In the production of heating systems, the most promising innovative technology is the condensation of water vapor, which is formed during the combustion of hydrocarbons. According to this principle, they work condensing boilers. This new heating equipment has appeared on the Russian market recently, but is already in considerable consumer demand. Condensing boilers of both foreign and domestic manufacturers are on sale.
A wide range of condensing boilers is offered by BAXI, which, thanks to the high quality of its products, has become the leader of the Russian market for boiler equipment. Baxi condensing boilers are floor-standing and wall-mounted condensing boilers with a high useful action. Other well-known brands of boiler equipment in the domestic market include condensing vaillant boilers and wisman.
condensing boiler
Principles of combustion and condensation
Any hydrocarbon fuel releases heat when burned. During the combustion process, the final products are carbon dioxide(CO 2) and (H 2 O) water, which, under the influence of high temperatures, turns into steam. When evaporating, water expends heat, but it can be obtained back in the process of condensation, that is, if the water from the gaseous phase passes back into the liquid.
How condensing boilers work
The principle of operation of condensing boilers has been known for a long time, but it was impossible to use it in boiler equipment made of cast iron and steel, since water condensate, having high acidity and containing carbon dioxide, caused corrosion of steel and cast iron boilers. Only with the advent of corrosion-resistant alloys and stainless steel, it became possible to introduce this technology into the production of boiler equipment.
As we already know, when cooled, the vapor again turns into liquid state and releases a certain amount of heat. If we consider a conventional boiler, then during its operation there is a struggle with the condensation process, and in condensing boilers, condensation is only welcome. Their design provides special heat exchanger, in which the condensation process takes place, and the heat released during this process is taken for the heating system
The condensing boiler has an efficiency of 108-109%. How is this possible if, according to the laws of physics, the efficiency cannot exceed 100%, since energy losses in any processes are inevitable.
In non-condensing boilers, not all of the thermal energy, but only a large part of it. The heat flow in the heat exchanger is cooled only to a temperature of 140-160 ° C, when it is cooled to a lower temperature, the draft decreases in the chimney, aggressive condensate is formed, causing corrosion of the boiler elements. Thermal energy that can be obtained in the process of condensation in conventional boilers is not used, it is called latent.
Condensation gas boilers use in their work the energy hidden in condensing water vapor, so their efficiency, in comparison with the efficiency of conventional boilers, exceeds 100%. The main element of any boiler is a heat exchanger. There are two heat exchangers in the design of condensing boilers. They can be separate or combined (two-stage). The first heat exchanger works in the same way as in conventional boilers. A heat flow passes through it, but does not cool below the dew point. The second condensing heat exchanger removes the heat remaining from the combustion products and cools it down to a temperature below the dew point.
Water vapor condenses on the walls of the second heat exchanger and releases latent heat energy to water. At this moment, additional heat is taken from the combustion products; their temperature at the exit from the heat exchanger is only 10-15°C higher than the coolant temperature.
To solve the problem of corrosion caused by aggressive condensate, manufacturers use materials that are resistant to corrosion and chemical attack (stainless steel, silumin (aluminum-silicon alloy)) in the manufacture of boilers.
In Europe, and in particular in Germany, there are regulations requiring that condensate be neutralized before being discharged into the sewer. The neutralizer is a container with granules of magnesium and potassium. By passing through these alkaline reagents, the condensate is neutralized, and when discharged into the sewer, it does not pose a danger to environment. In Russia sanitary norms do not require condensate neutralization, so it is simply collected in a special tank provided in the boiler design, and, as a result, is discharged into the sewer in its original form. In boilers with a capacity of up to 30 kW, intended for heating private houses, about 30 liters of condensate are formed in 24 hours a day.
Advantages and disadvantages of condensing boilers
Wall mounted heating boiler
The condensing gas boiler can be called one of the most economical and highly efficient heating appliances. Its efficiency is 10-15% higher than the efficiency of a traditional boiler. In addition, condensing boilers are 20% more economical than conventional boiler equipment.
The design of condensing boilers uses high-tech burners that prepare fuel-air mixtures in optimal proportions, which minimizes the possibility of incomplete combustion of the fuel. This reduces emissions harmful substances.
Exhaust gases have a low temperature (below 40 °C), which makes it possible to use plastic chimneys for condensing boilers, thereby reducing the cost of installing the heating system.
