Energy saving technologies and economical use with maximum efficiency of energy resources are becoming more and more relevant topics. Condensing boilers- this is the result of the application of the latest unique technologies in the technology used for heating. They have the highest efficiency - 15-17% higher than that of conventional atmospheric boilers, their service life is 2 to 3 times longer, and a wide power range (up to 100 kW and more).
Due to its effectiveness condensing boilers are highly popular in Europe, for example in Germany 70% of heating boilers are condensing.
Condensing boiler operating principles based on the receipt and transfer of additional thermal energy to the coolant, released in the process of condensation of water vapor.
In a direct combustion gas boiler, the transfer of thermal energy to the coolant occurs by heating the heat exchanger with a gas burner in which the gas is burned. One of the constituents of gases formed during combustion is water vapor, which in turn appears as a result of the combustion of hydrogen present in natural gas. Part of the water vapor from the heating boiler, together with the flue gases, goes out through the chimney into the atmosphere, and part in the form of condensate is discharged through the condensation pipe of the chimney (usually to the bathroom).
In gas boilers of direct combustion, condensation is a negative factor, in condensing boilers the process of condensation of water vapor is the main condition on which the operation of the boiler is based.
It is arranged in such a way that water vapor having a temperature of 130 to 150 ° C is cooled by the heat carrier from the return line of the heating system to a temperature below 57 ° C. It is at this temperature that water condensation occurs, and the latent thermal energy from the condensation process is transferred to the coolant itself and is added to the heat obtained as a result of the combustion of natural gas. As you can see, to ensure the process of condensation of water vapor, the heat carrier of the return line of the heating system is used.
The lower the temperature of the return line coolant in the boiler, the more heat of condensation is released, and, accordingly, the higher the boiler efficiency - this is the main principle of operation of any condensing boiler.
The maximum efficiency of the condensing boiler can be achieved at a return temperature of 50 - 30 ° C. In the process of condensation, a slightly acidic environment is formed, 3-5 pH, therefore the materials from which the boiler units are made used in the humidification zones must be resistant to acidity. In high temperature areas, aluminum alloys and stainless steel are most commonly used; in low temperatures, plastics (eg polypropylene) are the most cost effective.
The heat exchangers of the condensing boilers are made of stainless steel and aluminum, equipped with a condensate collection and drainage system, as well as a blower fan with a step power system. By controlling the speed of the fan, the optimal ratio of air and gas for the combustion process is achieved and high efficiency is achieved. For an efficient gas combustion process, injection burners with flame modulation are used. The removal of combustion products of gases occurs forcibly through a coaxial pipe. The flue gas temperature is 40-50 ° C
OPERATION
To achieve maximum efficiency condensing boiler must be operated within a certain temperature range. If the operating temperature is between 60 and 80 ° C, slight condensation of water vapor will occur and the efficiency of the condensing boiler will be approximately 98%. For comparison, a traditional chimney gas boiler has an efficiency of 92% - there is a difference, but it is not significant. If the operating temperature of the heating system is from 53 to 30 ° C, then significant condensation of water vapor will occur and the efficiency will increase to 107-111%. When calculating the efficiency, the thermal energy from the combustion of the gas is taken as 100%, the energy obtained from the condensation process is added to it, so a value of more than 100% is obtained.
The main condition for achieving maximum efficiency is to use condensing boilers on low-temperature heating systems, preferably specially designed for them, with a temperature regime not higher than 60-40 ° С, maximum 70-50 ° С).
Underfloor heating systems with a heating agent supply temperature of 40-45 ° C and a return line temperature of 35-30 ° C are most suitable for these requirements; radiator heating systems with a coolant supply temperature of up to 70 ° C and a return line temperature of 50 ° C are less suitable.
Modern energy-saving technologies can significantly save on heating, condensing boilers allow you to further reduce energy costs and improve living comfort.
