[RE-wrenches] Using the North Facing Roof

[August Goers]

I think the point of view Peter shared has more to do with lower sloped
North facing or other non-ideal orientations. The proof is in the pudding –
just simulate the production and utility bill offset and see if the
proposed orientation makes sense financially. We haven’t done any North
facing arrays (yet?) but we have a few that are North-West in orientation
and they are working as projected.



I think a side question that this poses is whether, for example, it makes
sense to install a reverse tilt on a North facing roof or just mount the
panels flush and install more of them. My calculations show that the
reverse tilt is still a better economical choice but it is no longer as cut
and dry as it once was when modules were more expensive. Of course reverse
tilt arrays pose structural engineering and aesthetic considerations so we
really try to shy away from them.



Best,



August



*From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
Behalf Of *jerrysgarage01
*Sent:* Tuesday, July 28, 2015 12:29 AM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Using the North Facing Roof



Wrenches

I see this working south of the tropic of cancer but at 1000 watts per
meter squared tilted north might work for a month a year but I don't think
the tax credits were proposed for poor performance module installations. I
see enphase annual  readings prove the point.

Jerry







Sent from my Verizon Wireless 4G LTE smartphone



-------- Original message --------
From: Peter Parrish <peter.parrish at calsolareng.com>
Date: 07/27/2015 7:21 PM (GMT-10:00)
To: 'RE-wrenches' <re-wrenches at lists.re-wrenches.org>
Subject: [RE-wrenches] Using the North Facing Roof

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

petertor at pobox.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20150728/2ecdde96/attachment-0002.html>