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# how much btu a pipe can give down

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Member Posts: 4
HI does anyone know of how much max btu a pipe size with give down by the liner foot ? for ex : i would like to make a heating coil for a pool with coper pipe !! i think we have to know first how much liner feet of a pipe will = a sq foot and then figure out of how much btu it can give down

• Member Posts: 22,260
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heat exchange is usually calculated by square footage area of the material

Temperature differential, flow rate, one or two pumped flows, etc. The math gets fairly complicated

Take a look at factory built pool HX to get some sizing ideas
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
• Member Posts: 60
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I doubt you'd want to use copper in contact with typical pool chemicals. Chlorine is corrosive, salt even worse.
Most pool heat exchangers are stainless or titanium.
I think chlorine can eventually damage pex...
Maybe I'm not following what you're trying to do.
• Member Posts: 15,624
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Take a pc of pipe or tubing 1 ft long and visualize splitting it down 1 side and unrolling it until it is flat. Then L X W would give you the surface area.

Example: a pipe 2" diameter x 12" long would be: 2" x 3.14= 6.28"

so 6.28" x 12"= 75.36 sq inches or 75.36/144=.5233 square feet per foot of pipe that has a 2" od

it's just one pc of the puzzle. As @hot rod said there are many factors that go into it.

• Member Posts: 2,997
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are you trying to heat a pool by a boiler or by solar? If solar I would use black water pipe...
• Member Posts: 22,260
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EYoder said:

I doubt you'd want to use copper in contact with typical pool chemicals. Chlorine is corrosive, salt even worse.

Most pool heat exchangers are stainless or titanium.

I think chlorine can eventually damage pex...

Maybe I'm not following what you're trying to do.

As longs the pool chemistry is keep in line cooper is fine. Laars and Raypak have been making copper tube pool heaters for a long time.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
• Member Posts: 60
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Hmm, I was wrong then.
I've seen the copper brazing in a flat plate eaten out by pool chemicals. Tube and shell heat exchangers I've used are 316 SS or titanium heating the pool from a wood boiler.
• Member Posts: 22,260
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EYoder said:

Hmm, I was wrong then.

I've seen the copper brazing in a flat plate eaten out by pool chemicals. Tube and shell heat exchangers I've used are 316 SS or titanium heating the pool from a wood boiler.

I agree, if the chemistry goes south I have seen solid bronze pool pumps destroyed by pool water.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
• Member Posts: 60
edited March 2018
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I am curious what mottywalter has as a heat source. What the whole scenario is, water temps, etc.