Oval flue performance?

Posts: 20

posted 7 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

I am building an 8" batchbox.

I would like to use an existing chimney that has an oval shaped flue (see photo).
By my calculations the CSA of this oval is exactly the same as an 8" circular flue.

Question: How much will the oval shape of flue (instead of circular) affect performance?

IMG_0881.JPG

Satamax Antone

gardener

Posts: 3471

Location: Southern alps, on the French side of the french /italian border 5000ft elevation

194

posted 7 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

You have a bit more friction on the sides. The only way to know is to build i would say.

God of procrastination https://www.youtube.com/watch?v=q1EoT9sedqY

Peter van den Berg

gardener

Posts: 1054

Location: +52° 1' 47.40", +4° 22' 57.80"

447

I like...

posted 7 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Kelly Pridgen wrote:Question: How much will the oval shape of flue (instead of circular) affect performance?

Not much, I'll second Max in this. Most of the friction in square and rectangle shapes are from the corners. Yours is still quite good although the fast streaming, hot core of gases isn't round but stretched out a bit. As long as the chimney is straight up, smooth inside and the height is more than 16' I don't see any problems.

regards, Peter

I promise I will be the best, most loyal friend ever! All for this tiny ad:

Freaky Cheap Heat - 2 hour movie - HD streaming

https://permies.com/wiki/238453/Freaky-Cheap-Heat-hour-movie