The range of wall-mounted boilers presented in the distribution network is wide and varied, so the consumer can easily choose a technically perfect unit. Towall-mounted condensing boilers operating on main gas fuel are among the most efficient and environmentally friendly- methane.
About the tricky calculation method
Gross calorific value of fuel- this is the entire amount of heat that can be used in the combustion of fuel, including its share contained in the water vapor of the exhaust gases. Net calorific value- the amount of heat without taking into account the energy hidden in the steam of exhaust gases. To show their product in a favorable light, sellers of heating equipment almost always indicate the efficiency of the heat generator, calculated according to the method using the net calorific value of the fuel. However, the buyer is not informed about this. ATas a result, instead of efficiency 80–85%, real for a traditional heat generator, an indicator of 92–95 appears%, and the efficiency of the condenser instead of 93–96% is at the level of 107–109%, which contradicts the law of conservation of energy. This fact causes a certain skepticism among consumers who are unfamiliar with the basics of heat engineering. But you still should not be afraid of the ultra-high efficiency of a condensing boiler.are the costs of the existing calculation method.
Traditional wall-mounted boilers utilize the heat generated during gas combustion using a convection heat exchanger (in fact, this is a tube on which numerous copper plates are mounted). The combustion products of methane heat this unit, and it transfers the heat received to the heat carrier of the heating system. The draft required to maintain combustion in conventional wall-mounted boilers is provided by the vacuum that occurs in the gravity chimney; the average temperature of the combustion products removed into the atmosphere at the outlet of the boiler is 120
Where does the condensate come from? When natural gas (like any other hydrocarbon fuel) is burned, a chemical reaction occurs, and as a result, water is formed, which instantly turns into steam in a fire. It is steam that contains up to 11% energy of methane burned. Purpose of the condensing boiler- use this energy by reducing the temperature of the exhaust gases to the dew point (for gas combustion products- approximately 57
one.Condensing wall-mounted boilers Innovens (De Dietrich) provide an optimal level of comfort in heating and hot water preparation.
2.MCR boilers with a capacity of 6.3–39kW run on natural gas or propane. For hot water supply, boilers are equipped with flow-through heat exchangers that allow hot water to be obtained immediately after gas is ignited, or connected to boilers. Capacity at 80l mounted next to the boiler, at 130l- under him.
3.Condensing boilers ecoTEC plus (Vaillant) are very economical and do not pollute the environment.
four.The wall-mounted condensing boiler Vitodens 200‑W (Viessmann) is installed in a row with wall-mounted kitchen cabinets.
What is the difference between condensing boilers and conventional boilers? The former have a special heat exchanger made of acid-resistant materials (stainless steel, silumin andt.P.). It has a large outer surface in contact with flue gases, which, by the way, can self-clean with fluctuations in the temperature of the coolant, as in the ComfortLine model (Wolf, Germany). Such a heat exchanger is capable of operating both in low-temperature mode (the temperature of the water returned to the boiler,- around 30
A modern wall-mounted condensing boiler (both single- and double-circuit) is functionally superior to almost any wall-mounted gas appliance of traditional design. The power of wall-mounted condensers ranges from 5–125kW. This means that with just one unit it will be possible to heat a fairly large house. If the heat demand of the dwelling exceeds 120kW, condensing boilers, if desired, are combined into a cascade, which allows you to satisfy the appetites of any private country house. For example, condensing boilers Rendamax (Netherlands) can be equipped with a cascade control device, which includes up to eight devices.
The condensing boiler produces hot water in significant quantities. So, a single-circuit condenser can always be connected to a remote boiler. For example, ProCon (MHG, Germany) is able to work with an external boiler up to 500l. With a small water consumption (say, a faucet in the kitchen and a shower in the bathroom), it is a good idea to buy a double-circuit condensing boiler that heats the water using a plate heat exchanger built into it. This can be, for example, a dual-circuit ComfortLine (Wolf). Very compact and productive models with a built-in mini-boiler. ATVitodens 333‑F boilers (type WS3C, Viessmann, Germany) have a built-in water heater tank with a capacity of 86l.
5.A high-efficiency wall-mounted condensing boiler Vitodens 200‑W (Viessmann) is installed in the kitchen of a country house. The device heats the heat carrier for heating and water for the DHW system.
6–7.Condenser CGB-K-24 Comfort-Line (Wolf) with built-in control panel(6) and remote controller calorMATIC 330 (Vaillant)(7).
eight.Biasi wall-mounted condensing boilers can be combined in a cascade to increase output. Installation of equipment will be greatly simplified by special metal cell cabinets.
Is the game worth the candle?