The users of our portal have a unique opportunity to follow how, within the framework of the project with FORUMHOUSE, we, with our partners, are building a comfortable and energy-efficient country house in the Moscow region. For this, the most modern materials and technologies are used in the construction of the cottage.
The USHP was chosen as the foundation, and the heating system was underfloor heating. In addition, a wall-mounted condensing gas boiler became the boiler room. The technical specialist of the company will tell you in the format of a master class about why this particular equipment was chosen for our project, and what are the advantages of its work.
- The principle of operation of a condensing gas heat generator.
- Benefits of using a condensing gas boiler.
- In which heating system is it best to use this equipment.
- What to look for when operating a condensing gas boiler.
The principle of operation of the condensing gas heat generator
Before we talk about the nuances of condensing technology, we note that an energy efficient, and therefore comfortable and economical country house is a balanced structure. This means that, in addition to the closed thermal insulation loop, all elements of the cottage, including the engineering system, must be optimally matched to each other. Therefore, it is so important to choose a boiler that is well combined with a low-temperature heating system "warm floor", and will also reduce the cost of purchasing energy in the long term.
Sergey Bugaev Ariston Technician
In Russia, in contrast to European countries, condensing gas boilers are less common. In addition to environmental friendliness and greater comfort, this type of equipment allows you to reduce heating costs, because such boilers work 15-20% more economically than conventional ones.
If you look at the technical characteristics of condensing gas boilers, you can pay attention to the efficiency of the equipment - 108-110%. This is contrary to the law of conservation of energy. While, indicating the efficiency of a conventional convection boiler, manufacturers write that it is 92-95%. Questions arise: where do these numbers come from, and why does a condensing gas boiler work more efficiently than a traditional one?
The fact is that such a result is obtained thanks to the thermal calculation method used for conventional gas boilers, which does not take into account one important point of evaporation / condensation. As you know, during the combustion of fuel, for example, main gas (methane CH 4), thermal energy is released, and carbon dioxide (CO 2), water (H 2 O) in the form of steam and a number of other chemical elements are formed.
In a conventional boiler, the temperature of the flue gases after passing through the heat exchanger can reach 175-200 ° C.
And water vapor in a convection (conventional) heat generator actually "flies out into the pipe", taking with it a part of the heat (generated energy) into the atmosphere. Moreover, the amount of this "lost" energy can reach up to 11%.
To increase the efficiency of the boiler, it is necessary to use this heat before it leaves, and transfer its energy through a special heat exchanger to the coolant. To do this, you need to cool the flue gases to a temperature of the so-called. "Dew point" (about 55 ° C), at which condensation of water vapor occurs with the release of useful heat. Those. - use the energy of the phase transition to maximize the use of the calorific value of the fuel.
We return to the calculation method. The fuel has a gross and gross calorific value.
- The gross calorific value of a fuel is the amount of heat released during its combustion, taking into account the energy of water vapor contained in the flue gases.
- The net calorific value of the fuel is the amount of heat released without taking into account the energy hidden in the water vapor.
The efficiency of the boiler is expressed in the amount of thermal energy received during the combustion of fuel and transferred to the coolant. Moreover, indicating the efficiency of a heat generator, manufacturers can calculate it by default using the method using the lowest calorific value of the fuel. It turns out that real efficiency of the convection heat generator actually is about 82-85% , a condensation(remember about 11% of the additional heat of combustion, which it can "take" from the water vapor) - 93 - 97% .
Hence, the figures for the efficiency of the condensing boiler appear, exceeding 100%. Due to its high efficiency, such a heat generator consumes less gas than a conventional boiler.
Sergey Bugaev
Condensing boilers provide maximum efficiency if the return temperature of the heating medium is less than 55 ° C, and these are low-temperature heating systems "warm floor", "warm walls" or systems with an increased number of radiator sections. In conventional high temperature systems, the boiler will operate in condensing mode. Only in severe frosts will we have to maintain a high coolant temperature, the rest of the time, with weather-dependent regulation, the coolant temperature will be lower, and due to this, we will save 5-7% per year.
