- #1
fog37
- 1,549
- 107
- TL;DR Summary
- Understanding the physics of chimneys
Hello,
While watching survival show, I saw a shelter with a fireplace and a chimney and I started thinking how chimneys work.
My understanding is that hot air rises and cool air sinks. The fire, confined to the fireplace, heats up the air inside the enclosed space. the hot air rises everywhere but some travels up the chimney. Because of the Bernoulli's effect, the hot air moving inside the speeds up and a draft is generated pulling more of the heated smoky air inside the chimney and to the outside.
Assuming what has been said so far is correct, why do chimney need to be taller than any other structure in the house/shelter, higher than the roof? What happens if they are not?
Additionally, is it true that the chimney work "better" the warmer is the air inside the room? Why?
Wouldn't the draft create by the chimney pull the heated air away from the room making it colder? Clearly removing the smoke is important but the purpose of the fireplace is to warm the interior and the chimney's draft negatively affect that objective...
Thanks!
While watching survival show, I saw a shelter with a fireplace and a chimney and I started thinking how chimneys work.
My understanding is that hot air rises and cool air sinks. The fire, confined to the fireplace, heats up the air inside the enclosed space. the hot air rises everywhere but some travels up the chimney. Because of the Bernoulli's effect, the hot air moving inside the speeds up and a draft is generated pulling more of the heated smoky air inside the chimney and to the outside.
Assuming what has been said so far is correct, why do chimney need to be taller than any other structure in the house/shelter, higher than the roof? What happens if they are not?
Additionally, is it true that the chimney work "better" the warmer is the air inside the room? Why?
Wouldn't the draft create by the chimney pull the heated air away from the room making it colder? Clearly removing the smoke is important but the purpose of the fireplace is to warm the interior and the chimney's draft negatively affect that objective...
Thanks!