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Surely this must be the end of stove related legislation for now?

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11 hours ago, Martin du Preez said:

Furthermore, most the so called “kiln dried” logs I’ve seen or checked is over 20% and even advertised as such. They it’s for the better for the environment but all this is going to result in is people imported kiln dried from Eastern Europe, what about that carbon footprint and for what imagine the majority of which is unsustainably sourced.

Not only the carbon footprint of importing Kiln Dried logs from Eastern Europe but the systematic destruction of their forests by the Mafia and the Government officials they have in their pockets. I would not support anyone or any business buying Logs from there. 

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1 hour ago, trigger_andy said:

Not only the carbon footprint of importing Kiln Dried logs from Eastern Europe but the systematic destruction of their forests by the Mafia and the Government officials they have in their pockets. I would not support anyone or any business buying Logs from there. 

Well said - Forest destruction as a direct result of the timber supply chain from overseas is often overlooked and forgotten about.

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On 23/05/2020 at 18:16, Philip Anderson said:

Possibly not for much longer people might be looking to source all goods a little 

closer to home .

MC wise I have 3 wood burners all working well on barn stored air dried the same as I supply with no issues .

Its the crap that’s supplied at the garages that wet and rubbish.

2022 regs will make the supply of wet wood in small quantities below 2cu m an offence. Pre lockdown my local BQ were selling kd birch,  looked nice stuff,  special offer 6 quid for a bag of just 6 logs. Looked like they had shifted 30 plus bags from a large crate.  Unbelievable.   

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On 23/05/2020 at 18:16, Philip Anderson said:

Its the crap that’s supplied at the garages that wet and rubbish.

That's very true, so stuff my dad got from a local "country superstore" looked like it needed to be stacked for a year.

But larger scale suppliers aren't all blameless either.  We got a load of "seasoned" wood not that long ago, and that looked like it had been left in the rain.  Luckily it was only to top up our normal stocks but it was far from ready to use. 

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On 23/05/2020 at 20:23, Martin du Preez said:

Furthermore, most the so called “kiln dried” logs I’ve seen or checked is over 20% and even advertised as such. They it’s for the better for the environment but all this is going to result in is people imported kiln dried from Eastern Europe, what about that carbon footprint and for what imagine the majority of which is unsustainably sourced.

We had a sample from Latvia. Described just as "hardwood" I think it might have been mainly Alder.  With my cheap meter I read something like 13% at the outside, inside a freshly split piece it read zero, too dry for the meter to measure.  It's anyone's guess what the m/c would have reached by the time it got to the end user.  But it shows that drying to that extend is simply a waste of energy unless it's going to be transported and stored in sealed containers.

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On 25/05/2020 at 09:07, aesmith said:

We had a sample from Latvia. Described just as "hardwood" I think it might have been mainly Alder.  With my cheap meter I read something like 13% at the outside, inside a freshly split piece it read zero, too dry for the meter to measure.  It's anyone's guess what the m/c would have reached by the time it got to the end user.  But it shows that drying to that extend is simply a waste of energy unless it's going to be transported and stored in sealed containers.

I had a container in a few weeks ago,  it was kilned to specification.

 

A

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On 23/05/2020 at 08:06, arboriculturist said:

Another other point that fails to get a mention is this :

 

'Most' Kiln dried firewood may produce a higher value  kWh / kg when burnt due to having been force dried  -  for arguments sake lets say 4.5 kWh / kg  -  compared to naturally air dried firewood.

 

However what is never, ever mentioned is the fact that although kiln dried firewood, that has been cooked in a large oven, may produce a marginally higher kWh / kg than naturally air dried firewood, kiln dried firewood burns away far faster than air dried, so in reality burns for less time per Kg !

This fact completely changes the economics of burning kiln dried.

 

In addition, it is also overlooked that during the force drying process,  a percentage of the volatiles within the timber that are lost due to heat being applied to dry it. 

 

I would suggest that if these facts were common knowledge, the general public may well take a different view on buying kiln dried firewood.

 

Any comments?

