How to plumb a movable solar collector

[Mikey]

I've had a solar domestic HW system since November, and am very happy with it. We turned off the electric WH backup during installation and didn't notice it until mid-December during a spell of cloudy weather. It's now been off since early January, and we've not wanted for hot water.

Now on to my question. The collector is mounted on an East-facing, shallow-sloped roof (see picture). It's plumbed with 1/2" soft copper tubing, soldered up tight to through-roof fittings at the NW and SE corners of the collector. I'd like to be able to lie the collector down flat on the roof during hurricane season (which would also improve collector effectiveness with the sun more directly overhead). What sort of fittings and piping do you experts suggest I use to allow this?

I've thought about sweating on male adapters and using something like braided stainless steel loops to provide the flexibility, but I've heard bad things about it. Flexible nylon risers would probably not survive the Florida UV, I'm guessing.

 

[Master Plumber Mark]

braded connectors

if you use some 24 inch
Stainless Steel braided connectors it would
probably be your best bet......

simply insulate the connectors with some rubber aramaflex
to keep the UVS off of them.......

iI would probably leave them alone and take my chances

 

[Sponsor]

 

[Markts30]

I would increase the bracing around it with some angle iron and leave it as is...
I don't know how much bracing that there is right now, but for hurricane season, I don't think a 1" angle iron frame bolted to the house would hurt....

 

[Mikey]

Right now it's held on by 1" x 1/8" aluminum angle on the north (raised) side, and a couple of aluminum brackets on the low side. All brackets are lag-bolted through the deck into the joists. I suspect it would survive in a Cat 3 storm OK, but am wondering about flying debris hitting the glass. If I could make it easy to lower, I'd be inclined to do that. My neighbor calls it my "hurricane sail"...

 

[hj]

collector

1. The glass is tempered and it can be shattered just as easily, or more so, by something falling on it as impacting it.
2. Solar collectors, like sun dials, should be facing South and at the same angle as your latitude from the equator.

 

[Mikey]

1. Good point. I'll mull that over for a while.
2. That's true only on the equinoxes, but it's commonly used for fixed panel installations. At my location (28.167N,81.822W, 143Ft msl), the solar elevation at solar noon varies from about 38 degrees (Dec 21) to 85 degrees (Jun21). Ideally, you'd track the sun from sunrise to sunset, but that's another project (which I'll probably try to do some day). I'd be happy now with just making it relatively easy to adjust from 38 to 85 degrees as I feel the urge. A good tool for determining these angles is at http://www.susdesign.com/sunangle/.

 

[Rancher]

I guess if you really want it to survive, plumb the bottom right and top left with unions, hinge the bottom edge somehow and when the storm is coming, disconnect the 1" supports, disconnect the unions flip it over using the hinges on the bottom edge, and attach it to some previously attached angle on the roof. Now it's flat, glass side down and no longer a sail.

Rancher

 

[Mikey]

Yes, or I could just disconnect everything and store the collector in the garage, although it's pretty heavy. I had assumed it would keep working while "stowed", but I'm not opposed to shutting it down altogether if things look really bad. The lower edge is hinged, but I don't think the hinges allow for 180 degrees of movement. I'll check it out tomorrow. I could also use standard hurricane panels to protect it if it could be easily stowed flat, glass-side-up. Looks like I'm looking at 3 "standard" positions: 52 degrees (winter), 5 degrees (summer), and flat (stowed for storm protection). I love it when a plan comes together.