# Was given a solar water heater project.



## Ky-Jeeper (Sep 5, 2010)

I was given a 3/4" copper pipe solar project. It has 14 45" pipes with 2 90 degree elbows at each end connecting each pipe and so on. Water in one side then following all the pipe to the outlet. That's around 55' of pipe in a collector. This makes it around 47"x23" roughly. It has been sweat fitted and pressure checked.

My question is how would you build a collector box to maximize heat out-put for this copper coil of sorts?


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## SolarGary (Sep 8, 2005)

Hi,
It sounds like the 45 inch long pipes are quite closely spaced to each other?

The total area (47 by 23) is only 7.5 sqft -- this is pretty small for a solar water heater. 

You would get a lot more heat from the system if you spaced the 45 inch runs further apart -- about 6 inches is good. Then attach alum sheet fins to each of the 45 inch runs. This way, the sun that falls on the fins get transferred into the 45 inch pipes. The fins increase your collection area from about 5 sqft up to 27 sqft -- the heat output will go up accordingly. 
To see how you attach the fins, have a look at these two links:
http://www.builditsolar.com/Experimental/CopperAlumCollector/Construction.htm
and
http://www.builditsolar.com/Projects/WaterHeating/Fins/Fins.htm

If you just want to use the collector as is, I'd try something like building a glazed box that is about 6 inches or so wider than the copper grid, and about 2 ft taller than the copper grid -- then place the copper grid up near the top of the glazed box. That extra glazed area will increase the output somewhat from just a box that covers only the copper grid. It behaves a bit like this Khanh collector: http://www.builditsolar.com/Experimental/ShurcliffPart3/khanhms.htm
But, adding the fins is the way to go if you possibly can.

Gary


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## Ky-Jeeper (Sep 5, 2010)

Thanks Gary, I was hoping you would chime in. The copper pipe is really close at 1 1/8"-1 1/4" apart. Friend of mine would probably take it personal if I cut it up since he spent all that time and money on it. 

I've contacted Tom at the link you provided about the absorber plates. I will be using cartridge heater contact fuild with the plates and pipes. With your suggestion on a bigger box, I may use a slave box along with it.

Will post pics soon as I figure it out.

Thanks, Tommy.


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## SolarGary (Sep 8, 2005)

Hi,
Sounds good -- make sure Tom knows that you are using 3/4 inch pipe so the groove is the right size.

Gary


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## Ky-Jeeper (Sep 5, 2010)

Can someone direct me to the info I need to post pics. I only have a android phone. 

I have started on the solar heater.


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## Ky-Jeeper (Sep 5, 2010)

I'm at the point of deciding single or double glazing. I have two single pane storm Windows to work with. What is some of your thoughts on glazing?

After glazing, wrapping the treated wood frame in aluminum will finish the collector itself.

Thank, Ky-Jeeper.


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## woodsy (Oct 13, 2008)

single glazing works fine for me even this far north.
If you post your pic to a site like photobucket you can then transfer them here using 
the share feature, copy and paste the URL to bring it here.


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## SolarGary (Sep 8, 2005)

Ky-Jeeper said:


> I'm at the point of deciding single or double glazing. I have two single pane storm Windows to work with. What is some of your thoughts on glazing?
> 
> After glazing, wrapping the treated wood frame in aluminum will finish the collector itself.
> 
> Thank, Ky-Jeeper.


Hi Jeeper,

If the KY is for Kentucky, I'd say the single glazing is fine.
Double glazing does pay off for colder climates.

In the summer, double glazing may actually reduce output because the 2nd pane of glass absorbs about 12% of the incoming radiation, and the summer air temps are warm enough that the extra R value of the 2nd pane is not doing you that much good.
In the winter, the 2nd pane cuts the heat loss from the collector a lot, so that improves winter efficiency.

Especially for a small collector like this one where you won't have any excess production even in the summer, and living in a warmish climate, it seems like single would be the choice for best year round output?

Hope you will tell us how the collector works out. 
If you put it in at the start of winter, the initial results might be a bit disappointing, but it may do well in the other 3 seasons.


Gary


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## Ky-Jeeper (Sep 5, 2010)

Just an update. Collector itself is near completion. I still like wrapping the box in aluminum. 

So now I'm getting ready to order a P.V. powered low flow pump. In the mean while I thought I would try thermosihiping. 

Filled up the collector with a deluted antifreeze mix. Intalled a flow meter with temp and press gauge. I knew the temp was the only one that would function at this point. Added a chille4 plate (something used in a industrail setting) to cool off the fluid after leaving the flow meter. Couple hours later the collector was hot and fluid temp was 125*F with a small flow. The chiller plate was in open low 50's air temps with a breeze and I could hardly touch it.

There was some air in the line. I can bleed that out after I get my pump. Collector may of not been in the optimum position either.

Gary since this is not a drain back system what options do I have besides automotive antifreeze and gylcol? Someone suggested windsheild wiper fluild.

Ky-Jeeper


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## SolarGary (Sep 8, 2005)

Hi,
You might look at the TopsFlo pump:
http://www.sun-pump.com/
I've had one for the summer doing various things, and it seems well made.
One odd thing about it that the threads on those nice brass fittings are not quite a standard US thread. The threads are close, and the work OK if the fittings you are mating to are plastic. In spite of this little problem, I do like the pump quite a bit.
If money is no object, the Liang D5 has a really solid reputation:
http://www.faucetdirect.com/laing-d...circ-solar-series/p1285753?source=gba_1285753

On the antifreeze, I'd use propylene glycol -- its non-toxic -- won't hurt pets or people -- its actually used as a food additive. The auto ethylene glycol used in cars is quite toxic.

The RV antifreeze is usually propylene glycol, and is cheap -- this is made for keeping RV toilets from freezing and the like.

There is antifreeze made for use in solar systems that is propylene gycol based but also has a number of additives that make it work better in solar systems where it might get cooked at fairly high temperatures. I think DOW might make one of the versions? Its more expensive, but the people who work with these systems a lot say its worth it.

Gary


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## Ky-Jeeper (Sep 5, 2010)

I have an gas water heater and have a wood burner in my garage. I have a similar set up in mind on the back burner.


Thanks, Ky-Jeeper.


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