due to chemical underburning of combustible gases (applicable to gas boilers);
q4 – loss of thermal energy with mechanical underburning;
q5 – heat loss from external cooling (through the heat exchanger and housing);
q6 – heat loss with physical heat of slag removed from the furnace.

Net efficiency of the heating boiler according to the reverse balance method:

ηnet = ηbr - Qs.n, where

Qс.н – total consumption of thermal and electrical energy for own needs in % expression.

Gross efficiency and net efficiency

Not all the heat generated during fuel combustion is used to heat the coolant; a certain part is spent on the boiler unit’s own needs: turbine, fan or smoke exhauster, circulation pump, operation of automation and electronic display, operation of the electric drive (as you already understand, all types of energy received are used in the calculation , including electricity, if the boiler is volatile).

Taking this into account, it is customary to divide the boiler efficiency by the generated heat ( gross efficiency ) and the released heat ( net efficiency ).

This classification allows us to highlight the degree of technical perfection of the boiler - gross efficiency or efficiency of fuel and electricity consumption - net efficiency.

How to increase efficiency

You can actually create the correct operating conditions for a gas boiler and thereby increase the efficiency without calling a specialist, that is, with your own hands. What do I need to do?

Adjust the blower damper. This can be done experimentally by finding at what position the coolant temperature will be highest. Carry out control using a thermometer installed in the boiler body.
Be sure to ensure that the heating system pipes do not become overgrown from the inside, so that scale and dirt deposits do not form on them. Today it has become easier with plastic pipes, their quality is known. Still, experts recommend periodically purging the heating system.
Monitor the quality of the chimney. Do not allow it to become clogged or soot to stick to the walls. All this leads to a narrowing of the cross-section of the outlet pipe and a decrease in the boiler draft.
A prerequisite is cleaning the combustion chamber. Of course, gas does not smoke much like wood or coal, but it is worth washing the firebox at least once every three years to clear it of soot.
Experts recommend reducing chimney draft during the coldest time of the year. To do this, you can use a special device - a draft limiter. It is installed at the very top edge of the chimney and regulates the cross-section of the pipe itself.
Reduce chemical heat losses. There are two options here to achieve the optimal value: install a draft limiter (this has already been mentioned above) and immediately after installing the gas boiler, carry out proper adjustment of the equipment. We recommend entrusting this to a specialist.
You can install a turbulator. These are special plates that are installed between the firebox and the heat exchanger. They increase the area where thermal energy is collected.

Timely cleaning of unit components

These are the reasons, by eliminating which you can count on increasing the efficiency of boiler equipment. Of course, there are many such reasons, but these are considered the main ones that answer the question: how to increase the efficiency of a gas boiler.

Don't forget to rate the article.

What to do to increase personal efficiency in World of Tanks. It is not very easy to achieve good statistics in the game, but the task is quite feasible.

It must be said right away that increasing (raising) efficiency will take time and this is the most valuable thing that will have to be sacrificed in the pursuit of a beautiful “statue”.

It will be extremely difficult to raise an old account with the number of battles over 20-25 thousand, but it is also possible.

The essence of the method is that you will have to imagine for a while that you are starting everything from scratch. Only from the real creation of a “twink”, you will have to take those tanks for which the statistics are depressing. Including sold tanks, they will also need to be bought back and taken out of the hangar for “pumping”. You can see which tanks you have have the worst statistics by using the notorious “deer measurer” mod.

Having equipped tanks with low efficiency to the maximum with additional equipment, you will need to play from 30 to 300 battles as a typical “extra.” Of course, it depends on the level and degree of drawdown of that same efficiency factor of a single piece of equipment. The effect of pumping up indicators for individual tanks will smoothly flow into an increase in overall efficiency.

How to upgrade?

Quite a simple answer. If you already have quite a bit of experience in the game, then you will have to endure insults from your allies. First of all, we get the allied frags. In the literal sense of the word, we wait and deliver the final blow.

Shot from afar. It would be a good idea to develop the skill of long-range combat, even on heavy and light tanks

It is important to shoot at least 100% of the damage from your XP. Therefore, we are actively learning to fight from the bushes, if we did not know how before. We work comprehensively on frags and get maximum “damage” per battle

We do not launch frontal attacks and stay away from the main clashes. The allies will be indignant at such a game, but the life of an extra is not complete without it

We work comprehensively on frags and get maximum “damage” per battle. We do not launch frontal attacks and stay away from the main clashes. The allies will be indignant at such a game, but the life of an extra is not complete without it.

Team game

Another method that can be quite effective is team play. Use the game as a platoon, having a couple of experienced players as friends, you can very quickly push the lagging behind to the desired level of efficiency in platoon battles.

Rule of successful statistics

What is the point of bringing a tank onto the field? Of course, the goal is to remain in a combat-ready state for as long as possible and at the same time accomplish something useful, for example, inflict incredible damage, illuminate enemy tanks, prevent the capture of a base, and so on.

You should not immediately merge, even if your nickname is at the end of the list. You need to be patient and wait. As soon as it becomes clear what positions the tanks occupy, you can begin to plan your actions.

It also happens that players on a team merge, and you have to be left alone with enemy vehicles. Just don’t give up right away, even if it seems like you can’t handle it, continue the game. Sometimes such tactics help to increase the number of unfinished tanks and recapture HP.

How to calculate the efficiency of a heating boiler

ηbr = (Q1/Qir) 100%, where

ηbr (read “this”) – boiler efficiency “gross”;
Q1 (MJ/kg) – the amount of heat that was accumulated, i.e. used for heating the house.
Qir(MJ/kg) – the total amount of heat released during fuel combustion;

ηbr = 100 – (q2 + q3 + q4 + q5 + q6), where

q2 – heat loss with exhaust gases;
q3 – heat loss due to chemical underburning of combustible gases (applicable to gas boilers);
q4 – loss of thermal energy with mechanical underburning;
q5 – heat loss from external cooling (through the heat exchanger and housing);
q6 – heat loss with physical heat of slag removed from the furnace.

Net efficiency of the heating boiler according to the reverse balance method:

ηnet = ηbr - Qs.n, where

Qс.н – total consumption of thermal and electrical energy for own needs in % expression.

How to take into account the height of ceilings when calculating?

The formula below is suitable when the ceilings in the house are of standard height.
Those. do not exceed 2.6 - 3 meters. If the ceilings are higher, calculation by area will not work.