The maximum possible (theoretical) energy saving when using the heat of condensation is:
- with natural gas combustion - 11%;
- when burning liquefied gas (propane-butane) - 9%;
- when burning diesel fuel (diesel fuel) - 6%.
Benefits of Using Condensing Gas Boiler
So, we have dealt with the theoretical part. Now we will tell you how the design features of a condensing boiler affect its efficiency and durability. At first glance, it seems that it is possible to use the additional energy of water vapor hidden in the flue gases in a conventional boiler, specially "driving" it into a low-temperature mode of operation. For example, by connecting the boiler (this is wrong) directly to the underfloor heating system or by significantly lowering the temperature of the coolant circulating in the radiator heating system. But, we have already written above that during the combustion of the main gas, a whole "bunch" of chemical elements is formed. Water vapor contains: carbon dioxide and carbon monoxide, nitrogen oxides, as well as sulfur impurities. During condensation and the transition of vapor from a gaseous to a liquid state, these impurities appear in water (condensate) and a weak acidic solution is obtained at the exit.
Sergey Bugaev
The heat exchanger of a conventional boiler will not withstand long-term operation in an aggressive chemical environment; over time, it will rust and fail. The heat exchanger of the condensing boiler is made of materials that are resistant to corrosion and acidic environments. The most resistant material is stainless steel.
Only durable and wear-resistant materials are used in the construction of the condensing boiler. This increases the service life and reliability of this equipment, and also reduces the cost of service.
In addition, increased requirements are imposed on other structural elements of the condensing heat generator, because it is required to cool the flue gases to the desired temperature. For this, the boiler is equipped with a high modulation forced draft burner. Such a burner operates in a wide power range, which makes it possible to optimally regulate the heating of water. Condensing boilers are also equipped with automation that ensures accurate maintenance of the combustion mode, the temperature of the flue gases and water in the return line. Why are circulating pumps installed that smoothly change the force of the pressure of the coolant flow, and not as simple 2-speed and 3-speed pumps. With a conventional pump, the heating medium flows through the boiler at a constant speed. This leads to an increase in the temperature in the "return", an increase in the temperature of the flue gases above the dew point, and, consequently, a decrease in the efficiency of the equipment. It is also possible overheating of the heating system (warm floor) and a decrease in thermal comfort.
An important nuance: the burner of a conventional boiler cannot operate at a power lower than 1/3 of the maximum (nominal) power of the heat generator. The burner of a condensing boiler can operate at a power of 1/10 (10%) of the maximum (nominal) power of the heat generator.
Sergey Bugaev
Consider the following situation: the heating season has begun, the outside temperature is -15 ° C. The power of a conventional boiler installed in a house is 25 kW. The minimum power (1/3 of the maximum) at which it can operate is 7.5 kW. Suppose the building has a heat loss of 15 kW. Those. the boiler, continuously working, compensates for these heat losses, plus there is a power reserve. A few days later there was a thaw, which, you see, often happens during the winter. As a result, the outdoor temperature is now around 0 ° C or slightly lower. The heat loss of the building, due to the rise in temperature outside, has decreased and is now about 5 kW. What happens in this case?
An ordinary boiler cannot, working in continuous mode, to issue 5 kW of power required to compensate for heat loss. As a result, it will go into the so-called cyclical mode of operation. Those. will constantly turn on and off the burner, or the heating system will overheat.
This mode is unfavorable for the operation of the equipment and leads to its accelerated wear.
A condensing boiler, with the same power and in a similar situation, in continuous operation will quietly deliver 2.5 kW of power (10% of 25 kW) ¸ which directly affects the service life of the heat generator and the level of comfort in a country house.
The condensing boiler, supplemented by weather-dependent automation, flexibly adjusts to changes in temperature conditions during the entire heating season.
