Absolutely, the operating environment and temperature is higher than a panel mounted 3" off the roof deck. There are some roofing methods intended to help minimize the heat buildup, but nothing beats air flow. You can used what is called an elevated or counter batten system to help with air flow under the tiles. Some counter batten systems can achieve a 2 - 4" air gap under the tiles. The back of the roof tile has an open web design that allows air to flow across the back tedlar sheet. I think that there is some de-rating incorporated into the PTC value of the tile, but was not involved in that portion of the testing. I tend to use a 40° addition to the expected ambient air temperatures when calculating string Voltages. Brian C. White Sr. Design Engineer - PV System Eagle Roofing Products 120 North Auburn Street - Suite 212 Grass Valley, CA 95945 Phone: 530-273-2948 Cell: 530-575-5550 e-mail: [email protected] <mailto:[email protected]>
________________________________ From: [email protected] on behalf of Antony Tersol Sent: Tue 3/31/2009 1:08 PM To: [email protected] Subject: Re: [RE-wrenches] RE-wrenches Digest, Vol 2, Issue 364 Since the tiles are the roof, how does increased temperature affect production? What factor do you use to reflect the decrease in production as compared to PV modules mounted on racks at 3+" above the roof? Message: 1 Date: Tue, 31 Mar 2009 11:11:46 -0700 From: "Brian White" <[email protected]> Subject: Re: [RE-wrenches] PV shingles again To: "RE-wrenches" <[email protected]> Message-ID: <7b501a61b33b934dab214db9faf493b132a...@biexchange.burlingameindustries.com> Content-Type: text/plain; charset="iso-8859-1" We are using the Open Energy / Applied Solar Inc. roof tile, but I guess it is not a shingle technically speaking. The product is better suited to new construction (90% of our business) than retro-fits when it comes to cost. One thing that you have to remember when selling a tile product is that you are offsetting some of the cost associated with the roof, i.e. roofing material and installation. With the tile product from OE / ASI (which is actually manufactured and warranted by Suntech) it does not go on the roof, it is the roof, class A rating and everything. To all getting ready to send me an e-mail about marketing, I am not trying to sell the product, but did help design it when I worked for them, so I have first hand experience. Someone made a comment about running conduit from one tile to the next. We do not view this requirement the same, and do not install any type of conduit above the roof. The requirement for metal conduit states that metal conduit has to be used from the point of building "penetration" to the first disconnect. The one advantage that I really enjoy, is that with the tile, it makes system sizing much easier as far as string Voltage is concerned. Each tile is a 6.07 Voc, so you can just add or subtract as many tiles as needed to get to the sweet spot of the inverter. My 2 cents. (to all, my apologies if that funky attachment comes with my e-mail that I was informed of previously, it has something to do with my remote access, and is not harmful) Best Regards, Brian C. White Sr. Design Engineer - PV System Eagle Roofing Products 120 North Auburn Street - Suite 212 Grass Valley, CA 95945 Phone: 530-273-2948 Cell: 530-575-5550 e-mail: [email protected] <mailto:[email protected]>
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