You need to use volume.

Knowing the volume of the room, you can calculate the predicted heat loss (HL) using the formula:

PT = V (volume) x Pt (difference t) x k: 860.

Pt – difference in average temperatures outside and indoors. Example: in winter the average temperature is -30 C, but in the house you want it to be 22 C. Pt = 52. The higher this indicator is, the more the building will lose heat.

k is the dispersion coefficient. It depends on the building materials from which the structure is made:

Wood or corrugated iron, no insulation = 3–4.
Single brickwork, regular windows and roof, average thermal insulation = 2 – 2.9.
Double brickwork, good thermal insulation, few windows = 1 – 1.9.
Excellent thermal insulation, plastic windows, well insulated floor and ceiling = 0.6 - 0.9.

Now that all the basic data is known, you can calculate the boiler power using the formula:

M = PT x kz.

Kz in these calculations is the safety factor. It is equal to 1.15 - 1.2 (that is, 15 - 20%)

Example. Brick house with good thermal insulation, area 60 m2. And the ceiling height is 3m.

Let's calculate the volume. 60m2 x 3 = 180m3. Pt = 52, k = 1.5.
We substitute the data into the formula: PT = 180 x 52 x 1.5: 860. PT = 16.32.
We multiply this indicator by the safety factor: 16.32 x 1.2 = 19.58.
We round up and get a boiler with a capacity of 20 kW.

How to increase the efficiency (efficiency) of a solid fuel boiler

Solid fuel boilers (hereinafter referred to as STN) have a sufficient percentage of efficiency compared to other heating units (gas boilers, for example) to be competitive and lead the market. The latest THP models are equipped with the latest automation systems to optimize operation.

Solid fuel boilers operate on the principle of stove heating: heat is transferred to the coolant (water) by generating energy during the combustion of coal, wood, pellets in the firebox. Each boiler has its own coefficient of performance or efficiency and depends on many conditions: choice of fuel, operating rules, quality of installation, etc. Let's take a closer look at what the efficiency of heating devices is, and how to increase this coefficient for solid fuel boilers.

What is efficiency - coefficient of performance

To correctly select the boiler power relative to the square footage of the room to be heated, we recommend paying attention to the efficiency of the unit, its efficiency, especially when it comes to solid fuel boiler houses. The coefficient of performance or efficiency is an indicator that is calculated based on the ratio between the energy expended (thermal - when burning products in the firebox) and useful heat - which enters the heating system for transfer to the room

After calculating a simple formula, we get the efficiency percentage

The coefficient of performance or efficiency is an indicator that is calculated based on the ratio between the energy expended (thermal - when burning products in the firebox) and the useful heat - which enters the heating system for transfer to the room. After calculating a simple formula, we get the efficiency percentage.

q1 + q2 + q3 + q4 + q5 = 100%

Let's decipher:

q1 is an indicator of the heat that was transferred to the coolant - water.

q2 – physical underburning – heat loss with exhaust gases.

q3 – chemical undercombustion – heat loss due to incomplete combustion of fuel.

q4 – heat loss during heat dissipation.

The efficiency percentage increases when the boiler operates optimized.

The key point that affects the efficiency indicator is how well the solid fuel boiler is installed. In addition, the choice of fuel (coal, firewood, pellets), the presence of ventilation, and operating conditions are taken into account.

Let's look at it with an example.

If the passport of the purchased boiler indicates an efficiency of 90%, it should be taken into account that this is an indicator that can be achieved if the unit operates in nominal mode and burns high-quality fuel with a low ash content. Under other factors during operation, the efficiency of a solid fuel boiler may decrease to 60% or 70%.

How can we get closer to the ideal and extract maximum heat when operating a heat pump?

How to increase the efficiency of a solid fuel boiler

Let's look at some recommendations on how to make a solid fuel boiler work at its maximum, work economically, consuming a minimum of firewood, coal or pellets.

Load only dried fuel into the fuel pump. If you burn wet wood or coal, some of the energy will be spent drying it.
Do not use fuel with large amounts of debris, impurities, or dust, because these inclusions will quickly clog both the heat exchange channels of the boiler, as well as the grate and chimney.
Solid fuel boilers require mandatory periodic cleaning of the chimney and internal surfaces of the boiler, because any fuel pump becomes clogged much more than another gas boiler.
Ensure proper draft in the chimney channel: it should not be too strong, but not too weak. If we exclude the moment of correct design of the chimney, then for this there is a throttle valve on the chimney or on the heat pump, which regulates the air draft in the chimney - it should be set to the correct value. In order to load a solid fuel boiler once or twice a day and ensure efficient heating operation in general, it is imperative to design a buffer tank (heat accumulator).
Buy a solid fuel boiler only with a blower fan, which can accurately regulate the combustion process in the boiler and control the temperature of the flue gases.

We will select equipment, design and install a solid fuel boiler room for your premises in order to save heat and money as much as possible. To consult about the installation of a solid fuel boiler and the cost of heating installation, call tel. or or Book a consultation! We are always in touch!

How to quickly calculate boiler power for a typical building

The thermal power of a boiler is the amount of heat that the heat generator is able to transfer to the coolant by burning fuel or converting electrical energy into heat (electric boilers).

Heating system of a private house

Heat loss from a building occurs through the external surfaces - the building envelope. To maintain a constant temperature indoors, it is necessary to fully compensate for heat losses. They depend on several factors:

external and internal air temperatures;
surface area of enclosing structures (walls, roofs, ground floors), their material, degree of thermal insulation;
the presence of windows and doors in the building, their area, design;
ventilation of premises, which can be either natural or forced with recovery (reuse) of heat from the removed air.

Note: A boiler with insufficient power will not be able to heat the air in the room to the set value. Operating the boiler with excess power will cause excessive fuel consumption and less smooth operation of the heating system. The result is a waste of money and a reduction in the operating life of the heat generator.

To simplify calculations, an indicator of the specific power of the boiler was introduced, linked to the climatic features of the area. For Russia the following values are accepted:

southern regions: 0.7-0.9 kW;
northern regions: 1.5-2.0 kW;
central part: 1.2-1.5 kW.

These figures indicate the required amount of thermal energy to heat 10 m2 of room area with a ceiling height of 2.5 m. Let's consider a specific example: you need to heat a private house with a total area of 150 m2, located in the Moscow region.

