Firewood kiln- anyone made one?

[ecotreecare]

I've just about sold out of dry wood- very annoying as its not even winter yet!

 

I'm wanting to build a kiln out of a 20ft container. Was thinking of using a diesel air forced heater blowing in one end and a electric fan sucking the air through into some heat resistant ducting out around the side of the container back into the heater. Hopefully this way I'll get plenty of warm air flow through the container drying the wood out.

 

I would split the wood into custom made narrow metal crates and load them in with the fork lift. Even if we can do 40cube a week I would be happy.

 

What do you guys think? Would it work? Has anyone built one?

[b101uk]

Rather than burn diesel would it not be better to burn some wood to provide some heat via an old stove with a back boiler then put some radiators as well as the stove in the container then just have some small fans to move the air within while the natural draw of the stove along with vent holes in the container expel damp air.

 

After all its hardly “green” to burn diesel to dry wood

[treequip]

Last one I looked at was an insulated van body with an electic heater and a de humidifier. That's a lower energy profile than a diesel heater and fan, probably cheaper to set up as well.

[18 stoner]

Here's mine, its cheeper to set up, free to run, greener, and much bigger!

 

 

 

[ThrustSSC]

18 stoner, out of interest, what dimensions have you gone for there, and how do you find it for vehicular access? Forklift, tractor or telehandler?

[18 stoner]

They are 27foot hoops, spaced at 8 feet, 12 bays long. I think its around 12 feet high.

 

We usually split outside(unless its raining) straight into bags on pallets and put in the tunnel with a small tractor with forks on the rear. When it comes to delivery we pick them up with front end loader tractor straight into truck/trailer. The hoops/doorway is high enough for access with a medium sized tractor with a cab on.

 

Although its nearly 100foot long, circulation is good with no doors on, and acheives 16% M.C. in one summer on hardwoods.

[ecotreecare]

Whilst I like the idea of burning wood to dry more wood we are not insured for fires at our yard. it’s a pain in the bum but we cant do anything about it. Burning diesel isn’t very green however I’m wanting we can turn on and leave on whilst were away working.

 

Was hoping for a one week turn around, I like the idea of a tunnel house but I don’t think it will be quick enough.

[renewablejohn]

Your just to impatient. During the summer our solar kilns dry to less than 20%MC in 3 months during the winter it is more like 6 months.

 

Our kilns similar to 18 stoner but with concrete bog mat floors to allow forklift to stack either 1x2x1 or 2x2x2 in tunnel depending on tunnel shape. Processor in front of tunnel to allow processing in Manchester sunshine.

[openspaceman]

Here's mine, its cheeper to set up, free to run, greener, and much bigger!

 

Can you get a year's logs in it?

 

To my mind this looks a very good use of solar energy to season wood. Would it be worth erecting one of these on piers to increase capacity or would the wind loading be too great?

 

How many years use out of the covering?

 

Can you reckon a cost per M3 of solid wood seasoned?

 

The thing about seasoning a luxury good like firewood logs is the increased value can easily exceed the change in fuel value.

 

On the industrial scale the plant design allows for clean burning and the energy cost of venting steam up the chimney is a small proportion of the whole. As far as I can see there is little incentive to supply dry woodchip to the big users, who pay about £30/tonne as long as the wood is <45%mc wwb. So little incentive to dry this now. When NFFOs were first announced a large wood burning power station did commission a gas oil powered converted grain dryer because the premium on electricity generated from wood was great and gasoil relatively cheap.

 

How much it's worth spending per M3 solid wood for a luxury market is the interesting question. At the small scale the polytunnel looks appealing, get larger and the logistics all change. The physics stays the same though and the simple fact is 0.7kWh of energy leaves the system with every kg of moisture that leaves the logs. If you want big scale then you need an accelerated process to get the water out and match your throughput. A big business wants to keep output up to meet demand whatever the vagaries of the weather for drying. At this end of the business we decided the capital cost of the containment meant the drying cycle had to be less than 24 hours, the only quick way of meeting this was high temperatures because the limit wasn't the ability to move the water vapour away from the logs but the rate of migration of the moisture from the logs and the ability to deliver the necessary energy into the log.

 

Having a client that was adept with the grant system was the crux.

[gensetsteve]

18 stoner, out of interest, what dimensions have you gone for there, and how do you find it for vehicular access? Forklift, tractor or telehandler?

 

worth looking out for one of these. Brinkman britruk made mid 90's kubota diesel watercooled engine and comes with side shift. low mast and lifts 1000kg.