iDRY Vacuum Kilns

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Drying w/ solar

Started by Shutterman007, August 17, 2021, 08:16:16 AM

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Shutterman007

Good morning everyone! My friend and I wondering.... Is sunlight important or the resulting temperature? If we use black plastic instead of clear the temp would rise more, thus killing bugs and the sunlight wouldn't bleach out the wood inside?

JoshNZ

The wood should never be in direct sunlight, it will be covered by baffles. The collector collects heat and fans pass it through your boards directed by baffles.

I'm sure it would work with black plastic but not as efficiently. Light wants to pass through clear plastic, be absorbed by black material (which your stack is hiding behind), converted into heat and then trapped by the plastic and be put to work.

I guess a black mat left out in the sun by itself would get hot to the touch but the heat it gave off would blow away, unless you trapped it inside a clear container, which it would then heat the inside of.

peakbagger

I am using black plastic over a stack of firewood. Its on a steel conduit frame with room for air flow on all sides and the base of the stack. If the sun is out it warms right up and there is significant airflow out the vents on the side of the top. One thing is that the wood does not look like its seasoned as its under plastic and the wood does not "cook" so its not gray at all.

GeneWengert-WoodDoc

Although black plastic will get hotter, you will not be getting all the heat inside the kiln to heat the air that goes through the lumber pile.  Also, the solar drying rate is dependent on how much energy you get into the kiln.  So, a clear cover with the interior painted black will trap more energy.

Ordinary black plastic will deteriorate quickly due to ultraviolet light, high temperatures, and flexing in the wind.  It probably has a life of six months.  Clear lactic or fiberglass oftentimes has us absorbers to slow down the up damage.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

farmfromkansas

I have an old reefer with solar panels to collect heat, using a furnace blower to circulate the heat into the reefer box, and it is dark inside, but uses solar heat to warm the wood.  Good system, just wish I had a couple more solar panels so it would get hotter.  Hottest I have seen is about 120 degrees f. Does get the wood dry, but not hot enough to sterilize.
Most everything I enjoy doing turns out to be work

GeneWengert-WoodDoc

Be careful with adding heat to a reefer as the insulation may not be rated for warmer temperatures...it will essentially evaporate into a small pile.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

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