How Much Coal Is Wasted Per Day Through a Barometric Damper?

Freddy wrote:My tiny brain can't wrap around much so I keep it simple for myself: Would I rather have 72 degree air go up the chimney (barometric damper), or would I rather have 500 degree air go up the chimney? (no barometric damper).

That's a good argument Freddy. That 500 hundred degree air can't go up the chimney if it can't be replaced. Air in equals air out and vice versa.

Lightning wrote:

Freddy wrote:My tiny brain can't wrap around much so I keep it simple for myself: Would I rather have 72 degree air go up the chimney (barometric damper), or would I rather have 500 degree air go up the chimney? (no barometric damper).

That's a good argument Freddy. That 500 hundred degree air can't go up the chimney if it can't be replaced. Air in equals air out and vice versa.

That's putting it in a way that everyone should understand Freddy! I like it. And yes make up air is required. But make up air is required no matter which type of damper you use. The trick is to supply that make up air right to the area where the stove or boiler is located. I've got a 4" PVC pipe through the basement wall bringing outside air to the boiler room. If I had a stove in a finished area I would rum make up air right to the stove.

I bet the results would be different as to which saves more coal, dependent on the stove, house, and person running the stove. If it worked the same for all of us, there wouldnt be so many different opinions on it anytime its mentioned.

I think if you want to know you'd have to hook 2 identical stoves up side by side, burn them at the same temps, one with a MPD and one with a baro. But after all the experiments it will probably only be a bag or 2 of coal a year difference.

I'm slowly leaning toward a MPD only in my own situations.

I have run my stove with and without a baro,I don't know if I saved or wasted any coal or not but all I can say is this without one I never knew what temp would be when I got home.If the wind started blowing during the day it was to hot and if I set the stove for a wind and it stopped it was to cool so with the baro(I am away from home 14hrs a day so I need something that doesn't require my attention) the temp is steady and predictable.My make up air intake is at the other end of the house so I have a good amount of air moving a crossed the floor which is quite breezy at times.Keepaeyeonit

Pressure difference between walk out basement and outside -.025 WC. Next, the main floor.

Carbon12 wrote:Pressure difference between walk out basement and outside -.025 WC. Next, the main floor.

WOW!!! I knew you would pick it up, I expected around a -.005 to a -.01 though..

lsayre wrote:If an older 2,000 sq-ft home normally drafts 8,000 cubic feet of 70 degree air out per hour, and it is -20 degrees outside, then it is simultaniously drafting 8,000 cubic feet of -20 degree air in per hour.

Air weighs a nominal 0.0807 lbs. per cubic foot. (give or take, this being only an average)

The difference between 70 degree air drafting out and -20 degree air coming in to replace it is 90 degrees.

8,000 x 0.0807 x 90 = 58,104 BTU's of output required to heat the home when it is -20 degrees outside. At 65% efficient, a stove (furnace, boiler) of about 90,000 BTU's rated input would be required for that -20 degree day. This seems to be in the ballpark.

I would think there must some formula for this question of loss.

If you know the area of the damper opening, the draft value on the up side of the damper and the ambient pressure and temp of the room air, surely there is a formula to calculate the amount of air passing into the damper.

How much coal is wasted per day through a barometric damper? Exactly the same amount of unburnt coal you can pick out of the ashes.
Put your baro on the floor and pipe it up to the thimble. Drawing colder floor air thus saves you money!

who started this *censored* storm again (give that man a Cigar )

I hate saying this because its frowned on by all except the most savvy real world coal burners but Ideally I like the idea of having both Baro & MPD.

The fact is... Rev. Larry says it best... "use of Baro's and/or MPD's are unique to every installation and there is no hard and set in concrete rule on the use of, or lack of use thereof, in any fuel burning device."

any coal gained or lost is very specific to the install, stove, circumstances, weather, etc. so the question (though new) CANNOT be answered and will inevitably lead down that thread from the bowels of hell itself that we call "Baro or MPD thread"

Pressure difference between outside the front door and inside the front door -.005. Small but measurable. I have no idea what these measurements mean other than there is a pressure difference between the cold dry air outside the house and the warm, humidified air inside the house. I guess one would expect that. Anyway. My former Hitzer 983 did not have a Baro,....essentially no way to install one. The coal insert was just slid into the fireplace opening and the insulated shroud attached to block off the fireplace opening. The stove did have a slide damper which I kept at minimum unless shaking the grates. The draft through the air slots on the ash door always ran -.02 to -.04. Heated the whole house well until sustained below zero temps. Then the furthest rooms got a bit chilly. Mid 60's can't complain. That insert worked as advertised! As far as my stoker boiler,.....the Baro is not optional.

Mr Carbon 12,where there's a will there's a way .Keepaeyeonit

Wow! That is so SWEET! I'm thinking of getting another 983 for the new house fireplace next year. I kinda miss my hand fired!

Thanks,now that I have the chimney draft problem fixed this stoves runs like a swiss watch, It's never ran this good before.Keepaeyeonit

Keepaeyeonit wrote:Mr Carbon 12,where there's a will

IMG_2463.JPG

there's a way .Keepaeyeonit

Wow! Nice work!

Carbon12 wrote:Pressure difference between outside the front door and inside the front door -.005. Small but measurable. I have no idea what these measurements mean other than there is a pressure difference between the cold dry air outside the house and the warm, humidified air inside the house.

What you are seeing is the stack effect principal acting on the house.. Warm is trying to rise and is finding ways out, up higher in the house creating a lower pressure in the basement. I suspect a measurement up higher would be slightly positive Nice work partner!