Efficiency and selection criteria for pyrolysis solid fuel boilers

Selecting the ideal heating system for your house is essential for both efficiency and comfort. Because of their effectiveness and favorable effects on the environment, pyrolysis solid fuel boilers have become more and more popular as an alternative heating option. These boilers use a technique known as pyrolysis, in which biomass or wood is heated in a low-oxygen atmosphere to create combustible gases that are subsequently used for heating. While upgrading their heating systems, homeowners can make more informed decisions if they are aware of the efficiency and selection criteria of these boilers.

One of the most important factors in pyrolysis solid fuel boilers is their efficiency. Pyrolysis boilers, as opposed to conventional boilers, which burn fuel directly, first turn biomass into combustible gases, which can lead to increased efficiency and decreased emissions. Boilers with high efficiency can produce the most heat with the least amount of fuel and environmental impact. To ensure optimal performance, factors like insulation, residence time, and combustion temperature must be taken into account when evaluating the efficiency of these boilers.

A number of factors should be considered when choosing a pyrolysis solid fuel boiler in order to match the boiler’s capabilities to the heating needs of your home. The heat output capacity of the boiler should be adequate to meet the heating needs of your space, so start there. Furthermore, evaluate the amount and kind of biomass fuel that the boiler can handle, as this will affect maintenance needs as well as operational effectiveness.

An essential consideration when choosing a boiler is its ease of operation and maintenance. Seek for boilers that have easily navigable controls and easily accessible parts for upkeep and cleaning. To guarantee the boiler’s longevity and effectiveness, routine maintenance is necessary. To quickly resolve any issues, take into account the availability of spare parts and technical support.

In general, homeowners looking for cost-effective and environmentally friendly heating options have a promising alternative in pyrolysis solid fuel boilers. Through comprehension of the efficiency attributes and selection standards of these boilers, homeowners can make well-informed decisions that complement their heating requirements and ecological objectives. When the right boiler is selected with efficiency and other important factors in mind, energy costs and environmental impact can be decreased and home comfort can be greatly increased.

Criteria	Description
Efficiency	Measure of how well the boiler converts fuel into heat for the house.
Environmental Impact	Assessment of emissions and sustainability of the boiler"s operation.
Cost	Initial purchase price and ongoing operational expenses.
Size and Installation	Physical dimensions and ease of installation in your home.

What are solid fuel pyrolysis boilers

To begin with, the majority of these boilers are energy-dependent single-circuit models. An extra gas combustion chamber is the primary—and essentially the only—difference between traditional solid fuel boilers and pyrolysis boiler units. To obtain thermal energy at a lower cost per kilowatt-hour, high-energy gas must first be separated from solid fuel and then burned. And all of this without the need for human intervention, with high efficiency, prolonged combustion, and dependable control.

Device and principle of operation

Wood gas and charcoal are produced when organic compounds are allowed to break down over an extended period of time at temperatures as high as 800 °C without the presence of oxygen, resulting in the production of high-energy fuels. A pyrolysis solid fuel boiler is the apparatus meant to extract these products, burn them later, and produce hot water.

A gas-generator boiler works on the basic principle of separating solid fuel into two fractions, namely gas and coal, in order to extract as much energy as possible from their combustion. Their various devices share these characteristics:

• the combustion chamber of solid fuel in the mode of the greatest release of gases;
• gas combustion chamber;
• forced air control (by fans or mechanically).

The loaded fuel burns in the combustion chamber in the normal mode, and the air supplied to the combustion zone raises the temperature there to a point where there is abundant gas emission, but not higher. Fuel slowly burns to ash, heats the boiler’s water jacket, and releases gas when the oxygen supply is restricted.

Gas travels through the flue tract and into the afterburning chamber, where it burns intensely and abundantly in oxygen due to the pressure difference (draft). The heat transfer medium and the heat exchanger pipes warm up at high combustion temperatures.

The mechanical draught regulator, which regulates the blower door and high chimney during autonomous operation, is what causes the draught inside the unit. A blow fan regulates the oxygen supply to the combustion zone in high-tech, automated boilers, while a smoke pump fan regulates the draught of burning gas passing through the heat exchanger.

