Drying the wood using wood drying kiln for example is important because drying contributes to obtaining logs with a high calorific value. It consists of lowering the moisture content of wood using natural or artificial methods. Here are some tips for drying the wood used for heating stoves and fireplaces.
Drying The Logs In The Open Air
This process involves drying each log by exposing it to the open air outside the house for several months. It is nature (in this case, the sun and the wind) which takes care of the wood drying by eliminating the water inside the fuel. During this long period, the wood can also withstand bad weather. Rain, hail, or snow can dampen the pile of logs. To protect them from this bad weather, it is interesting to cover the wood with a waterproof covering such as a well-fixed corrugated sheet. Likewise, the logs must be insulated from the ground to prevent the rise of humidity. The average drying time for freshly cut wood is 2 years for the south of France and 3 years for the north.
Put the wood in the oven
This artificial drying makes it possible to have dry wood at a precise humidity level and in record time. The drying process takes place in four stages:
store wooden pallets/containers (cut and split logs) inside the oven,
heat the oven to a temperature of 85 ° C (2-3 days),
Put the wood out of the oven. This rest is essential for the wood to dry completely. Indeed, after the passage of the logs in the oven, only the outside of the latter is dry. Hence the usefulness of eliminating the water inside the wood for 15 days by letting them rest in a shelter.
To accelerate the drying speed and its performance for the heart of the logs, some more advanced processes use several cycles of raising and lowering the temperature over variable durations. The energy used for these ovens often remains the biomass recovered during the cutting of the logs and the bark. The process remains environmentally friendly.
There is also the possibility of drying the logs in low-temperature ovens, generally solar ovens (with another biomass boiler). The process is longer (counts in weeks) but also more economical.
Wood drying time
For the natural method, the firewood drying time ranges from 24 months to 36 months to arrive at 20-25% dry wood. These values are valid for split wood, and log sacking takes longer. This drying time also varies according to the type of wood. Softwoods dry faster with 6 months to 1 year less, while hardwoods have a longer drying time. For artificial drying, it takes between 2 weeks and a month to have completely dry logs ready to use.