The Forestry Forum

General Forestry => Drying and Processing => Topic started by: jaybird on May 25, 2018, 07:33:15 AM

Title: Angle of solar kiln panels, 20° toward north
Post by: jaybird on May 25, 2018, 07:33:15 AM
I have an existing structure I would like to set up for drying 2" boards of Ash and maple. It's a carport attached to the north side of our garage, It gets a ton of direct sunlight, but the exiting beams are built angled about 20° facing north. I was wondering if it would be worth it to remove the old tin roof and just install the clear poly as is. Would the inside ever get hot enough? Would there be any effect at all say if the temp in the kiln hovered around 110 or 120? I'm not in a super rush, but it would be great to the lumber dry by winter. Rebuilding the beams to the proper angle would be pricier and a pain in the tail
Title: Re: Angle of solar kiln panels, 20° toward north
Post by: GeneWengert-WoodDoc on May 26, 2018, 07:37:53 AM
The biggest key for any collector is the shadow it casts at noon.  Your description seems very poor in this respect, for a location in the northern hemisphere.  Another big concern is that the northern sky is cooler in the evening and nighttime than the southern sky.  So, overall, such a collector will have low solar input (about half of a south-facing collector of the same size) and will have high heat losses.  You do not mention the insulation in the walls and floor...important factors as well.
Title: Re: Angle of solar kiln panels, 20° toward north
Post by: jaybird on May 26, 2018, 10:33:51 PM
Thank you for answering☺ I`'ll rebuild the beams on the roof, I'd rather know it'll work then waste a few months expierementing. The walls will be just 3/4 ply, painted black with a foam insulated floor. I'm pretty excited about it. I make furniture and have hesitated on milling a medium sized strip on our property of maple, ash and basswood for a long time before I came across these solar kilns
Title: Re: Angle of solar kiln panels, 20° toward north
Post by: firefighter ontheside on May 27, 2018, 05:41:43 PM
If you're not going to insulate the walls, it won't work very well at anything but the heat of summer.  I would consider sandwiching poly iso in between 2 layers of plywood.
Title: Re: Angle of solar kiln panels, 20° toward north
Post by: GeneWengert-WoodDoc on May 27, 2018, 10:50:33 PM
Do you have a copy of the Virginia Tech plans?  They tell you how much insulation in walls and floor and so on.  They suggest 1 square foot of roof per 10 bf of lumber in the kiln.  I suggest that you do not go with your own design, as there are critical features that are essential.
Title: Re: Angle of solar kiln panels, 20° toward north
Post by: jaybird on May 28, 2018, 12:54:38 AM
Ok....Ok I was working off of a Woodworking Magazine plan from 1994. I did note the bf/solar panel ratio, I 'll admit I was planning on skipping the wall insulation for just black plastic. Thank you guys for steering me clear of throwing away my time. I only use the port for a few mowers and firewood. I think I'll just scrap the front half and reuse the materials to build a kiln strictly to plan. Thanks again☺ this forum (unlike my hare brained schemes) has been well worth my time😎 
Title: Re: Angle of solar kiln panels, 20° toward north
Post by: YellowHammer on May 28, 2018, 08:23:00 AM
I think your conclusion is the best plan.  If you follow the Va Tech design, you will have a good, solid, functional solar kiln.  Guaranteed.