Long burning pyrolysis boilers

It is noteworthy to discuss the category of long-life boilers separately. The pyrolysis boiler enters its maintenance mode once the heat carrier has been rapidly heated to the desired temperature. The fuel in the smoldering mode burns progressively, layer by layer, as the oxygen supply to the combustion chamber is essentially cut off. The quantity and quality of the fuel that is loaded determine how long it takes to burn a single tab.

A single charge of coal can burn for an average of 8 to 15 hours in a conventional pyrolysis boiler, while a conventional solid fuel boiler requires refueling every 3 to 6 hours. Modern long-burning pyrolysis boilers are distinguished by their roomier furnace and superior combustion control, which enable them to operate with a single load for as long as 48 hours or longer.

How much more efficient pyrolysis technology is than direct combustion

Efficiency in direct combustion boilers rarely exceeds 75–80%, and that is only when high-quality fuel is burned. For instance, 3.9*0.75 = 2.925 kW of heat energy can be produced by 1 kg of wood with a 20% moisture content (the specific calorific value of wood is 3.9 kW/kg). 10% moisture content in hard coal yields 7.5*0.75 = 5.625 kW (hard coal’s specific calorific value is 7.5 kW/kg).

Today’s pyrolysis combustion technology often achieves 92% efficiency, and the unit will produce the following fuel from the same source:

• 1 kg of wood – 3.9*0.92 = 3.588 kW ( +22,7% );
• 1 kg of hard coal – 7.5*0.92 = 6,9 kW ( +22,7% ).

The substantial discrepancy illustrates the amount of heat lost through emissions as opposed to the associated gases burning (the outcomes will vary depending on the efficiency differential).

Effective combustion control in pyrolysis makes it possible to extend the boiler’s operating time while keeping the coolant at a constant temperature, which improves thermal energy accumulation even more. Since the pyrolysis gases burn at a higher temperature than in the traditional method, the set mode exits much faster.

What kind and how of coal is best for heating a solid fuel boiler in a home?

Reviews of household gas-generator boilers: advantages and disadvantages

The global community’s concern over environmental pollution has improved the standing of pyrolysis boilers in the long-burning heating unit market. A small amount of steam and carbon dioxide are released into the atmosphere when this kind of boiler is operating as intended, based on owner reviews and operating practices. When any organic fuel is burned, the chimney releases a minimum amount of unburned material without cinders, smoke, odor, or color. The outcome is also seen in emissions that enter the boiler room, such as during refueling, and particularly in the boiler’s pollution and the frequency of cleaning.

Advantages	Disadvantages
Due to afterburning of pyrolysis gases the efficiency can reach 95%.	The cost of the equipment is 1.5-2 times higher, although it pays off relatively quickly
Larger loading chamber allows for longer operation from a single load (1.5-3 times) than conventional units	High costs of fuel preparation in terms of moisture content. It should not exceed 20%, otherwise the pyrolysis process will not take place
Fuel combustion with almost no residues and the design of combustion chambers makes cleaning and maintenance less frequent and easier.	Most industrial and domestic units with high automation use blow fans and smoke extractors, which makes them dependent on electricity supply
High temperatures imply the device of heat exchanger from heat-resistant steels, which makes it possible to heat the building faster	At low temperature of the heat carrier in the return pipe, the boiler may extinguish, it is necessary to add hot water through a three-way valve or bypass.
Emissions of combustion products are minimal	The overall dimensions and weight are significantly higher than those of other types of boilers
The units can work on any organic fuel without significant modification, but with different efficiency	At low loads (less than 50%) it is difficult to obtain stable combustion
High efficiency implies economical fuel consumption and reduces fuel costs
High level of automation of the boiler operation allows to control the combustion process less frequently

In the realm of home heating and insulation, the selection of an efficient pyrolysis solid fuel boiler is crucial. These boilers offer a sustainable and environmentally friendly way to heat homes by utilizing organic materials like wood pellets or chips. The key thesis of this article is to highlight the importance of efficiency and the criteria for choosing the right pyrolysis solid fuel boiler. Efficiency matters because it directly impacts heating costs and environmental impact. Factors such as the boiler"s heat output, combustion efficiency, and emissions performance are critical in making an informed choice. Additionally, considerations like boiler size, maintenance requirements, and integration with existing heating systems play a pivotal role in ensuring optimal performance and cost-effectiveness. By understanding these selection criteria, homeowners can make informed decisions to enhance their home heating systems with efficient and eco-friendly pyrolysis solid fuel boilers.

