In the context of the constant increase in the cost of energy, there is a need to use alternative heat sources. Recently, pellet fuel has become popular for heating private houses.
The first thing to do when installing a solid fuel boiler is to calculate the consumption of pellets for home heating.
What is pellet fuel
Pellets are compressed granules made of combustible materials. They can be made from any organic components: wood processing products, coal industry waste, cake, 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. During the production of pellets, the waste goes through the stages of crushing, screening out large fractions, and pressing. Then drying takes place. After that, the finished product is packaged in bags of various capacities and goes on sale.
At the stageproduction, the main factor affecting the consumption of pellets is the raw material from which they are obtained.
Varieties of pellets by composition and quality
Depending on the raw materials, as well as their purpose, fuel is divided into 3 categories:
- Pellets for general purposes. These granules are mostly white in color, may have inclusions of gray and brown. They are made from waste wood products. Coniferous trees are mainly used, which ensures 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 variety produces a smell, as when heating with ordinary wood
- Agropellets. As the name implies, they are produced from the waste of growing crops. Mostly straw. The quality of pellets 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 pellets, which is important for use in low-power domestic boilers. Such fuel has a lower calorific value, so the consumption of pellets in this category is higher than that of the previous one.
- Industrial. This species is distinguished by color and low price. It has darker shades, which indicates the inclusion of a large amount of tree bark, as well as materials such as peat, cake. These pellets are distinguished by a high ash content - more than 0.7%, therefore they are more suitable for industrial boilers that are unpretentious in terms of fuel quality. Desire to save moneybuying such fuel may result in higher consumption and frequent cleaning of the boiler.
Features of boilers for using 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 efficient, so the consumption of pellets in them is higher than that of narrow-profile ones.
The differences between these 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 container for loading a large amount of fuel and a feeder. The bunker has large dimensions, exceeding the dimensions of the boiler. This is necessary for long battery life. Up to several days.
The price of boiler equipment increases significantly if pellet equipment is installed on a standard solid fuel boiler. For example, the cost of a heating boiler "Cooper OK 9" is 21 thousand rubles. When connecting the APG-25 pellet burner, the price will be 98 thousand rubles. The cost has more than tripled.
When should pellet boilers be used
To understand how expedient it is to use pellet heating, you need to compare several factors:
- Gasification of the settlement. This isthe main criterion for the use of a solid fuel boiler. Blue fuel is more convenient. Gas boilers are cheaper than solid fuel ones. They do not require expensive automation to operate. They do not need constant supervision.
- Presence of good quality pellets on sale. In the regions, the production of this type of fuel has not been mastered everywhere, and delivery makes its use more expensive.
Benefits of heating with pellets
Although gas heating is unbeatable, 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 financial cost of pellets is less than that of electricity.
- Fuel is a non-toxic, environmentally friendly material. Therefore, its storage does not require special conditions, except for low humidity in the room.
- Increase in prices for other heat carriers does not affect the cost of pellets so much. Especially when you consider that they are made from waste, there are no sharp jumps in prices.
- The installation of a solid fuel pellet boiler does not require approval from permitting organizations, unlike a gas one.
- The ash left from the combustion can be used as fertilizer in the garden.
Flaws
It would seem that with all the advantages of pellet equipment should be everywhere. However, certain disadvantages prevent this:
- Expensive equipment. This includes not only a boiler and a pellet burner with a bunker, but also automation that provides automatic ignition and flame adjustment 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 electric systems.
- Control over the level of fuel in the bunker and the need to maintain it.
- The need for storage space for fuel bags. Even a small pellet boiler has a pellet consumption of 2 kg/h. With continuous burning during severe frosts, more than 50 kg can be consumed per day.
- Problem with maintenance and repair in remote areas.
Consumption of pellets for heating a house 100 m2
When buying a solid fuel boiler, the heat output of the heating system is taken into account. Equipment for heating the coolant should 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, the heat loss of the house is taken into account, depending on the materials from which the building is 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 a simplified scheme:
- To begin with, it is determined how much heat leaves the house during the coldest time of the year. For mediumstrip it is assumed that an abstract building with ceilings no higher than 2.8 meters and an area of 100 m22 loses 10 kW of heat per hour.
- Then, the number of pellets burned per hour is determined. It depends on the type and quality of the fuel. It is believed that pellets emit 4.5-5 kW during combustion. In addition, losses associated with incomplete combustion occur in the boiler. Therefore, this number needs to be adjusted for the efficiency of the boiler.
- Since there are not so many coldest days of the year, and the temperature during the heating season varies from +10 degrees to -35, the heat loss at home should be halved. Accordingly 5 kW.
- Now you need to determine how long the heating season lasts. Basically it is 6 months, that is 180 days.
Knowing all these data, you can calculate the consumption of pellets for heating a house of 100m2 per season:
- 245 / 0, 8=125 - the number of kW per day for heating.
- 12530=3750 - heating power during the month.
- 37506=22,500 - heat input per season.
- 22 500 / 5=4500 kg - consumption of pellets in the boiler for 6 months of heating in winter.
Conclusion
To calculate the cost of heating, you need to include not only the cost of purchasing fuel, but also take into account the fact that the operation of the feeder, the ignition system of the pellet boiler requires electricity, the consumption of which reaches 500 W in industrial models.
