Thread: my solar kiln finaly under way

teh fans would be powerd directly by solar power so when teh sun goes down the fanse stop.

its a good idea haveing flafs over the outlets so that when the airflow stops tehy shut and help keep the air in.

so are teh folowing correct.

1. hot air inlet is best to be at the bottom.
2. wet air outlet is best to be at teh top.
3. airflow of 1m/min or greater (how mutch is to mutch)

click teh little paper clip on the top line of the rply to thread thingy to attach your pics.

if u cant work it out email them to me and i will post them for you.

Originally Posted by weisyboy

teh fans would be powerd directly by solar power so when teh sun goes down the fanse stop.

its a good idea haveing flafs over the outlets so that when the airflow stops tehy shut and help keep the air in.

There are fancy solar power vents/flaps you can buy for green houses that would also work. They look like this.

so are teh folowing correct.

1. hot air inlet is best to be at the bottom.
2. wet air outlet is best to be at teh top.
3. airflow of 1m/min or greater (how mutch is to mutch)

You need two air speeds
a) air VOLUME exchange with the outside. This depends on the size of the kiln and the air temp you can generate - Kiln design books are you best bet on this combo.
This is the one you need to get this right or you can ruin the timber.

a) Internal Air speed - moving the air inside the shed at 1 m/s evens out the air and evens out the drying. Otherwise you end up with some timber bone dry and other bits still wet. The internal air speed doesn't really matter as long as it's ~1 m/s - too high doesn't really matter.

Originally Posted by nifty

With those two designs, I can see alot of moist air sitting around at night and not being released which is the name of the game. If anyon can help me to post photos Ill take some of my two to give you an idea Carl

Posting Pictures to Your Post

here is my updated desighn.

what do u think.

more changes to come.

Sorry but no Cocoanut. look at the size of your fan and the size of your vent then ask yourself why would hot air travel through the stack when the easiest path is straight up as it enteres the chamber then along the top to the vent, there will be no air movement at all through the stack.

The fan will be fighting the direction that the hot air wants to go so you would be better off reversing the intake - like this.
Slope on roof doesn't need to be very steep either



Plus you will need a big fan inside to drive the air inside at 1 m/s

sorry that was teh rong pic.

will upload the othetr pic when i find it its in amoungst about 1000 others i really should organise my pics better.

let us assume that you use 1" spacers in your stack. You need to lower the stack to the same 1" spacing , and lower the roof to that spacing. the sides of the stack also need to be 1" obviously you paint the end grain of the wood. The only large areas are your in chamber and your out chamber. There is no point in giving a place for air to pass without doing something. Your chamber is full of useless spaces where most of your air finds no friction so will not blow through the stack

A few other things that u could do is paint the chimney black, (as in BobL's modification), also have the chimney as long as practicable, it then becomes a solar chimney and provides natural draught.
Can these things get too hot?
If they can addition of vents at the top of slope in roof and at bottom of downdraught where fan is to allow normal outside air into so as to not overheat the whole thing.
Also u could investigate the use of a Trombe wall to provide thermal mass and more natural draught.
When the commercial guys rehumidify (that's not the right term) introduce steam to destress the timber in the final stages of drying, Does it have to be steam at 100+° or could we just put a bucket of water in the space and let that evaporate?
Would probably take longer but
Peter.

Originally Posted by weisyboy

well not actualy under way yert i am still finalising a desighn.

below is some quick sketches of my 2 desighns (i can upload the full desighns as tehy are to big)

the top one is teh simples and cheepest it requires no fans/extraction as the airflow is achived via convection. this would be my preferance. however i am woried about the airflow not being suficient to keep the humidity down. and i would have to close teh outlet at night to keep the heat form escaping

the bottom one is a diferent desighn that erquired fans to force teh hot air in and wet air out. i would use solar powred fans so the air flow stops when teh sun goes down and the outlet is low down to the hot air is captured in there keeping it warm overnight.

teh walls will be studs with a timebr clading internaly and externaly filled inbetween with sawdust for insulation. the heat sync (roof) will be builders plastic in a few layers.

so opinions, problems and coments?

Carl,
Dont dick around there are great proven Solar Kilns out there in Cyberspace
Try
http://www.builditsolar.com/Projects.../wood_kiln.htm
http://www.woodweb.com/knowledge_bas...olar_kiln.html
There heaps more on woodweb.com
http://www.truthaboutax.com/site/1515517/page/858958
http://www.laymar-crafts.co.uk/linkr.htm
http://www.solarkilninfo.com/solar-k...nd-solar-kilns

Once you have read all of this. I expect a 1000 word summary
Regards Whitworthsocket

Originally Posted by whitworthsocket

Carl,
Dont dick around there are great proven Solar Kilns out there in Cyberspace

WWS, If you trawl back through this forum you will see carl has already been advised of this many moons ago. But like most of us we all have to do our own thing even if it is reinventing the wheel!

yer i know there are lots of plans around.

but i am a born tinkera when i finaly get round to buildign it i wont have the diagrams but will have absorbed all (well most) of the info and will jsut play it by ear. often teh best ideas come when im half finished.

Sometimes the wheel does need reinventing sometimes it dont
I had a look at the sites WWS listed there, some seem to be a repeat of others....
As far as reinventing, the solar chimney has to be worth a try, the Peterson site may have been indicating something like it
Just a thought
Peter