Heat loss of a private home

Qst.= kst.* Sst.(tin. – tout.)

Letter designation:

Qst. – heat losses of the wall.
kst – wall heat transfer coefficient (depends on the material and insulation of the wall and is calculated using a separate formula).
Sst. – wall area (calculated using the formula: wall height multiplied by length).
tvn. – indoor air temperature (assumed 200C).
tnar. – the lowest outside air temperature (this value is individual for each area, indicated in the directory).

Heat loss through the wall

The calculation formula for windows is similar to the previous one: Qwindow = kwindow* Sst.(tin. – tout.). The meaning of the letters remains the same, you just need to replace the word “wall” with “window”.

Designation of window zones

On a note.

Calculation of heat losses is carried out only for walls, ceilings and floors in contact with outside air. Internal partitions do not affect heat loss.

Q= k* S*(tin. – tout.).

This calculation is suitable for a floor installed above the ground (on joists or above an unheated basement). If the floor is in contact with the ground, then the heat transfer coefficient is calculated using a different formula:

Rc – division of the floor into zones, each of which has its own value: first zone = 2.1, second zone = 4.3, third zone = 8.6.

Dividing the floor area into zones

d – thickness of the insulating layer.
λ – thermal conductivity coefficient of insulation.

Q is the amount of heat required to heat the supply cold air.
Lп – air flow rate removed from the room (assumed 3 m3/hour for each m2 of area).
p – air density = 1.1.
C – specific heat capacity of air = 1.
tr – internal air temperature.
ti – temperature of supply air from the ventilation system.
k – coefficient for taking into account counter heat flow = 1.

Note: By reading reference books and spending time, you can make an accurate calculation of the heat loss of a building yourself. But making a competent design of the heating system as a whole is very difficult, if not impossible, for a non-specialist. The right decision is to entrust the design to a professional heating engineer who will determine heat loss and adequately select a heat generator based on power.

Ways to increase efficiency

In order for the heating system to operate with minimal heat loss, you should familiarize yourself with effective ways to improve the efficiency of a gas boiler

. To do this, it is necessary to eliminate as much as possible all types of heat loss.

To reduce the percentage of physical underburning, you should monitor the condition and cleanliness of the flame tubes and water circuit. Soot forms on the pipeline, and scale forms on the circuit, so these elements of the heating system require regular cleaning.
There should be no excess air in a gas boiler, since heat that could be used to heat the coolant also goes into the chimney with it.
This problem can be solved by installing a draft limiter on the chimney pipe. How gases circulate in the boiler
Adjusting the blower damper. This can be done using a thermometer installed in the boiler. You just need to put the damper in such a position that the maximum coolant temperature is achieved.
Make sure that normal traction is maintained. It decreases as a result of the narrowing of the chimney cross-section. This can be avoided if you regularly clean the outlet pipe, because soot sticks to its walls.
It is necessary to regularly clean the combustion chamber, as soot forms on the surface of its walls, which increases fuel consumption.

Installation of a coaxial chimney

If you are looking for options on how to increase the efficiency of a gas boiler, pay attention to what kind of chimney is installed. Traditional outlet pipes have a number of disadvantages, the main one of which is their dependence on weather conditions. An alternative to a conventional chimney can be a coaxial chimney, which has the following advantages:

An alternative to a conventional chimney can be a coaxial chimney, which has the following advantages:

significantly increases the efficiency of a gas boiler;
resistant to high temperatures;
can be made in different versions;
allows you to save fuel;
ensures long-term maintenance of room temperature.
Coaxial chimney

The installation of a coaxial chimney does not require much effort. The design consists of two exhaust pipes of different diameters, one transports exhaust gases, and the other carries oxygen-saturated air.

If you have no experience working with heating equipment, but there is a need to resolve the issue of how to improve the efficiency of a gas boiler, contact a specialist. They will perform the work at the highest level, ensuring the most efficient functioning of your home's heating system.

Choosing a torch for soldering

Soldering or cutting cannot be done using ordinary gas torches. For this purpose, powerful and productive devices are needed, equipped with an air blower or an injector. By adjusting the composition of the supplied mixture, you can achieve the flame of the required strength and perform the necessary work related to soldering metals or other materials. Professional torches used for soldering are expensive, and therefore they are needed by a narrow circle of specialists. The power of such devices is 10-15 kW.

Attention! This material is the subjective opinion of the authors of the project and is not a guide to purchase

What's wrong with too much power?

Let's look at setting the power of a gas boiler using the example of a double-circuit device Protherm Gepard 23 MTV. This model is an analogue of the Protherm Panther unit. The same manufacturer that produces Protherm gas appliances produces Vaillant brand boilers in another production facility. Their price is much more expensive, since they use higher quality components. In design and settings, Vaillant gas devices are very similar to Protherm models.

The operating instructions say that the useful thermal power of the Protherm Gepard 23 MTV boiler is adjustable from a maximum of 23.3 kW to a minimum of 8.5 kW. In production, the units are set to a power of 15 kW.

It is good if the heating system to which the gas boiler is connected has a power within the capabilities of the burner device, in our case - from 8.5 to 23.3 kW. But what if the existing radiators require less performance?

For example, let's take an apartment with an area of 50 m². For its heating there are radiators with a thermal power of 4 kW. The installers installed a gas boiler, but did not set the appropriate power. A 4 kW heating system will not be able to accept the installed unit performance of 15 kW. The large difference between the produced and the required indicator makes it impossible to automatically adjust the boiler. Then you need to adjust the device yourself.

Note! Experts categorically do not recommend installing a gas boiler whose power significantly exceeds the required one. This leads to cyclical operation of the unit and its rapid failure.

The characteristics of the gas boiler Protherm Gepard 23 MTV indicate that the efficiency of the device when operating at full thermal power is 93.2%, and at minimum - 79.4%. If the unit operates at a capacity of 4 kW, its efficiency will decrease even more. It turns out that almost a quarter of the thermal energy will “fly down the drain.”

Cyclicity of a gas unit and its consequences

Cycling or “clocking” of a gas boiler means that the burner, after being turned on, quickly turns off when the liquid reaches a given temperature in the pipe at the outlet of the unit. But the batteries do not have time to warm up. After a short period, the circulation pump pumps cold water from the heating system into the unit circuit, and the burner turns on again.

