Pellet are very small wood chips compressed mechanically to take a cylindrical shape, 4-6 mm in cross-section and less than 30 mm in length.
Pellets are divided into three main categories, Woodpellets which are made from 100% wood, Biopellets which are made from energy plants and Agropellets which are made from agricultural residues, such as wheat, artichoke, corn, etc.
The best Pellet quality and the one that practically and commercially should be of interest to a private urban consumer is that of woodpellet.
What types of wood the Pellet consists of, and what percentage of each of them participates in the final mix, will predetermine a series of many and important parameters, such as:
– thermal efficiency (thermal power expressed in Kw/kg, or, Kcal/kg, or KJ/kg)
– combustion quality (percentage of solid combustion residues)*
– purchase cost, euro per kilo.
*Remark: The Pellet burner also has a decisive role in the percentage of solid residues, which contributes decisively, with its degree of combustion efficiency, to the percentage of solid residues. There are specific guidelines from the EU for the acceptable percentage of solid residues
The best woods for Pellet production are in order:
Oak - Beech, Olive, Fir, Cypress - Pine, etc.
In the following photos you can see different types of woodpellet and how they differ in color.
Too many stores, heating-plumbing-paint shops and wood sales yards already have Pellets and it is expected that the number of Pellet outlets will increase dramatically for purely commercial reasons. The usual packaging is in 15 kg plastic bags.
Yes, since September 2011, by ministerial decision the burning of Pellets is allowed in Athens and Attica.
Here we should pay attention not only to the price per kilogram of Pellet, but also to how much energy (thermal efficiency) one kilogram of Pellet gives us. Don't forget that you are ultimately buying energy and not kilos. On the market today we find pellets from 20 to 40 euro cents. An average price of good pellets is 30 cents per kilo. With the answers that follow, we will better understand the "cost-performance" relationship and finally how much one kilogram of pellets costs.
Yes, there are many different Pellet qualities. Obviously, the serious industrial production units certify the quality of the Pellet and inform us precisely, not only about the thermal efficiency of the Pellet per kilogram, but also about the moisture it has, which is a very important element for a proper combustion. "Good" Pellet is therefore what is produced from specific woods, based on very specific European guidelines (DIN 51731 with a moisture content of less than 10%) and with specific admixture ratios of the various woods.
For many reasons.
a. The good Pellet gives us more thermal energy per kilogram, so we achieve savings in heating costs.
b. It burns much better and leaves much less solid residue (ash) in the burner and boiler. So the Pellet system requires less maintenance and creates less pollution in the environment.
c. It does not create a problem for the burner which works smoothly and without problem. It is certain that a "bad" Pellet will stop the burner and leave you without heating.
Empirically. The first combustion will show us immediately how much pollution the Pellet creates in the system and how much solid residue it leaves behind. Another empirical way is when we press the Pellet with our hand so that it does not crumble easily and does not become dust.
A liter of oil when burned gives us 9.800 kcal/h, or 11,40 kw/h
One kilogram of pellets, of average good quality, gives us 4.300 kcal/h, or 5 kw/Kg
The equivalence in our example is:
1 liter of oil = 2 kg of pellets.
On the market we find pellets with a certified calorific value of 5,4 kw/kg, but also with 4,6 kw/kg, at different natural prices per kilogram.
If we accept the above equivalence, 1 liter of oil to 2 kg of pellets, and take as a basis for calculation, the cost of oil 28 euros per liter (October 1,40) and the cost of pellets 2012 cents per kg, we see that for every 32 Euro of oil required 1,40 cents of Euro Pellet.
So we have an economy of the order of 48,15% (depending on the quality of the Pellet) in relation to the use of oil.
Note: Every change in fuel prices or pellet quality will give us another percentage of euro savings.
Pellet is not a monopoly fuel like oil or natural gas and as a product of competition its price will always be "compressed". Don't forget that its production and distribution belongs to the free market which is too big and free to be able to collude and set high prices.
From the boiler, the Pellet burner, the Pellet tank and all the other components of a classic oil boiler station (circulator, expansion tank, safety measures, valves, etc.).
Categorically on all types of boilers. But it also depends on the Pellet burner and whether it can respond. Usually a Pellet burner lights a solid fuel boiler, a wood boiler, but this is not mandatory. What characterizes solid fuel boilers is the ease with which their door can be opened for regular cleaning. But we should always be interested in the degree of efficiency of the boiler, a quantity that determines the final operating cost.
Definitely YES. However, we should be aware of some particularities created by this change, such as:
a. The boiler door needs to be modified to accommodate the Pellet burner. Usually the door hole must be enlarged and at the same time its thermal insulation must be maintained.
b. Oil-gas boiler doors are bolted to the boiler body and are usually hinged on one side of the support. So, every time we have to clean the boiler or the burner, we have to unscrew the door from the two support screws, a process not so easy and possible for all of us, especially in the large sizes.
c. A pellet burner will fire a pressure oil boiler at less than its rated output. In many cases it lights up at 70% of the nominal power of the boiler.
d. We should have a chimney with good draft.
Apart from the Pellet boiler-burner system and the tank (silo) for the Pellet, no other changes are required, both in the boiler room and in the compartments inside. As the whole system worked with oil - gas, it will work in the same way with Pellet.
No you can't. What you can, if you have the right spaces, is to install the second system in parallel and isolate with manual valves the one that is not working. With the appropriate hydraulic connections, you can share the other elements of the boiler room, such as, circulator, expansion tank, etc. In any case, however, you need the guidance of a Mechanical Engineer who will also be responsible for the conversions.
Yes you can, like any other solid fuel e.g. coal or lignite or agricultural residues.
A Pellet burning system needs a periodic visit from you to clean both the boiler and the burner mouth from ashes and any solid residues. Depending on the quality of the Pellet, this check can be done every week. The pollutants themselves will determine this interval for you and empirically you will find the time interval required for cleaning. But don't forget that cleaning the boiler yourself does not mean that the annual, necessary check of the boiler technician who checks all the electrical and automation that a boiler room has, measures the system and delivers you a certificate of good combustion, is abolished, just as he did and with the oil system (KYA, 07/11/2011, with performance and pollutant limits according to ELOT EN 303.05).
Nuclear fuel is crushed olive pit used as fuel. After the first processing of the olive, the olive oil and the biomass of the olive are obtained, which is the broken pit and the olive core. The olive pit goes to the mill for further processing, from which the heartwood and the lampade olive oil are obtained. Heartwood is a solid, dry and completely oil-free fuel used for energy production and for the production of a! feed material.
Greek Energy Systems Industry