Log Drying Kiln

[Woodworks]

7 minutes ago, Big J said:

Would a large solar powered fan be productive?

 

 

 

That's what I was getting at when I mentioned PV. Seems a good way to improve circulation when it's probably most needed. 

[Big J]

Assume you're doing the drying on a fairly commercial basis and you had a 30ft x 90ft polytunnel. It's 12ft high, and almost half of a cylinder so has an internal volume of around 720 cubic metres. There are large axial wall fans on eBay that consume 1.1kw and move 14000 cubic metres of air per hour, so you'd have a full change of air every 3 minutes. One fan would easily suffice. 

[Luckyeleven]

It would be for my own 15 cube a year, but just thinking out loud really. The idea being that with really very simple components and no electricity, it could maybe knock a few percentage points off the humidity before winter.

[openspaceman]

2 hours ago, Luckyeleven said:

It would be for my own 15 cube a year, but just thinking out loud really. The idea being that with really very simple components and no electricity, it could maybe knock a few percentage points off the humidity before winter.

IME as long as the logs are decently stacked and inside the polytunnel by end of May in my part of England they are below 20% by autumn with natural air movement and diffusion. You only have to enhance air movement if you need to run a number of batches in the drying season, even then you may need a bit of additional heat to make best use of the air movement.

 

Others in more humid areas claim this is not possible but that's not necessarily a problem as a modern brick/refractory lined stove will burn 25% mc logs without visible smoke, though I grant below 20% is harder to produce smoke.

[sandspider]

What he said.

 

I season logs for my own use in a polytunnel (no fans at all), they dry far quicker than logs stacked outside, even under cover. They do seem to reabsorb moisture over winter once the sun no longer hits the polytunnel, but that's life. Wonder if a fan might help air movement in winter...

[Pinkfoot]

A few years ago I made my own kiln in a refrigerated lorry body.

It was fibreglass and  I stuck a 28 kw workshop stove in there.

Burned sawdust or wood.

It wasn't the best installation but it did work.

I cut the roof lights out so it could vent and small house fans blowing under the bulk bins .

I bought a diesel space heater later on with a thermostat so it cut in at 50 °c.

This worked well but I will change it around next time , mainly for logistics.

Feeding the stove was a pain so was loading , had no forklift but the idea worked.

Ideally two stoves outside in their own insulated room blowing hot air into the kiln.

[scott-1978]

On 05/03/2019 at 18:15, ash_smith123 said:

No problem!
The attack is plumbed into a 40ft container. Not the best in all.honesty! We rotate the tops in the winter as the bottoms don't dry properly in a week.
We have an insulated timber framed kiln inside the unit with 2 X 50kw fans bolted to the ceiling facing down. This seems to dry far better and we can fit 30 ibc cages in there.
We just used a tidy plumber for our second kiln. It's very basic stuff in all honesty. If they can fit a central heating system in a house they can fit a biomass boiler. The boiker manual will have all the specs and drawings of how it should be fitted so it should be a doddle! Anyone that "specialises in biomass boilers" will charge you a fortune and there's some real cowboys out there. I've only had the displeasure of dealing with 3 "renewable energy" companies over the last 5 years and they were all useless. The lack of knowledge was dangerous, but anyway that's another story! 

cheers Ash, how often do you need to re-fuel these type of boiler. Looking for something that doesn't need an hourly top up if i can help it!