Broken Glass on Panel!! Replacement?

[oliverbutthead]

I recently purchased a 4x8 sun power solar water heater panel. I live in a rural area and don't have access to help often. I tried to put the panel on my roof by myself and dropped the panel. Thus, I broke the low iron tempered matte finish glass. Very expensive piece of glass to find! Unless you have access to the manufacturer way out in CA of course.

My question here is how much if any efficiency will be lost by going to polycarbonate instead of glass?

[Mike90250]

Don't know. It's not as transparent or as long lived as glass. But it is more insulative than glass. Depending on the internal temps, poly carbonate is only good up to about 240F then it starts to soften and will begin to sag over time.

Upper working temperature 115 °C (239 °F)

For use in applications exposed to weathering or UV-radiation, a special surface treatment is needed. This either can be a coating (e.g. for improved abrasion resistance), or a coextrusion for enhanced weathering resistance.

http://en.wikipedia.org/wiki/Polycarbonate

[oliverbutthead]

Well, I am sure the efficiency loss will not be too bad especially in West TX. I pretty much have to get polycarbonate and make sure it is UV stabilized due to the high replacement cost of the type of glass on the panel - $450! Almost as much as buying a whole new panel! I imagine efficiency loss will not even be as high as 10%

Here is an interesting study with twinwall polycarbonate vs. plexiglass :

http://www.builditsolar.com/Experimental/TwinwallvsPlex/TwinwallvsPlex.htm

[Ian S]

I recently purchased a 4x8 sun power solar water heater panel. I live in a rural area and don't have access to help often. I tried to put the panel on my roof by myself and dropped the panel. Thus, I broke the low iron tempered matte finish glass. Very expensive piece of glass to find! Unless you have access to the manufacturer way out in CA of course.

If you purchased it recently with a credit card, accidental damage may be covered by the card. Many Mastercards and Visas have this coverage.

[J.P.M.]

Well, I am sure the efficiency loss will not be too bad especially in West TX. I pretty much have to get polycarbonate and make sure it is UV stabilized due to the high replacement cost of the type of glass on the panel - $450! Almost as much as buying a whole new panel! I imagine efficiency loss will not even be as high as 10%

Here is an interesting study with twinwall polycarbonate vs. plexiglass :

http://www.builditsolar.com/Experime...wallvsPlex.htm

Twinwall, because it is in effect and in effect a 2 cover system, may cause that inner cover of the Twinwall to exceed +240F. by a fair amount especially under stagnation and/or high ambient temps., especially if the absorber is non selective.
Perhaps a single cover would be better. Single layer of polycarb. for example. Plex will work for a while but will probably yellow and soften besides being mostly transparent to IR off the absorber. A long time ago, I used something called sunlite from an outfit called Kalwall. It worked quite well as I recall. UV trans. was higher than glass but less than plex, and it was pretty impervious to weather and UV. Price was not too bad and it was relatively easy to work with, just wear a mask and gloves when cutting w/ a saw.

J.P.M.