Another difficulty lies in the fact that low-power heating pipes have a smaller diameter and higher hydraulic resistance; accordingly, the coolant flows in them more slowly. If you heat the liquid in the heat exchanger with high power, it will reach the set temperature very quickly and the burner will turn off. At the same time, the rest of the water that did not have time to reach the burner will remain cold.

Automation without human intervention will not be able to react to the situation and adjust the optimal power of the device.

Note! With the correct settings of the heating system, the temperature difference between the inlet and return should be no more than 15ºC. Cycling of a gas boiler significantly reduces the service life of the unit and increases fuel consumption

It is known that the components suffer the most wear at the moment of switching on. Also, when ignited, a maximum portion of gas is supplied to the burner, most of which evaporates into the pipe. Frequent re-ignition of the burner further increases fuel consumption and reduces efficiency. To avoid this, it is necessary to adjust the power of the unit, that is, to equalize the performance of the gas boiler and heating system

Cycling of a gas boiler significantly reduces the service life of the unit and increases fuel consumption. It is known that the components suffer the most wear at the moment of switching on. Also, when ignited, a maximum portion of gas is supplied to the burner, most of which evaporates into the pipe. Frequent re-ignition of the burner further increases fuel consumption and reduces efficiency. To avoid this, it is necessary to adjust the power of the unit, that is, to equalize the performance of the gas boiler and heating system.

What determines the thermal efficiency of boiler units?

The operating principle of a classic floor-mounted gas atmosphere.
The efficiency of heating boilers is not equal at any power; there is a proportional dependence on the load: an increase in the thermal load (the amount of fuel burned) also increases heat loss through the body or chimney. Likewise, operation at minimum power does not always ensure complete combustion of fuel, which leads to a decrease in efficiency.

For example, the service instructions for gas boilers Protherm Wolf KSO with a power of 12.5 kW and 16.0 kW indicate that when operating at maximum power (12.8 kW and 16.3 kW, respectively), the efficiency is 92.5%, while time when operating with a minimum load (4.5 kW and 5.8 kW) - will decrease and amount to only 78.4%.

This is one of the main reasons why you should take a conscious approach to choosing the power of the boiler unit. The most optimal operation in most models is achieved at a load in the range of 60-90% of maximum power.

Otherwise, the efficiency depends solely on the technological excellence of the model, aimed at reducing the above-described q2-6 (reducing the temperature of exhaust gases, efficient combustion of fuel, modulating burners, thermal insulation, etc.), as well as on the quality of maintenance and operation of the boiler unit. Cleanliness of the coolant, regular cleaning and flushing - all this over time seriously affects the efficiency.

How to choose a room thermostat and save up to 30% per month on heating

Methods for increasing boiler efficiency

At the first stage, you need to choose the right type of heating equipment. The determining indicators for organizing heating with high efficiency are the type of fuel used and the power of the boiler. Gas-powered models have proven themselves to be the best.

As can be seen from the graph data, there is no significant difference when the boiler operates in normal mode. The difference in efficiency for gas heating boilers occurs only at the time of startup until the required temperature conditions are reached (50-70°C). Then the work and the efficiency indicator stabilize. But to improve the latter, you can take the following steps:

The difference between the calculated and actual boiler power should not be more than 15%. Exceeding the value will lead to incomplete combustion of gases, which will further increase fuel consumption;
Use of condensation factor. This will slightly increase the efficiency of the entire heating system. However, the cost of condensing boilers will differ from traditional ones by 35-40%;
Reducing heat losses through the chimney. An increase in the efficiency of a heating battery directly depends on this factor.

By fulfilling these conditions, you can increase the efficiency of heating devices by 1-1.5 percent. But it is best to initially purchase a suitable cat model that best matches the parameters of the entire system.

Calculate boiler power online

Many manufacturers, realizing that not everyone can do the calculations, have made sure that it is extremely easy to find out the required power. Websites contain special calculators where, by setting indicators, you can instantly get the calculation result.

You just need to know:

desired temperature for the room;
average t in the coldest week of the year;
will the boiler heat drinking water;
is there a ventilation system;
ceiling height;
number of storeys;
thickness of external walls;
material of walls and ceilings;
length of each wall;
number and sizes of windows;
window type.

So. Correctly calculating the boiler power is one of the most important tasks in organizing heating. And doing it yourself is quite possible. Online calculators can also help.

Operating rules for boiler devices, compliance with which affects the efficiency value

Any type of heating unit has its own optimal load parameters, which should be as useful as possible from a technological and economic point of view. The operation process of solid fuel boilers is designed in such a way that most of the time the equipment operates in optimal mode. This operation can be ensured by following the rules of operation of heating equipment operating on solid fuel. In this case, you must adhere to and follow the following points:

it is necessary to observe acceptable modes of blowing and exhaust operation;
constant control over the intensity of combustion and completeness of fuel combustion;
control the amount of entrainment and failure;
assessment of the condition of surfaces heated during fuel combustion;
regular boiler cleaning.

The listed points are the necessary minimum that must be adhered to during the operation of boiler equipment during the heating season. Compliance with simple and understandable rules will allow you to obtain the efficiency of an autonomous boiler stated in the characteristics.

We can say that every little thing, every element of the design of a heating device affects the value of the efficiency factor. A properly designed chimney and ventilation system ensure optimal air flow into the combustion chamber, which significantly affects the quality of combustion of the fuel product. Ventilation performance is assessed by the excess air coefficient. An excessive increase in the volume of incoming air leads to excessive fuel consumption. Heat leaves more intensely through the pipe along with combustion products. When the coefficient decreases, the operation of boilers deteriorates significantly, and there is a high probability of oxygen-limited zones appearing in the furnace. In this situation, soot begins to form and accumulate in large quantities in the firebox.

The intensity and quality of combustion in solid fuel boilers require constant monitoring. The combustion chamber must be loaded evenly, avoiding focal fires.

During combustion, it is important to prevent failure of the fuel resource, otherwise you will have to face significant mechanical losses (underburning) of fuel. If you do not control the position of the fuel in the firebox, large fragments of coal or firewood falling into the ash box can lead to unauthorized combustion of the remaining fuel mass products. Soot and resin accumulated on the surface of the heat exchanger reduce the degree of heating of the heat exchanger

As a result of all of the above violations of operating conditions, the useful volume of thermal energy required for the normal operation of the heating system decreases. As a result, we can talk about a sharp decrease in the efficiency of heating boilers

Soot and resin accumulated on the surface of the heat exchanger reduce the degree of heating of the heat exchanger. As a result of all of the above violations of operating conditions, the useful volume of thermal energy required for the normal operation of the heating system decreases. As a result, we can talk about a sharp decrease in the efficiency of heating boilers.