Modern automation makes it possible to significantly simplify the process of controlling the boiler, including remotely, using a special mobile application for smartphones, which increases the convenience of using the equipment.
We add that the heating season in Russia, depending on the region, averages 6-7 months, starting in autumn, when it is not very cold outside, and lasts until spring.
About 60% of this time, the average daily temperatures outside are kept around 0 ° C.
It turns out that the maximum power of the boiler may be required only in a relatively short period of time (December, January), when real frosts were established.
In other months, the boiler is not required to reach the maximum operating mode and increased heat transfer. Consequently, a condensing boiler, unlike a conventional boiler, will work effectively both with temperature drops and with a little frost. At the same time, gas consumption will decrease, which in tandem with a low-temperature heating system (underfloor heating) will reduce the cost of purchasing energy.
Even when using a condensing boiler together with a high-temperature radiator heating, this equipment works more efficiently than the traditional one by 5-7%.
Sergey Bugaev
In addition to efficiency, an important advantage of condensing boilers is the ability to obtain high power with a compact size of equipment. The wall-mounted condensing gas boiler is especially relevant for small boiler rooms.
In addition, the condensing boiler has a turbocharged burner, which makes it possible to dispense with the standard expensive chimney and simply lead the coaxial chimney through the hole in the wall. This simplifies the installation of equipment or the installation of a new condensing boiler instead of the old one, when renovating an existing heating system.
Features of the operation of a condensing gas boiler
Frequent questions from consumers: what to do with the condensate obtained during the operation of the boiler, how harmful it is, and how to dispose of it.
The amount of condensate can be calculated as follows: 0.14 kg per 1 kW * h. Consequently, a condensing gas boiler with a capacity of 24 kW when operating at 12 kW of power (since most of the heating period the boiler works with modulation, and the average load on it, depending on the conditions, may be below 25%) on a fairly cold day produces 40 liters of condensate at low temperature.
The condensate can be discharged into the central sewerage system, provided that it is diluted in a ratio of 10 or better 25 to 1. If the house is equipped with a septic tank or local treatment plant, neutralization of the condensate is required.
Sergey Bugaev
The neutralizer is a container filled with marble chips. Filler weight - from 5 to 40 kg. It must be changed manually on average once every 1-2 months. Condensate, usually passing through the neutralizer, flows by gravity into the sewer system.
Summarizing
This modern equipment is distinguished by its reliability, economy and efficiency of work. Also, emissions of harmful substances into the atmosphere are reduced, which is especially important when the standards for environmental friendliness are tightened. In addition, the installation of this type of heat generator, by reducing gas consumption, will reduce heating costs in the long term and increase the level of comfort in a country house.
For most modern people who, in one way or another, are faced with the choice of a heating boiler, a unit such as a condensing boiler is associated with reliability, durability and efficiency. This is a relatively new development, with which a person has not yet fully figured out - yes, many advantages are attributed to him, but whether this is really so, time will tell. We will not overtake it, but simply consider what it is and how it works. Together with the website, we will understand the principle of operation, according to which a condensing gas heating boiler functions, we will get acquainted with its advantages and disadvantages, as well as with many other things characteristic of this combustion unit.
Double-circuit gas condensing boiler photo
Condensing gas boiler: what is it
If we compare a standard gas boiler with its condensing analogue, then we can come to the conclusion that their differences lie not only in some innovations, but in radically different principles of operation. Yes, in both cases, the heating of the coolant occurs due to the combustion of the gas, but in the condensing boiler, the heating of the coolant is additionally performed with the help of exhaust gases.
Moreover, the smoke removal system in this case produces the primary heating of the liquid - the exhaust gases, which contain a large amount of water vapor, first heat the coolant, and only then directly the gas heats it up to the specified temperature. It is thanks to all this that fuel savings occur - the efficiency of condensing boilers is 15-20% higher compared to standard units of this type.
