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[just a reminder] wood vs oil
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Author:  wurst [ 12.02.13 ]
Post subject:  [just a reminder] wood vs oil
oki thats just a reminder..

wood is beeing sold in cubic metres here.
since theres different kinds of wood / humidity / even cubic meters while oil is beeing sold in litres, its very hard to compare.
KWh and Euro are my target units.

##burning wood in numbers

1.) kind of wood
Hard (oak/beech) --> 4,2 KWh / Kg
Soft (birch/christmastree) --> 4,4 KWh / Kg

2.) Moisture
Hardest part.
Water must not only be vaporized, burning will be more ineffective with wet wood.
--> Where theres smoke theres money waste!
The values in 1.) base on typical 48 Months of storage before use.
Storing wood close to the oven 2 weeks before use raise efficiency by 5-10%.
Outside stored wood contains less acid which saves oven and chimney secondary cost. Such Wood will produce less soot, burns 2-3 % more effective.
Real dry wood contains typical splittings at the frontal side.
Humidity meters are not expensive but non-precise, they measure only electrical resistance.
--> Do it yourself or find 1 to trust in.

3.) Square metres
1SRM = 0,6 m3 = 500Kg hard or 350Kg soft wood
1FRM = 0,9 m3 = 750Kg hard or 525Kg soft wood

4.) Prices
usual selling unit is SRM.
100,--/SRM for hard and 80,-- for soft wood is kinda average. Incl delivery.

conclusion for wood:
hard wood delivers 21 KWh / Euro
soft wood delivers 19 KWh / Euro

##burning oil in numbers
(thats more easy...)

1 liter oil delivers 10 KWh.
1 liter costs 83 cent.

conclusion for oil:
oil delivers 12 KWh / Euro

##notes / conclusion
Oil heatings work more efficient. We have a ratio 90/70 %.
When i take the wood average (20KWh / Euro) and substract efficiency loss:
wood serves 15,5 KWh / Euro, compared with oil in a modern heating.

Thoughts:
this means that the wood wins marginal 15,5:12. In Euro/KWh, meaning far less comfort in acquisition and more work. --> time = money.
pyromaniacs and romanciers have else reasons to use wood.
a modern oil heating has higher maintenance cost. i cant get rid of it. --> no argument for me.
for real savings u get some trees, strong hands, tools, vehicles, 2 years time to w8.
wood is co2 neutral, another hard to calculate vector (:
Author:  havoc [ 12.02.13 ]
Post subject:  Re: [just a reminder] wood vs oil
yep, cut down the damn trees.
Author:  wurst [ 12.03.13 ]
Post subject:  Re: [just a reminder] wood vs oil
no i just ordered 2 SRM beech.
btw SRM = Schüttraummeter, that means 1 cubic metre (loose thrown) which is a pretty cheetish measure.
u know mikado? order some wood, invite teh grand masters of real life mikado! (:
i think i go ok with that for the rest of the season.
just need it to add some extra power on cold days or to impress women etc.
im having no tv, so theres something that i can watch at night.

thinking about to really kill a tree, im having the opportunity.
when i think that i would have to do it for the winter 2015/16... eeehm... lata.

it was just hard to bring classic heating in some relationship with wood.
anyone seems to have different numbers.
eu wanna make a standardized efficiency test duty for new ovens, that makes sense.
they should force them to sell wood in weight measures.
btw the most ineffective fires are those wheres no air supply from downside, open fire, eg this classic land house thingy.
their efficiency is 5%, you pay the most due to their fresh (and cold) air suction.
a classic potbelly stove brings up efficiency to 50%, it was a milestone invention.
those modern cubic steel ovens with a window (and hot gas circulation) range between 60 and 70 %
some wanna sell u 90% effective ovens. they cheat.
as long as we have > 300°C exhaust leaving the house, were far from being efficient.

the major problem with wood burning is the transmission of the generated heat.
where its hot enough to burn the soot, counter current principle can work pretty well.
(it means heating the fresh air with the exhaust gas in order to keep the energy inside the system.)
modern gas burners can reach a chimney temperature as low as surrounding temp + 5°C.
that temperature exchange is happening in very long chimney tubes.
those heatings suck air from the top of the chimney, no fresh air suction will cool the house.
anyways, the most modern ovens have it just around the main box which interrupts the (wanted) 250°C radiation.
they are hell expensive.

ah, theres a cheaper way: burn stinking brown coal briquettes^^
theres exact measures in weight and energy.
they are 25 KWh / Euro in our example box, thats far more then 15,5.
you have no hassles with moisture.
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