branchburner said:
I'll quote you: "Otherwise, the new charge will drop internal temps substantially, lowering flue temps, and reducing draft..."
Aren't you saying the draft strength is dependent upon the moisture content or size of the new charge of wood?
Sorry, I thought you meant split size, not the mass of the load itself.
No matter, if the coal bed is substantial you will get high flue temps even with marginal (i.e. between 25% and 30% water by weight) wood. Those extra few ounces of water in each split won't do much to immediately and directly rob the coal bed of the heat needed for combustion to begin, not compared to the effect of the actual total mass of the load (including all the wood fiber) itself. The only difference as far as an immediate cooling effect will be in the higher specific heat of water compared to that of wood fiber. And we're talking marginal wood here, not dumping massive rounds of green oak at 45% water by weight. Again, not that much extra water to account for the heat loss you are describing.
Even at 30% water, a 20 pound charge will only need 280 BTU to raise that extra water all the way to 212ºF. And that's assuming that all of that water will need to be raised to that temp before the wood will begin to burn. That is certainly not the case. Once the outside has charred and begins out-gassing, flame will be sustained while the inner water is still coming up to temp. Anyone who has ever dropped a large round of green wood directly on a massive bed of hot coals will see that it begins to burn almost immediately, and continues to burn, even while water is steaming out the ends.
As far as air vs. wood quality, I find it perplexing that folks will obsess over getting their saws at the ideal air:fuel ratio, but then assume that they don't need to do it in the stove. I have seen much more research that indicates that proper air is more crucial to a good burn than using perfect wood... however it is defined. And forget the old "you wouldn't want to use gas with water in your saw" argument. Firewood
always contains a substantial amount of water, gasoline can't have any at all. Apples and watermelons comparison AFAIC.
In fact, I have seen some hard data that shows that oak in the 40% MC range burns substantially cleaner in a conventional airtight stove than oak at 20% MC. Yes, there is a small hit on overall efficiency Less than you imagine), but the measured emissions are actually significantly lower. This trend reverses itself with the modern designs, but since the new stoves burn cleaner by nature, the difference between burning seasoned and unseasoned is so low in total emissions that there is a greater difference between stove types/models. To wit, a cat stove will produce less PM and other nasties when burning marginal wood at lower temps that a non-cat will when burning bone-dry wood at the same temp.
You should remember that this isn't EPA/Hearth.gov. Just because many folks made the switch to an EPA stove doesn't mean everybody did. Many here still burn the older stoves to great success. They deserve to know the truth about their stoves' emissions under varying moisture contents.