# Combustion heat and calorific value of wood versus humidity.

 Humidity [%] Value fuel wood [GJ / t] 0 19,00 15 15,79 20 14,72 25 13,72 30 12,58 35 11,51 40 10,44 45 9,37 50 8,20 55 7,23 60 6,16

If you purchase “by weight” will be performed by the user, which will allow the wood to dry then the calculation can be made as follows in Example 2.

Table. The calorific value of wood – different species.

 LP TYPE WOOD kg/mpu water 25% kg/mpu fresh wood l/mpu evaporated water GJ/mpu calorific value 1 PLUM 576 10.13 2 GRAB 570 700 130 10.00 3 ACACIA 530 627 97 9.15 4 MOUNTAIN ASH 511 700 189 8.98 5 PEAR 504 750 246 8.86 6 BUK 490 750 260 8.61 7 OAK 475 715 250 8.35 8 APPLE 468 700 232 8.23 9 ASH 461 551 90 8.10 10 NUT 459 664 205 8.07 11 ELM 459 594 135 8.07 12 CLONES 447 679 232 7.67 13 BIRCH 440 595 155 7.92 14 CHERRY 400 630 230 7.03 15 LARCH 396 585 189 7.30 16 CHERRY 370 585 215 6.35 17 CHESTNUT 367 630 263 6.30 18 Douglas fir 367 490 127 6.61 19 PINE 353 574 221 6.50 20 ASAP 324 567 243 5.70 21 SPRUCE 310 560 250 5.84 22 POPLAR 309 525 216 5.30 23 FIR 300 595 295 5.53 24 WILLOW 238 610 372 4.01

explanation to the table:

mpu to metr przestrzenny drewna ułożonego (fireplace),

water 25% to 25% wood moisture,

– fresh wood to drewno niesezonowane, bezpośrednio po ścięciu,

– evaporated water to ilość wody jaką trzeba odparować z drewna świeżego, do optymalnego poziomu 25% humidity 1 wood (need to put approx 10% wood shrinkage, a więc o te 10% więcej drewna trzeba wysuszyć i z niej też odparować wodę)

– Calorific Value to calorific value 1 mpu,