On average, due to the difference in efficiency, a good condenser spends 1kW of heat for gas heating needs by 15% less than traditional wall-mounted boiler. For example, for heating a house with an area of 200m2 traditional boiler with a capacity of 24kW for the heating season will consume 60$.m3 gas, and condensing of similar capacity- total 5100m3. Then if price is 1000m3 gas 3690rub. (this is how much main natural gas now costs for owners of dachas near world), for the indicated period, the owner of condensing equipment will save approximately 3321rub. For 10years, this amount will increase to 33,210thousandrubles, or even more, as natural gas prices for the population are growing, and recently at a fairly rapid pace.
from condensing boilers
However, assuming that gas prices in EU remain unchanged (which is unlikely), the economic feasibility of buying a condensing boiler can be called into question. After all, for example, a condenser with a capacity of 24kW is more expensive than a traditional heat generator of the same power, just by the same 30–35thousandrubles, which will be saved on fuel and fully returned to the owner of the boiler only after 10years of its operation. In addition, although this equipment has an increased resource (which, by the way, partially compensates for the high cost of condensers), it still requires regular and expensive maintenance.
Photo by V.Balashova
9.Modern condensing boilers are usually very compact in size, light in weight, and are delivered assembled. All this greatly simplifies their installation and allows you to fit the equipment into any interior. High-quality condensing equipment works with a fairly low noise level even at maximum power.
ten.The Vitodens 300‑W (Viessmann) condensing boiler is equipped with a SMART diagnostic system (Self Monitoring And Reporting Technology), which promptly detects malfunctions in the operation of the heat generator and informs the user about this.
11–12.Condensing boilers BWC 42 (Bosch)(11) and Logamax plus GB 162 (Buderus)(12) equipped with multifunctional control systems, extremely easy to set up and easy to maintain.
Nevertheless, condensing boilers should be preferred primarily because they are environmentally friendly. Since the emissions into the atmosphere of condensers are environmentally cleaner (compared to the products of combustion of traditional units), this equipment can be placed in residential buildings without constructing high chimneys. Due to the preliminary mixing of fuel and air, as well as lowering the temperature of the exhaust gases, it is possible to suppress the formation of nitrogen oxides NOX and reduce the content of CO (carbon monoxide), since the latter is oxidized to less dangerous CO dioxide2 (carbon dioxide). ToIn addition, condensate captures a significant part of harmful substances, so the amount of harmful emissions into the atmosphere is sharply reduced. For example, the content of nitrogen oxides and carbon monoxide in Baxi condensers (Italy) is reduced by 80 and 90, respectively, compared to conventional wall-mounted gas boilers.%.
There is another important advantage of a condensing boiler over a traditional one.- the first is adapted to low-temperature heating systems (more comfortable than conventional, high-temperature ones). ATsuch systems use large heaters. Their set will cost the owner of the house 20–50% more expensive than when creating a high-temperature heating system (for a dwelling with an area of 150m2- at 10–20thousandrub.). But on the other hand, the radiators of low-temperature systems heat up only up to 40–45
13.The Logamax plus GB 162 (Buderus) boiler is equipped with a heat exchanger with a capacity of up to 100kW, the high efficiency of which is due to its large heat exchange surface.
fourteen.The ceramic burner of the GB 162 boiler allows you to change its power from 18 to 100%.
fifteen.ATThe GiegaStar (Giersch) gas-fired wall-mounted condensing boilers use a cylindrical stainless steel burner mounted in the upper zone of a corrosion-resistant heat exchanger made of high silicon aluminum alloy (11%).
16.Scheme of operation of the MCR boiler (De Dietrich).
Unfortunately, the condensing boiler “produces” a significant amount of condensate. Of course, even during the operation of an ordinary boiler, quite a lot of this liquid sometimes turns out to be in the chimney, especially in frosty weather, but these volumes are incomparable with the “productivity” of the condenser. Thus, a condensing boiler with a capacity of 25kW gives up to 3.5l / h of condensate, almost two buckets of it will be collected per day, and per year (with continuous operation)- up to 7thousandl. In fact, the condensateis a weak solution of carbonic and sulfuric acids in water. Its pH value depends on the type of fuel, the design of the heat exchanger, the excess air coefficient, the final temperature of the condensate, and when using main gas, it is 4–6.
The question arises: where to drain the condensate? After all, you can’t divert it into a stream flowing next to the house, onto the ground or into a gutter at the border of the site (thus, you will worsen the ecological situation both on your territory and among your neighbors). If at the heart of the building’s sewer- a biological treatment plant, it is undesirable or even unacceptable to drain an acidic solution into the pipes (as a result, a colony of bacteria that provide wastewater treatment may die). So, for many high-tech models of treatment facilities designed for a country house, the required pH value of the effluents- not less than 6.5.
However, there is a very efficient and inexpensive equipment that allows you to prepare condensate for disposal in traditional ways. So, before draining into the house sewer, the condensate must be subjected to deoxidation in the neutralizer. The latter is usually mounted next to a wall-mounted condensing boiler (on the floor or wall). Converter- this is usually a small container, at the inlet to which a filter is installed that cleans the condensate from solid particles. Once in the neutralizer, the condensate gradually seeps through the backfill of alkali-containing granules or marble chips that fills it and at the outlet is a liquid with a pH that is quite safe for any septic tank6.5–9.
