FAFCO Solar collector advice

[tcat]

Split by moderator from HERE. jblizzle

This thread is a bit old, but I was wondering the same if anyone has any of the FAFCO products, please chime in. I'm looking to install 160-200' of panel as a winter project (not that winter ever strikes Austin). I was curious how this type of panel compares to DIY 1/2" black tubing. How many "feet" of tubing are in a 2' x 20' panel?

 

[jblizzle]

Well the tubing is smaller in the panels so it is more efficient at heating.

Some pretty basic math would show you could put 48 of the 1/2" poly pipes next to each other to be 24" wide. Times the 20' length = 960 feet of 1/2" poly to have the same footprint.

 

[tcat]

So 960' of pipe must be more efficient than one panel. I've read I need about 3000' of pipe or 4-5 panels for a pool my size. Buying panels seems a lot less work. Just wondering about efficiency. And what the difference is of panels in op.

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[jblizzle]

That is not at all what I said.
I said that it would take 960' of 1/2" pipe to give the same exposed area as one 2'x20' panel. BUT, the smaller tubes in the panel are more efficient at heat transfer. It takes a lot of tube to give the same heat as a panel which is why it is rarely if ever cost effective to try to DIY a solar setup instead of buying a panel.

 

[gwegan]

3000 sq ft of panels? Pushing water through that much tubing will eat up a lot of energy. 1/2 inch tubing will not capture that much heat.

As Jason said DIY panels just don't compare to the efficiency of commercial panels. Every time I feel it I am amazed at how much heat the panels get off my roof.

I suggest you actually have some solar companies out and give you bids. You can then talk to the sales people and learn more about how they operate and are installed. They will give you very good estimates of how much you need. FAFCO sells a system called the solar bear that is not sold through dealers you can get it on ebay that is very reasonably priced. Or do like Jason did and buy a used one.

 

[tcat]

Thank you. It just looked like there are fewer tubes in the panels. I figured more water would get heated in 48 pipes than in what looks like maybe 24 smaller channels in the panels. I was going to add a canopy over my pump area to support whatever I do. Don't trust installers walking on my tile roof. I'll be buying panels and still diy.

That 3000' was referring to feet of .5" pipe (not panels), probably coiled into 6 plates, what I was trying to compare the FAFCO panels to.

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[gwegan]

I'd look at FAFCO's Solar Bear system you can find it on EBay and Amazon. Reasonably priced, you can install it yourself and its built by FAFCO so it generates a lot of heat.

 

[tcat]

From what I can tell "Sun grabber" panels are the same panels as Solar Bear but cheaper. Decided to go with panels, trying to narrow it down. Going to build a roof over my pump area, probably 10'x20'. How much support do these need? Is a 2x4 every 2' adequate? I've read that plumbing in parallel is better than series. Is running off my 2 speed pump on low speed adequate? I currently run on low 12 hrs/day.

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[jblizzle]

I think the panels will sag if not fully supported. Solar heating is most efficient at higher flow rates. Likely the panels will need primed on high speed. They might get enough flow on low speed, but may not heat as much.

 

[bobodaclown]

There's a lot of great info on this site: https://secure.fsec.ucf.edu/en/consumer/index.htm

It not a commercial site so they're not trying to sell anything, they also offer panel ratings.

 

[tcat]

Great info, thanks! Pretty much settled on Fafco Sunsaver (Solar Bear), two 4' x 20' panels. Can the center valve be bypassed, so with 2 panels flow can go down all the tubes one way, then return in the second panel? Or better to hook up 2" pipe in parallel to feed each separately? Roof will only be 6-8' above pump area, I'm hoping low speed will be adequate, but no problem running on high when I really need to warm things up.

Totally unrelated, but I hate to start a thread for this: I have a leak on the output (waste) of my multiport valve, a short section of 2" pipe right out of the valve appears to have a crack that leaks like crazy backwashing. The joint is cement not thread. Is there a way to fix this? Maybe an inner pipe?

 

[jblizzle]

Best to run through all the tubes in the same direction (parallel). So remove all the center baffles. Feed the panels on one end and return to the pool from the opposite corner.

 

[tcat]

Anyone that has Solar Bear panels, are both 2" manifolds the same at each end? (one end has a valve in the middle) Just want to make sure they are easy to install in parallel. Pictures seem to show 1.5" female threads, is that at all 4 openings? Not sure why they would put a 1.5" thread on a 2" manifold. Can't find a thing to determine if a 20' Solar Bear is just a long Sunsaver (those only seem to come in 8,10,12'). BTU output is about same for either (1,014 per sq. ft).

PS: Fixed my multivalve pipe leak... nice thick coat of epoxy. Figured out why the pipe cracked. There was a threaded bulkhead on the output pipe that I unthreaded. As soon as I did my DE filter dropped an inch. I guess the installer had to tilt the filter to get the fitting to line up, so there was constant force on that section of pipe. Rather than repipe it all, I just added a shim under the filter to relieve the pressure, then epoxied the crack.