Energy efficiency is at the forefront of the boiler

Russia has a very short summer, and the end of the next heating season always poses acute problems of repair, modernization and renewal of boiler equipment. Fuel becomes more expensive every year, therefore, when designing and equipping a boiler room, energy-saving aspects, inextricably linked with the energy efficiency parameters of the basic equipment, are becoming increasingly important. Efficiency is nothing, technical specification is everything? The fundamental indicator of energy efficiency is the coefficient of performance (COP). The lower the efficiency of the boiler unit, the more fuel needs to be burned to heat one unit of useful volume (area). At the same time, the efficiency can never be more than 100%, since heat losses are inevitable: with exhaust gases, from chemical and mechanical underburning of fuel, and losses to the environment. Using various technologies, materials, and equipment, boiler manufacturers have learned to reduce heat loss, achieving impressive results in increasing efficiency, that is, increasing the basic indicator of energy efficiency of installations. For example, a kind of “standard” of modern gas boilers is an efficiency of 92%. In some models and series of equipment of this type, the efficiency factor (declared by the manufacturer) reaches 94% and even 96%. Not all the useful heat generated by the boiler unit is sent to consumers; some is spent on its own needs. Taking this into account, the boiler efficiency is also distinguished by the heat produced (gross efficiency) and the heat released (net efficiency). Based on the difference between the generated and released heat, the consumption for own needs is determined, and this is not only heat, but also electrical energy (for example, to drive a smoke exhauster, fan, feed pumps, fuel supply mechanisms), i.e. consumption for own needs includes the consumption of all types of energy spent on the production of steam or hot water. As a result, the gross efficiency of a heating boiler characterizes the degree of its technical perfection, and the net efficiency characterizes its efficiency. It is clear that an energy efficient boiler must have high parameters of both gross efficiency and net efficiency. “All boiler installations are designed with a power reserve of 20 to 30%, most of the time the boiler operates at 60-70% of full load,” says Andrey Varvarkin, regional director for sales of industrial equipment at Vissman LLC (Vyssman, Russia Ekaterinburg). – The energy efficiency of equipment largely depends not even on design, but on competent and deeply developed technical specifications. When a good analysis is done, or even an energy audit of the system, then the project and the boiler room will have the power that the customer really needs.” “Pre-design work is required, the development of a heat supply scheme that solves the problem of rational heat supply. To achieve an energy-saving effect, it is necessary, but not enough, to have only energy-efficient equipment,” says Alexey Yablonskikh, General Director of TD “Buster Boiler-Ural” LLC (Ekaterinburg). Their morals... In the USSR, fire-tube and smoke-fired boilers were abandoned for a long time, relying on the use of water-tube structures. During installation, such boilers were lined with bricks or a protective coating was applied with a layer of heat-resistant insulation. In Europe, a different approach prevailed. While maintaining the production of water tube boilers, the companies simultaneously developed the production of compact, energy-efficient units with high factory readiness. Gas-tight boilers with one (or two) automated block burners had factory thermal insulation and did not require the installation of high-cost smoke exhausters and regulation of vacuum in the furnace. With the beginning of market reforms, Western companies began to actively promote fire-tube boilers using diesel and gas fuel in Russia. Among the large number of foreign brands of this equipment, the most famous are German ones - Viessman, Buderus, Loos. The Viessman “line” is dominated by three-pass boilers (Fig. 1). The firebox flame heats the first gas duct - the cylindrical combustion chamber, the flame tube of the first stroke, after which the combustion products generated during the operation of the burner, through the pipe at the end of the firebox, enter the flame pipes of the second gas duct of the boiler block and through them into the front part of the boiler. After this, the direction changes again by 180, and through the smoke tubes of the third pass, the gases move to the combustion product collection chamber. To intensify heat transfer and protect the final passes from condensation, Viessman uses a patented technology for manufacturing multilayer pipes - Duplex. “The Vitomax series of hot water boilers has incorporated advanced technical solutions in the world boiler industry,” says Andrey Varvarkin. – Everything is taken into account: water-cooled front and rear walls, cooled burner tube, the ability to service tube sheets without dismantling the burner, protection from cold water entering the pipe, wide space between the pipes, eliminating massive sludge deposition. Higher water content provides a larger volume of hot water and fewer starts of the automated burner, i.e. gas consumption and operating costs for the burner device are reduced. The maximum efficiency of the series is 94.5%.” Rice. 1. Viessman Vitomax-300LT hot water boiler. Fire tube boilers dominate the foreign product segment of the modern Russian market. But there are also alternative technologies. For example, steam-water-heating vacuum boilers from the South Korean company Booster Boiler (Fig. 2). “Energy saving is a distinctive feature of the boiler design, which consists of two chambers: a lower chamber (furnace) and an upper chamber with heat exchangers,” says Alexey Yablonskikh, General Director of LLC TD Booster Boiler-Ural. – The rectangular combustion chamber is made of two rows of pipes filled with water, heated by flue gases; the upper level of water is an evaporation plane from which steam, rising upward, washes the heat exchanger pipes and condenses, heating the water circulating in them; The condensate flows into the water volume of the chamber and mixes in a closed internal water circulation loop. Effective heat exchange during steam condensation reduces the surface area of the heat exchangers several times. In turn, this gives very little resistance to the movement of network water, sharply reducing energy costs during pumping. So, for a boiler with a capacity of 3 Gcal/h, the pressure loss is only 4 m.water.st. A vacuum environment is the best insulator. Due to this, heat exchange in hot water production occurs with virtually no losses. Start-up duration from a cold state is no more than 6 minutes, efficiency is 95%.” Rice. 2. Steam-water-heating vacuum boiler Booster Boiler. And our answer... As already mentioned, for a long time Russia had its own - “special” - path of development of boiler building, but now fire tube structures are produced by a number of enterprises: Biyskenergomash, Belgorod Power Engineering Plant, Dorogobuzhkotlomash, Uralkotlomash and some other. At the same time, “traditional” water-tube boiler construction is also developing and improving. All heating surfaces of KV-G gas boilers () are made of smooth and finned steel pipes in the form of one solid block (Fig. 3). The design ensures the passage of network water in one stream sequentially, first through the pipes of developed combustion screens, where it is heated by 50% of the total heat removal from the boiler, then through the convective part along with the movement of flue gases. This ensures the highest water temperature in the place of the lowest flue gas temperature at the boiler outlet; the formation of condensation and low-temperature corrosion are eliminated. The boiler can be used without recirculation pumps, which reduces capital and operating costs. Efficiency is within 93-96%, depending on the water temperature and load. Rice. 3. Water-heating water-tube boiler KV-G. In Russia, the share of boiler houses operating on solid fuel is still large. Despite the fact that the efficiency of such equipment is lower than that of gas equipment, the cheapness and availability of coal makes its use economically feasible. In turn, manufacturers are improving combustion technologies. The Barnaul Boiler Equipment Plant produces water-heating boilers of the KVTs series (3.15 and 4.0 MW, efficiency - 83%) based on the fluidized bed technology (Fig. 4). According to Alexey Bolotov, leading design engineer of the production preparation and dispatching department of NPO BZKO LLC , the technology of fuel combustion in a low-temperature “fluidized” bed (LTFL) allows reducing toxic gas emissions and increasing economic performance. The firebox contains an air distribution grill with a mass of granular material (sand, slag, ash, etc.) placed on it, through which air is blown from bottom to top. The mass fraction of fuel in the “fluidized” layer is 1-3%. This allows you to remove ash from any point in the layer with minimal losses from mechanical underburning. It is possible to burn fuel with an ash content of up to 90%, operating at low loads (30-50%) without illumination with liquid fuel. Rice. 4. Water heating boiler KVC. The system efficiency coefficient of the heating boiler is the most important indicator of energy efficiency, but this value is not decisive when assessing the efficiency of the heating system as a whole. Russian regulatory documents defining technical requirements for boilers (GOST 20219-74, GOST 11032-80, GOST 10617-83) require calculating the heat load of gas boilers using the formula: N = B*QH , kcal/h, where B is the hourly flow rate gas, cubic m/hour, QH - lower calorific value of gas, reduced to normal conditions, kcal/cub.m. Unlike Russian standards, US standards for gas boilers (when calculating the load) apply a higher calorific value, which is 1.11 times higher than QH for natural gas and 6% higher for light liquid fuel. As a result, the value of the heat load, calculated based on the higher calorific value of natural gas, is 11% greater than that accepted according to Russian standards (higher and lower heats differ by the value of the latent heat of vaporization, i.e., by the amount of heat released during complete condensation of water vapor formed during gas combustion). Since the efficiency value is a function of the thermal load (and, accordingly, the heat of combustion of the gas), the efficiency values calculated in accordance with the US standard are 11% lower than the Russian ones. The efficiency value calculated based on higher heat for any boilers is never more than 100%, while the efficiency of condensing-type boilers calculated based on lower heat (used in Russia, the CIS countries and many European countries) exceeds 100%. In the USA, the boiler efficiency is not given such decisive importance as in Russia and the CIS countries. This is due to the fact that the efficiency value is a characteristic of the boiler only in continuous operation (at rated output). This mode is used on test benches when determining the actual parameters of boilers, or in a continuous production cycle with a constant load, but this mode is not possible for heating systems. This is due to the variable thermal load on the boilers during the annual operating cycle of the system. That is why, in accordance with the recommendations of the Department of Energy and the US National Bureau of Standards, in engineering calculations it is customary to consider not the efficiency value of boilers, but the system efficiency coefficient . The least energy efficient operating mode of boilers (regardless of the theoretical value of its efficiency) occurs during transition periods of the heating season. Estimated Seasonal Fuel Consumption = Total Building Heat Consumption for the Season/AFUE Rating (decimal) The US Department of Energy has established a standard for estimating the seasonal energy consumption of heating appliances. The AFUE (Annual Fuel Utilization Efficiency) indicator established by this standard is currently used in the United States to evaluate the performance of the system as a whole. The AFUE value is expressed, like the efficiency, as a percentage, but - unlike the efficiency value - it takes into account the influence of numerous transition periods throughout the heating season (i.e. all periods of time when the boiler is operating at non-rated load). Thus, the AFUE indicator is used to estimate the real cost costs of the heating season. For example: data on a decrease in system efficiency under transient loads. (Based on the heating system of a building in Syracuse, New York): Ratio:

