Sun Coils

[Dawnweaver]

We are looking at these Gull Sun Coils for heating our pool. They are made of low-density polyethylene irrigation tubing.

They seem to comprise only a single fluid path along a spiral. In comparison, fluid seems to flow in "parallel" in competing rectangular coils like Heliocol or Fafco. This makes me worried about a single blockage point affecting the entire system, instead of just taking out a small portion of one panel. However, the fluid capacity seems rather high at 11 gallons. This makes me think that the caliber of the tubing might be larger, too. Perhaps this mitigates blockage concerns somewhat, but not entirely?

If the tubing really is larger, I also wonder if efficiency of thermal transfer would suffer.

Any thoughts? How would you think these would compare to the more standard rectangular thermal panels, e.g. from Heliocol or Fafco? Anyone with experience with these or the competitors?

[Dawnweaver]

Here is an image of the Gull Sun Coils:

thm_Y10_53026.jpg
thm_Y10_49631.gif

[Dawnweaver]

Here is the technical data that Gull provides. They claim that it meets the performance of a standard 4' x 10' rectangular thermal panel.

Size 6½' diameter
Net Collector Area 30.64 sq. ft.
Gross Collector Area 44.10 sq. ft.
Dry Weight 35 lbs.
Wet Weight 127 lbs.
Fluid Capacity 11 gal
Maximum Flow Rate 10 GPM
Recommended Flow Rate 5 GPM

[Dawnweaver]

One more point: On a tile roof, only a single penetration is needed to attach the sun coils. This seems like an advantage, since rectangular panels would require quite a few more penetrations, especially the ones that require straps like Fafco.

What do you think? Should roof penetrations be a concern?

[russ]

Look at the Rimstar link - good info - there is no reason to buy this from some company like Gull - just wasting money

1) Black pipe coil pool heater http://rimstar.org/renewnrg/solar_po...ter_diy_fp.htm

[J.P.M.]

FWIW, I'd go with Fafco.

[skeeter_ca]

Each panel is plumbed in parallel to all the other panels. If one did happen to become blocked the other panels would still work normally. Blockage is usually not concern because the panels are placed in the filtration system after the mechanical filter so nothing goes into the panels that could block them. Also another point is that if on some rare occasion something did get through the filter to the solar panels, the larger internal passages of the Gull Sun Coils would most likely just allow it to pass through. The normal rectangular flat solar plans have smaller passage and may have a better chance of getting clogged by something in the system, even though I think this would be very rare in either case.

As for building your own, that is definitely a possibility but you have to ask yourself are you the type of person that likes to do this type of experimenting or do you just want to install them and be done with it. For me building a solar pool heating system is interesting, fun, exhausting, time consuming, frustrating and very rewarding all at the same time. Does this sound like something you would like to do? If not just buy them.

skeeter

[skeeter_ca]

Oh yeah, I forgot to mention the type of hose they use for the Gull Sun coil are not the normal irrigation hose that we use on the homemade coils at home. There hose is a special larger diameter hose made out something different that can even be exposed to freezing temp without a problem. I forget what they call it but it is different.

skeeter