The advantages of condensing boilers include:
- small dimensions and light weight of boiler equipment;
- efficiency (gas savings are 35% per season);
- deep modulation (saving gas at partial loads);
- low vibration and low noise;
- possibility of cascade installation;
- savings on the chimney (you can install chimneys with a smaller diameter);
- reduction of emissions of harmful substances NO X and CO 2 (7 times lower than conventional boilers).
Cascade of condensing boilers
Due to the small dimensions and low weight of the boiler equipment, the installation of the boiler requires less space at the same time, the cost of its transportation and installation is reduced. There is a misconception that condensing boilers work effectively only with underfloor heating systems. In another case, their efficiency is no more than that of traditional boilers. But it's not. The design of the condensing boiler has a modulating burner that allows you to achieve deep power modulation, while reducing the cost of gas and air.
The process of condensation in the boiler also occurs during the operation of heating equipment with a radiator heating system. At reduced loads, the efficiency of a condensing boiler may well reach high values, unlike conventional gas boilers, in which the efficiency in this mode drops due to an excess of air.
For cascade installation of condensing boilers, manufacturers offer special regulators (for example, firm BAXI sells the RVA47 regulator for its boilers), which turn boilers installed separately into a single system.
Benefits cascade system is ease of installation and compact dimensions of the boiler room. Due to the reduced vibrations and low noise level during the installation of condensing boilers, there is no need to make vibration-proof platforms and soundproof the room intended for the boiler room. Which also saves cash when installing a heating system.
To save on the size of the chimney, the fan working in condensing boilers allows. It develops a rather high pressure, so the diameter of the chimney can be two times smaller than when installing a heating system with traditional boilers.
Due to low NO X and CO 2 emissions, condensing boilers are classified as environmentally friendly equipment, they are often used to equip boiler houses in resort and protected areas. Finding flaws in condensing boilers is very difficult. The main disadvantage of this heating equipment is the high price, which is twice the price of conventional boilers.
Application
By appearance condensing boilers are not much different from traditional ones. They are made in wall version and outdoor version. Wall-mounted gas condensing boilers have less power than floor standing ones and are used in everyday life for heating private houses and cottages.
Floor-standing condensing boilers with high power used for heating industrial facilities and office space.
Condensing gas boilers produce single and double circuit. Apply double-circuit boilers for both heating and hot water. The power of single- and double-circuit boilers is 20-100 kW. This is enough for domestic use boilers. For industrial applications produce models with higher power.
The main differences between the design of condensing boilers and conventional boilers
Condensing boilers differ from traditional boilers in the material used for the heat exchanger. Their heat exchanger is made of acid-resistant silumin alloy or stainless steel. The water condensate formed in the boiler has hyperacidity and causes corrosion of materials such as steel and cast iron, which are used in the manufacture of non-condensing boilers. The shape of the heat exchanger is a pipe of complex cross section with additional helical fins. This form of heat exchanger increases the heat exchange area and increases the efficiency of the boiler.
In condensing boilers, a fan is installed in front of the burner, which “sucks” the gas from the gas pipeline and mixes it with air, after which it directs the mixture of gas and air to the burner.
Condensing boiler device
Flue gases are removed through coaxial chimneys made of heat-resistant plastic. In addition, the condensing boilers have an electronically controlled pump that optimizes the heating output, saving energy and reducing noise from the heating medium flowing in the heating system.
The design of traditional boilers does not provide for the condensation process and the use of indoor energy, so the temperature of the combustion products is maintained at high level. Part of the heat in such boilers is not used, but is removed with combustion products through the chimney.
Since condensate is chemically aggressive, in order to use it, it is necessary to make boiler elements from chemically resistant materials, the cost of which is quite high. It is much easier for manufacturers to sell cheaper products than to invest in progressive, but expensive technologies. Therefore, most of the boilers on the market are based on outdated technologies. For users, it is more profitable to buy albeit expensive, but more efficient condensing boilers that save on fuel consumption.
Manufacturers offer connection kits, condensate neutralizers, expansion tanks, safety devices, boiler piping kits, exhaust systems flue gases.
In European countries, condensing boilers are the most popular type of heating appliances. There are countries where the installation of non-condensing boilers is prohibited. The reason for this is the higher efficiency and lower emission of harmful substances in condensing boilers.
