# Thermosyphon solar water heates with homemade collectors



## SolarGary (Sep 8, 2005)

Hi,
Don't know if this is of interest or not, but I just finished up trying two types of homemade collectors in a solar thermosyphon water heating arrangement.

The one that used the copper tubes with aluminum fins collector is here:
http://www.builditsolar.com/Experimental/ThermosyphonTest/CopperCol.htm

And, the one that used PEX tubes with aluminum fins is here:
http://www.builditsolar.com/Experimental/ThermosyphonTest/PEXCol.htm

I have to say that aside from how the collectors did, I'm pretty impressed with how simple these thermosyphon systems are -- no pump, no controller, no power -- pretty nice.

Maybe ideal for non-freezing climates, as they get more complicated if you need freeze protection. 

Gary


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## Roadking (Oct 8, 2009)

Been messing with thermosyphon air collectors, and have been very pleased (and surprised) at how well they work. The water heater has been on the drawing board for a bit now, and, yes, builditsolar was my jump off point...great site. But, being in NE PA, pretty cold winters, so I am planning on incorporating both air and water heat in the next retro fit (1860 Victorian...still sketching it out so it kinda blends in). I do enjoy working with solar; if only solar electric would come to a sustainable price, I'd go for it.
Matt


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## ForestCoCabin (Mar 22, 2006)

Just a basic question. If you changed the diameter of the inlet and outlet hoses and made them smaller wouldn't that speed up the flow and be more efficient at forcing air thru the system? ... or would that be a dangerous thing to do?


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## SolarGary (Sep 8, 2005)

ForestCoCabin said:


> Just a basic question. If you changed the diameter of the inlet and outlet hoses and made them smaller wouldn't that speed up the flow and be more efficient at forcing air thru the system? ... or would that be a dangerous thing to do?



Hi,
I don't think it would be dangerous since both the inlet and outlet end in the tank which is vented to the atmosphere -- basically the tank is open on top except for the insulation board.

I had actually thought about making the inlet and outlet tubes larger in diameter to reduce pipe flow friction. But, I see your point about making the flow fast enough to push the bubbles along.


On the copper one, I plan to open up the collector and re-plumb the inlet and outlet so that they can come out without the elbow. I think that the area just before the elbow, which has a bit of an upslope might be a bubble trap.

Gary


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