kiln dryer

[briquette_seller]

Heating oil is 20p a litre locally. Energy is 11kwh per litre so 1kwh will cost 1.8p. Woodchip would cost circa 2.8p per kwh.

 

Conclusion excluding RHI then heating oil is way cheaper and easier. Factor in RHI on med tariff and its a different story.

 

The big risk with oil is of course the price shooting back up again.

 

Writing this after a couple of glasses of wine so sorry if maths is out !

 

What's the energy per litre for red diesel?

If I remember, it burns hotter but quicker than kero, which burnt slower and cooler.

 

Kero had to be at least 5p cheaper to make it worth while.

 

Would you agree with that?

[Duffryn]

Yes i will be in touch on this with you. I would be very happy to pay you for your time and input I think the saving on price and hassle would be big and also a donation to Arbtalk Childrens trust. Your advice so far has been very much appreciated.

 

Thanks but a small donation to the charity and retruning the favour to someone else would be more than sufficient

[Duffryn]

What's the energy per litre for red diesel?

If I remember, it burns hotter but quicker than kero, which burnt slower and cooler.

 

Kero had to be at least 5p cheaper to make it worth while.

 

Would you agree with that?

 

Honest answer is that I don't know but even if it were 5p a litre cheaper it still wouldn't pay over biomass with RHI now let alone when oil prices go back up

[Lancer]

Thanks but a small donation to the charity and retruning the favour to someone else would be more than sufficient

 

Very good of you. I will PM you my details, I am off soon to Norway for a week so will probably be mid January time before in touch.

[twistedhicap]

What's the energy per litre for red diesel?

 

If I remember, it burns hotter but quicker than kero, which burnt slower and cooler.

 

 

 

Kero had to be at least 5p cheaper to make it worth while.

 

 

 

Would you agree with that?

 

 

Think you will find it the other way round !

[briquette_seller]

Oh ok, thanks, it was a long time ago.

 

Diesel burns slower and cooler.

Kero burns faster but hotter.

 

Kero had to be at least 5p cheaper to make it more cost effective.

[openspaceman]

Oh ok, thanks, it was a long time ago.

 

Diesel burns slower and cooler.

Kero burns faster but hotter.

 

Kero had to be at least 5p cheaper to make it more cost effective.

 

Adiabatic flame temperatures are virtyually the same, around 2100C, wood is a bit behind at less than 1900C , of course these temperatures are never reached because of excess air, and wood needs more excess air.

 

KG for KG 28 sec kerosene is the same energy as 35 sec gas oil, the difference in energy arises because oil is sold by litre and gas oil is more dense.

 

So yes a litre of kerosene has to be worth less than a litre of gasoil

[openspaceman]

I buy in woodchip from a friend currently paying £85 per tonne for chip at 30% get walking floor lorry with 18 tonnes approx at time. We average 58000 KW from 18 ton so 58 divided by 18 gives us 3222 KWH per ton so numbers virtually same as mine.

 

 

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.

[openspaceman]

£60 per tonne assumes you are buying green wood, seasoning it and hiring in a chipper ?

 

Assuming above assumption is correct re cost of fuel then Woodchip at 30% is c 3500 kwh per tonne. Boiler will be max of 90% efficient so 3150 kwh per tonne or 1.9p per kwh.

 

Current chip is low 20s and that probably cost a bit less than £60 if you are splitting hairs.

You didn't mention boiler efficiency in your original comparison so wouldn't the energy from oil cost be higher as well?

 

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.

[Duffryn]

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.

 

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.