# Solar Hot water



## Quercus21 (Nov 25, 2009)

I was wondering what the R value and type of installation everyone is using for the outside fluid pipes coming from your panels? I can expect winter temps to hit -10 here and summer highs of +100.
Thanks
Kaj


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## woodsy (Oct 13, 2008)

Not sure the R value but for copper piping you should be able to find foam pipe covers 3/8" thick and possibly thicker. Found some at wally world in 3' lengths, hardware stores and lumber yards carry it also.


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## Virgil (Sep 29, 2009)

Not sure either what the realistic R-value would be of the standard type of slip over poly-foam insulation would be. There is a lot of information on line about copper pipe foam insulation. And, it is relatively cheap at all of the local big box stores., Lowes etc.. The biggest problem is finding an insulation that is easy to work with and will stand up to the rigors of the Northeast Weather and ultraviolet rays. Poly-foam plastics will deteriorate with long term sun exposure and will suck up moisture like a sponge. Both conditions will of course destroy the insulation value of the material. The commercial solar installers use some sort of white hard shell fiberglass over the piping. It would need to be tightly sealed from the rain water if not, it would also deteriorate quickly. I have tried fiberglass insulation inside of homemade wooden collectors even with weep holes and the fiberglass soaked up moisture over time and rotted the collectors from within the frames. Currently we are life testing the standard poly-slip-over-foam pipe insulation wrapped over, (encased) on the outside with Reflextix aluminum faced bubble plastic insulation. It is very soft, easy to work with, and reasonably water repellent. It's survival to the sun's long term radiation, though, is questionable. The overlapped seams of the outer reflextix material is sealed with a good quality aluminum tape. The tape I believe is about 3 inches wide. This tape is not cheap about $20 per roll. However, it is surprising how much area one roll will cover. If this technique holds up this winter I plan on covering all of the Reflextix insulation which is exposed to the outside weather and sun with the aluminum tape. Time will tale on that. I recently read on the Reflextix web-site that they now produce a variety of this Reflextix insulation which is more UV resistive. You can Google their site for more information. Please post here any information or alternative insulation material which may be of help to us alternative energy Do It Yourself 'rs, Enjoy...


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## Virgil (Sep 29, 2009)

Not sure either what the realistic R-value would be of the standard type of slip over poly-foam insulation would be. There is a lot of information on line about copper pipe foam insulation. And, it is relatively cheap at all of the local big box stores., Lowes etc.. The biggest problem is finding an insulation that is easy to work with and will stand up to the rigors of the Northeast Weather and ultraviolet rays. Poly-foam plastics will deteriorate with long term sun exposure and will suck up moisture like a sponge. Both conditions will of course destroy the insulation value of the material. The commercial solar installers use some sort of white hard shell fiberglass over the piping. It would need to be tightly sealed from the rain water if not, it would also deteriorate quickly. I have tried fiberglass insulation inside of homemade wooden collectors even with weep holes and the fiberglass soaked up moisture over time and rotted the collectors from within the frames. Currently we are life testing the standard poly-slip-over-foam pipe insulation wrapped over, (encased) on the outside with Reflextix aluminum faced bubble plastic insulation. It is very soft, easy to work with, and reasonably water repellent. It's survival to the sun's long term radiation, though, is questionable. The overlapped seams of the outer reflextix material is sealed with a good quality aluminum tape. The tape I believe is about 3 inches wide. This tape is not cheap about $20 per roll. However, it is surprising how much area one roll will cover. If this technique holds up this winter I plan on covering all of the Reflextix insulation which is exposed to the outside weather and sun with the aluminum tape. Time will tale on that. I recently read on the Reflextix web-site that they now produce a variety of this Reflextix insulation which is more UV resistive. You can Google their site for more information. Please post here any information or alternative insulation material which may be of help to us alternative energy Do It Yourself 'rs, Enjoy...


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## Quercus21 (Nov 25, 2009)

I used a couple of types of insulation for the pipes. First I started off with the rubber pipe material you would find in the big box stores. Next I warped the pipes in a reflective and foam type of insulation. Third thing I did, was to warp white duct tape around everything to protect the insulation as much as possible from the environment and to have the pipes blend into the house. In the spring, I'll paint the everything. So far, the snow isn't melting to fast off the pipes. The insulated pipes are "cool" to the touch when the panel shows 160+F degs.

Kaj


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## Virgil (Sep 29, 2009)

Good that you are trying different insulation and wrap materials for the exposed pipes. I tried some of the more expense white duct tape that was supposedly made for outside extreme use. It didn't last through the summer months before it started peeling off the foam insulation or the Reflectix warp. So. let us know how it holds up this winter. The aluminum foil tape that I used to seal the Reflectix material this summer thus far has not shown any signs of peeling off or otherwise deteriorating. I will also post my findings here later in how it holds up through the winter. I thought about also painting the outer insulation wrap for aesthetic reasons to blend in with the color of the house. However, I was concerned with the chemicals in the paints', whether it be latex or oil base, degrading somehow the insulation. Oh well, the silver looks ok to me and the Reflectix wrapped around the foam insulation seems to do a very good job of retaining the solar heat within the pipes as you pointed out.


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## byexample (Aug 28, 2009)

I've run several homemade solar hot water systems now and tried a variety of approaches to insulating exposed pipes. I haven't found any solution that would protect against freeze down to -10F. The best solution I can think of for freeze protecting collectors that directly heat fresh water is a drain-back system that empties the exposed pipes / collector when freezing temperatures are present.

In more extreme winter climates it might be better to explore the viability of using a heat-exchanger and running an anti-freeze solution through your collector to prevent freeze damage.

Best of luck!


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## fishhead (Jul 19, 2006)

What about using thinwall pvc pipe just large enough to go over the pipe insulation and then keeping it protected with exterior paint?

Or box it in with 2" of blue foam and then coating the foam with surface bond cement. That's what I did to insulate the exposed foundation of my house.


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## Virgil (Sep 29, 2009)

Yes, I agree. The Fresh Water Drain Back system is the best way to go in a temperature extreme environment. That is the type of system that we installed. We also considered pvc and the flexible black drain pipe as the outer shell over the pipe insulation. However, our collectors are some distance from the cellar mounted water tanks and are rack mounted over a side porch roof. And, thus trying to fit either over all the twists, turns, and fittings would have been a very difficult job. Though, as you indicated I still may encase the insulated pipes which are close to the exterior wall in a foam-board insulated enclosure. I have noted the installers of those outside wood burning furnaces use a poly-insulated soft drawn copper piping for the water system. I never used it. It might be something else to look into. 

Learn By Doing, Virgil


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## SolarGary (Sep 8, 2005)

Hi,

You might have a look at the scheme that Tom used:
http://www.builditsolar.com/Projects/SpaceHeating/TomLargeCol/TomCol.htm

He basically encloses the pipes in an insulated wood box structure.

Some commercial products listed here:
http://www.builditsolar.com/References/Suppliers/SolarHeating.htm#Pipe

Gary


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## Dutch 106 (Feb 12, 2008)

Hi Guys,
What about a combination of the foam pipe insulation and covered with recycled plastic or aluminum down spout? Its made to be out in the weather and UV. resonably durable light weight and cheap.
Just a thought,
Dutch


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## gusty60 (Jan 18, 2010)

I made the mistake of using polyolefin pipe insulation on my solar hotwater system and found out how quickly it can melt! I switched to elastomeric ( i believe ) and haven't had a problem since.


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