Increasing Fireplace Efficiency
I am looking to increase the heat output from my fireplace. I remember years ago seeing a series of “C” shaped tubes bent to fit the firebox. Colder air from the bottom would be heated and accelerate toward the top (heat-a-lator??). Does anyone know of a souce for such a product ?
Replies
I used to use one and got great results.
I'd really like to have one now to run CO tests on, though.
Check with local fireplace stores. Here's one internet source I got from google with "fireplace tubes grate:" http://www.newenergyinc.com/Products_htm/Mil_Heater/Grate_Heater.htm
Be sure to use a good CO monitor (see 49763.4 and ther rest of that thread) and toss the grate when the tubes burn through.
The key to forgiving others is to quit focusing on what they did to you, and start focusing on what God did for you. Max Lucado
Sojourners: Christians for Justice and Peace
Thanks, that seems like exactly what i thinking of. .... now if i can get some good stainless tubing, and duct some outside air in thru the bottom....hmmmmm.
As long as the fireplace is open and has an open flue, I think anything you do is only tinkering around the edges. The vast majority of the heat will go up the chimney, and heated air from the house will continue to go up the chimney long after the fire has died down.
My solution was to install a small wood stove that sits in the fireplace. It has a glass door, so I can still enjoy the flames. Now, when I sit by the fire, I'm warmer and know that I'm actually saving on the gas bill.
Al Mollitor, Sharon MA
I had something similar in my last house. It was mounted below the glass doors. (I had to raise them when I installed it.) Air was pulled in on the right side of the fireplace, from the room, pushed through the tubes by a small AC powered fan, and then back out into the room, on the left side of the fireplace. It put out a LOT of air and was so hot you couldn't keep your hand in front of the grate. It did have 2 negatives: The fan was somewhat noisy, for my taste. I considered mounting a quieter fan, outside of the firebox, but never got around to it. 2. It would easily keep a large room warm but obviously wouldn't work in a black-out. (During an ice storm, when I was without power for 5 days, I was able to stay in the house by hooking up a car heater blower fan to a battery, and pushing air through that way.) ;-)
Thon
Increasing fireplace efficiency involves several variables that are mostly ignored these days.
Your firebox should have sides angled as close to 45* as possible, the width of the front is 3x the width of the back, the throat should be narrowed to 2-3", etc. In effect, "rumfordized".(See taunton's On Masonry).
An important aspect is to draw cold air from outside, not from the room, else you'll feel a cold draft behind you as the fire pulls in this air. Mine is connected via cast iron pipe underneath the hearth to outside.
Open fireplaces are generally so inefficient that nothing can be done to materially improve the situation.
Tests I have read indicate that open fireplaces have negative net heat output to the structure.
This is primarily due to the amount of heat that escapes up the chimney during the smokey cooldown period, before the damper can be closed (assuming anyone is awake to close it).
The best answer is to install a sealed firebox unit or woodstove, with intake air directly from the outside. Many of them can operate with open doors to get that fireplace ambience, then closed tight when it's time for bed.
Setup your damper so you can operate it easily with a fire going.
Install doors on the fireplace (glass or otherwise)
line the walls of the fireplace with sch 40 1/2 pipe or better(attachment) - install circulating pump with a heat exchanger in your ducts, circulate water thru fireplace pipes and heat exchanger. Note can heat 5300 sq feet with this.
It will take you probably at least 2 days to do the install, assuming you have pipe threading machinery/tools, etc.
In past posts, recall David Thomas said he'd also done some installs with circulating water heat transfer.