The pH value of the deoxidized condensate must be systematically controlled (at least 1once amonth). To do this, you can use the test strip supplied with the neutralizer or a pH meter. You will have to regularly pour pellets into the neutralizer or (if required by the operating instructions) completely change the backfill 1every 6–12months Examples of Neutralizers- Neutrabox GENO I‑25 (Grunbeck, Germany), NS33 (De Dietrich, France). The price of a neutralizer for a condensing boiler with a capacity of 25kW (the delivery set, as a rule, includes deoxidizing granules per filling) is about 10–19thousandrub. Additional bag with granules (5kg) costs about 1–1.5thousandrub.
ATsettlement sewerage (if several dozen houses are connected to it) condensate can be drained without neutralization if the boiler capacity does not exceed 200kW. After all, household drains, including those from washing machines and dishwashers, often have a weakly pronounced alkaline composition (pH7.2–7.8). Therefore, the condensate is already neutralized directly in the sewer, due to the contact of alkaline and acidic environments. However, in this case, it may be necessary to install a deoxidizing device.- for example, if pipes and sewer seals are made of a material that cannot withstand prolonged contact with a weak acid solution, or if the condensate does not mix in sufficient proportion with domestic sewage water (at least 1:25).
17.The “heart” of the Vitodens 200‑W wall-mounted condensing heat generator is the spherical Matrix burner made of stainless steel, which allows to significantly reduce the emission of harmful substances into the atmosphere.
18–19.heat exchanger(18) and cylindrical burner(19) Biasi condensing wall mounted boilers are made of acid-resistant durable materials.
twenty.Condensing wall-mounted gas boilers CGB-K-24 (Wolf) are equipped with a stainless steel hot water heat exchanger. These heat generators are designed for heating and hot water preparation in flow mode. If over time the needs of a country house for warm water increase, a boiler can be connected to the boiler, for example CSW-120.
Andone more circumstance. If the boiler is located in the basement or basement of the house, below the entrance to the sewer, the condensate will not fall by gravity into the sewer. It will be necessary to install a container with a float valve behind the neutralizer, which, as the vessel is filled, will turn on the pump, or a special sewer installation, for example, Conlift (Grundfos, Denmark, about 6.2thousandrub.) to automatically remove condensate into the sewer.
It is very important to choose the right chimney for a condensing boiler. The design of the latter is such that the combustion products are discharged forcibly. This makes it possible to connect the boiler to a coaxial chimney, as well as to a branch pipe for air intake from the street or from a room and removal of combustion products through a chimney. The temperature load on the chimney of a condensing boiler is small (by the time it enters the chimney, the flue gases cool down to 40–60
Photo by V.Balashova
Photo by V.Balashova
Photo by V.Balashova
21.Removal of condensate into the village sewer. When removing condensate from a wall-mounted condensing boiler into a city or large village sewer, you do not need to use a device for its neutralization. Normalization of pH will occur as a result of mixing the condensate with wastewater.
22.Backfill pellets in the condensate neutralizer.
23.Neutralizer Neutrabox I‑25.
24.Conlift unit (Grundfos) with built-in non-return valve for automatic condensate removal (pressure- 5.3m).
What does the market offer?
Currently, condensing boilers are produced by almost all leading boiler-building companies. ACV products (Belgium) can be noted: Prestige series; Ariston: Genus Premium; Beretta: Exclusive Green and Power Plus (both- Italy); Baxi: Prime HT, Luna HT, Luna HT Residential and Nuvola HT. Very good equipment is produced by De Dietrich: Innovenc, MCR. Let’s also call Immergas: Victrix; Ferroli: Energy Top, Econcept; Sime: Format Dewy.zip and Planet Dewy (all- Italy); Protherm (Slovakia): “Lion” series; Thermona (Czech Republic): KD, KDC, KDZ rated power 28kW, as well as the Therm 45 KD condensing boiler with a nominal output of 45kW with a combustion chamber made of heat-resistant plastic. One of the trendsetters for condensing equipment is the company Rendamax (in EU, for example, boilers of the R30 series are popular). Finally, condensers of excellent quality and thermal performance are supplied by German boiler manufacturers.- Buderus (Logamax plus three series: GB022, GB112, GB162), Junkers (Cerapur), MHG (ProCon Streamline), Vaillant (ecoTEC plus), Viessmann (Vitodens 200‑W, 300‑W and 333‑F), Wolf (Comfort Line). The approximate cost of a household wall-mounted condensing boiler can be determined by multiplying its rated power by 3thousandrub.
The editors would like to thank Biasi, Buderus, De Dietrich, Vaillant, Viessmann for their help in preparing the material.