How does such a boiler work? If you do not delve into its design in detail, then the sequence of the technological cycle of heating the coolant can be described as follows.
Everything is simple, but in fact, such an approach to heating the coolant requires some boiler re-equipment. Firstly, the supply of the coolant to the heating system in such units is carried out in the lower part of the boiler. Secondly, the upper low temperature condensing heat exchanger is equipped with a condensate collection tank. Thirdly, all these innovations significantly increase the dimensions of the boiler. In principle, it is easy to put up with all this if such equipment really allows you to save gas, which is the main advantage of this type of boiler. But besides him, this gas equipment has other advantages.
Pros and cons of condensing gas boilers
As you already understood, the main advantage that gas condensing boilers have is their high efficiency - without increasing fuel costs, they generate more power than classic gas equipment of this type. In addition, the following points can be attributed to the positive aspects of the operation of these boilers.
All this is very good, but along with the advantages, gas condensing boilers also have disadvantages. Firstly, the maximum efficiency and economy in operation is achieved only at low-temperature operating modes - if the temperature of the coolant in the return pipeline exceeds 50 degrees, then the boiler will operate as standard gas equipment. This imposes some restrictions on the scope of its application - in order to ensure the efficiency and economy of the condensing boiler, a large area is required. Alternatively, they can be used in systems with a large amount of underfloor heating. Secondly, the cost, which exceeds the price of a conventional gas boiler by more than 2 times. Thirdly, the complex and difficult setting of the heating system, which is very difficult to implement without specialists. And, fourthly, it is the need to drain the condensate - a branch must be drawn to the boiler equipment of this type.
And this is not all the unpleasant moments of using gas condensing boilers - paired with conventional linear boilers, they do not work quite as expected. The maximum efficiency of this equipment is possible only with collector wiring diagrams of heating systems.
Types of condensing gas boilers
Like most other gas boilers, this type of condensing equipment can be classified according to several criteria.
Like all other boilers, condensing units differ in power, which should be paid attention to in the first place, since the ability of the boiler to heat a room of a particular area fully depends on this indicator. The maximum power of wall-mounted condensing boilers cannot exceed 24kW - in contrast to them, the same indicator of floor-standing equipment of this type can reach up to 100kW.
Condensing boiler manufacturers
It's no secret that the quality of any product depends on the manufacturer - condensing boilers are no exception. They cost a lot of money and, when purchasing such units, you need to be sure that the money is not wasted, and they will be able to work for a long time. In this regard, it is better to give preference in choice to trusted manufacturers, which include the following companies.
If we talk about economy class condensing equipment, then here we can highlight the BAXI boilers, which have an optimal combination of technical characteristics and cost - a 28 kW boiler will cost the consumer about $ 1,500. At the same time, the manufacturer gives a rather rather big guarantee for its products, which makes this boiler very affordable for a wide range of people.
In conclusion of the topic about a condensing gas boiler, I will say a few words about one very important point that affects the duration of operation of equipment of this type. We are talking about a heat exchanger, or rather the material from which it is made - almost all condensing boilers are equipped with heat exchangers made of stainless steel or silicon-aluminum alloys. In principle, both options work well, but stainless steel is less susceptible to corrosion by condensation. Both of them will work for a long time, but it is the stainless steel that works the longest.
For heating a private house, there is a wide variety of boilers that are capable of operating on gas, wood, sawdust, pellets, liquid fuel or electricity. When choosing the type of fuel on which the heating device will operate, the fundamental decision is based on the cost and availability of this or that energy carrier. The most common, due to its low cost, is natural gas. Why, then, is the condensing boiler so popular in the European market? Due to the annual increase in prices for this type of fuel, heating engineers have developed a new type of boiler, which is distinguished by the complete use of fuel energy.
Gas condensing boilers, in contrast to convection (traditional) boilers, use a higher calorific value due to the recuperation of energy carrier residues.
In the first steps, the process is very similar to that of a conventional convection boiler.
