kiln dryer

[Lancer]

Is that measured over the weighbridge and through the heat meter? Have you checked the average moisture content?

 

I could do with some empirical results as we never got good figures back once the boilers were commissioned. When I did any sampling during snagging visits the moisture content was always in excess of 30% wwb.

 

I considered the chip suppliers to be overcharging and they would never agree to be paid on the heat meter apart from one golf club in Scotland where the local estate funded the installation. They effectively had a contract to supply heat but I only worked down south so was not involved.

 

Yes over a weigh bridge and from a heat meter. I have checked moisture before and had one load that wasnt great but generally my supplier does a good job drying the chip to about 30% give or take a bit

[arboriculturist]

I don't see any point in splitting hairs. The point of the post that generated these comments was to show that oil just doesn't add up when taking into account RHI and it doesn't regardless of the efficiency of the boiler.

 

If 20 years was up today and the RHI payments ceased today, what do you think it would cost to dry your next batch of Firewood using chip at your current costs ?

 

In addition if you had an oil boiler of the required rating linked to your installation what do you think it would cost to dry a batch using oil. This is really usefull to know for those who may have the option to use oil to dry or boost there own batch boilers at night but have no feed in tariff.

 

I am not sure if you have posted before that you woudn't dismiss drying wihout the RHI if you had an unlimited supply of dry waste wood. Do you agree?

[R5log]

If 20 years was up today and the RHI payments ceased today, what do you think it would cost to dry your next batch of Firewood using chip at your current costs ?

 

 

 

In addition if you had an oil boiler of the required rating linked to your installation what do you think it would cost to dry a batch using oil. This is really usefull to know for those who may have the option to use oil to dry or boost there own batch boilers at night but have no feed in tariff.

 

 

 

I am not sure if you have posted before that you woudn't dismiss drying wihout the RHI if you had an unlimited supply of dry waste wood. Do you agree?

 

 

What kiln have u got?

Thanks

[BARNSLEY BOB]

If 20 years was up today and the RHI payments ceased today, what do you think it would cost to dry your next batch of Firewood using chip at your current costs ?

 

In addition if you had an oil boiler of the required rating linked to your installation what do you think it would cost to dry a batch using oil. This is really usefull to know for those who may have the option to use oil to dry or boost there own batch boilers at night but have no feed in tariff.

 

I am not sure if you have posted before that you woudn't dismiss drying wihout the RHI if you had an unlimited supply of dry waste wood. Do you agree?

 

well,

that sounds like the log pro scenario, disregarding the $ 38.000 capital cost of hardware which was logpro"s anyway.

[arboriculturist]

What kiln have u got?

Thanks

 

Just bog standard with no RHI.

[Duffryn]

well,

that sounds like the log pro scenario, disregarding the $ 38.000 capital cost of hardware which was logpro"s anyway.

 

LogPro assumed an 80% efficiency (as per manufacturer claims at the time) where as we learned the reality with a batch fed boiler is closer to 60%. If you can run a batch fed boiler on waste wood / straw and claim RHI then its is still a wise move so long as you are around to keep loading it.

 

Oil cost - assuming 3.5 day trying time for a 20ft container ( 16m3 of logs) with 100kwh of heat going in and oil at 20p a litre you would be looking at :-

 

8,400 kwh / 10kwh per litre is 840 litres so £168. Plus say 5-10% for efficiency loss then circa £180. Oil is at an all time low and I would hate to invest in an oil boiler for a kiln on the assumption that costs would remain at 20p a litre.

 

To do the same on chip 8,400kwh at 2.2p per kwh = £184

Edited January 3, 2016 by Duffryn

[R5log]

Just bog standard with no RHI.

 

 

Why not get a rhi payment one?

Or import kiln dried

[cornish wood burner]

Let's split some hairs:

 

I'd like to know what the 90% figure refers to? Is it combustion efficiency, which would indicate incomplete combustion or is it conversion efficiency of the chemical energy in the wood to heat in the water leaving less that returning to the boiler? In which case I'd like to see flue gas temperature after the boiler fire tubes as well as O2 content of flue gas and rate of burning in kg as well as moisture content. I think anything over 80% would be remarkable in a wood boiler in the absence of a flue gas condenser. Even gas boilers at best will only achieve an extra 6% over LHV in condensing mode.

Unicomfort eos boiler rated efficiency up to 93% which as far as I know is energy from wood in verses water energy out. Can't think what it's called but the manufactures did a type approval test to verify this at our site. I will try and find the results if they were sent. Dealer went bust soon after this so might not have them but I believe from memory it flew through. From memory flue gas after the heat exchanges is around 105 and O2 is currently set about 11%. Moisture content varies quite a lot from summer slab wood at 18% or even just below to

round wood at up 30%.

[openspaceman]

Unicomfort eos boiler rated efficiency up to 93% which as far as I know is energy from wood in verses water energy out. Can't think what it's called but the manufactures did a type approval test to verify this at our site. I will try and find the results if they were sent. Dealer went bust soon after this so might not have them but I believe from memory it flew through. From memory flue gas after the heat exchanges is around 105 and O2 is currently set about 11%. Moisture content varies quite a lot from summer slab wood at 18% or even just below to

round wood at up 30%.

 

Thanks Ian

 

Using Lancer's figures there's a gross energy of 66500

kWh going in from the wood which I make 87% conversion but he's losing 5.4 tonne of water from the wood's moisture up the flue with woodchip as received at 30% so deducting this to give a net energy in the wood it could be 93% if his flue gas is similarly low.

 

I'll have to do some calcs on your 105C exhaust and 100% excess air figure.

[cornish wood burner]

Thanks Ian

 

Using Lancer's figures there's a gross energy of 66500

kWh going in from the wood which I make 87% conversion but he's losing 5.4 tonne of water from the wood's moisture up the flue with woodchip as received at 30% so deducting this to give a net energy in the wood it could be 93% if his flue gas is similarly low.

 

I'll have to do some calcs on your 105C exhaust and 100% excess air figure.

That 105 obviously varies a bit with return water temp. I would be interested in your thoughts about the O2. It's on my list of things to experiment with. In to work tomorrow so can give you exact figures. There should be some scope to up that output I believe but my successor is playing with it at present so not quite sure what it's set to produce. The other boiler we run the O2 at 8.5 unless demand is high then sometimes drop it to 8. From memory that's about 115 deg exhaust but it modulates down to 20% according to demand.