Condensing heating boilers are an innovative development that has been successfully used in the EU countries. Due increased efficiency the device allows you to save on heating, which is very important in our time. In this article I will talk about its device and features.
Condensing boilers
Operating principle
Condensing gas boilers are a type of heating equipment designed to heat a heating system and sanitary water(in the case of a two-circuit version).
Like conventional boilers, there is:
- gas combustion chamber;
- heat exchangers;
- expansion tank;
- coaxial chimney;
- control automation;
- circulation pump.
However, there are also significant differences.
The principle of operation of the device is based on the fact that when the heat of the burnt fuel is released, the vapors formed from the water in natural gas condense. As a result, the energy of vaporization hidden in these vapors is not emitted through the chimney to the street, but goes to additional heating of the coolant.
As you know, dew point temperature is required for water to condense. In conditions gas boiler it is equal to 57 °C. Therefore, for the system to work, it is necessary to cool the heat exchanger or part of it below the dew point temperature.
To do this, the return temperature of the coolant must be at the level of 40 - 50 ° C or lower. This means that the condensing boiler will work productively only with a low-temperature high-inertia heating system. It can be "warm floor" or panel heating.
Another condition effective work device is special a heat exchanger that can sufficiently cool the combustion products of the fuel. First, these products pass through the most distant part of the heat exchanger from the return, they are pre-cooled, then they again pass through the coldest and closest to the return part of the economizer and are cooled below 57 °C.
The water vapor contained in the combustion products condenses on the walls of the heat exchanger and gives off the thermal energy released during condensation. This, at first glance, is an insignificant amount of heat. can increase the efficiency of the boiler by 9 - 11% compared to a conventional convection device.
So, we have a boiler that receives additional heat by cooling the products of gas combustion. As a result steam condenses on the walls of the heat exchanger, and the released energy is used to heat the coolant.
Device
In general, the device of the condensate unit resembles the design of a conventional gas boiler.
To implement the principle described above, the following nodes are required:
- Special heat exchanger made of corrosion-resistant material (copper or silumin), which is divided into two sections. In one of the sections, the main heating of the coolant takes place, then the combustion products are sent to an additional section with the coldest water, where the water vapor condenses and gives off its energy;
- Closed combustion chamber with coaxial chimney allows you to more accurately control the process of movement of gas combustion products and the saturation of the mixture with oxygen;
- A blower fan in front of the heat exchanger with a variable speed allows you to maintain the optimal ratio of air / natural gas;
- Chimney made of ceramic or heat-resistant plastic. Here it is possible to use plastic, since the temperature of the smoke does not exceed 70 ° C;
- Flue gas pump with electronic power control. It optimizes the operation of the device, reduces noise and helps to set the optimal mode;
- Condensate removal system. The water settled on the walls of the heat exchanger is discharged into the sewer.
In the photo - a plastic coaxial chimney.
For the most productive and comfortable operation of the device, it is necessary to have a low-temperature heating system, for example, "
You can set up the device with your own hands, but it is better to call a specialist.
Among the advantages of using condensate units, the following features are usually distinguished:
- Most effective use thermal energy of fuel combustion;
- The highest efficiency of all known heating boilers;
- Simple instructions for operating the device;
- Significant savings on energy costs;
- Reliable and durable performance.
It is important to understand that this is not an innovation at the development stage. The devices are successfully used in many European countries, and their residents have not asked what it is for a long time. In some of the countries, such as the UK, only condensing boilers are sold, as the government cares about savings and the general well-being of citizens.
The only drawback is the high price of the device, but it quickly pays for itself by saving gas which is very expensive in Europe. Considering that the problem of the high cost of energy resources is gradually becoming relevant for everyone, the citizens of Russia should also take a closer look at this technology.
Conclusion
We examined the condensing boiler and dismantled the principle of its operation. This device allows you to achieve maximum efficiency and significant savings on heating. You can learn even more information from the video in this article, and ask your questions in the comments.
Energy-saving technologies and economical use with maximum efficiency of energy resources are becoming more and more relevant topics. Condensing boilers is the result of applying the latest unique technologies in the technology used for heating. They have the highest efficiency - 15-17% higher than conventional atmospheric boilers, service life is 2-3 times longer, a wide power range (up to 100 kW or more).
Due to its effectiveness condensing boilers are very popular in Europe, for example in Germany 70% of heating boilers are condensing.