When liquid or gaseous fuels are burned, carbon dioxide and water vapor are formed. The steam condenses into the rear, cooler parts of the heat exchanger, because it is warmer than its surface.
Heat is generated during the formation of condensation, this heat of condensation is fed back to the heating circuit and used to heat the chilled water in the return line of the pipeline. Thus, the burner is already supplied with preheated water from the heating system. Therefore, in the end, to heat the same volume, it is necessary to spend less energy.
In the last stage, the residual heat of the flue gas is still used. Through the air supply pipe located in the chimney, the incoming fresh air necessary for the operation of the burner is heated by the heat of the exhaust gas. Thus, already warm air enters the burner, which provides additional savings.
The clear operating principle of the condensing boiler
Pros and cons of condensing heaters
The condensing boiler has significantly more advantages over traditional ones, which explains the higher cost. In other words, the higher price will be compensated in the near future in the form of lower gas consumption.
Advantages of a condensing boiler
- High efficiency
Often, the efficiency in boilers exceeds the usual 100%, additional percentages are obtained due to the cooling of flue gases and condensation of steam in the second part of the heat exchanger. Thanks to this, there is a significant saving in energy consumption reaching 35%. - Quiet operation
The boilers have a very low noise level, which increases the comfort level. - Environmental friendliness
When compared with convection boilers, the harmful emissions are reduced by 80%.
Disadvantages of a condensing boiler
- High price
The price will be 30-50% higher compared to traditional boilers. - Condensate disposal
The need to dispose of condensate is not entirely a disadvantage, since for boilers with a capacity of less than 28 kW, it is possible to drain into the sewer. - Loss of efficiency in high temperature systems
In high temperature applications, where the flow and return temperatures are 80/60 ° C, the efficiency will drop to 98-99%.
On average, a 25 kW boiler produces 70 liters of condensate per day.
Comparison of condensing boilers
Boiler models are in the same price segment.
Selection conditions:
- Power: 24-25 kW
- Efficiency: more than 100%
- Single-circuit
- Price: up to 50,000 rubles
Considering these parameters, two models were found that fully satisfy the established parameters.
| Gas boiler Baxi Duo-tec Compact 1.24 | Gas boiler Protherm Lynx K 25 MKO | |
| Cost, September 2017 | 44590 | 49585 |
|
Maximum thermal power, kW |
24 | 25 |
|
Minimum thermal power, kW |
3.4* | 6 |
| Efficiency,% | 105.7 | 108.5** |
|
Heat exchanger material |
stainless steel |
aluminum-silicon alloy |
|
Natural gas consumption |
2.61 m³ / hour |
* According to reviews, in the Baxi model, the minimum thermal power is underestimated, in fact, it is 4.7 kW.
** Regarding the Protherm model, the table shows the indicator at a frequency load mode (approximately 30%) and a temperature of 40/30 ° C. When operating in a full low-temperature mode of 50-30 ° C, the efficiency will be 104%. Among other things, the noise level of the turbine is significantly higher than that of the Baxi.
Since the model from Protherm has recently been on the Russian market, there are very few reviews, but if we take into account the reviews of convection boilers of the same brand, we can assume that the quality is at a high level.
Today, condensing gas boilers are the most popular models of equipment for heating systems due to their positive operational features, which distinguish them favorably from other types of heating equipment.
Device and purpose
The main purpose of condensing heaters is to equip the heating system in private houses.
Among the main elements of a condensing gas heating boiler, it should be noted:
- A device that is designed to collect condensing liquid, where the coolant enters after cooling the discharged air masses. Thus, the steam condenses and gives up heat energy to the water. Then the condensate is discharged into a special container through a drain device.
- Heat exchanger of cylindrical shape with a large heat exchange surface. This device is made of acid-resistant materials: "stainless steel" and aluminum-silicon alloys. High capacity boilers have a pair of heat exchangers.
