With the constant increase in the cost of energy, there is a need for the use of alternative heat sources. Recently, pellet fuel has become popular for heating private homes.
The first thing to do when installing a solid fuel boiler is to calculate the pellet consumption for heating the house.
What is pellet fuel
Pellets are compressed pellets consisting of combustible materials. They can be made from any organic components: wood processing products, waste from the coal industry, oilcake, peat and even manure. Granules are up to 5 cm long and up to 0.8 mm in diameter. They are obtained by pressing. Therefore, their cost is low. In the process of production of pellets, waste goes through the stages of crushing, screening of large fractions, pressing. Then drying occurs. After that, the finished product is packaged in packages of various capacities and goes on sale.
At the production stage, the main factor affecting the consumption of pellets is the raw material from which they are obtained.
Varieties of pellets in composition and quality
Depending on the raw material, as well as its purpose, the fuel is divided into 3 categories:
- General Purpose Pellets. These granules are mainly white, may have inclusions of gray and brown. They are made from waste wood processing. Coniferous trees are mainly used, which provides a low ash content of -0.5%. This fact has a positive effect on the interval between cleaning the boiler. It can be from a month or more. In addition, when burning, this species produces a smell, as when heating with ordinary wood
- Agropellets. As the name implies, they are produced from crop waste. Mostly from straw. The quality of granules from this raw material is an order of magnitude lower than from wood. In addition, during transportation, difficulties arise in maintaining the shape of the granules, which is important for use in small-capacity home boilers. Such fuel has a lower calorific value, so the consumption of pellets in this category is higher than in the previous one.
- Industrial. This view is distinguished by color and low price. It has darker shades, which indicates the inclusion of a large amount of wood bark, as well as materials such as peat, cake. These pellets are characterized by high ash content - more than 0.7%, therefore they are more suitable for industrial boilers, unpretentious to the quality of fuel. The desire to save on the purchase of such fuel can lead to higher consumption and frequent cleaning of the boiler.
Features of boilers for the use of pellets
Boilers using pellets as fuel are structurally different from conventional solid fuel boilers. Of course, there are universal ones - those that were originally designed for firewood, but have the ability to install a pellet burner. But this option is less effective, so the pellet consumption in them is higher than that of narrow-profile ones.
The differences between such boilers are in a small combustion chamber, where there is a more complete heat transfer to the water jacket. In addition, these devices are equipped with a tank for loading a large amount of fuel and a feed mechanism. The hopper has large dimensions that exceed the dimensions of the boiler. This is necessary for long battery life. Up to a few days.
The price of boiler equipment increases significantly if pellet equipment is installed on a standard solid fuel boiler. For example, the cost of the Cooper OK 9 heating boiler is 21 thousand rubles. When connecting the APG-25 pellet burner, the price will be 98 thousand rubles. The cost has more than tripled.
In which cases it is worth using pellet boilers
To understand how appropriate it is to use pellet heating, several factors need to be compared:
- Gasification of the village. This is the main criterion for using a solid fuel boiler. Blue fuel is more convenient. Gas boilers are cheaper than solid fuel boilers. For their work does not need expensive automation. They do not need constant supervision.
- The presence of pellets of good quality on sale. In the regions, the production of this type of fuel is not universally mastered, and delivery makes its use more expensive.
The benefits of pellet heating
Although gas heating is unrivaled, pellet heating has its advantages:
- High fire safety in comparison with gas and other types of heating. In the event of an emergency, the automation immediately stops the fuel supply to the burner.
- The amount of financial expenses for pellets is less than for electricity.
- Fuel is a non-toxic, environmentally friendly material. Therefore, its storage does not require special conditions, except for low humidity in the room.
- The increase in prices for other coolants does not affect the cost of pellets so much. Especially when you consider that they are produced from waste, there are no sharp price spikes.
- The installation of a solid fuel pellet boiler does not require approval in permitting organizations, unlike a gas one.
- The ash remaining as a result of combustion can be used as fertilizer in a personal plot.
disadvantages
It would seem that with all the advantages, pellet equipment should be everywhere. However, certain disadvantages interfere with this:
- Expensive equipment. This includes not only the boiler and the pellet burner with a hopper, but also automation, which provides automatic ignition and adjustment of the flame depending on the temperature of the coolant.
- Periodic care. Since this type of fuel has both volatile and solid combustion products, the boiler and chimney system require periodic cleaning, unlike gas or electrical systems.
- Control over the fuel level in the hopper and the need to maintain it.
- The need for a room for storing fuel bags. Even with a small pellet boiler, pellet consumption is 2 kg / hour. With continuous burning during severe frosts, more than 50 kg can go per day.
- The problem with maintenance and repair in remote regions.
Pellet consumption for heating a house 100 m2
When buying a solid fuel boiler, the heating capacity of the heating system is taken into account. Equipment for heating the coolant must provide it with a margin. Therefore, the power of the boiler will directly affect the consumption of pellets per day. The more powerful it is, the higher the consumption.
In addition, heat losses of the house are taken into account, depending on the materials from which the building was built, and the climate in the region. All these factors will affect the consumption of pellets. However, to determine the right amount for the season, it is not necessary to resort to complex calculations. You can use the simplified scheme:
- To begin with, it is determined how much heat leaves the house during the coldest time of the year. For the middle strip, it is accepted that an abstract building with ceilings no higher than 2.8 meters and an area of 100 m 2 loses 10 kW of heat per hour.
- Then the amount of pellets burned in an hour is determined. It depends on the variety and quality of the fuel. It is believed that pellets during combustion emit 4.5-5 kW. In addition, losses associated with incomplete combustion occur in the boiler. Therefore, this number must be adjusted for boiler efficiency.
- Since there are not so many coldest days of the year, and the temperature in the heating season varies from +10 degrees to - 35, then the heat loss at home should be reduced by half. Accordingly, 5 kW.
- Now you need to determine how long the heating period lasts. Basically it is 6 months, that is 180 days.
Knowing all these data, it is possible to calculate the pellet consumption for heating a house 100m2 per season:
- 24 * 5 / 0.8 = 125 - the number of kW per day for heating.
- 125 * 30 = 3750 - heating power for a month.
- 3750 * 6 = 22 500 - consumed heat for the season.
- 22 500/5 = 4500 kg - pellet consumption in the boiler for 6 months of heating in the winter.
Conclusion
To calculate the cost of heating, it is necessary to lay not only the costs of purchasing fuel, but also take into account the fact that for the operation of the feeding mechanism, the ignition system of the pellet boiler, electricity is required, the consumption of which reaches up to 500 W in industrial models.