The compressed log wrote:The compressed wood can be used in all wood stoves, fireplaces (with or without insert) and in all types of open or closed fireplaces. However, logs of compressed wood change your heating habits, they contain little moisture, so they need less air to burn. Too much draft often leads to burning too fast. It is often advisable to control the air intakes to take full advantage of the high heat output of the compressed wood.
The combustion will release the log of the pressure undergone in its manufacture. It expands slightly, it is important to position it behind the andirons to prevent it from touching the glass during combustion. The logs are easily scored, when starting the fire, breaking the first two logs can improve the speed of heating.
The fire is lit in the same way as with cutting wood, it is enough to have a lit fire and small wood, then to arrange the half-logs compressed on top of the small woods. It is important not to put too many logs in the fireplace, compressed wood releases more heat than natural wood.
Calorific power
The heating value indicated on the logs is the PCI or the PCS. Many manufacturers talk about PC (calorific value) without specifying whether it is PCI (lower) or PCS (higher). The latter is always superior but it does not correspond to reality, because it takes into account the latent heat of the evaporation of water that is not returned to a stove or a chimney, contrary to what happens in a condensing boiler.
The burning time of a compressed wood log depends on its quality. It should only be hardwood, dry (between 8 and 11% moisture only), preferably densified by compression, for combustion expansion. A poorly dried wood mobilizes an expensive part of its calories to evaporate the water it contains. Therefore, the more the wood is wet, the lower its calorific value. It is therefore very advisable to keep the wood well away from moisture.
Under these conditions, a good continuous fire supposes a reloading of the fireplace all 2 to 6 hours.
More technically, the PCI is a unit of measure for calculating the heat of combustion of a combustible material. It can be expressed as Kilojoule per kg (kJ / kg) or Kilowatt per kg (kW / kg).
1,7 kWh / kg at 60% humidity;
4,0 kWh / kg at 20% humidity;
4,4 kWh / kg at 11% humidity.
The density of the wood being variable, the calorific value varies strongly.
The energy balance of compressed wood is positive, unlike that of fossil fuels or electricity, which is always negative. This means that densified wood requires energy for its production. Thus, 1 unit of energy consumed for production, restores 6 consumption of granulated wood; he restores 15 in shredded wood.
What to think of this type of logs?
In addition, it is now forbidden to burn vegetable waste because of fine particles, and the dump sites are undersized to receive all this surplus of plant waste (this is particularly a problem in my community). The main solution implemented is therefore to grind this waste, which, on the one hand, greatly reduces the volume, and on the other hand, produces chips used as BRF to amend the land of vegetable gardens and gardens.
We did some brushing in our neighborhood and the brushing company left us several m3 chips.
Do you think it is possible to turn these chips into heating logs, and how?
I read that compressed logs are decompressed on combustion. I deduce that compression is mainly used to facilitate the transport and storage of logs. So it does not seem essential to provide a huge compression to make these logs, maybe even it would be enough to agglomerate the chips with a binder or a natural glue (eg wet flour).
A compression system can be simple with the principle of a lever that compresses a small volume of chips in a metal cylinder.
Does it seem feasible?
Here is already a prototype
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