Principles of operation of a condensing boiler is based on the receipt and transfer to the coolant of additional thermal energy released in the process of condensation of water vapor.
In a direct combustion gas boiler, the transfer of thermal energy to the heat carrier occurs by heating the heat exchanger gas burner in which the combustion process takes place. One of the components of the gases formed during the combustion process is water vapor, which in turn appears as a result of the combustion of hydrogen present in natural gas. Part of the water vapor heating boiler together with flue gases they exit through the chimney into the atmosphere, and part in the form of condensate is discharged through the condensate pipe of the chimney (usually to the bathroom).
In direct combustion gas boilers, condensation is a negative factor; in condensing boilers, the process of water vapor condensation is the main condition on which the operation of the boiler is based.
It is designed in such a way that water vapor having a temperature of 130 to 150 °C is cooled by a heat carrier from the return line of the heating system to a temperature below 57 °C. It is at this temperature that water condenses, 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 combustion. natural gas. As you can see, to ensure the process of condensation of water vapor, the coolant of the return line of the heating system is used.
The lower the temperature of the return heat carrier in the boiler, the more condensation heat is released, and, accordingly, the higher the boiler efficiency is main principle operation of any condensing boiler.
The maximum efficiency of a condensing boiler can be achieved at a return temperature of 50 - 30 °C. During the condensation process, a slightly acidic environment, 3-5 pH, is formed, therefore the materials from which the boiler components are made, used in humidification zones, must be resistant to acidity. In high temperature areas, aluminum alloys and stainless steel are most commonly used, in the area low temperatures the most cost-effective are plastics (eg polypropylene).
The heat exchangers of the condensing boilers are made of stainless steel and aluminum, equipped with a condensate collection and discharge system, as well as a blower fan with a stepped power system. By controlling the fan speed, an optimal air-to-gas ratio for the combustion process is achieved and a high efficiency is achieved. For an efficient gas combustion process, injection burners with flame modulation are used. Removal of products of combustion of gases occurs forcibly through a coaxial pipe. The flue gas temperature is 40-50 °C
OPERATION
For maximum efficiency condensing boiler must be operated within a certain temperature range. If the operating temperature is between 60 and 80°C, little water vapor condensation 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 gas combustion is taken as 100%, the energy received from the condensation process is added to it, therefore, 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 ° C, maximum 70-50 ° C).
Most meet these system requirements warm floors with a heating medium supply temperature of 40-45°С and a return temperature of 35-30°С, less suitable are radiator heating systems with a heating medium supply temperature of up to 70°С and a return temperature of 50°С.
Modern energy-saving technologies can significantly save on heating, condensing boilers 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, together with our partners, are building a comfortable and energy-efficient country house in the Moscow region. To do this, when building a cottage, the most modern materials and technology.
The UWB was chosen as the foundation, and the heating system - a warm floor. In addition, a wall-mounted condensing gas boiler became the boiler room. About why this equipment was chosen for our project, and what are the advantages of its work, in the format of a master class, the technical specialist of the company will tell you.
- 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 pay attention to 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 building. This means that, in addition to a closed thermal insulation circuit, all elements of the cottage, including engineering system should be optimally matched to each other. That is why it is so important to choose a boiler that goes well with the 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, unlike European countries, condensing gas boilers are less common. In addition to environmental friendliness and greater comfort, this species equipment allows you to reduce heating costs, tk. such boilers work 15-20% more economically than conventional ones.
If you look specifications condensing gas boilers, then 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 method of heat engineering calculation used for conventional gas boilers, which does not take into account one important point 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 others are also formed. chemical elements.
In a conventional boiler, the temperature of the flue gases after passing through the heat exchanger can reach up to 175-200 °C.
And water vapor in a convection (conventional) heat generator actually "flies into the pipe", taking with it part of the heat (generated energy) into the atmosphere. Moreover, the value 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 heat carrier. To do this, it is necessary to cool the flue gases to a temperature of the so-called. "dew point" (about 55 ° C), at which water vapor condenses 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. Fuel has a lower and higher 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 flue gases.
- The net calorific value of a fuel is the amount of heat released without taking into account the energy hidden in water vapor.
