MiniQuick Firewood Kiln (Gas 1) Home Kiln theory Heat treat and dry firewood Firewood operation

There is no substitute for seeing the result of an actual HT/drying process. Below is the data collected during the example HT/drying process plus a picture gallery at the very bottom of this page.

Example specification and conditions.
Firewood kiln model:	Gas Heated MiniQuick
Location:	Eastern Iowa
When:	End of May, 2009
Kiln load:	10 baskets of half cord = 5 cord load.
Loading method:	Wire baskets

Kiln operating parameter:
Chamber temperature set point	275F (entering firewood at the end of process) (only reached 260F)
Wet temp set point	240F (existing firewood at the end of process) (only reached 223F)
Treatment temp set point	160F (USDA HT schedule 314-b)
Treat time	10.5 hours + 5 hours cool down using forced venting
Approx. Gas consumption	50 gal. of LP gas @ $1.40/gl = US$: 70.00 to run load
Approx cost per cord	$14 per cord in Gas plus $1-2 in Electric.

Firewood before drying	Fresh split oak and other mixed hardwoods in the 45-70% MC range. Split to a general diameter of 3 inches or less.
Summary after drying	Avg: 20%MC on the surface (/18" deep) Avg: 35%MC in the core (split and then measure

Observations for HT/dry process in graph above:

10-11 hr process seems to be sufficient for most seasoned firewood needs, but it could be longer if the firewood is very cold when the process is started.
If you want a true kiln dried firewood (average below 20% MC), then expect a 20-22hr process.
The bottom baskets were 4% lower in average MC%, so you can choose to consider this a better quality. (Might help you squeeze a few more dollars out of the same firewood).
The chamber never reach the temperature setup, so the burner was on all the time and final temperature reach was about 260F
Actual USDA HT temperatures were reached 350 minutes into the process and completed at 425 minutes (see gray vertical lines)
The kiln was loaded with 10 baskets (5 on top and 5 on the bottom).
We took four samples after the process from each basket and used a Delmhorst MC meter with 1/4" pins.
Final average MC content of firewood was about 20% on the outside and 35% in the core.

Actual MC readings after 16hr HT/Drying process
	TOP BASKET	BOTTOM BASKET
Row 1	Before: 45% MC (37,42,45,55) Outside: 23% MC (24,32,22,15) Core:35% MC (36,37,33,32)	Before: 49% MC (35,38,54,70) Outside: 14% MC (17,9,15,12) Core:31% MC (32,32,29,30)
Row 2	Before: 43% MC (41,46,36,47) Outside: 22% MC (17,23,26,22) Core:34% MC (33,32,32,37)	Before: 49% MC (55,53,43,42) Outside: 20% MC (17,17,23,21) Core:40% MC (36,41,39,42)
Row 3	Before: 51% MC (38,46,48,70) Outside: 19% MC (15,22,20,18) Core:33% MC (33,31,31,35)	Before: 53% MC (70,47,47,48) Outside: 27% MC (33,22,20,31) Core:41% MC (46,35,37,46)
Row 4	Before: 44% MC (47,42,39,45) Outside: 18% MC (17,18,17,18) Core:32% MC (30,36,30,33)	Before: 57% MC (70, 70, 38, 48) Outside: 18% MC (16,18,22,14) Core:33% MC (33,32,35,31)
Row 5	Before: 46% MC (41, 50, 43, 49) Outside: 20% MC (17, 21, 22, 21) Core:34% MC (28, 36, 39, 34)	Before: 52% MC (54,53,59,48) Outside: 21% MC (26,30,28,18) Core:35% MC (35,40,33,32)

Start MC:	48.9% wood moisture content
End MC (core)	34.8% wood moisture content	(bottom avg: 36%, Top avg: 34%)
End MC (outside)	20.2% wood moisture content	(bottom avg: 20%, Top avg: 20%)

Picture gallery of HT/Drying process.
Baskets was loaded directly from the Firewood processor.
Kiln was loaded using Kiln-direct half cord baskets Notice the basket has been raised 8" (200mm) up over the floor for better air circulation.
Kiln has been loaded and we are ready to close the door.
There are 6 temperature sensors to be placed into the firewood. Here we drill a hole into the end and insert the sensor, then you dig 6-8" down into the basket and place the sensor. Finally you cover the temp sensor location to get an accurate reading.
Back side of kiln while running.
When load was done we took 4 pieces of firewood from the top of each baskets for our study. (see above) We choose piece that were on the larger size to make sure we got realistic MC readings. Each piece was measures on the outside and then split and measured in the core.
Baskets were dumped and ready to be filled with another load of firewood for the kiln.

MiniQuick Firewood Kiln (Gas 1) Home Kiln theory Heat treat and dry firewood Firewood operation

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