Flame me now I burn wood green and other wise

[Eric Modell]

I've burned green wood too, only in an emergency tho. I'm starting on the red oak which I felled/split last Jan./ Feb., stored under roof, seems to burn just fine.

In our situation last years spring wood seems about perfect for us. Not to dry not to green

 

[Eric Modell]

When in doubt split it smaller.

Smartest statement in entire thread.

Or do not split it !!!!

 

[mizzou]

Mizzo

I was sarcastic. Us older people from yesteryear burned and do burn green wood , because that is the way our equipment operates.

Realized that too late.:msp_biggrin:

 

[AIM]

The water in green wood is going to need around 10% of the BTUs in a cord to burn off. Less in some species, more in others like willow & cottonwood that are notoriously waterlogged. But most will work out to around 10%

Could you expand on this further?

Are you saying that if I get a million BTU's per cord of dry whatever.
I'd get 900,000 out of a cord of same whatever wood wet?

 

[Whitespider]

Yep AIM, that’s what he’s trying to say… but it ain’t correct.

What he’s trying to do is make linear calculations using numbers from a Saturated Steam table. Saturated steam is in direct contact with the water, and under the same exact pressure. The steam coming off an open pot of boiling water is saturated steam, as is the steam occupying the headspace of a pressure cooker. The saturated steam tables are based on pooled liquid water, not water held in a medium such as wood. To understand what is actually going on in the wood stove requires knowledge of fluid dynamics in a particular medium, how far apart the steam and water are from thermodynamic equilibrium, the difference between saturated steam and dry steam (superheated steam), the linear and volumetric expansion coefficients of both the water (at existing pressure) and the medium containing it, the amount of heat being applied both before and after the water converts to steam, the heat capacity ratio of gasses in the stove, the amount of surface contact the steam makes with the steel, the duration of that contact, the temperature of the steel, the volume of air entering the stove vs. gasses leaving the stove, plus a bunch more stuff... more than what can be explained here.

Suffice to say it can’t be figured using linear calculation… and the 10% number is way off base.

 

[chopperfreak2k1]

Yep AIM, that’s what he’s trying to say… but it ain’t correct.

What he’s trying to do is make linear calculations using numbers from a Saturated Steam table. Saturated steam is in direct contact with the water, and under the same exact pressure. The steam coming off an open pot of boiling water is saturated steam, as is the steam occupying the headspace of a pressure cooker. The saturated steam tables are based on pooled liquid water, not water held in a medium such as wood. To understand what is actually going on in the wood stove requires knowledge of fluid dynamics in a particular medium, how far apart the steam and water are from thermodynamic equilibrium, the difference between saturated steam and dry steam (superheated steam), the linear and volumetric expansion coefficients of both the water (at existing pressure) and the medium containing it, the amount of heat being applied both before and after the water converts to steam, the heat capacity ratio of gasses in the stove, the amount of surface contact the steam makes with the steel, the duration of that contact, the temperature of the steel, the volume of air entering the stove vs. gasses leaving the stove, plus a bunch more stuff... more than what can be explained here.

Suffice to say it can’t be figured using linear calculation… and the 10% number is way off base.

i don't know what you said here and i certainly don't mean to discredit it, but what Dalmation has said so far is jiving with my limited experience with burning unseasoned wood. i say "unseasoned" because it's not fresh cut and thrown in the furnace, to me thats green. my unseasoned wood has been drying 3-6 months.

 

[AIM]

Yep AIM, that’s what he’s trying to say… but it ain’t correct.

What he’s trying to do is make linear calculations using numbers from a Saturated Steam table. Saturated steam is in direct contact with the water, and under the same exact pressure. The steam coming off an open pot of boiling water is saturated steam, as is the steam occupying the headspace of a pressure cooker. The saturated steam tables are based on pooled liquid water, not water held in a medium such as wood. To understand what is actually going on in the wood stove requires knowledge of fluid dynamics in a particular medium, how far apart the steam and water are from thermodynamic equilibrium, the difference between saturated steam and dry steam (superheated steam), the linear and volumetric expansion coefficients of both the water (at existing pressure) and the medium containing it, the amount of heat being applied both before and after the water converts to steam, the heat capacity ratio of gasses in the stove, the amount of surface contact the steam makes with the steel, the duration of that contact, the temperature of the steel, the volume of air entering the stove vs. gasses leaving the stove, plus a bunch more stuff... more than what can be explained here.