Source: Konstantin Litvinenko, Energyland.info The article uses materials from https://www.laarshs.ru

What is the efficiency of heating devices

For any heating unit whose task is to heat the interior space of residential buildings and structures for various purposes, operating efficiency was, is and remains an important component. The parameter that determines the efficiency of solid fuel boilers is the efficiency factor. Efficiency shows the ratio of the expended thermal energy produced by the boiler during the combustion of solid fuel to the useful heat supplied to the entire heating system.

This ratio is expressed as a percentage. The better the boiler works, the higher the interest. Among modern solid fuel boilers there are models with high efficiency, high-tech, efficient and economical units.

The efficiency of heating equipment strongly depends on what type of fuel is used and what are the design features of the device.

For example: when burning coal, wood or pellets, different amounts of thermal energy are released. Efficiency largely depends on the technology of fuel combustion in the combustion chamber and the type of heating system. In other words, each type of heating device (traditional solid fuel boilers, long-burning units, pellet boilers and devices operating by pyrolysis) has its own technological design features that affect the efficiency parameters.

Operating conditions and quality of ventilation also affect the efficiency of boilers. Poor ventilation causes a lack of air necessary for the high intensity of the combustion process of the fuel mass. Not only the level of comfort in the interior, but also the efficiency of heating equipment and the performance of the entire heating system depend on the condition of the chimney.

The accompanying documentation for the heating boiler must contain the equipment efficiency declared by the manufacturer. Compliance of real indicators with the declared information is achieved through proper installation of the device, wiring and subsequent operation.

Basic values for calculating heating power

The easiest way to obtain data on the heating performance of a boiler by area of the house: take 1 kW of power for every 10 sq. m. However, this formula has serious errors, because modern construction technologies, the type of terrain, climatic temperature changes, the level of thermal insulation, the use of double-glazed windows, and the like are not taken into account.

