Stoves with large amount of coal..

I have a thermal camera but not a catalytic stove. The thermal camera isn't going to show air flow though. It's been interesting the past couple years to look at the radiant effect with the camera. It is just another spectrum of light, so you actually see "shadows" of cold behind anything that is blocking that light, just like shadows from the sun and you can see the falloff the further from the stove you get.
Airflow for me is very obvious. The vent fan in my kitchen is still the old wall mounted type with a spring loaded flapper hanging straight down and springs weak from age. Normally a small gap, that allows combustion air in, and makes that corner of the kitchen counter quite cold, but whenever the doors are open on the stove, it is banging back and forth from the greater air current pulling it all the way closed, then gravity pulling it open again. Stops the instant I close the doors. It's a considerable increase.

 

I wondered if you could do that. Now Im gonna have to try it.

 

Yep, agreed.
Just be curious to see if or rather how much of a gain in velocity is created. It’s not like a huge vacuum is instantaneously sucking all the heat out of a given room. Seems like that is what’s implied.

 

My first year college physics professor used to make a sport out of punishing anyone in the class that slipped and said the words "heat rises". One student early on continued to argue the subject and was handed an aluminum rod & told to hold it upright in his hand, while the teacher heated the portion several inches above his hand. The student was told that if he was right, the heat would only go up and he would be fine. He even tried not to show his pain while the heat moved though the rod in all directions and the professor continued to heat it until he dropped it waving his hand furiously.

I don't want to be argumentative or to come off as a know it all, but I do enjoy discussing things in depth and the reciprocal learning that come from it, so... As we were discussing coals and radiant heat, I'm taking the position that radiant heat, being infra-red light, does not rise and that the only air flow involved is going from the room, into the stove and up the chimney. You do of course get an increase in that radiant heat when you take away the door that is obstructing it and also when the air rushing in feeds more O2 to those coals, but there is a significant loss also. We did evolve from open fireplaces to airtight stoves for a reason.

Bear, my apologies. We seam to have drifted your thread well off course.

 

I've noticed the same thing as far as radiant heat when I have a big pile of coals in my insert and the door is open, I tried leaving the door open to heat up my space and also have tried closing the door with the cat active and blower on and could tell that eveyrthing heated up better and longer with the door closed.

 

Now that's clever.Is that a brick you have your frying pan on ?

 

When I get a huge mound of coals I noticed that I get more heat from the stove when I open the door and let the coals send out heat.I do put a screen in front of the opening to catch any sparks.When the coals burn down I refill the stove.This extends my heat times.For some reason the coals alone don't emit as much heat into the room with the door closed as they do with the door opened.

 

Too bad no wise azz student asked him to hold a lit candle by the base and put the other hand over the flame and ask which hand is warmer. You know, for context.

 

So heat doesn't rise?

 

If warm air rises, then why is there snow on the mountain tops?

I hang with a couple of plumbers, one a teacher. Eventually the discussion will come around to heat and warm air. We've been going back and forth, for years. I usually get flipped off when I get around to the snow question.

 

When i did maintenance in a plastics thermal forming plant....it was always miserable bein on a manlift next to the ceiling....20-30* s warmer than bein on the floor....
also ...we live at about 2000 ft. elevation....80% of the time its colder below us by several degrees or more....however....we have a better chance of getting more freezin rain or snow than the lower elevations.
If heat doesnt rise....someone explain why these 2 situations occur?

 

Heat moves in all directions.

Warm air rises.

 

One of first things I thought of

 

Can someone please clarify this for me?

From my Country Woodstove Model 260 Instruction Manual:

Also, do not load wood for a long burn on a deep bed of hot coals. Try
stirring the coals a few minutes before loading the stove for a low burn
to allow some of the unburned coals time to burn.

My question is if we control the burn rate via air intake, then "Why not?"

 

Unless I'm not looking for more heat, I load my stove when it looks like yours.

 

Unless the bed of coals is so high, you can't get a full load of wood in it

 

Ramifications of burning with door open?

 

Because for the longest burn you want the highest ratio of fresh wood to coals and ash as possible.
This is precisely where/when I'll have a pine fire (or two) to give the coals the time they need to burn down so I can squeeze more oak in later to go overnight. Timing is everything, you don't want to be doing this at 11PM.
When pushing a smaller stove with red oak you can end up with a coal bed quite a bit higher than what you've got there.
That's not what I'd call a deep coal bed in that pic.
Deep to me is up to or higher than the door threshold or 'doghouse'.

 

Warning nerd alert,

Its been awhile since physics but here goes, both questions are related. Heat causes the molecules to move faster and if not contained to spread apart (think steam from boiling water). This expansion results in a lower density, the surrounding non heated,more dense molecules fall causing less dense molecules to rise (milk and cream).

Now put a lid on the pot of boiling water and you will see the steam trapped at the top, that’s what happens with the heat inside a building.

Now in the mountains the heated molecules rise while surrounding cooler molecules sink, as you go up in altitude the density of the atmosphere decreases considerably. Oxygen which is 20.9% of the atmosphere at all altitudes. As the altitude increases the density decreases and by 10,000 feet the effective oxygen is down to 14%. It’s the same as a pound of wood produces approximately the same BTU, a cubic foot of white oak has a lot more BTUs than a cubic foot of Cottonwood all because of density!
People get altitude sickness because while breathing in the same volume of air it has less molecules of oxygen, it gets worse the higher you go.

If you’ve read this far your probably wondering what does this have to do with snow in the mountains. The less dense air is like having a sheet rather than a blanket on, it does not trap the heat as well resulting in more rapid heat loss as you gain elevation. The opposite also is true, the higher elevation warms up faster because the thinner atmosphere acts like a thinner hot-pad compared to lower elevation. You are also closer to the sun with less atmosphere to protect you = bad sunburns!

Did you ever wonder why you have to cook pasta longer at higher elevations?
Its because water boils at 194 degrees at 10,000’ it takes longer to cook at the lower temperature.