- Gas burner with a closed combustion chamber. It is possible to automatically change the flow rate of the supplied gas and air masses.
- Control and management system.
For a more detailed study of the principle of operation of condensing boilers, you need to have some idea about conventional boilers. Traditional boilers generate heat energy by heating the heating medium using the heat accumulated in the combustion products. The temperature of the gases entering the combustion chamber is no more than 200 degrees. This is justified by the fact that with a decrease in temperature, the thrust decreases, active condensate is formed, leading to corrosive destruction of heating equipment.
As mentioned, condensing heaters have one two-stage or two separate heat exchangers. The initial stage works on the same principle as in heat exchangers of classic heating units. The decomposition gases enter a heat exchanger called a condensing unit.
In this case, the vapor present in the decomposition gases is cooled and condensed before the onset of the liquid phase. The heat released in the process is transferred to the coolant. Thus, in condensing devices, a certain part of the expended energy is returned for the possibility of its reuse.
The heat, which is usually removed by classical units into the atmosphere, is used in the condenser to increase their efficiency. Condensing gas boilers are available in two versions: floor-standing and wall-mounted devices, however, they are similar in design features.
In condensation-type devices, condensate is usually directed into a special container provided for by the design of the equipment, and then into the sewer.
Since condensing-type heating units are equipped with closed combustion chambers, the exhaust gases are forced out of them. This is explained by the fact that the exhaust gases have a relatively low temperature, and an additional heat exchanger unit will increase the resistance to transportation of the output products. As a result, the natural draft is not enough for the withdrawal of products, for which the forced method is used.
The air into the combustion chamber is supplied under high pressure by means of a turbine, which ensures complete removal of exhaust gases from the chamber. As a result, there is no need to equip boilers with chimneys, since the products are removed from the room through the supply and exhaust duct. Condensing boilers can be installed in rooms without chimneys, as well as in buildings with short chimneys, in order to create a certain draft.
Condensing equipment is considered to be more fireproof, since combustion is carried out in complete isolation from the building where the apparatus itself is located.
Advantages and disadvantages
Positive characteristics of condensing equipment:
- There is no need for a chimney, which has a complex structure. Since the temperature of the combustion products is low, it is possible to arrange a chimney from aluminum and plastic pipes. It is also allowed to install coaxial chimneys, where the air mass is supplied and removed according to the "small pipe in a large pipe" method, that is, combustion products are removed through the wall into the atmosphere.
- Compactness combined with high performance. The line of condensing units with a capacity of 120 kW are made in wall-mounted variations. Traditional gas appliances take up much more space and are only floor-standing.
- Extraction of air mass for optimal functioning from the building in which they are located. Thus, there is no need to equip special boiler rooms for equipment with a capacity of less than 60 kW.
- Reducing the release of harmful gases and vapors into the atmosphere.
- Significant gas savings. With a high-quality installation of a 60 kW device, about 2000 m3 of fuel can be saved during the winter.
Negative characteristics of condensing equipment:
- High cost. On average, the price of standard boilers of the same capacity is up to 40% lower than the cost of convection boilers.
- Condensate cannot be drained into a septic tank, therefore, a special reservoir is needed to collect condensate, where it is neutralized with the help of neutralizing components, and only then it can be sent to a container for draining. The condensate tank must be of a sufficiently large capacity, since the equipment, even with a small capacity, produces a high volume of condensate.
- The need for a heating system that operates at low temperatures.
- Inefficient operation at too low temperatures, since it becomes necessary to increase the temperature of the thermal carrier.
- Volatility.
Based on the feedback from the owners of private houses who have installed gas condensing boilers, taking into account all the pros and cons, you can make the right choice of the device for the heating system.
Features of functioning
Condensing equipment uses natural or liquefied gas as fuel. The first is widely used in everyday life, and the second in industry. The functioning of the condensation device is based on the laws of physics. Fuel burns producing water and carbon dioxide. In this case, the liquid evaporates and a certain amount of heat is released. The formation of condensation ensures that the lost thermal energy is returned to the system, which leads to an increase in the efficiency in the system. In standard boilers, condensate is considered an undesirable phenomenon that must be disposed of.
