kiln dryer

[openspaceman]

The BIG advantage of a batch fed boiler is the cost, including install you are looking at circa 25% of the cost of a woodchip boiler.

 

As I said in a previous post, possibly on another thread, the two are not mutually exclusive if you don't want to go the RHI route

 

If I were looking again at a batch fed boiler to power a kiln then I would use a kiln rather than a forced air dryer. A kiln is a more efficient method of drying logs.

 

The difference being one recirculates and the other vents the air after one pass?

[Lancer]

Thanks for that. I will take a look at the farm 2000. Do you know of people using them for this purpose? Straw is a good option for us as we have large quantities on the farm and get you point about loading time. Do you know if rhi will accept us burning straw and wood together? We have fair amount of scraps coming from the processors

[Duffryn]

Interested to hear more from people who have the glen farrow kiln. Considering getting one but concerned heat produced will be well down on what is claimed and labour time needed to load it. Have a wood chip kiln running all the farms heating and that is fantastic but this sort of setup will be too expensive for a kiln. Any advice from people who have them would be appreciated.

 

PS why not run the kiln off your woodchip boiler ? If you are struggling for capacity in the winter then you could still power the kiln in the summer. You could put one in for under £8K

[Duffryn]

Thanks for that. I will take a look at the farm 2000. Do you know of people using them for this purpose? Straw is a good option for us as we have large quantities on the farm and get you point about loading time. Do you know if rhi will accept us burning straw and wood together? We have fair amount of scraps coming from the processors

 

Yes I know of someone who has two of them powering forced air dryers. I presume you can mix fuels but you would need to check with Farm 2000 to be sure. You need to ensure that the straw if loosely baled for the boiler to burn it efficiently.

[Duffryn]

As I said in a previous post, possibly on another thread, the two are not mutually exclusive if you don't want to go the RHI route

 

The difference being one recirculates and the other vents the air after one pass?

 

Agreed on first point

 

On 2nd point . A kiln works by heating up the air to the point where the relative humidity is at its maximum for the air temperature at which point the air is flushed out of the kiln and the process starts again. A forced air drying constantly blows hot air out of the rear of the kiln regardless of the relative humidity. A hybrid would be to use a force air dryer set up but link the fan speed controller of the heat exchangers to the RH level. I hope to do this myself over the next couple of weeks on my set up

[Ambisawrous]

Good thread, I have a Farm 2000 newly installed with a 20' by 20' spare shed bay right next to it. I would like to put a kiln in that can dry logs and milled timber. Using the hot water coming in at 80 C would it be relatively easy to control the heat for the two different needs? I guess for the milled timber it would need to be warm air recirculation rather than forced air and maybe just run higher temp for the firewood? By the way the new Farm 2000 HT boilers can burn both wood and straw and still get rhi's

[openspaceman]

 

On 2nd point . A kiln works by heating up the air to the point where the relative humidity is at its maximum for the air temperature at which point the air is flushed out of the kiln and the process starts again. A forced air drying constantly blows hot air out of the rear of the kiln regardless of the relative humidity. A hybrid would be to use a force air dryer set up but link the fan speed controller of the heat exchangers to the RH level. I hope to do this myself over the next couple of weeks on my set up

 

Much as I thought you meant.

 

The point being the forced air method gets most heat out of your hot air if the distance the air has to pass through is long enough to saturate the air at the exit temperature, The recirculating type lets the air have more passes to reach saturation but the air leaves at a higher temperature *unless* there is some form of heat recovery.

 

Border biofuels woodchip dryer was pretty efficient in terms of heat as air leaving the top of the heap was always saturated and there was a distinct visible boundary between dry and wet woodchip which you cannot see with logs. As the air was always being blown against the constant back pressure of chip there was a trade off between the *free* low grade heat used and the higher electricity cost, which militated against it when the free heat did not materialise.

 

I was denied access to our high speed kiln once it was commissioned so never did work out whether the recirculation power was optimised.

 

So yes a datalogger of temperature air speed and humidity at entry and exit of the dryer should allow you to modulate fan power for the cheapest result but you will still need a bigger container than the recirculating kiln.

[Duffryn]

Good thread, I have a Farm 2000 newly installed with a 20' by 20' spare shed bay right next to it. I would like to put a kiln in that can dry logs and milled timber. Using the hot water coming in at 80 C would it be relatively easy to control the heat for the two different needs? I guess for the milled timber it would need to be warm air recirculation rather than forced air and maybe just run higher temp for the firewood? By the way the new Farm 2000 HT boilers can burn both wood and straw and still get rhi's

 

Yes very easy to do both in terms of controlling temperature. For the kiln itself make sure you have fully insulated the area. Much easier to make an effective kiln in a smaller rather than larger area so you might want to consider not using the whole of the 20 x 20 shed. I'm no expert on drying milled timber but presume for this the temperature would be a lot lower, for firewood getting the kiln as hot as possible is key.

[arboriculturist]

It appears that many underestimate the fact that maintaining close to 80 degrees water temp. with a batch boiler is an uphill struggle unless you have perfect fuel and the labour to manage the boiler.

 

I think that many who think their 'kiln dried' wood is actually the final moisture content they assume it is, would be shocked at high how the MC actually is on average throughout the container if they were to oven try a range of representative samples to determine the true average MC of a complete batch.

 

Those investing 38K on a new setup, are facing an increasing risk of public awareness, as some of the people I have spoken to about kiln dried are not keen on buying firewood based on a production process that is partly funded by their Income Tax contributions.

This is purely the findings of my market research and one of the first rules of business is 'always carry out market research'.

 

I would be interested if other's have found this to be the case when researching the market.

[ash_smith123]

It appears that many underestimate the fact that maintaining close to 80 degrees water temp. with a batch boiler is an uphill struggle unless you have perfect fuel and the labour to manage the boiler.

 

 

 

I think that many who think their 'kiln dried' wood is actually the final moisture content they assume it is, would be shocked at high how the MC actually is on average throughout the container if they were to oven try a range of representative samples to determine the true average MC of a complete batch.

 

 

 

Those investing 38K on a new setup, are facing an increasing risk of public awareness, as some of the people I have spoken to about kiln dried are not keen on buying firewood based on a production process that is partly funded by their Income Tax contributions.

 

This is purely the findings of my market research and one of the first rules of business is 'always carry out market research'.

 

 

 

I would be interested if other's have found this to be the case when researching the market.

 

 

I think there is 10 times more people coming into the "buying firewood market" looking for kiln dried than people that are sceptical about kiln dried firewood. Most shops in the UK use the words "buy kiln dried firewood" not "buy wood of a moisture content of 15%" so people will just look and ask for kiln dried firewood.

My split of seasoned/kiln dried is 50/50 at the moment.

I was helping a guy that got shafted by a renewable energy company with a copy of my kiln design and he's been trading for 30 years only selling seasoned firewood. He Was sceptical with how much kiln dried he would sell but within 6 months he's also at a 50/50 split in sales and he can't believe it! It's not like the seasoned firewood sales have dropped for him they are just new customers that wouldn't have come to him because he hasn't offered kiln dried. That's a massive jump in for someone's sales thats been stagnant for 30 years!