Heat Exchanger Assembly

Eric Johnson Posted By Eric Johnson, Dec 25, 2007 at 3:31 PM

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  1. brad068

    Feeling the Heat 2.

    Nov 20, 2007
    Central Wisconsin
    That looks like a pretty cool hx. I am a little concerned about the solder joints. You say that the pipes are soldered into holes drilled into the 1'' . I would be worried because all the stress is on the solder. Most solder joints into pipes like that are a t-tap style solder joint where the pipe is actually pulled outward to make a sleeve fit like any type of sweat fitting. Same thing for solvent weld fittings. More surface area for the solder or solvent to cover and take hold the stronger the joint and then the stresses are exerted on the two materials slid together not on the solder alone. Now if that was a weld joint that would be OK.
  2. Eric Johnson

    Eric Johnson
    Mod Emeritus 2.

    Nov 18, 2005
    Central NYS
    I'm aware of that concern. However, I've seen assemblies just like this hold up just fine in a solar water heater, and I can hammer and wail on these joints and not break them. Anyway, it's built and I'm going with what I've got. If it works at all, it should work pretty well.
  3. dscamp

    Member 2.

    Dec 28, 2007
    PEI, Canada
    Hey gang
    I'm new to the forum and love it. I was just wondering about the heat exchanger in the storage tank. Could you use the pipes from baseboard rads? Same idea as the fin tube, not sure how the price would compare. I think you wouldn't need nearly as much tubing in the tank since it should transfer heat much better than just copper pipe.
  4. BrownianHeatingTech

    Minister of Fire 2.

    Oct 5, 2007
    Northwood, NH
    Yes. The only issue is the thin-wall copper tubing used in the baseboards. It can be more susceptible to corrosion than thicker tubing, if the water in the tank isn't maintained at the right pH.

  5. Nofossil

    Moderator Emeritus 2.

    Oct 4, 2007
    Addison County, Vermont
    Every once in a while, a project comes along that combines function and beauty in a relly cool way - I think this is one of them. Nice work, Eric!

    There were some questions about heat loss from storage tanks. I finally got a hands-off baseline - no heat in or out of the storage tank for several days. Mine is well insulated and outdoors.

    Average outdoor temperatures: about 25 degrees.
    Time period: 77 hours.
    Starting tank temp: 120 degrees.
    Ending tank temp: 117 degrees.

    With a 95 degree temperature difference between the tank and the outdoors, I'm losing about a degree a day. Not as good as I hoped, but not too bad either.
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