The efficiency of the boiler is expressed in the amount of thermal energy obtained from the combustion of fuel and transferred to the coolant. Moreover, indicating the efficiency of the heat generator, manufacturers can by default calculate it according to the method using the net calorific value of the fuel. It turns out that real efficiency of a convection heat generator is actually about 82-85% , a condensation(remember about 11% of the additional heat of combustion, which he can "pick up" from water vapor) - 93 - 97% .
This is where the efficiency figures of a condensing boiler appear, exceeding 100%. Thanks to 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 coolant 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 very coldy we have to support high temperature coolant, the rest of the time, with weather-dependent regulation, the temperature of the coolant will be lower, and due to this, we will save 5-7% per year.
The maximum possible (theoretical) energy savings when using the heat of condensation is:
- when burning natural gas - 11%;
- during combustion liquefied gas(propane-butane) - 9%;
- during combustion diesel fuel(solar fuels) - 6%.
Benefits of using a condensing gas boiler
So, we figured out 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 already wrote above that when the main gas is burned, a whole “bunch” of chemical elements is formed. Water vapor contains carbon dioxide and carbon monoxide, nitrogen oxides, and sulfur impurities. During condensation and the transition of steam from a gaseous to a liquid state, these impurities end up in water (condensate) and a weak acid solution is obtained at the output.
Sergey Bugaev
The heat exchanger of a conventional boiler will not withstand long work 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 corrosion and acid resistant. The most resistant material is stainless steel.
In the manufacture of the condensing boiler, only durable and wear-resistant materials are used. This increases the service life and reliability of this equipment, and reduces maintenance costs.
In addition, increased requirements are also imposed on other structural elements of the condensing heat generator, because. it is required to cool the flue gases to the required temperature. For this purpose, the boiler is equipped with a forced draft burner with a high degree of modulation. Such a burner operates in a wide power range, which allows you to optimally regulate the heating of water. Also, condensing boilers are equipped with automation, which ensures accurate maintenance of the combustion mode, the temperature of the exhaust gases and water in the return line. Why are circulation pumps installed that smoothly change the pressure force of the coolant flow, and not like simple 2- and 3-speed pumps. With a conventional pump, the coolant 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 to overheat the heating system (underfloor heating) and reduce thermal comfort.
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 source. The burner of the condensing boiler can operate at a power of 1/10 (10%) of the maximum (nominal) power of the heat source.
Sergey Bugaev
Consider the following situation: the heating season has begun, the temperature outside is -15 °C. The power of a conventional boiler installed in the house is 25 kW. The minimum power (1/3 of the maximum) at which it can operate is 7.5 kW. Assume that the heat loss of the building is 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 outside temperature is now around 0 °C or slightly lower. The heat losses of the building, due to the increase in temperature outside, have decreased and now amount to approximately 5 kW. What will happen in this case?
An ordinary boiler cannot working in continuous mode, to give out 5 kW of power necessary to compensate for heat losses. As a result, it will go into the so-called cyclic mode of operation. Those. will constantly turn the burner on and off, 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, will quietly give out 2.5 kW of power (10% of 25 kW) in continuous operation, which directly affects the service life of the heat generator and the level of comfort in a country house.
Condensing boiler, supplemented by weather-compensated automation, adapts flexibly to changes temperature regime throughout the 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 usability of the equipment.
We add that the heating season in Russia, depending on the region, averages 6-7 months, starting in the fall, when it is still not very cold outside, and lasts until spring.
Approximately 60% of this time, the average daily temperature outside is 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 have set in.
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 one, will work effectively both with temperature differences and with a slight frost. At the same time, gas consumption will decrease, which, in tandem with low temperature system heating (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 compact equipment. Condensing gas boiler in wall-mounted especially relevant for small boilers.
In addition, the condensing boiler has a turbocharged burner, which allows you to abandon the standard expensive chimney and simply lead the coaxial chimney through a hole in the wall. This simplifies the installation of equipment or the installation of a new condensing boiler to replace the old one - conventional, in case of renovation existing system heating.
Features of 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 kWh. Therefore, a condensing gas boiler with a power of 24 kW when operating at 12 kW of power (because most of heating period the boiler works with modulation, and the average load on it, depending on the conditions, can be below 25%) on a fairly cold day produces 40 liters of condensate in low temperature mode.
The condensate can be drained into central sewerage, provided that it was diluted in a ratio of 10 or better 25 to 1. If the house is equipped with a septic tank or a local treatment plant, condensate must be neutralized.
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, by gravity enters the sewer.
