iDRY Vacuum Kilns

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solar collector questions

Started by scot wolf, March 27, 2015, 11:41:44 AM

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scot wolf

I was gifted some glazing that may force me into a solar build.  I have 4 pieces of 1/4" clear tempered glass that are 26x80". I think that may just be enough for a vt style kiln. I don't need massive  capacity.  Most of what I have is  10'  or less. So I'm thinking 12'x?.  What's the best way to flash those glazings8sor the roof. I'm thinking rafters 26" oc with a strip screwed over the 2 panels for where the panels butt each other. But not sure how to handle the top and bottoms.
Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

jueston

once upon a time there was a post on the forum about a builder who did an entire end of a TF building with glass. and that post had a lot of good details and links to good glazing methods, but i can't seem to find it in the search, maybe someone else knows how to find it...

jueston

found it.

read this thread, it might have some helpful info, and if it doesn't help, it has lots of pretty pictures...

https://forestryforum.com/board/index.php/topic,52270.0.html

scot wolf

Thanks for the link. The guy I got the glazing from can also order me another the same size for about $100.  Current collector would be14x4=56sf. If I add another glazing it would be 70sf.  I'm not in a hurry to dry loads and have been air drying first.
Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

scot wolf

Another question.  This build will most likely be on farm that is 70 miles away from home.  Is there such thing as load and forget?  It will most likely be check once a week or 2 scenario. I have been air drying for about 9 months. So the load won't be going in wet. 
Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

GeneWengert-WoodDoc

After air drying, you can safely load and forget.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

scot wolf

Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

scot wolf

Thinking of something like this for top and sides of glazing panels.


 
Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

GeneWengert-WoodDoc

The glazing does require substantial room for expansion.  This seems like the small spacing between panels is too little.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

jim blodgett

Scot wolf - That detail could work.  If you didn't have the edpm handy you could use a fat bead of a high quality silicone instead.  My favorite brand is Lexel (or maybe Lexal) -bulletproof.  But I'm sure there are other good brands.

scot wolf

Didn't really scale out the clearance on the drawing. I will most likely allow 3/8" clearance on top and 1/4" on sides. The bottom of glazing will sit on solid glazing blocks in a rabbit with edpm seal under glass cover with aluminum flashing caulked to top side of glazing.
Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

GeneWengert-WoodDoc

That sounds good.  I have seen many glass covers crack when they expanded without this clearance.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

scot wolf

More supplies scavenged.



  

 

Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

scot wolf

Hoping to get started soon on the kiln. It will be based loosely on this design:

http://forestandwildlifeecology.wisc.edu/sites/default/files/pdfs/publications/98.pdf

Except that I will be making it 12' long.  I will most likely be drying 500bf or less. How many fans will I need? And what is a good scource?  I was thinking about Attic gable fans because I assume they will withstand high heat.
Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

GeneWengert-WoodDoc

Note that this design and the Virginia Tech design are the same.

Two fans with enough capacity (cubic feet per minute or cfm) will be ok, especially for air dried lumber, but three smaller are better than two larger, especially with wetter lumber.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

scot wolf

 what cfm would be adequate?
Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

GeneWengert-WoodDoc

CFM = (sticker thickness in inches / 12) x (length of the load in feet, often 16 feet) x (number of layers of lumber) x (100 feet per minute minimum velocity for a small kiln) x (1.5  to allow for air leakage)

Example.  (0.75" / 12) x (16) x (24) x (100) x 1.5 = 3600 cfm from all fans
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

scot wolf

Thanks Gene.  It looks like 2 gable fans @ 1100cfm might work ok for me.  My loads will be 9.5 to 10' long and most will never get over 20 layers high (that would be 2 lifts).
Likes to play on the farms and in the shop
John Deere 4120 with 400x loader and grapple to haul out logs and firewood
Stihl saws of all sizes to cut 'em up

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