To make a more accurate calculation of the heating power of the boiler, you need to take into account a number of important factors that influence the final result:

dimensions of the living space;
degree of insulation of the house;
presence of double-glazed windows;
thermal insulation of walls;
building type;
air temperature outside the window during the coldest time of the year;
type of heating circuit wiring;
ratio of the area of supporting structures and openings;
heat loss of the building.

In houses with forced ventilation, the calculation of the boiler's heating output must take into account the amount of energy required to heat the air. Experts advise making a gap of 20% when using the resulting heat output of the boiler in case of unforeseen situations, severe cold weather or a decrease in gas pressure in the system.

An unreasonable increase in thermal power can reduce the efficiency of the heating unit, increase the cost of purchasing system elements, and lead to rapid wear of components. That is why it is so important to correctly calculate the power of the heating boiler and apply it to the specified home. Data can be obtained using the simple formula W=S*Wsp, where S is the area of the house, W is the factory power of the boiler, Wsp is the specific power for calculations in a certain climatic zone, it can be adjusted according to the characteristics of the user’s region

The result must be rounded to a large value in conditions of heat leakage in the house.

For those who do not want to waste time on mathematical calculations, you can use the online gas boiler power calculator. Simply enter individual data on the characteristics of the room and receive a ready-made answer.

Formula for obtaining heating system power

The online heating boiler power calculator makes it possible to obtain the required result in a matter of seconds, taking into account all the above characteristics that affect the final result of the data obtained. To use such a program correctly, you need to enter the prepared data into the table: the type of window glazing, the level of thermal insulation of the walls, the ratio of the floor area to the window opening, the average temperature outside the house, the number of side walls, the type and area of the room. And then click the “Calculate” button and get the result of heat loss and boiler heat output.

Thanks to this formula, each consumer will be able to obtain the necessary indicators in a short time and apply them in the design of the heating system.

You can select a boiler of the required power on the Teplodar company website https://www.teplodar.ru/catalog/kotli/ heating boilers from the manufacturer.

Boiler performance formula

Video on boiler power

Video:

https://youtube.com/watch?v=po1bqy2dlqg

Video:

Step-by-step instructions for building a solid fuel boiler

So, the whole process of how to make a boiler with your own hands according to the drawings can be divided into several successive stages:

Using a grinder, you need to cut blanks from pipes and profiles. The profiles will be racks; you need to cut round holes in them with a gas cutter for joining with the pipes. You will need to make 4 holes along the Ø50 mm pipe in the front pillars and the same number in the rear ones. In addition, we also need holes for inserting into the heating system. Sagging and deposits as a result of cutting or welding must be cleaned with a grinder so that they do not interfere with the movement of water through the pipes.
Next, the blanks are assembled into a single structure. Two people will have to work - the welder will need an assistant to hold the tubes in a stationary position. To make it more convenient, you can place the racks with pipes on a flat surface and weld the front and back parts of the boiler.
Now you need to ensure the supply and drainage of water from the boiler. The incoming and return pipes are welded to the finished frame, and the ends of the rectangular profiles are welded with pieces of metal 60x40 mm.
Before installing the heat exchanger, it is checked for leaks. To do this, install it vertically, close the bottom hole and fill it with water. If there are no leaks at the seams, then you can continue working.
The boiler body is built from brick and a heat exchanger is built into it, leaving a gap of at least 1 cm between them. The register must be installed in such a way as to create a rise towards the exiting hot water. The level difference between the outlet and the front right upper corner of the heat exchanger must be at least 1 cm. This will improve coolant circulation and eliminate air pockets.
The brickwork should overlap the heat exchanger from above by 3-4 cm. A cast-iron slab is laid on top of the masonry. The chimney is installed at the discretion of the owners - brick, metal, or led into a ready-made pipe.

Save with Programmable Thermostats

Many modern boilers support the ability to connect thermostats. You can place the thermostat in the room that can be used as a reference room. (Just never install thermostats in the kitchen. Due to the operation of the stove, it is always warmer there) Using the reference room, you set the temperature and the boiler already starts working from the thermostat signal. Practice shows that this method does little to make gas heating more economical.

In addition to simple thermostats, there are so-called programmable ones. They can be wired, wireless, powered or battery-powered. Options start from 2000 rubles and go on to infinity. Such thermostats allow you to set weekly operating modes.

How does this work in practice? Let's say you are a working person. And your whole family is often away from home. Study, work, etc. In fact, in your absence there is no need to heat the house to a comfortable temperature. It is enough just to maintain an adequate positive mode so that furniture, decoration and other parts of your home do not suffer. With a programmable thermostat, you can set the temperature by the hour.

Let's say you all leave for work at 9 o'clock and return home at 6 o'clock. You set the thermostat to lower the temperature from 9 am and raise it from 5 pm so that the house is already warm when you arrive.

In fact, in your absence, the heating will operate in economical mode. Savings in such scenarios can reach up to 30%.

We talked about this in more detail in the video:

There are a great variety of programmable thermostats. There are even some that can be controlled remotely from a smartphone. Here you can choose everything to your taste and color. The main thing is that they can all change their temperature depending on the time and day of the week.

The only important thing is that your boiler has the ability to connect thermostats. If you are using a simple boiler, then most likely there may not be such an opportunity.

All modern wall-mounted boilers support the connection of thermostats. This also applies to many floor-standing boilers.

Here is such a simple and uncomplicated way to make your gas heating more economical.

How does a condensing heat generator work?

This type of boiler is the younger brother of a conventional gas-fuel convection boiler. Conventional gas boilers, the operating principle of which is similar, have an efficiency of approximately ~90%. Where is another 10% lost? The answer is simpler than you might imagine - they go down the drain. The products of gas combustion that leave the system through the chimney are heated to a temperature of about 150 - 250 ° C, therefore, the lost 10% heats the air outside.

The operating principle of a condensing gas boiler is somewhat different. After working out the main combustion process and having given most of the heat released during the process to the heat exchanger, the unit cools the gaseous products of the combustion results to 50-60°C, that is, until the formation of water condensate begins. This is quite enough to significantly increase the efficiency, in a particular case, the amount of heat energy that is transferred to the coolant. But that is not all.

When the dew point (temperature 56°C) is reached, steam particles begin to gather into drops, scientifically speaking, the process of condensation occurs. At this time, additional energy is released from condensed vapors, which was previously spent on water evaporation and, in standard gas boilers, goes into the pipe along with the steam-gas mixture. The condensing boiler “takes” the heat that is released when water vapor condenses and transfers it to the coolant.

