My house has a classic, wood-burning fireplace. No fans, no nothin' to push warm air back into the house. As a result, it makes the area immediately in front of the fireplace a cat-magnet, the remainder of the living room pleasant, and drops the temperature of the rest of the house by a few degrees (3°F, if you believe Mythbusters). All that heat leaving my house annoyed me.
I started thinking about to recover it. I had a brilliant insight! The chimney is basically a metal pipe running inside the masonry. Why not wrap the chimney in a water-jacket, or pipe, and send the heated water through a radiator?
Turns-out I'm not the first to think of this. Also turns-out it doesn't work. The interweb says that (1) there isn't enough heat in the chimney to be usefully extracted; (2) if I pull heat from the chimney, I'm reducing the energy that is propelling combustion products out of the building -- which is another way of saying that I'm increasing the soot & smoke in my living room, and raising the probability of a chimney fire. <sigh> Yet another brilliant theory undone by physical reality.
On the other hand, I did accidentally learn about firebacks. These are either big, heavy cast-iron plates that sit in the back of the fireplace and re-radiate absorbed heat, or lighter, stainless-steel sheets that reflect heat back into the room.
I started thinking about to recover it. I had a brilliant insight! The chimney is basically a metal pipe running inside the masonry. Why not wrap the chimney in a water-jacket, or pipe, and send the heated water through a radiator?
Turns-out I'm not the first to think of this. Also turns-out it doesn't work. The interweb says that (1) there isn't enough heat in the chimney to be usefully extracted; (2) if I pull heat from the chimney, I'm reducing the energy that is propelling combustion products out of the building -- which is another way of saying that I'm increasing the soot & smoke in my living room, and raising the probability of a chimney fire. <sigh> Yet another brilliant theory undone by physical reality.
On the other hand, I did accidentally learn about firebacks. These are either big, heavy cast-iron plates that sit in the back of the fireplace and re-radiate absorbed heat, or lighter, stainless-steel sheets that reflect heat back into the room.
