In Yuma, AZ, north facing modules will have direct sunlight for small part of the year. In the picture, look at the yellow area above the East-West line. Thats direct sunlight from the north. The green top line in the picture shows summer solstice showing sunlight from sunrise to about 0930 and from 1530 to sunset. The energy harvested during those hours will be tiny compared to the peak sun hours on the south side. The angle of incidence will also reduce the total power generated during those hours.
The thin brown middle line is the equinox. By then, there is no direct sunlight on the north side. I can not see any benefit in AZ even at todays low prices. Now, if I were building in Quetzaltenango, Guatemala, that would be a different story. But then again, I would have to clean off the volcanic ash each morning. Larry Crutcher Starlight Solar Power Systems chart came from http://www.gaisma.com/en/ On Jul 27, 2015, at 11:21 PM, Peter Parrish <peter.parr...@calsolareng.com> wrote: I recently read a short piece that caught me up short, and I quote: “The fast dropping cost of solar, while a huge boon to the adoption of solar PV, has counter-intuitively altered design parameters. No longer is the north-facing roof considered unusable because limited application in less-than optimal orientations can still show a positive net benefit. Arrays are thus designed now with elements or sub-arrays in these locations, increasing overall kW installation while reducing the energy production per capacity installed. This might have been anticipated based on sheer economic analysis from a users perspective, but so long has solar been expensive that these less optimal orientations were never seriously considered.” I doubt that the individual who wrote this piece came to these conclusions him/herself. Does anyone know of a recent article that argued this perspective? Is this an emerging design practice? If so, I’d like to know more about it. - Peter Peter T. Parrish, Ph.D. President, SolarGnosis 1107 Fair Oaks Ave., Suite 351 South Pasadena, CA 91030 (323) 839-6108 peter...@pobox.com _______________________________________________
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