How to choose a pyrolysis boiler

The user’s preferences and the amount allotted for their purchase will determine which model and brand they ultimately decide to purchase for their gas generator unit. However, it is necessary to assess the qualities listed below at first estimations.

Location of the afterburning chamber

The idea behind how the pyrolysis gas combustion chamber operates remains the same, but the unit’s design takes on new characteristics.

Forced ventilation is not necessary for the upper afterburning chamber, which is situated above the fuel loading and combustion chamber. This type of boiler arrangement is better suited for independent operation without electricity or fans. The combustion chamber’s natural pressure drop causes gas to rise. Nevertheless, some of the burning gases that contain residues of unburned fuel escape into the atmosphere. These boilers have a slightly lower efficiency, but at the subsequent loading, the ash that has crumbled into the feed chamber can be easily removed.

Advanced solid fuel pyrolysis boilers typically have a bottom afterburning chamber. Forced draught burning of pyrolysis gases passes through the heat exchanger’s whole complex path, releasing all of its stored heat energy. These boilers have an efficiency of up to 92%, and in certain cases, higher, thanks to well-known brand designs. The fuel loading and combustion chamber’s combustion waste crumbling into the lower chamber is the annoyance. This makes maintenance more difficult.

Fuel

The most prevalent kind in the area dictates the fuel option for the solid fuel unit. This will ensure supply stability and a reasonable price. The length of combustion is a crucial raw material characteristic for long-burning pyrolysis boilers. They should ideally use fuel that has a smoldering time of:

• hard coal – up to 15 hours;
• brown coal – up to 11 hours;
• wood – up to 10 hours.

But since not all models are made to burn coal, it’s crucial to read the information about the fuel types that the boiler can use. Although the manufacturer may not have considered other solid fuels like sawdust, wood chips, or peat as fuel, they also burn more quickly and need to be refueled more frequently.

The humidity of the raw materials is crucial to the pyrolysis process; if it is higher than 20%, a large portion of the energy used will go toward drying, the efficiency will be low, and it will be difficult to recover large equipment purchase costs. Hardwood with a moisture content of 10% works well as fuel for most boilers.

Natural or forced draught

In order to regulate the combustion process in a pyrolysis boiler, the oxygen flow in the lower combustion chamber or feed chamber of the pyrolysis gases must be adjusted. Additionally, the burning gas must be advanced through multiple elbows of a contemporary heat exchanger. It is impossible to arrange a draught of this magnitude from the chimney’s height. As a result, modern boilers come fitted with blower fans, smoke exhausters, and numerous feedback sensors that allow the computer that controls the heating system as a whole to monitor and analyze the operation. The equipment is costly and energy-dependent due to this automation. Although the cost of such a unit is high, it is necessary due to its high efficiency, economic efficiency, and consumer comfort.

Energy-independent pyrolysis boiler can be with the upper chamber of gas combustion. The mechanical draught regulator, which regulates the oxygen supply, controls the under-blower flap, thus prolonging the smoldering of fuel in the loading chamber. Pyrolysis gas enters the upper chamber independently, due to the pressure difference between the chimney and the furnace. In it, mixed with the oxygen of the secondary air (second damper), it burns to completion. Most of the heat is used to heat the coolant, some of it goes through the chimney to the atmosphere. The process of setting up pyrolysis combustion requires very scrupulous fulfillment of the manufacturer"s regulations, but it is possible to gain real energy independence.

Boilers that can burn a single fuel deposit for up to seven days

Do pellet boilers that feature an automated fuel supply make a good investment?

EFFICIENCY

As stated in the pyrolysis solid fuel boiler efficiency documents, higher is preferable. This implies that a faster payback of the equipment’s cost will be possible due to operating costs. Nonetheless, the manufacturer establishes the passport efficiency under ideal circumstances—a specific fuel, chimney, etc.—for each product. Based on my expertise and guidelines for pyrolysis boiler operation, the subsequent prerequisites need to be fulfilled:

• accurately perform the necessary boiler settings for efficient operation;
• Fuel quality in terms of moisture and ash content must comply with;
• loading of the fuel chamber should be performed at 100% of the volume;
• fuel placement in the furnace must also be carried out in accordance with the recommendations.