Summarizing
it modern equipment, characterized by reliability, economy and efficiency. Emissions of harmful substances into the atmosphere are also reduced, which is especially important when environmental standards are tightened. In addition, installation of this type heat generator, by reducing gas consumption, will reduce heating costs in the long term and increase the level of comfort in a country house.
The term "condensing boiler" for many is synonymous with reliable and economical heating equipment. However, not everyone can explain what this concept means, and how a condensing type unit differs from a conventional gas boiler.
Principle of operation and internal structure
In traditional gas heating units flue gases, the temperature of which is +100-(+170 0 C), together with the resulting water vapor is removed into the atmosphere. The calorific value of the fuel used in such installations is called the net calorific value. Condensing gas boilers, thanks to the use in their design and production the latest technologies, are capable of converting the energy of condensation of water vapor into heat.
Definition! The total energy of combustion of a gaseous fuel, including the energy of converting water vapor into a liquid, is called the gross calorific value of the fuel.
Features of condensing device heat exchangers
Almost every gas boiler can theoretically be made condensing by retrofitting it with a condenser / heat exchanger and ensuring that additional aerodynamic drag removal of combustion products.
Attention! Surface temperature condensation heat exchanger must be below the dew point of the fuel used.
At the beginning of the development of condensing technologies, the production of units of this type followed this path. The operating heat generating plants, as a rule, were floor-standing units made of cast iron, equipped with lamellar condensing modules made of corrosion-resistant steels.
Relatively recently, unified gas heating installations began to be created, originally designed to operate in the condensing mode. The heat exchangers of such units must:
- ensure intensive and efficient removal of steam condensation energy;
- be resistant to condensate, which provokes corrosion processes.
Definition! The condensate of gas boilers is a mixture of carbonic, nitric, sulfuric acids of low concentration.
Gas condensing boiler is manufactured with one or two heat exchangers:
- In the first case, this is a double heat exchanger with a branched heat exchange surface, made of stainless steels.
- In the second case, the high-temperature heat exchanger is made of aluminum-silicon alloys, copper, and stainless steel. As a rule, such a heat exchanger is made of stainless steel.
Attention! AT wall boilers for high-temperature heat exchangers, cast iron is not used because of its significant mass.
Advantages of condensing gas heating equipment
- Innovative burner design provides virtually complete combustion fuel, due to the high efficiency, the amount of gas used is reduced (by 10-15%) and, consequently, the amount of emissions into the atmosphere is reduced.
Attention! The maximum efficiency is obtained when using units of this type in low-temperature heating, for example, in underfloor heating systems.
- equipment thanks to design features, is virtually silent.
- Wall-mounted models can have a power of up to 100 kW, while traditional wall-mounted gas boilers produce a maximum power of 35 kW.
- The service life of this heating equipment is 2-3 times higher than that of conventional gas units.
Manufacturers of heating equipment of the type in question
To the condenser heating technology upper class products can be attributed German companies Viessmann and Buderus, the Italian company Baxi.
- Condensate gas Viessmann boilers Vitodens have a power range from 4 to 66 kW. These units are manufactured using a fundamentally new design of the heating surface. The Inox-Radial heat exchanger is a parallelepiped coiled into a coil. Stainless steel is used for its production. The company completely abandoned the installation aluminum heat exchangers due to less corrosion resistance and therefore shorter service life.
Attention! The design of Inox-Radial heat exchangers provides for the possibility of installing, if necessary, devices for condensate neutralization.
The Vitodens 300, 333, 343 are equipped with modulating burners to save fuel and modulating circulation pumps minimizing power consumption. The cost of installations with a capacity of 26 kW is approximately $ 1,800.
- The German company Buderus is a pioneer in the production of condensing technology. Logamax plus GB 112 models are manufactured with a capacity of 80 and 100 kW, which is a record for wall-mounted gas boilers. At the same time, the units have compact dimensions - their width is equal to that of conventional boilers with a capacity of 24 kW. This equipment uses a finned heat exchanger made of silicon-aluminum alloys. approximate price boilers of this brand with a capacity of 24 kW - $ 1,400.
Models of the BAXI brand are a combination of excellent performance characteristics and reasonable price. The 28kW Prime HT costs approximately $1,500. This economy-class condensing wall-mounted boiler is equipped with the possibility of electronic modulation of the flame, both in heating mode and in hot water mode.
