Fabricating A Header For Solar Collector WIthout Reducing T's

Discussion in 'Solar and Geothermal Water Heating Forum' started by driz, May 14, 2009.

  1. driz

    driz New Member

    Messages:
    36
    I am making a couple solar collectors and no way am I paying that extortionist price for reducing T's for the header at the top. I have lots of experience with the torch and sweating ect. I want to drill and solder connect the 1/2" along the top to a 1" for the header. Can this be done using silver solder for the joint and a nice tight fit or am I farting into the wind here? I suppose regular 50/50 is out of the question for an application like this. What say ye, better than I plumber fabricators?
  2. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,043
    Location:
    Cave Creek, Arizona
    tees

    IT will not work. To do that you would need a "Tee Turner" machine and that will cost a lot more than a bunch of reducing tees. You do not say what you will do about tees for the bottom manifold. And 1/2" copper is a poor choice because it has a very low surface area to volume ratio. What are you doing to increase the radiation absorbtion?
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,043
    Location:
    Cave Creek, Arizona
    collectors

    That is the proper way to do it.
  4. driz

    driz New Member

    Messages:
    36
    What I Am Thinking Is Similar To This

    http://builditsolar.com/Experimental/CopperAlumCollector/Construction.htm

    Something like this but shorter in length and more closely spaced together. For the fins I will use the same aluminum flashing as shown here. I see he just uses T's and half inch for the top and bottom and says it works well. Just what is the purpose of a larger lower and upper anyways, overheating? That isn't much of an issue where I live here in NY. Here all it serves is as a preheater only but every little bit helps. For a tank I scrounged a very nice stainless steel boiler fed 30 gallon cell in nice shape.
  5. Scuba_Dave

    Scuba_Dave Extreme DIY Homeowner

    Messages:
    885
    Location:
    South of Boston, MA
    That's a nice link
    I think I have seen something like that before
    I almost think 1/2" feed & more 3/8" pipes would be better

    With my greenhouse exceeding 110 I am definitely going to be building a solar water heater. It would be nice to reduce the electric use
  6. Bill Arden

    Bill Arden Computer Programmer

    Messages:
    584
    Location:
    MN, USA
    There are several methods to join two copper pipes together without using T's

    1. It is possible to weld copper using copper wire and get a strong fillet, however it is a very difficult process to control.

    2. It is also possible to soften the copper in a fire and then start with a small hole make a it flair out using a small mandrill like piece on a drill. This would also be tricky to get right.

    In the end you are better off spending the money and using T's. If it is worth doing, it is worth doing right.
  7. wallyworld

    wallyworld New Member

    Messages:
    21
    I plan on building the collectors shown at www.Builditsolar.com, I emailed Gary about that same thing and he said 1/2 is alot cheaper and works fine. I'm going to use mine for heating a slab and will build mine bigger as I'm building them into a south facing wall. I'm worried about pressure drop so was thinking of upsizing the headers and still might?
  8. pressure drop is not an issue...

    if you actually make one of those panels,
    the only thing that can be a problem is proper
    equal flow through all the pipes.....

    as long as everything is made perfectly all the same with no restrictions in any of the pipes, , you will
    have a even equal flow up through that panel,

    you should be able to capture an even heat and flow through all the pipes...

    Now, cranking up the pressure and volume through the panel will probably make the water take the quickest route
    through only 30% of the pipes and will defeat the whole purpose and idea...
  9. wallyworld

    wallyworld New Member

    Messages:
    21
    I don't understand your last comment, why would uping the pressure make it go thru only 30% of the tubes? Seems if every thing is equal it wouldn't matter. I would think one would want the fluid flow to be slow enough to get maximum heat transfer anyway?
  10. path of least resistance




    Sorry if I mi-stated what I meant to say...

    the pressure does not really matter, its the VOLUME of fluid
    that is passing through the panel that is important........

    fluid must flow evenly up through the panels...

    it almost has to "rise like bread " through them
    to make them pass equal through them a ll to get the max heat out of them......


    if you were kick up the PRESSURE, and do not throttle down the amount of fluid passing through the panels, the fluid will natrually just find the easiest path through the panel and it will probably bypass more than half the tubes...




    does that make better sense...????
    Last edited: May 31, 2009
  11. wallyworld

    wallyworld New Member

    Messages:
    21
    What happens when you add glycol to the system? No Burst or some other brand made for heating sysytems
  12. water rises.....

    ok,

    when I installed the damn things way back when,

    if you had an array of them tied in together, you wanted the water to pass slowly up through the panels

    you basically have a parallell type of system that you have set up through the panel..or panels.....filling up the bottom one inch copper manifold, then disperseing up through the 3/8 tubes....YOU WANT IT TO RISE EVENLY

    the water comes in on the bottom on the left and goes out on the top on the right.....

    if you put the fluid it through the panel too quickley, the water or glycol will simply find the quickest path through the panel... wether it be the first two or three tubes , bypassing and ignoreing the other tubes going up the panel.... it is takeing or finding the quickest route through the panel...

    (just like in a parallel water heater layout, if anything gets out of wack, it draws much more off one and not the other)

    Pressure is not really an issue, but the volume you are passing through the panel will determine how much heat you collect and also how efficient the panel is,,,,
    we used to actually install these glass flow meters in the lines to the panels which could be throttled down with ball valves. to the right gpm.......

    does that make any sense,

    ......it has to rise like bread , slowly and evenly


    if you were to buy a real set of panels
    it would tell you the proper GPM for max effect....


    look around at panels for sale and see what they advise
    Last edited: Jun 1, 2009

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