Our kiln does not "cook in a large oven"

 

The principle of kiln drying, at least in my kiln, is that you create a flow of warm air, over and through the stack of firewood you are trying to dry. Warm air holds more moisture and so it absorbs the moisture from the wood as it passes through, thereby drying the wood. Its the same as drying your hands in a hot air drier. 

 

Once the moisture is absorbed into the air, you have to eject that humid air and replace it with new fresh warm air which will continue the process. People seem to have a vision that a drying kiln is like a furnace. Its not.  

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2 hours ago, Chalgravesteve said:

Our kiln does not "cook in a large oven"

 

The principle of kiln drying, at least in my kiln, is that you create a flow of warm air, over and through the stack of firewood you are trying to dry. Warm air holds more moisture and so it absorbs the moisture from the wood as it passes through, thereby drying the wood. Its the same as drying your hands in a hot air drier. 

 

Once the moisture is absorbed into the air, you have to eject that humid air and replace it with new fresh warm air which will continue the process. People seem to have a vision that a drying kiln is like a furnace. Its not.  

Agreed and  I should have made it clear that some kilns dry at lower temperatures.

However some kilns dry at temperatures up to 130c and volatiles start to migrate over circa. 105c.

 

I still stand by my view that the concept that force drying firewood is an environmentally good way to reduce atmospheric pollution is flawed, especially as many producers are burning waste wood over 20-25% MC.

Understandable that if you have invested in the process you will wish to keep business as usual.

The next generation of producers will be larger scale operations, mainly farm based who air dry all products, that said there are a surprising number with that setup already - far greater initial investment of course.

Edited by arboriculturist

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4 hours ago, Chalgravesteve said:

Our kiln does not "cook in a large oven"

Yes in general an oven does not have air changes (and those mine does bleed is to keep the fan motor and bearing cool) any unnecessary air mass flow is wasted heat.

4 hours ago, Chalgravesteve said:

 

The principle of kiln drying, at least in my kiln, is that you create a flow of warm air, over and through the stack of firewood you are trying to dry. Warm air holds more moisture and so it absorbs the moisture from the wood as it passes through, thereby drying the wood. Its the same as drying your hands in a hot air drier. 

Yes  but that warm air actually cools as it absorbs the liquid water and turns it into a vapour and takes it away, so the heat in the air needs constantly to  be replenished as it supplies heat to the wood.

4 hours ago, Chalgravesteve said:

 

Once the moisture is absorbed into the air, you have to eject that humid air and replace it with new fresh warm air which will continue the process. People seem to have a vision that a drying kiln is like a furnace. Its not.  

I think you mean it need not be and most are not but the hotter you supply the air up to the point it starts changing the wood, the faster it will dry. The decision on temperature is mostly to be to do with cost and heat loss, the heat loss at the higher temperature has to be balanced with the lower heat loss but over a longer time with the low temperature. The higher temperature driers offer the opportunity to reuse some of the heat in the exhausted gases or vapours.

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13 minutes ago, openspaceman said:

Yes in general an oven does not have air changes (and those mine does bleed is to keep the fan motor and bearing cool) any unnecessary air mass flow is wasted heat.

Yes  but that warm air actually cools as it absorbs the liquid water and turns it into a vapour and takes it away, so the heat in the air needs constantly to  be replenished as it supplies heat to the wood.

I think you mean it need not be and most are not but the hotter you supply the air up to the point it starts changing the wood, the faster it will dry. The decision on temperature is mostly to be to do with cost and heat loss, the heat loss at the higher temperature has to be balanced with the lower heat loss but over a longer time with the low temperature. The higher temperature driers offer the opportunity to reuse some of the heat in the exhausted gases or vapours.

Yes thats all correct. Its way more complicated than just heating up a kiln and keeping it hot.

 

I agree that if you can get the air to higher to higher temperatures at the start then you can re use the air/heat so you dont have to reheat it back to the full highest point, but you then also have to run that cooling air through a dehumidifier to remove the moisture it now holds, before you heat it up and send it back into the kiln. If you just keep reheating the moisture laden air, it wont absorb any more water 

 

so it becomes a balance between how much does it cost to get the water out of the air against the cost of heating fresh air drawn from outside to a level that enables the wood to dry in the timescale that is acceptable. 

 

 

 

 

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