The science behind forced log drying

[arboriculturist]

On 2/24/2018 at 13:40, Chalgravesteve said:

That's exactly the problem with seasoning wood against kiln drying it. The sheer volume of space required to properly season firewood is enormous, and certainly in the London/Home Counties/south East England area, you can find many other uses for such large covered areas that produce more/same income for less work. Stock is simply money tied up. If someone holds £100,000 worth of stock for two years to season it, whilst I hold £5,000 worth of stock and keep replenishing it, and I turnover my stock once a week for a 26 week season, then I actually sell £130,000 worth but only tied up £5,000 at any one time......Its not how much stock you hold, its how fast you sell it and replace it and sell it again that counts.

 

On 2/24/2018 at 13:40, Chalgravesteve said:

That's exactly the problem with seasoning wood against kiln drying it. The sheer volume of space required to properly season firewood is enormous, and certainly in the London/Home Counties/south East England area, you can find many other uses for such large covered areas that produce more/same income for less work. Stock is simply money tied up. If someone holds £100,000 worth of stock for two years to season it, whilst I hold £5,000 worth of stock and keep replenishing it, and I turnover my stock once a week for a 26 week season, then I actually sell £130,000 worth but only tied up £5,000 at any one time......Its not how much stock you hold, its how fast you sell it and replace it and sell it again that counts.

Another way of looking at things - It costs approx  £10,000 to dry 1000m3 using forced air.

 

If you have the space / infastructure / suitable conditions you can air dry that amount in a season.

Edited February 25, 2018 by arboriculturist

[Chalgravesteve]

1 hour ago, arboriculturist said:

 

Another way of looking at things - It costs approx  £10,000 to dry 1000m3 using forced air.

 

If you have the space / infastructure / suitable conditions you can air dry that amount in a season.

£10k? You are doing it wrong! Electrics cost me about £2k per annum. We burn seasoned arb waste that is difficult to split in the boiler. If I didn’t have to jump through hoops to get the RHI accreditation I could have built the boiler and kiln for substantially less. 

 

As it is the whole thing is paid for now so the cost of operating the kiln for a year is about £2.5k and we could in theory get 40m2 a week through it so 2000 M2 

 

i reckon it costs me about £4 a cube if I ignore the rhi 

[Woodwanter]

3 hours ago, arboriculturist said:

 

Another way of looking at things - It costs approx  £10,000 to dry 1000m3 using forced air.

 

If you have the space / infastructure / suitable conditions you can air dry that amount in a season.

Can you share the break down for that please.

 

what do use for drying

[arboriculturist]

2 hours ago, Chalgravesteve said:

£10k? You are doing it wrong! Electrics cost me about £2k per annum. We burn seasoned arb waste that is difficult to split in the boiler. If I didn’t have to jump through hoops to get the RHI accreditation I could have built the boiler and kiln for substantially less. 

 

As it is the whole thing is paid for now so the cost of operating the kiln for a year is about £2.5k and we could in theory get 40m2 a week through it so 2000 M2 

 

i reckon it costs me about £4 a cube if I ignore the rhi 

I am amazed you have enough waste to run those numbers, but I have no knowledge of the scale of your Arb. business.

 

The £ 10 came from large producers who buy in the Softwood to run their boilers. The boiler etc. will of course need replacing after 10 years  approx. running at low return temperatures.

[Woodwanter]

23 minutes ago, arboriculturist said:

I am amazed you have enough waste to run those numbers, but I have no knowledge of the scale of your Arb. business.

 

The £ 10 came from large producers who buy in the Softwood to run their boilers. The boiler etc. will of course need replacing after 10 years  approx. running at low return temperatures.

Do you know what boilers and what MC they are burning at? Are they RHI approved?

 

i guess a lot if those costs is the initial fuel purchase costs?

[arboriculturist]

31 minutes ago, Woodwanter said:

Do you know what boilers and what MC they are burning at? Are they RHI approved?

 

i guess a lot if those costs is the initial fuel purchase costs?

Some run chip others gassification. 25% MC most of them. RHI yes. RHI is a non starter now of course.

[gdh]

51 minutes ago, Woodwanter said:

Do you know what boilers and what MC they are burning at? Are they RHI approved?

 

i guess a lot if those costs is the initial fuel purchase costs?

We're just under £10 a cube before rhi if you do realistic costs including buildings and repairs. That's with an evoworld woodchip boiler drying to below 17% moisture. 

 

Probably £3-4 is chip and 2 electric. 

Edited February 25, 2018 by gdh

[Woodwanter]

2 minutes ago, gdh said:

We're just under £10 a cube before rhi if you do realistic costs including buildings and repairs. That's with an evoworld woodchip boiler drying to below 17% moisture. 

Have you ever worked how many kWh / cube?

[gdh]

22 minutes ago, Woodwanter said:

Have you ever worked how many kWh / cube?

I think around 100 depending how wet when it goes in but it's hard to work out because we also dry chip which is less efficient. I'll try to have a work out some time, I usually only work it annually so that could be way off.

Edited February 25, 2018 by gdh

[Chalgravesteve]

1 hour ago, arboriculturist said:

I am amazed you have enough waste to run those numbers, but I have no knowledge of the scale of your Arb. business.

 

The £ 10 came from large producers who buy in the Softwood to run their boilers. The boiler etc. will of course need replacing after 10 years  approx. running at low return temperatures.

I don’t have an arb business. I’ve got 8 tree surgeons who bring me their arb waste and chip foc. They don’t have yards and need empty trucks every day. I don’t want to do surgery. Mutually beneficial relationship. 

 

Boiler heats an accumulator tank which runs the kiln. I’ve no idea how long it will last but I look after my kit. It seems pretty solid after 3 years running so far.