In general, a number of requirements must be met in order for the declared efficiency to match the actual one; however, this is also the case with traditional solid fuel boilers. Speaking of declared efficiency, though, I advise beginning with an indicator of 88% or higher when making your selection. Efficiency levels between 86 and 87% show a flaw in the design and frequently don’t warrant the extra expense.

Minimum required power

When choosing a specific boiler, a heating engineer uses the norms and coefficients of SNiP 2.04.01-85 to precisely calculate the minimum output.

In actuality, use the rule of 1 kW per 10 m 2 heated area in domestic settings, plus an additional 20% reserve for single-circuit boilers.

For instance, the minimum boiler output required to heat a room with standard ceilings (2.7 m) and enough light or insulation (180 m 2) is (180/10)*1.2 = 21.6 kW. The unit with the closest larger nominal capacity must be selected.

The best known manufacturers and models: characteristics and prices

Numerous varieties of Russian-made and imported equipment have oversaturated the gas-generator boiler market. Manufacturers in Germany have long been considered leaders in the development of advanced heating systems based on pyrolysis units. Their equipment satisfies the strictest standards for economic, environmental, and efficiency. Additionally, the costs of German boiler units are commensurate.

Czech and Italian companies are a noticeable presence on the market for gas-generator boilers, producing comparable high-quality products that fall into the middle price range.

In recent years, Russian boiler equipment production has made great strides toward producing decent-quality gas generator units for heating at prices much lower (2–3 times) for products that are nearly identical to imported ones in terms of features and performance. Considering that it is more suitable for the current fuel and operational realities, buying it makes sense for those with a wider range of budgets.

Burzhuy-K "Modern-12"

This series is among the best pyrolysis boilers available for heating a private home because it combines energy independence with an economical price. The time difference between laying coal and wood is fifteen hours. With a slight decrease in efficiency, the boiler remains efficient when the fuel moisture content is up to 50%. 92% efficiency when using the right fuel is a very good indicator, especially considering the number of domestic manufacturers.

The boiler can run on any type of solid fuel, but a minimum 7-meter-high chimney is required for natural draft (which is a lot, but realistic). The construction is 220 kg in weight, fire-safe, and covered in steel sheets coated in basalt. Permission from supervisory authorities is not needed. It makes sense that the design is as straightforward and energy-independent as possible given that operation is said to be completely problem-free.

Effectiveness and selection standards for coal-fired boilers with a long burn time

Trajan TB-10-2KT

A gas-fired, two-circuit boiler with a 10 kW nominal output can have up to 40% of the nominal output reduced within its control range. not autonomous, but under mechanical control. Efficiency ranges from 82–85%, depending on fuel and adjustment. Apart from the DHW circuit, the primary characteristic is its incredibly small size, measuring just 450x890x730 mm (WxHxH). Comes with a Honeywell mechanical damper regulator for the air supply, a thermometer, and a pressure gauge.

When the boiler is operated properly, it can operate safely and simply, allowing ten hours to pass between loads of dry fuel. An optional TEN up to 3 kW can be connected to maintain the coolant temperature at low load. A complete suite of energy-independent automatics is also available as an option. The boiler has a weight of 190 kg.

Price range: 43,000–53,00 rubles.

Buderus Logano S171-22W

Included in the ranking as one of the most advanced boilers, featuring a bottom chamber for German-made pyrolysis gas afterburning. Logs up to 58 cm in length are the primary fuel source, which is highly convenient. With the most up-to-date automation systems installed, efficiency rises to 89%. These systems include temperature sensors in the rooms, programmable blower fan and smoke extractor motors, pump control for the heating system, and PC and mobile phone control.

The heating system’s quality control guarantees excellent environmental safety and reduces fuel consumption. The large loading chamber allows for an average firewood consumption of 6.2 kg/hour and a burning time of 3–4 hours. Ensuring optimal user comfort while adhering to high service requirements and intuitive operation. Overall measurements: 1136 x 620 x 1019 mm; weight: 362 kg. The fact that it is designed exclusively for wood burning, that it weighs a lot because of the 5 mm steel heat exchanger, and that it is expensive are its only drawbacks.

179,000–198,000 rubles is the cost.