The main difference between condensing boilers and convection boilers is that the latest models are considered obsolete. Also, the efficiency of condensing equipment differs from conventional and convection equipment up to 15%.
Most buyers note that the cost of purchasing condensing-type equipment is offset by the high efficiency of the device, which is provided by the condensation of vapors contained in the flue gases. After cooling the flue gases in the heat exchanger to 55 degrees, condensation of water vapor begins with the release of additional heat, due to which the efficiency increases.
Condensation is possible only if the temperature of the coolant is not more than 57 degrees and the greatest effect is achieved at 35 degrees of the coolant in the return.
Installation of condensing-type equipment is relevant in heating systems with low temperatures.
Criterias of choice
With regard to the technical characteristics of the boilers, you need to pay attention to the following points:
- Performance. Too much power may not always be a good option, and operating at half strength will soon lead to equipment failure. Therefore, before buying a device, it is necessary to calculate the optimal power for heating the house. To do this, you need to calculate the area of the building, the height and the level of insulation. You can even use special tools to research a private home. With the help of them, the existing heat losses will be revealed. The optimum capacity of the condensing units depends on the climatic zone. For example, for Moscow, for 10 m2 of a house, the power of the equipment should be in the range of 1-1.5 kW. Thus, for a private property heating system with an area of 200 m2, equipment with a capacity of at least 20 kW is needed.
- The number of contours. Liquefied gas double-circuit devices work as follows: the first heat exchanger heats the heat carrier for the heating system, and the second for hot water supply. A single-circuit turbocharged boiler heats only the heating agent. For many buyers, the second option is not entirely convenient, but when organizing a hot water supply system, you can simply install an additional boiler. With intensive use of hot water, you can also purchase double-circuit boilers with a boiler. Thus, opinions on which condensing type equipment are better are convergent.
Double-circuit devices most often have a low power - up to 24 W, and are installed in rooms with a good level of insulation or with an autonomous heating system. In other cases, the most optimal options are with one circuit.
- Gas consumption rate depends on the boiler performance, efficiency, as well as the load of the heating system. - The material from which the heat exchanger is made.
The speed of heating response to external factors largely depends on it:
- Silumin, or an alloy of silicon and aluminum, is designed to combat aggressive condensation. In this case, the heat exchanger must be seamless, since the presence of seams increases the risk of corrosion.
- "Stainless steel" is considered an inexpensive material compared to silumin. The advantages of stainless steel include resistance to corrosion, lack of inertness and immunity to thermal shock. Therefore, the rating of materials for the manufacture of heat exchangers is headed by "stainless steel".
- Environmental friendliness. Conventional turbocharged boilers, when burning fuel, emit vapors with acid impurities into the atmosphere, and in condensing devices the vapors dissolve in condensate and are neutralized.
- The operating temperature affects the efficiency of the equipment. With a decrease in temperature, the intensity of condensation increases. So, at a temperature of vapors from 30 to 40 degrees, the highest rate of condensate formation. In this case, condensation occurs in a constant mode.
- Control. Modern condensing devices are equipped with an automated control system. Automation allows you to monitor and control the temperature regime, flow rate and pressure in the circuits. The most advanced boiler models are controlled through a special application on a smartphone.
- Installation method: floor or wall. Floor-standing models with one circuit are produced with a capacity of more than 100 kW, they are easily connected to boiler equipment using pumping units. For intensive use of hot water, a floor-standing boiler will be an excellent solution. If the area of the house is small, and water is consumed much less, it is recommended to give preference to wall models with two circuits. They are compact and have a low power - up to 100 kW, are easy to install and do not require a special chimney.
- Pricing policy of gas boilers of the condensing type.
