calorific value of wood??

[John Barleycorn]

Nope, if you follow the quote trail, I was referring to firewoodman's method of quantifying his delivery.

 

Well I am referring back TO THE ORIGINAL QUESTION

 

"does anyone know how to work out the calorific value of firewood.

 

being fedup of all this rubbish about what burns best at what moisure content and whatever species, i would like to try and work out the calorific value of species of wood for firewood"

 

AND NOT TO SUBSEQUENT RAMBLINGS

[Albedo]

Pete B's been a long time at the pub....

[Pete Bannister]

Ho ho Albedo...very good!

Backandpack may be interested in the paper you've cited from or maybe that's rubbish too!

Alternatively, calorific value could be measured DIY style. Easy to show relative differences but more difficult to measure absolute values because lab facilities would be necessary. Wood would be preconditioned to consant moisture content (sorry but it is crucial) uniform size and shape of particles of a known mass and heated in a sealed vessel to above its combustion temp. The combustion products (gas) given off is burnt in a controlled flame the temperature of which is pretty easy to measure. Temperature of flame x total burn time = calorific value. Repeat many times for a wood type/species and you end up with a statistically significant value ..well its the place Id start if I had to re-invent the wheel..but think its probably a lot quicker to read what's been done in the past!

[Albedo]

Thats very interesting Pete as you are now the first person to come up with a way of measuring CV for yourself, which was the OPs question. I'm gonna think about this more.

 

I find this info fascinating.

 

For example we can compare to other fuel types. So if wood is generally around 20000 Kj/Kg, coal (from memory) was about 40k. If a difference of

10k in types of wood could be found this would be significant.

 

However the water content and energy wasted evaporating it off is more significant and the method of burning, perhaps even more significant as you and others have said.

 

Nice to keep this thread alive, as I say, its fascinating to me.

[Pete Bannister]

Well to be honest n the cold light of day there are some holes in my initial proposal...However, that's pretty much the method I remember using in a school lab experiment to determine CV of foodstuffs......we had to come up with a method and apply it to measure relative difference between refined sugar, cheese ( can't remember the type, but lets pretend it was Wensleydale just for the effect!) bread, and peanuts. Anyone guess which had the highest value? It was over 35 yrs ago; well before www so understanding how to design an experiment was all about 'doing it'.

[skyhuck]

Peanuts?

[Albedo]

peanuts.

[Pete Bannister]

Sorry for the delay peeps..

Yes Peanuts it was..

I never did get round to setting fire to Charlie Brown though!

[firewood]

I know its not the DIY your after but it may be useful Firewood Information

 

 

slightly off-topic but if you look at the link above and scroll past the firewood tables the article goes on to describe the DIY constuction of a domestic biomass heatsource system. The feedstock being anything from grass cuttings to sawdust to straw to woodchip. heat generated by decomposition not burning. Most members of the forum have access to large volumes of woodchip so this should be of interest.

[Marko]

I am sure at some point the scale of the heap may make a difference but when we tried it the extraction of the heat stopped the process. ie everything worked fine until the pump was switched on.