Atmos DC 18S

Czech gas-generator long-burning boiler with integrated smoke pump and fan circuit. Even though the loading chamber of the 20 kW model is only 65 dm3, a single load of wood can take up to 12 hours to burn. Naturally, it is not very practical, but the best fuel for it is logs up to 33 cm long and 15 cm in diameter. However, with proper adjustment, a boiler can save up to 40% of fuel in a season, consume 3.8 kg of firewood per hour, and have an efficiency of up to 90%. The boiler needs to be connected to the power grid because of the fan and automatic controls, even though the control is partially mechanical. The heat exchanger is composed of 6 mm alloy steel.

One of these boilers’ key features is an integrated smoke pump that eliminates smoke while refueling wood, speeds up chimney heating, and eliminates odors. These kinds of pyrolysis units can be fitted with customized pellet burners. Total measurements: 590 x 1180 x 845 mm; weight: 269 kg.

"Suvorov-M" K-10

Domestic pyrolysis single-circuit long-burning boiler with a nominal capacity of 10 kW and a control range of 2.2 kW to 12 kW. It has an open furnace (air flow is not forced). Huge loading furnace: fuel briquettes can burn for up to 36 hours, and a stack of logs can burn for 10 to 14 hours. Using hardwood lengthens the combustion period by 20–30%, and high-quality sawdust briquettes prolong the smoldering period by several times. The logs can reach a maximum length of 45 cm, weighing 14 kg when fully loaded with dry firewood, and consuming 2.9 kg per hour.

Any solid fuel can be used in the boiler. To achieve a 92% efficiency, the raw material’s humidity should not be higher than 25%. Installing heating elements and connecting the DHW circuit are options that do not require energy. Total measurements: 990 x 535 x 780 mm; weight: 185 kg.

62 000–64 000 rubles is the cost.

"Suvorov Ultra" K-15U

Mine gas-generator long-burning boiler with a 15 kW nominal output and a 1.7–20 kW regulation range. Firewood can burn for up to 65 hours, while fuel briquettes can burn for up to 120 hours. A 140-liter firebox can hold logs up to 40 centimeters in diameter—not very useful, but sufficient—and can support 46 kg of weight when loaded. The moisture content of firewood should not be higher than 25% in order to achieve the highest efficiency of 94%–95.7%. It is standard procedure for the chimney’s height to be at least 6 meters measured from the grate.

By lengthening the unique three-turn gas path and utilizing a shaft layout that minimizes fuel combustion, the boiler was able to burn wood for longer periods of time, thereby extracting as much energy as possible. The boiler measures 1210 x 560 x 875 mm in total and weighs 295 kg.

Price range: 93 000–96 000 rub.

For both economy and efficiency, selecting the ideal solid fuel boiler is essential when it comes to your heating requirements. Boilers that use pyrolysis present a strong alternative because of their high efficiency and eco-friendly operation. With a process called pyrolysis, these boilers effectively use biomass or wood pellets to create combustible gases.

The efficiency rating of a pyrolysis boiler is an important consideration. Seek for boilers with high efficiency ratings—typically greater than 90%. This guarantees that the majority of the fuel’s energy is used to heat your house rather than being wasted. Over time, lower fuel consumption and lower heating costs are associated with higher efficiency.

The caliber of the components and construction is an additional crucial factor. Choosing boilers with sturdy construction will extend their lifespan and increase their dependability. For example, heat exchangers made of stainless steel are a good option for pyrolysis boilers because of their reputation for durability and resistance to corrosion.

Take into account the boiler’s size in relation to your heating requirements. An inadequately sized boiler can result in inefficiency and increased fuel consumption as it struggles to provide sufficient heating for your home. On the other hand, an oversized boiler may waste energy by turning on and off frequently. Select a boiler size based on how much heat your space needs.

Finally, search for pyrolysis boilers that are simple to use and maintain. Upkeep can be made a lot easier with features like ash removal mechanisms or automatic heat exchanger cleaning systems. To ensure safe and environmentally responsible operation, also make sure the boiler you select complies with applicable safety and environmental standards.

To sum up, pyrolysis solid fuel boilers provide a cost-effective and environmentally friendly means of heating your house with wood or biomass pellets. One can choose a boiler that optimizes efficiency and minimizes operating costs by taking into account various factors such as construction quality, size, ease of maintenance, and efficiency. Choose a manufacturer you can trust, and speak with experts in heating to find the best solution for your particular requirements.