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Pool pump heat recovery

  1. Apr 21, 2010 #1


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    I have been planning a heat exchanger for my pool for quite some time. I'd like some reco's about pressures and pipe diameters.

    See attached diagram.

    The pool hose is 1 1/4" flexible PVC hose like this:
    The pump is a standard Hayward 1/4 or 1/2 HP that generates somewhere around 20-40psi.

    It seems to me (and the pool expert who gave me the idea) that I should be able to use one of these saddle valves:

    and some flexible aquarium or other rubber tubing.

    Some questions:
    • Can I get a saddle valve for a 1 1/4" flexible PVC pipe?
    • At 20-40 psi, will the saddle valve still be water-tight?
    • What diameter tubing for the heat exchanger would be a good compromise between volume/throughput and surface area/heat exchange?
      1/4"? 3/8"? What's good?
    • I'll need a pressure differential to get the water flowing through the exchanger. Where? (see 1 and 2 in diagram) I'm sure 1 will work. Will 2 work? I mean, I'm adding water back into the input. Does that compromise total throughput?
    • Do I have to worry about whether the exchanger tubing will burst?

    Attached Files:

    Last edited by a moderator: Apr 25, 2017
  2. jcsd
  3. Apr 23, 2010 #2
  4. Apr 23, 2010 #3


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    Hm. Hadn't thought of that.

    But wait, if my draw is after the filter, where is my return? It's got to be somewhere of lower pressure.

    Good points on both. I was thinking that 5 or 10% might not be significant.

    Prolonging my motor is ancillary. I'm doing this to warm my pool by a critical fraction of a degree.

    Oh that's how I get a pressure diff...

    But I'm loathe to make any changes whose purpose is to lower the total throughput. You can never have too much throuput, but it's pretty easy to have too little.
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