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Scott Davis

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Reply with quote  #1 

The copper / aluminum, parallel flow solar hot water collector design is the often the design of choice for DIY solar hydronic collectors.  It performs really well and will withstand a stagnation event (when the sun is shining on the collector but your pump stops). 

Since I haven't yet learned the soldering skill here I haven't given this design a try myself, but I understand it is very easy to learn to solder.

Here are all the details from Gary's site:

http://www.builditsolar.com/Experimental/CopperAlumCollector/CopperAlumCol.htm

Have you built a copper / aluminum solar collector? Please reply and tell us about it here! Please be sure to include pictures if you can!

Do you have questions about the copper / aluminum solar collector? Please reply, this is the place to ask about it! We will do our best to help!


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Take care, Scott MD

darrynmck

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Reply with quote  #2 
I'm keen to build a solar hot water collector - does anyone recommend a serpentine loop or the hzier style?

Will try and build with copper using some shark bite style fittings if I do the hzier style.

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Bowral Australia
http://www.mckayphotography.com.au
moosemagicco

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Reply with quote  #3 

Darryn -

I think that there are advantages and disadvantages to both.

I think you mentioned viewing Scott's CPVC video previously.  If you haven't you should.
In it he mentions that he is getting better performance out of the riser style CPVC than that of his serpentine collector which is right next to it.

Lance here on the board has done both as well.

I have personally decided to try a "low profile" hizer type set up just because of drain back for my weather and space available to place it.

I don't think there is truly a right or wrong but just from my reading here and on BIS it seems that the serpentine seems to be less efficient in general.

-Scott


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Scott in CO
xactdude

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Posts: 44
Reply with quote  #4 
Quote:
Originally Posted by Scott Davis

The copper / aluminum, parallel flow solar hot water collector design is the often the design of choice for DIY solar hydronic collectors.  It performs really well and will withstand a stagnation event (when the sun is shining on the collector but your pump stops). 

Since I haven't yet learned the soldering skill here I haven't given this design a try myself, but I understand it is very easy to learn to solder.

Here are all the details from Gary's site:

http://www.builditsolar.com/Experimental/CopperAlumCollector/CopperAlumCol.htm

Have you built a copper / aluminum solar collector? Please reply and tell us about it here! Please be sure to include pictures if you can!

Do you have questions about the copper / aluminum solar collector? Please reply, this is the place to ask about it! We will do our best to help!


question,
I was looking at copper pipe today and I have both L & M available. The M is a thinner pipe. Will the M handle the pressure in a flat panel?

Keith671

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Posts: 142
Reply with quote  #5 
xactdude,
That is what I used in mine. It is also quite a bit cheaper than the L. If you are going to have a drain back system there is virtually no pressure.

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Keith R. in PA.
GaryBIS

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Reply with quote  #6 
Hi,
I've used M on all of the collectors I've done with no problems.

The pressure capability is way way more than you will ever see in a drain back.

I think the only issue is the potential for corrosion over the long haul, and the L providing more material than the M will last longer.
But, I think that if you measure the pH of the water in the tank once a year, and make sure that it is not going acidic (add some baking soda if it does), I think the M copper can last a lifetime.

Gary

darrynmck

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Posts: 52
Reply with quote  #7 
Hey thank Scott (sorry I missed your reply from above until now).

Yep think I'll go for a hzier design - the flow would seem to be better and I think this means more efficiency plus I'd need a less powerful pump if I go down that track.

I'm building a new horizontal air heater this week and after that will look to add a water heating component as well to make a hybrid.

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http://www.mckayphotography.com.au
Scott Davis

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Reply with quote  #8 
Sounds great darrynmck.  Please take lots of pictures of your new horizontal air heater and start a new thread in the member projects section with your thoughts and info!
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mattie

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Reply with quote  #9 
Hello all first post here,
I was just wondering if there has ever been any comparisons done on how well this copper /aluminum diy solar panel might perform against a commercial evacuated tube type panel for domestic hot water requirements?Apologies in advance if this has all-ready been posted (maybe somebody could point me to the link)
Regards Mattie
GaryBIS

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Posts: 243
Reply with quote  #10 
Hi Mattie,

You could get a pretty good idea of how the copper/alum collector compares to an evac tube in this way:

- Look at this test of the copper/alum compared to a commercial style copper tube soldered to copper fins collector: http://www.builditsolar.com/Experimental/PEXCollector/SmallPanelTests.htm
Basically, it says that the copper/alum performance is about 4% less than the all copper flat plate collector.

- Then use this calculator to compare a commercial flat plate collector to a commercial evac tube collector.  
http://www.builditsolar.com/References/Calculators/Collector/ColEfic.htm
For the flat plate collector, I would use the Heliodyne with the black painted absorber, as this is closest to the DIY copper/alum.  For the evac type, pick the brand you like.


If I compare the Heliodyne Gobi black painted absorber flat plate collector to the Seido evac tube at 40F ambient temp, 110F collector temp, and in full sun, the evac tube is about 3% less efficient than the flat plate.  So, for these typical winter conditions, I'd guess the copper/alum DIY collector is about equal in performance to the this Seido evac tube. 
The evac tube will do better as you lower the ambient temp, or raise the collector (tank) temp.

It seems odd that a high tech evac tube collector would not do better.  I think that a lot of the reason is that the evac tube collectors have open spaces between the tubes, and when the SRCC does testing they use full area of the collector in the efficiency calculation, so the evac tubes take a hit for that open space which counts in the collector area, but produces no heat.

Gary

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