Suffice to say it can’t be figured using linear calculation… and the 10% number is way off base.

Well ya whitey... Everybody knows that.:msp_biggrin:

 

[Whitespider]

OK, let’s just forget all that technical mumbo-jumbo and go directly back to original post by Dalmatian90 and assume he’s correct in his linear calculation, and use his numbers…

• A cord of White Oak equals 27 million BTU’s.
• 2200 pounds of water in green White Oak.
• 2.5 million BTU’s to convert the water to steam.
• 2.5 million / 27 million = 9.25%

EXCEPT that’s based on 100% of the BTU’s… and no wood-burning appliance is 100% efficient. Dalmatian90 then goes on to say that the newer high-efficiency stoves don’t do well with green wood… it’s the older 30-50 percent efficiency stoves that burn it well (or well enough). Now understand, a 50 percent efficiency stove will only do 50 percent efficiency under ideal conditions (supposedly), and wet wood ain’t ideal… is it? But anyway, let’s rerun the numbers using 50% efficiency…

• A cord of White Oak equals 27 million BTU’s.
• 50% efficiency equals only 13.5 million BTU’s available.
• 2200 pounds of water in green White Oak.
• 2.5 million BTU’s to convert the water to steam.
• 2.5 million / 13.5 million = 18.5%

Well now, by just allowing for the stove efficiency and none of the technical mumbo-jumbo, that 10% number doubles… So the best we can expect, if Dalmatian90 is correct in his linear calculation, is a heat loss of 18.5%... not 9.25%.
Now, let’s rerun the numbers using 30% efficiency…

• A cord of White Oak equals 27 million BTU’s.
• 30% efficiency equals only 8.1 million BTU’s available.
• 2200 pounds of water in green White Oak.
• 2.5 million BTU’s to convert the water to steam.
• 2.5 million / 8.1 million = 30.8%

HOLY CRAP!… If I burn green wood in my old pre-1980’s stove I’m gonna’ be losing near 31% of the heat available to me! And that’s best case according to Dalmatian90, figuring his stated 30% efficiency. I thought those old stoves were supposed to do the best with green wood? And WTF happened to that 10% number!

OK now, let’s just pretend that only one-quarter of the technical mumbo-jumbo I’m talking about is true… What do suppose the percentage of heat loss from burning green wood is?... 35%?... 40%?... More?

 

[Whitespider]

Now, Dalmatian90 will claim that a 30% efficient stove will use part of the normally lost 70% to convert water to steam… but that simply ain’t how it works. If it’s flying out the flue as unconverted potential energy, unable to be transferred onto the surface of the steel and radiated into the room… it will still be flying out the flue as unconverted potential energy, unable to be transferred into the water and turning it to steam… Ya’ can’t have your cake and eat it too.

 

[ray benson]

I have read burning green wood requires 30% to 50% of the wood’s BTU’s to be used to drive moisture out of the wood. Along with more tars and creosote.

 

[Eric Modell]

Now, Dalmatian90 will claim that a 30% efficient stove will use part of the normally lost 70% to convert water to steam… but that simply ain’t how it works. If it’s flying out the flue as unconverted potential energy, unable to be transferred onto the surface of the steel and radiated into the room… it will still be flying out the flue as unconverted potential energy, unable to be transferred into the water and turning it to steam… Ya’ can’t have your cake and eat it too.

So I can get a new stove hold my wood back a year or two and heat my uninsulated old farm house with a cord and a half of wood.

 

[psuiewalsh]

So I can get a new stove hold my wood back a year or two and heat my uninsulated old farm house with a cord and a half of wood.

YES, For one week!

 

[Whitespider]

So I can get a new stove hold my wood back a year or two and heat my uninsulated old farm house with a cord and a half of wood.

L.O.L.
Well if you can I wanna' know what stove you bought... and exactly how you installed it!

 

[Eric Modell]

I am confused now!!!

I burn a 30% efficient stave and waste 50% of the energy with the green wood.
I must be about 15% efficient. I burn 3 to 4 cord so if I can bring my efficiency up I should be able to bring my wood consumption way down.

I have know idea how efficient or setup is but I assume it is better then 15%.