I also agree with Dave that based on the current pricing of modules it is proabably more cost effective with less maintenance issues going with more fixed modules vs a tracker. Water pumping is one case where it may make sense to use a tracker. It is also good to consider a tracker here in the eastern slopes of the Cascade Mountains of the Pacific NW if you are grid tied and trying to maximize your pay back with a grid tied installation (Wa state incentives and green tags are based on yearly production). We have high overcast days predominatly in the winter further reducing our solar gain during those months. To get the most out of my system I must maximize my production during the summer months with a tracker. Also as a side note the 1kw system I currently have produces an excess of power during the summer months that almost carries me for the winter months when I need more from the grid. Resultng in a near zero energy home, even though I have electric heating (at $0.0175/kw hydro power off the Columbia no other source makes sense). In addition my energy demands are quite low with my small passive solar straw bale house.
Bill Hoffer PE Sunergy Engineering -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org]on Behalf Of Dana Sent: Sunday, January 03, 2010 12:17 PM To: dk...@aeesolar.com; 'RE-wrenches' Subject: Re: [RE-wrenches] Evergreen Dave, That is a good a point that we have mulled over. Here in CO we get a monsoon in summer that it will be clear in the AM and build up to showers and then clear at sunset. This would not validate the tracker all by itself but it does allow for max output while the sun shines. Lack of space could be part of the issue for a tracker decision over fixed too. And then there are clients who just got to have the tracker, no arguments there. One comment from my neighbors is that the fixed arrays and the flat plates do reflect in their windows a couple of times a year in spring and again in fall but never a complaint from the tracker as the azimuth and elevation are perfect all the time. Dana Orzel Great Solar Works, Inc www.solarwork.com E - d...@solarwork.com V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 I will be the shift in how the world uses power! - Dana Orzel From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of David Katz Sent: Sunday, January 03, 2010 12:35 PM To: RE-wrenches Subject: Re: [RE-wrenches] Evergreen Since modules are getting so inexpensive, the big questions is what is the best way to get 33% more power? Is it better to use 33% more modules on a fixed array, or use a tracker? Which one costs less? It costs $1.50 to $2.00 per watt for a tracker. If modules cost $3 per watt and a fixed mount costs $.040 per watt , 33% of $3.40 per watt is $1.12 per watt. And trackers don't come with a 25 year power output warranty. I see tackers making sense when the array is powering a centrifugal pump in the summer or possible a time-of-use grid tie that pays more in the summer. You are definitely better off with more modules on a fixed array in an off grid situation because you always need more power in the winter when the tracker is least effective. David David Katz Chief Technical Officer AEE Solar 1155 Redway Drive P.O. Box 339 Redway, CA 95560 Tel (707) 825-1200 Fax (707) 825-1202 dk...@aeesolar.com <mailto:da...@aeesolar.com> www.aeesolar.com <http://www.aeesolar.com/> DISCLAIMER: This communication, along with any documents, files or attachments, is intended for the use of only the addressee and contains privileged and confidential information. If you are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of any information contained in or attached to this communication is strictly prohibited. If you have received this message in error, please notify the sender immediately by e-mail reply and destroy the original communication and its attachments without reading, printing or saving in any manner. Dana wrote: You got it! It boggles my mind to watch the two OB FM60s and see the difference each day and then to go back and see the data over time. It is a very good argument for tracking. We have a Durango client that we installed 12 KW GIT tracked and it is outperforming the expectations of our client too. Dana Orzel Great Solar Works, Inc www.solarwork.com <http://www.solarwork.com> E - d...@solarwork.com <mailto:d...@solarwork.com> V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 I will be the shift in how the world uses power! - Dana Orzel From: re-wrenches-boun...@lists.re-wrenches.org <mailto:re-wrenches-boun...@lists.re-wrenches.org> [ mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Allan Sindelar Sent: Thursday, December 31, 2009 8:13 PM To: RE-wrenches Subject: Re: [RE-wrenches] Evergreen Dana, Thank you for this information. I would like to clarify what you wrote. We have long accepted that trackers may be expected to increase daily output by about 35-40% in the summer and 10-15% in the winter, due to the differences in the sun's seasonal elevation and the resultant length of the solar day. It sounds as if you measured the effective increase from approximately summer solstice - winter solstice and got a 32% gain. You previously got the same gain (33%) measuring from last winter solstice to summer solstice. This makes sense, as it averages winter and summer gains over two roughly equal periods, with variations (summer monsoons, etc.) being within acceptable error. And whether grid-tied, grid-tied with backup, or off-grid is irrelevant as long as you can compare and record the outputs of the two otherwise identical arrays, one tracked and one fixed. Do I understand this right? If so, it's good real-world data for design purposes. Allan Allan Sindelar al...@positiveenergysolar.com <mailto:al...@positiveenergysolar.com> NABCEP Certified Photovoltaic Installer EE98J Journeyman Electrician Positive Energy, Inc. 3201 Calle Marie Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com <http://www.positiveenergysolar.com/> Dana Orzel wrote: This is for a grid tied with battery backup Outback system. The 32% increased gain for the tracker VS. fixed mount production is an average of the last 180 days and I checked it in the spring for the last 180 days [over the winter] and it was 33%. The 12 - Evergreen 180 watt modules produce about 65 -70% of our home and office's electrical requirements. Thanks, Dana Orzel Dana, That 32% is a very useful number, and it matches with our experience as well. But I need to verify a couple of assumptions, please: Does this represent average annual production, rather than peak seasonal? And is it a grid-tied system? Thanks, Allan Allan Sindelar No virus found in this incoming message. Checked by AVG - www.avg.com <http://www.avg.com> Version: 9.0.725 / Virus Database: 270.14.124/2596 - Release Date: 01/01/10 02:20:00 _____ _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org <mailto:RE-wrenches@lists.re-wrenches.org> Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm <http://www.re-wrenches.org/etiquette.htm> Check out participant bios: www.members.re-wrenches.org <http://www.members.re-wrenches.org> No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.725 / Virus Database: 270.14.124/2597 - Release Date: 01/03/10 02:41:00
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