Most often I used 1" thick isocyanurate pre-adhered to the PVC wrap. I chose this method for the high R-value, about R7 per inch. A bit pricier than closed cell foam rubber insulation, but much better R-value, R7 vs R3ish. At first I would use a PVC sealant, extremely high in VOCs, to seal the PVC seams. The sealant kept freezing in the work van, and was so nauseous that I moved to just using the adhesive strip on the PVC and PVC tape at the seams. The PVC tape would peel so went to barbed tacks. I then realized that the isocyanurate was hydroscopic so it was very important to make sure that all the piping was waterproof, or the water would provide a very low impedance path for the heat. So I would try and work from the bottom of the pipe run to the top so that I could layer the PVC coverings, and keep the PVC covering overlap facing down on horizontal runs. However, where an elbow buts a straight piece, the seam cannot be overlapped by the PVC covering due to the angle. Thu s you wrap a 3" wide PVC over the seam. This however allows any water coming vertically down the straight piece to work its way behind the PVC lapping and into the seam, thereafter absorbed by the isocyanurate. Thus I would tape the joint, using two barbed tacks to hold the tape. Overall I am concerned that the potential to absorb water was too high and that using the foam rubber, which will not absorb water, will provide better overall results, despite the lower R-Value, for typical short exterior runs of residential systems (<50' total). The use of the foam rubber line sets provide a bit better R-value by adjoining the two pipes, but they almost always fall a few feet short of final connection with either the insulation or the PV resistant covering, the connection fittings are expensive, difficult to make longer runs look nice, and concern over the longevitiy of the lineset due to corrosion of the thousands of thin rippled edges made me use these sparingly. I have never done a real study on the thermal losses associated with real world application of the different types of insulation, but would like to see one. Good luck with the article Chris.
-----Original Message----- From: cwarfel [mailto:cwar...@entech-engineering.com] Sent: Tuesday, November 7, 2017 6:52 AM To: solar1onl...@charter.net; 'RE-wrenches@lists.re-wrenches.org' Subject: Re: [RE-wrenches] Outdoor rated insulation covering for Solar Water Heating Systems I thinkthis problem is really only "solved" by using the coverings suggested, especially it seems, aluminum jacketing. I will be going off island in a week and I will have the chance to go to a store that sells these products. I am hoping to put this system into HomePower, so, this will be part of the article. Thanks for everyone's responses. I hopefully responded to everyone off line. Stay tuned. Chris On 11/6/2017 4:57 PM, solar1onl...@charter.net wrote: > Hi Chris, Your question certainly generated a number of responses. > While the field applied covering I mentioned certainly peeled off and > had the consistency of latex paint, I did _not_ perform an analysis. > There is outdoor latex paint which should have UV inhibitors, so > perhaps it really was latex. The original owner is gone, so no help > there but a paint manufacturer may be able to verify latex paint as an > inexpensive _and effective_ covering solution. What made this solution > stand out in my mind so well was the flex roof flashings, which when > unprotected become brittle (and useless) oftentimes before the ten > year mark. This painted flashing was just as flexible as a new unit > and as you are well aware, replacing a solar flashing is way more > involved than a plumbing flashing. I am aware of many manufacturers > that rebrand/repackage a common item as a solution for a very specific > problem and charge an outlandish premium for the common item in a > shiny package (sometimes not even a shiny package). Bill > > ----------------------------------------- > > From: "cwarfel" > To: > Cc: > Sent: 06-Nov-2017 13:01:11 +0000 > Subject: Re: [RE-wrenches] Outdoor rated insulation covering for Solar > Water Heating Systems > > Hi Bill, thanks. I did not think latex would hold up anywhere near > that long. Chris > > > On 11/4/2017 9:13 AM, solar1onl...@charter.net wrote: > > Chris, > > The fitted covers certainly provide a more finished appearance. One of > my customers painted the insulation (w/o fitted covers) with latex > paint and after 30+ years the insulation was still quite flexible. My > take away was simply that eliminating the sun (UV) effects paid off > big time. As I remember they used white paint. > > Best wishes, > > Bill Loesch > Solar 1 - Saint Louis Solar > 314 631 1094 > > -----------------------------------------From: "Glenn Burt" > To: "RE-wrenches" > Cc: > Sent: 04-Nov-2017 00:21:14 +0000 > Subject: Re: [RE-wrenches] Outdoor rated insulation covering for Solar > Water Heating Systems > > How about the white PVC jacketing? You can buy fitted elbow covers > and other fitted parts as well. Probably paintable in any color to > blend into location. > > List-Archive: > List-Archive: > _______________________________________________ > List sponsored by Redwood Alliance > > List Address:RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > > List-Archive:http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > > -- > Christopher Warfel, PE > Entech Engineering, Inc. > 401-466-8978 -- Christopher Warfel, PE Entech Engineering, Inc. 401-466-8978 _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
