Questions about Kilning firewood

Kilning firewood can improve how well it burns.
It can even season green wood in a fraction of the normal time.
I've watched a few videos on the process that have me wondering, could you build a "black" oven to kiln dry the wood in?
I can see it being too hot, too fast, leading to case hardening of the wood.
That could be addressed with a bigger oven and a smaller fire.

Somewhere I saw someone posting about using a polytunnel (greenhouse) as a solar-powered wood kiln.  
I believe they were using it for lumber rather than firewood... and they might have had a rocket stove in there?

As someone who relies on a woodstove to heat my home in the Winter, having wood that is adequately dry makes a huge difference in having a hot fire, and a less-smokey fire.
If I have some wood that feels a little too heavy (i.e. wet), I might bring it in and arrange it around our big cast-iron woodstove.
Drying out wet wood by the heat of burning dry wood is a nice example of passive function stacking, I feel.  

I'm curious what you mean by "black" oven?  Are you trying to get super dry wood for a special fuel purpose, like blacksmithing?
I also wonder about getting wood TOO dry and losing heat value.
Wood that has sat in the shed for more than a few years seems to start losing its heat value... is that because the burnable gases have mostly evaporated?

I use my black oven to dry and heat bricks before glazing, so the glaze will dry fast during humid rainy season. I load around 12 bricks per heated oven after all the coals died out. Within 6 hours I have completely dry and hot to the touch bricks. Evaporated moisture is dripping through the door. I can imagine than doing it the same with green wood would produce much more water that would partially soak into the firebricks of the oven, so to some extent it would be counterproductive. It would work with smaller volume of wood and it would be better to use it on pre-seasoned material and not completely green.
Also, I would never do it during the firing session as the exhaust in black oven would ignite the wood eventually.

A black oven is a wood fired oven where the combustion gasses passes through the cooking chamber.
By the contrast,in a  white oven the combustion glasses heat the cooking chamber from outside of the chamber.
Wood kilns need venting to remove the water vapor that is exuded during baking, which is why I thought a black oven might be good.

Too much heat will torrify , then pyrolize the wood.
That would indeed reduce the fuel value of the wood.
I've looked into it a little and most wood combustion will have water in the exhaust, so a black oven might be counterproductive?
I

All wood combustion will have water in the exhaust; the products of complete combustion are mostly carbon dioxide and water.

I store my firewood around/behind the bell of my RMH, and if I put up wet half-green wood in autumn it is bone dry by midwinter. Also significantly lighter. The bell surface where the wood is never gets too hot to touch.

I think we are letting perfection be the enemy of the good here. I cure my firewood from April to November cut split and stacked in a 3 sided woodshed open to the south. It lights easily and burns cleanly. No nasty creosote in chimney.  That is good enough for me.  

Yes kiln dried will be drier with a moisture content of maybe 10%ish vs air dried of 15%ish but how would our lives be better?  

In a previous house, when I had a wood burning stove down in the basement, we would bring wood downstairs and stack it near the stove (but not too close) As we had plenty of wood, the wood could stay outside for a year before we needed it.
In the fall, we would bring as much of it as we could downstairs and it would finish drying. We did bring in a couple of mice and a number of insects, which wasn't too nice, but I regret my wood stove overall: It gave us a very comfortable heat.
It seems to me that if you kiln it, you have to build a kiln (not free) and are spending energy to dry it, though, which kinda defeats the purpose? or am I misunderstanding something?

I was thinking about using an open top steel barrel on it's side to dry out firewood in the sun.  I shall do some science and post back. Weigh it before and after a week is what I had in mind.

To me the point of kilning fire wood is to save time.
For example,in the case of a collapse, green wood will be immediately available but seasoned wood will be at a premium.


One YouTuber I've seen uses a sawdust stove to dry sawdust bricketts for sale and use.
Another drys firewood in the same shed that houses his forced air wood furnace.
As long as you are using otherwise wasted heat, drying fuel seems viable.
Burning scraps, sawdust or whatever just to dry fuel  is more iffy.

My personal preoccupation with making use of the heat from charcoal production is why I am curious about wood kilning.
As seen by the responses, drying fuel with incidental heat is very popular.
I think certified kiln dried firewood can cross state lines and this be sold at a premium.
There are other reasons besides fuel drying to have large oven that can get up to moderate temperatures.
Dehydrating of human foods or animal fodder, steaming of building materials, even cloths drying , maybe.
I think a white oven is probably the way to go for any of these uses.

This is a great thread on drying firewood:

https://www.hearth.com/talk/threads/solar-kiln-for-hardwoods-part-deux.175875/

Summary: The firewood should be stacked off the ground with air space underneath. IBC totes, pallet crates or any way to stack the wood in a sunny place. Create a peak at the top with a board or some of the stacked firewood. Cover the stack with clear plastic sheeting. Wrap the base with stretch wrap to hold down the cover. Cut u-shaped vent holes in the side near the top to allow air circulation. Adjust the vent hole size to limit the maximum temperature.

The thread also discusses target temps and how long to dry the wood.