Manufacturers of condensate-type boilers are sure to draw the attention of their future buyers to the fact that the efficiency of the device is much more than 100%. How does this happen? No laws of physics are violated in this case, it’s just that in this situation a different calculation system is used

When assessing the efficiency of heating boilers, the part of the generated heat that is transferred to the coolant is taken into account. If we sum up the heat that the boiler transfers to the coolant during its operation and the heat from the deep cooling of the gaseous combustion products, the result will be 100%. But if the heat that is released during steam condensation is added to these values, then the result will be about 108-110%.

If we consider the calculations from a physical point of view, we can say that they are not entirely correct. Efficiency of more than 100% is a cunning move by marketers who take advantage of the inaccuracy of outdated calculations. And yet, condensing gas heating boilers, unlike a standard convector, “squeeze” almost everything out of fuel combustion. The advantages are more than obvious - less resource consumption and higher efficiency.

Heat exchange within the system

The burning gas heats a container of water (coolant), which in turn heats the radiators. The latter affects the efficiency of the boiler only by how quickly and without loss the energy is transferred to the coolant. The most successful form of heat exchanger for this is a cylindrical one, inside of which the same burner is located. The coolant moves around them in a spiral, guaranteed to have time to heat up to the required temperature.

The heat exchanger material varies - from steel to cast iron and depends on the boiler model, each of which is calculated differently.

The operating principle of a condensing boiler is shown in the video below:

Removal of combustion products

The latest savings methods introduced relate to this point. The logic of the solution - if at the exit from the chimney the temperature of the combustion products was 200-250 ° C, then why not use them to heat the coolant? To do this, additional heat exchangers made of steel or cast iron (with high heating inertia) are installed along the path of the exhaust gases.

Additionally, work is underway to extract heat from evaporated water obtained as a result of the combustion reaction - this is done by “condensing” boilers, which set records in terms of efficiency - the temperature of the emitted gases is about 50 ° C, and the amount of heat used for its intended purpose reaches 98%.

Removal of combustion products

Manufacturing features and choice of materials

In addition to knowledge, skills, drawings and diagrams, for the manufacture of heating equipment you need to stock up on materials and tools. What is needed to make equipment?

Materials and tools for making equipment

Materials:

Heat-resistant steel plates 4-5 mm thick to create a firebox.
Steel sheets 2-3 mm thick for making the body.
Steel pipes for the heat exchanger, the length and diameter of which are calculated individually.
Metal pipes for the chimney.
Arched slab and grate.
Ash pan combustion chamber door.
Heat-resistant brick.
Cement solution.

Tools

Welding equipment with a supply of electrodes.
Device for gas cutting.
Grinder with discs.
Pipe bending machine.
Level, tape measure, marker.

Recommendations for the manufacture of equipment

Homemade boilers for heating a private home are usually made of metal. It is almost impossible to make a cast iron firebox at home; buying a new one will be expensive. Many homeowners order them from craftsmen who specialize in the manufacture of heating equipment. In order not to encounter defects in the heating operation in the future, it is recommended to take part in the process. The purchase of materials and components, assembly of the heating boiler, installation and testing of the finished device must take place in your presence.

Since the combustion chamber of a solid fuel device has a very high temperature, it is made of expensive alloyed heat-resistant steel (stainless steel) 5 mm thick. In order to save money and simplify welding work, ordinary thick sheets of steel are often used instead of stainless steel. Such products are short-lived, and steel walls can become deformed due to temperature changes.

A reliable and efficient homemade solid fuel installation will cost less than a factory one

The water jacket is made of ordinary metal St 20 3 mm thick. This steel is used in the production of pipes for hot water and steam. Therefore, smoke pipes with a diameter of 48–76 made of the same grade of steel are suitable for the heat exchanger. The design of the shirt should be as rigid as possible. This quality is ensured by welding stiffening ribs to the outer walls of the firebox in increments of 120-150 mm. The outer walls of the tank are also welded to the ribs.

The doors of the blower and firebox must be double-layered. Between the metal layers it is necessary to insert a thermal insulation layer of asbestos, basalt fiber or a combination of both. The same materials can be used to insulate the body. The hinges on the doors are made adjustable, and the recesses are sealed with asbestos cord. To avoid burning your hands, the locking handles are equipped with ebonite or textolite nozzles.

What should an energy efficient boiler be like?

The characteristics specified in the documents and rich practical experience show that imported boilers have the highest efficiency. European manufacturers pay special attention to the use of energy-saving technologies, which allows them to get the most out of their equipment. Let’s make a “portrait” of an ideal gas boiler:

modulation burner - automatically adapts to the operating mode of the system, minimizing the percentage of underburning;
heating the coolant no more than 70 degrees, exhaust gases - up to 110 degrees, which ensures an optimal balance of efficiency, it is desirable to have a condensation heat exchanger;
coaxial chimney - a closed combustion chamber requires the equipment to have a pipe-in-pipe channel for removing combustion products, which allows heating the air flow from the street;
recirculation system - allows you to use the heat of exhaust gases to heat the room.

Of course, such an ideal boiler does not exist, but a list of the best technical solutions will help you choose a worthy model.

Boilers with pyrolysis combustion type

Pyrolysis boilers also use solid fuel, in particular firewood, however, the principle of their operation is fundamentally different from the installations described above. They are able to heat a house much longer and more efficiently, and use fuel more economically. In this regard, the cost of such units is approximately 1.5-2 times more than others.

The secret of gas generator (pyrolysis) boilers is that under the influence of high temperature and lack of air, wood is converted into charcoal, releasing pyrolysis gas.

This reaction requires a temperature between 200℃ and 800℃. This releases a large amount of energy, which dries the wood and heats the air. Pyrolysis gas moves through pipes into the combustion chamber, where it ignites when mixed with air - this is how most of the heat is generated.

Active carbons participate in oxidative processes during the combustion of pyrolysis gas, so the smoke coming out of the chimney consists mainly of carbon dioxide and steam - the content of harmful components is negligible. In addition, pyrolysis boilers, in principle, emit much less smoke than classic installations. Since the fuel burns with virtually no residue, gas generator boilers require cleaning quite rarely.

Thanks to automation, the combustion intensity in such a boiler can be adjusted to save fuel and create an optimal temperature in the room.