Solar kiln

Carl_B · July 10, 2003, 07:46:12 PM

I am getting ready to take the first load of lumber out of my solar kiln. this was built from a plan that was in wood magazine. I will try and post pictures. Carl B.

Tom · July 10, 2003, 07:49:01 PM

Welcome to the Forestry Forum, Carl.

Wow! you jumped right in there with a kiln and picture and everything. Keep'em coming and tell us what you are doing. We have some members that want to build solar kilns. You'll hit it off with them right off of the bat.

sawwood · July 10, 2003, 08:10:32 PM

Welcome Carl. What type of wood are you drying and how
long did it take. I hope to build one soon, just a smaller one
to hold 500bf.

Sawwood

Carl_B · July 10, 2003, 08:26:40 PM

Tom · July 10, 2003, 08:35:36 PM

0h-h-h! That must be the other side. :D

chet · July 10, 2003, 08:52:24 PM

Welcome aboard Carl_B, but your making me look bad. :D I still aint got off my butt and posted pics of my solar powered lumber sauna. :( Maybe tommorow. :-/

oakiemac · July 10, 2003, 09:28:56 PM

Nice kiln! 8)

Carl_B · July 11, 2003, 06:31:39 AM

More details on my solar kiln. I made some changes to the plan We put it on skids so that it can be moved if needed.We sawed some 5 by12 white oak skids for it to set on.We used 6 inch joist hangers between the skids for the floor support floor joist are on 16" center.We raised the south wall to 47" inches . We made it 6 foot wide by 10 foot 8 inches long. We have 20 layers of lumber 44 inches wide and up to eight feet in lenght with 1 inch stickers in between. The first load of lumber that we put in is polpar with one row of green ash and 2 rows of walnut on the to just to see what will happen.We made it so that it would hold around 500 board feet of lumber. Carl B

Mark M · July 11, 2003, 07:26:57 AM

HI Carl

What material did you use for the "window"?

Mark

Carl_B · July 11, 2003, 06:02:07 PM

The solar roof I used are called patio panel clear weatherglaze. they come in 5 year 10 year & 20 year. Menards Lowes home depto all have this. I am only using one layer right now . Will add anothe layer before fall. I have been watching the temp.when I get home from work at night it is runing 30 to 35 degrees above the outside temp.this is between 5 and 6 p.m. The vents in the back are open about 1to 2 inches . I am using 4 gable end vents size 6x10 in the north wall. I put some wood slides on the inside of the kiln to adjust them. Carl B

biziedizie · July 11, 2003, 06:14:58 PM

  Carl looking at your kiln kinda makes me think that building 2 or 3 of these might be a way to go when drying different types of wood.
  Do you remember what it cost to build this one?
  I have a plan for a bigger kiln and I'm waiting for Deadheader to build it so I know how it works. :D :D :D

   Steve

Carl_B · July 11, 2003, 06:51:25 PM

I have between 400 & 500 in my kiln. We sawed all of the framing lumber. purchased t T-11 siding 5/8 cdx plywood for the floor & walls used fiberglass insulation for the floor and walls .Then we used 3 gallon of alum. paint to seal it one of flat black on the top. The plan said for the 1000 b.f. kiln using all treated framing lumber the cost was around 2000.00

smwwoody · July 11, 2003, 06:59:55 PM

have you thought of adding any fans ???

Carl_B · July 11, 2003, 07:22:10 PM

I have two 8 inch duck booster fans that are in the baffle board that hanges down 18 inches from the rafters. the fan have a 400 cmf rating each. Then black poly down to the lumber pile.The fan are on a 24 hour timer coming on 2 hour after sun up off 1 hour before sun down. This plan is one that is base on Dr. Gene design.

smwwoody · July 11, 2003, 07:26:34 PM

sounds good.

How long does it take to dry a charge of lumber? Softwood ? Hardwood?

Carl_B · July 13, 2003, 05:10:10 PM

Just a up date on my solar kiln. Low temp last night 61 temp in the kiln this moring 72. temp at ten a.m. 110 at 4 p.m. 130 ouside temp 81. Check moisture 11% is the high mostly poplar been in the kiln 23 dayes.The lumber was air dried one month in side before it went in the kiln. Carl B

Jacar · July 14, 2003, 10:39:38 PM

Carl,

I have a solar kiln I built about a year and a half ago. Works great I have some mesquite drying now and it got up to 136 inside today w/ a max OAT of 92.

