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desiccant dehumidifier for small dryer

Started by Marshall7199, August 06, 2021, 08:58:29 PM

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Marshall7199

I am running a small 200 cu ft wood dryer.  I air dry down to 15% and then into the DH dryer.  The loads are typically hardwood slabs up to 10/4.  I have been using a big box DH but believe it is on it last cycle.  Not getting much water from it unless I allow the temp to drop into the 80's.  

Has anyone tried using a desiccant type dehumidifier?  It is my understanding it is operational up to 104 deg F, and does not produce the heat a standard compressor type DH generates. My limiting factor is heat.  I can not run a typical DH much over 90 deg.  Or, is there another technology available?
Rookie learning from the masters.

YellowHammer

I've not tried desiccant, but it should work, assuming it would have the carrying capacity to remove the required mass of water.  1,000 bdft of typical hardwood should put out 3-5 gallons of water per day. 

Typically, heat is also required.   
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Marshall7199

Got it.  I am searching for a desiccant DH now.
Rookie learning from the masters.

mike_belben

Cutting paste of a post i just made elsewhere.


Another option is sodium polyacrylate aka polymer crystals aka dyper dessicant aka damprid aka miracle grow water storing crystals.  Same stuff in the fancy cooling headbands and stuff.  

A one time bulk purchase could be split into a few batches to rotate.  I would try making a miners type screen framed box to sit over a box fan turned ap at the sky and maybe suspended from the ceiling on wires or joists so that it is blowing wet air through the screen and crystals.  

Theyll swell into watery snots when saturated.  You dump them out a trampoline or tarp or piece of tin or something in the sun to dry back to rock salt sized granules then collect and reuse.  Theyll take a lot of water.  


A piece of gutter lined with crystals as a trough and a board over it to make that into and air duct could have wet air circulated by a little 3" round vent booster fan and some dryer ducting.  Cut a bondo spreader to squeegie the wet gel into a bucket and refill.


A propane heating appliance is probably cheapest easy way to raise the chamber temp and squeeze the water out for a dessicant to collect.  Im thinking wet air will sink low due to the weight of bonded water particles.  Another alternative to gutters is to cut a hinged lid into a piece of 4" pvc so that its like a coffin.  the flexible tubing can slip right on to the end. 
Praise The Lord

mike_belben

Got another one even cheaper.  


5 gallon bucket with a tight mesh spaghetti strainer ontop, or a coarse strainer and some hardware cloth screen in it to hold the crystals from falling through. 

Close up any big gap with a tshirt or foam pipe noodle insulation etc.

 Now cut a hole into the side for a computer fan or duct fan etc half way up the bucket to blow wet air in that must travel up through the polymer.  When it saturates the water drips into the bucket.  

Thats exactly what those damp rid things are.
Praise The Lord

Marshall7199

Thanks for the words of wisdom but i just ordered a $160 desiccant dehumidifier off Amazon.  I should have it on Friday and will she how it does.
Rookie learning from the masters.

GeneWengert-WoodDoc

Desicants can control the humidity of air in a closed room, but if you put several hundred gallons of water in the room (water in green lumber), the desiccant will fail as it does not have the capacity to hold that much water.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

Marshall7199

Got my desiccant DH up and running and is doing well.  As i am not running green wood, but wood that has air dried for 18-24+ months, I hope it will be successful.  I noticed that it is pulling moisture at higher temps compared to my previous compressor based DH.  Slow going but that is fine for a hobby. 
Rookie learning from the masters.

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