Here is some interesting information on firewood and what takes place as we heat with wood.
www.mha-net.org/docs/v8n2/docs/WDBASICS.pdf
www.mha-net.org/docs/v8n2/docs/WDBASICS.pdf
How Much Heat is in One Pound of Wood? by Sam Foote, P.Eng
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I think it is something to care about as there is a lot of myth surrounding what makes a quality fire wood.
Our wood burning appliances being limited by volume is not such a big deal when you consider that for the most part they have doors.
NSMaple1
Addicted to ArboristSite
So since volume is limited, all the better to try to use wood that has more pounds (i.e. btu) per volume. So btu/lb could actually be something a lot of people might care about.
Most people that burn wood are limited to the kind of trees in their area, Some have plenty of oak and some have only softwoods to burn. Doesn't matter what you get per pound because you burn what you have. Some just have to burn more than others, but at the end of the burning season we all stayed warm with the heat.
No but my point is people typically want to use the most power dense fuel they can get and power density is a function of volume. I can't open your file but I believe the btu/lb in popular is higher than most would assume but its not as good of a fuel source because it's low power density. IIRC it requires nearly 3 times the volume as quality hard wood.
IMO, no one cares about btu/lb. Amount of fuel going into the stove is limited by volume not weight...
Answer these questions for me...
1. What is the maximum lbs of firewood you can load into your firebox?
2. What's the maximum volume of firewood you can load into your firebox?
One more:
3. Is it necessary to load your firebox to it's maximum capacity each loading?
NSMaple1
Addicted to ArboristSite
1. Depends on what type of wood I put in. Going by some numbers in a chart in the linked PDF, it could be 90 lbs. of maple, or 60 lbs. of spruce. Or thereabouts or in between.
2. About 3 cu.ft..
NSMaple1
Addicted to ArboristSite
3. Depends how cold it is out & what kind of wood I'm loading & maybe if I want to come back again before the day is over to put more wood in.
I have a broad range of choice as every bit of fire wood that I burn or sell is a waste product of a tree service.
I sell what is salable and burn for home heating what isn't. For instance this winter will be Leland cypress and pine with all hardwood being sold for profit.
Actually 3X is not correct. There is a lot of myth surrounding this subject.
The density of poplar is about 30lbs pre cu. ft.
Red oak is about 44lbs. per cu. ft.
White Oak is 47lbs. per cu. ft.
On average, greater than 50% of the time my stove is filled 90% or greater. The other 50% of the time my wife throws a few cunks in it through the day to maintain the house. And on really cold days I bet she fills it close to 90%.
My point is the stove is stoked with volume in mind... 4 cube box was filled 90%... The maximum weigh of firewood my stove can hold is futile, just as the weight of the wood is also because I'm again, limited to size that will pass through the door and not how heavy of a chunk I and load. Unless you ask my wife, she can't load the chunkers like me.
I was going from memory, the number is something less than 3x... I might of been thinking btu/ft^3, 3 times the volume
You can't just compare btu/lb, if you want to compare apples to apples then you need to compare volume. If your heat load requires 100,000 btu then you are going to want to figure out how much volume of wood you need to achieve that heat requirement.
Can you give me a practical use for knowing btu/lb?
Can you give me a practical use for knowing btu/lb?
Yes.
Btu per pound is almost the same across all wood species.
The practical use for knowing this is understanding that almost all species are good for use as fuel.
Well sure they all burn and give off heat. It all depends on how often you want to load your stove. When I'm out scrounging or have to buy wood I know energy/volume is King. I'll happily walk over pine or popple to cut some ash because if the volume of those two species is 2x that of ash or cherry then I know I'm bring home twice the heat in a single truck load as compared to the popple or pine.
I added btu values per cord into your posting in red. Note that there is not a huge difference in the values.
...and if a pine or popple falls in the yard what do you do?
A good heating system shouldn't have to be run up against it's limits the whole heating season.
Mine never is.
Was just going to say something like this.
Birch/maple will burn 2-3 times as long in my boiler despite being only 45% more dense than aspen.
