heat exchanger help

 
Olllotj
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Post by Olllotj » Fri. Mar. 30, 2018 10:06 am

I am from the Buffalo area as well. I think I would spend a ton of coal to add a month to the pool season too.

Also, i thought it seemed like you were already doing this with propane?

 
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lsayre
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Post by lsayre » Fri. Mar. 30, 2018 10:53 am

If you go with a 150,000 BTUH exchanger, you will be reliably delivering 150,000 BTUH if any of the following conditions are met:

1) Flow = 5 GPM, and measured Delta-T = 60 degrees
2) Flow = 6 GPM, and measured Delta-T = 50 degrees
3) Flow = 7 GPM, and measured Delta-T = 43 degrees
4) Flow = 8 GPM, and measured Delta-T = 38 degrees
5) Flow = 9 GPM, and measured Delta-T = 33 degrees
6) Flow = 10 GPM, and measured Delta-T = 30 degrees
etc... (all degrees rounded to whole numbers)

If anything, once you know your actual Delta-T, you will pretty much know your actual flow in GPM across the exchanger, and from there you can calculate your systems friction head if so desired. You won't even need math. All you will need is a diagram of your circulators pump curve. Wherever the 'discovered' GPM falls on the curve, the friction head will be read for that GPM. One given is that a circulator will always deliver on its curve, and will not deliver off of its curve.

The more I ponder this, the less concern I have for the Delta-T becoming magically too low at some value. As long as the return is not shocking the boiler, there shouldn't be much else that would make one worry about it. Boiler skock was a way more serious concern back when boilers were cast iron. Steel is way more forgiving. I'm not sure of the welds shock resistance though. A 3-speed circulator might come in handy.

 
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lsayre
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Post by lsayre » Fri. Mar. 30, 2018 3:58 pm

For those wondering, Delta-T is the differential in temperature as measured on the supply side vs. the return side of the boiler. If water leaves the boiler at 180 degrees, passes through users, and then returns to the boiler at 150 degrees, the Delta-T is 30 degrees.

And:

BTUH = GPM * Delta-T * 8.33 Lbs./Gallon * 60 minutes/Hr.

 
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windyhill4.2
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Post by windyhill4.2 » Sat. Mar. 31, 2018 9:45 am

Amazed/frustrated/amused/baffled....... Those are all words that describe my emotions when i read a thread like this.

Someone worrying about the boiler burning 1 ton of coal to heat the pool... so what !! ... $160- $300 depending on the geographical location .

How much does a pool like that cost to install ??? Cost to maintain ???? What is the return for the investment ??

Is the pool efficient to operate ? :what:

OR..... is the pool for fun & recreation ? What is the efficiency factor for that ??
How much does a snowmobile cost ?? return of investment ??
4 wheeler.... riding mountain trails.... oh, trailer for this & the snowmobile too....

Boat & trailer..... i hear this choice has a very low efficiency factor :lol:

Conclusion.... if you have a pool & like being in the water for hrs.... if the idea of a longer season for enjoying the pool is favorable to you....

By all means... spend $300 for coal & enjoy your pool.. :yes:
Your EFM520 will love you for that decision .. :)

Hopefully i used enough of those little round faces so no other poster feels toasted :lol:


 
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StokerDon
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Post by StokerDon » Sat. Mar. 31, 2018 9:53 am

W.H. I don't see why this would frustrate anyone. Everyone already agreed that spending 1 ton of coal, whatever it costs, just for having fun is well worth it. I know I have used quite a bit of coal, just for fun.

-Don

 
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windyhill4.2
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Post by windyhill4.2 » Sat. Mar. 31, 2018 11:06 am

StokerDon wrote:
Sat. Mar. 31, 2018 9:53 am
W.H. I don't see why this would frustrate anyone. Everyone already agreed that spending 1 ton of coal, whatever it costs, just for having fun is well worth it. I know I have used quite a bit of coal, just for fun.

-Don
I wholeheartedly apologize for posting my thoughts based on several of the earlier posts as i read them...


I reread the whole thread several times & reread your post & now i am seeing everything just like you obviously do..

 
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Rob R.
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Post by Rob R. » Sat. Mar. 31, 2018 11:38 am

I heated my pool for one summer with my EFM. I don't remember how much coal it burned, but I do remember that it overheated my house. Since that time I have insulated the boiler and piping, so it probably would not be as bad today...but still a concern.

If the boiler heating the pool is in the basement, I would make sure that it is well insulated.

As for the cost, it will be about half (or less) of what it would take with propane.

 
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cArNaGe
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Post by cArNaGe » Sat. Mar. 31, 2018 12:20 pm

I heat my pool with my 520. It's an 18000 gallon 27' above ground. I use a plate exchanger that I already had from an OWB install. I do have to throttle the water to the exchanger to where the boiler will keep up. I get almost 1/2 degree an hour when running it. I've only heated it the last two summers and I've burned around 4 ton each summer. I also heat my domestic hw via an indirect.


 
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Post by cabinover » Sat. Mar. 31, 2018 3:16 pm

I heated my 24' round once for a party for my daughter. Went from somewhere in the 70s to high 80s in 24 hours, 300 pounds of coal turned to ash in the same timeframe. No longer have the pool but my daughter was happy and we used the pool more that week than ever. It was almost too warm and I thought about inviting friends over with blocks of ice to cool it down. :lol:

 
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Lightning
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Post by Lightning » Sat. Mar. 31, 2018 3:51 pm

I've had a 24 foot pool since about 2002. Some years we can use it for memorial day weekend, some years we can't. It all depends on how much sunshine we get in May. I use solar heating for the entire pool season unless the pool passes 90 degrees, which has happened several times. By Labor Day pool use interest fizzles out and that's fine with me. The latest I've gotten in the pool is mid September. I'm not really interested in extending pool season on the fall side, but having it ready in mid to late May would be great. Personally I would only see myself using coal heating for the pool for a couple weeks in May. The remainder of the season is fine with solar.

A BIG part of keeping the pool warm is to use a solar cover whenever nobody is in it. The cover prevents heat loss due to evaporation and acts as a blanket at night. A good cover is well worth the investment and the effort to keep it covered as well.

 
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2biz
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Post by 2biz » Sat. Mar. 31, 2018 6:05 pm

Another alternative...



There are folks around where I live that weaves black plastic pipe in chain link fencing to heat their pool. It can be done in a way that doesn't look hideous, making sort of a privacy fence around the pool. A small taco pump would be all it takes as a circulator. An 013 Taco pumps about 30 gallons a minute unrestricted. Uses only 2 amps @ 120v....So not going to spin the meter off the wall....A simple timer wired in could let the circulator run only during daylight hours...

Another installation I saw put the tubing on top of a garage roof with black shingles facing the sun and not visible from the front of the house. I'd say that would put off some serious heat! This type of installation keeps the piping away from the pool area.

Just another way to do the same thing only cheaper! No Heat Exchanger Needed!

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