Have you installed some sort of thermostatic controller for your fans? I am still manually controlling my fans, which is a hassle when your not around. I have been looking for some sort of themostat that I can set, to say, turn the fans on and off at 110 degrees. None of the home centers have anything like that. My fans run on 220 v, so your typical 110 v themostats will not work.

Have any ideas?

Jacar

woodhaven · July 15, 2003, 04:14:33 AM

Don't listen to the Home Center guys they are not electrical people. For the fans all you are doing is breaking one hot leg. A 120volt thermostat will work fine for that as long as the amperage rating is high enough for the motor you have. The voltage is really not important.(In this case). I will even draw you a wiring diagram if you need it.You could use any old 120 volt $10.00 furnace or even attic fan switch.

oakiemac · July 15, 2003, 07:25:27 AM

Jacar,

You could also use a temperature switch that would energize the coil on a 110volt relay. Then have the normally open contacts hooked up to your 220. Lots of ways to do it.

Jacar · July 15, 2003, 07:45:57 AM

oakiemac and woodhaven,

Electricity is my worst subject. I recently removed the attic vent fans and put ridge vents in my roof so I have those thermostats available. I asked an electrician friend who said I could not install 110 thermostat on 220 motors.

My fans are from the outside a/c units. I believe they draw very low amperage. My thought was that you had to interupt both hots on a 220 to shut the fans off so a 110 would not work. Woodhaven you may have to draw me a diagram. If I could find something real simple to install I could retire the manual shutoff. ME!

Thanks Jacar

Mark M · July 15, 2003, 09:08:00 AM

I think for safety purposes you would want to shut down both hot leads. Woodhaven is right about a switch in one leg stopping the fan, but it might not be very safe and I am sure it would not meet code.

Mark

beenthere · July 15, 2003, 09:09:03 AM

Jacar
Your electrician friend probably was saying "by the code, you cannot just switch one 110v leg". However, as woodhaven says, switching one leg on/off will certainly start and stop the fan. Just remember that doing it this way, leaves 110v live in the fan on the other leg just waiting to make ground contact, thus a source of a short circuit. A handy on/off switch ahead of the thermostat that can be off when working around the fan would be a good thing to have, and to use.
Maybe using a 220v relay that switches both legs on/off is another safe option.

(Now come on Mark, you say it so well in so few words too!) ;D

woodhaven · July 15, 2003, 09:44:44 AM

You are right, but he did not ask about a disconnect.
Only the thermostat!
And yes there should always be a disconnect as the first device in the line side. This should be there no matter what voltage you are using!!!!!! If you want to break both sides of the line and keep everybody happy then use a double pole t'stat even though it is not needed.
If you really want to have some fun.
Get a inspector a factory guy a good mechanic and the guy doing the work to discuss this same thing in 3 Phase. (Single Phaseing)

beenthere · July 15, 2003, 10:25:12 AM

You are right, woodhaven. I didn't mean to imply you were proposing something unsafe, but also didn't want to leave it "uncovered" or "unsaid" just in case. I gather Mark feels the same way.
Had a fire once in an oven that was an apparent result of only one leg being shut down by the thermostat, and something happened that the other leg just kept the oven element heating. Happened to have wood in that oven, drying it to "oven dry" for getting moisture contents. It went beyond the "oven dry" condition, to charcoal. Interesting that it was listed as an "electrical fire" by the fire fighters, so they would not use water to put it out! Now this was after the power to the oven was shut off with the disconnect. Go figure. The firefighters wanted to remove the fuel right away, so everytime the oven doors were opened to scoop out hot charcoal, a huge fireball erupted in their face. Any mention of "just leave the doors closed and let it cool off" were treated as "unwanted" suggestions. "We have to remove the fuel" from the fire". Seemed to me that the doors closed already removed the oxygen component, and all they really had to do was let it cool down and then remove the cold fuel when in no danger of flare-ups.
After all this, the oven was converted to a thermostat that shut off both legs of the 220, not just one.

woodhaven · July 15, 2003, 11:14:33 AM

Ok maybe I did get a little to defensive. I been doing this crap long enough to know not to asume something is known.
My Fault.
I do sometimes get ticked at what some of the inspectors ask for.
When a lot of factorys send stuff out the door that is a down right killer. I am also guilty of taken advantage of things sometime because I know its limiitations and not everyone does.

I Promise I do better.