Re: [RE-wrenches] Best angle - direct grid tie
Great format for an integrator and its staff. Thanks for sharing, Mike. David Brearley, Senior Technical Editor SolarPro magazine NABCEP Certified PV Installer david.brear...@solarprofessional.com On 1/7/10 1:26 PM, Michael Kelly m...@solarflair.com wrote: Drake, I did an analysis for optimum conditions based on tilt and azimuth a while ago for our area around Boston. I did it in such a way as any combination of tilt and azimuth gives you % of optimum conditions. See attached. All of the data was from PVWatts simulations. Maybe you can make one for your area when you have some free time. - Mike -- Michael Kelly Project Manager / Project Engineer NABCEP Certified Solar PV Installer SolarFlair Energy, Inc. 11 Mayhew Street Framingham, MA 01702 Direct Mobile: 617-899-9840 Main Phone: 508-293-4293 Main Fax: 508-293-4003 m...@solarflair.com On Wed, Jan 6, 2010 at 9:48 AM, Drake Chamberlin drake.chamber...@redwoodalliance.org wrote: Thanks for all of the excellent advice regarding the best tilt angle. It is a real privilege to be a part of, and have access to the incredible resource of the knowledge and experience represented by this list. It looks like a 30 degree angle will work fine for 39 degrees N. This corresponds well with the Unirac U-LA, pre engineered designs. Drake Drake Chamberlin Athens Electric OH License 44810 CO License 3773 NABCEP TM Certified PV Installer Office - 740-448-7328 Mobile - 740-856-9648 ___ List sponsored by Home Power magazine List Address: 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 Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Best angle - direct grid tie
Thanks for all of the excellent advice regarding the best tilt angle. It is a real privilege to be a part of, and have access to the incredible resource of the knowledge and experience represented by this list. It looks like a 30 degree angle will work fine for 39 degrees N. This corresponds well with the Unirac U-LA, pre engineered designs. Drake Drake Chamberlin Athens Electric OH License 44810 CO License 3773 NABCEP TM Certified PV Installer Office - 740-448-7328 Mobile - 740-856-9648 ___ List sponsored by Home Power magazine List Address: 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 Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Best angle - direct grid tie
Drake, Attached is a PDF which is the result of using PVWatts to perform an analysis which may be helpful. Assumption 1: No shading at the site and a due south facing array. The module tilt is varied from 0 to 90 degrees and the array estimated production leads you to select an optimum tilt. Assumption 2: Now that the optimum tilt is established evaluate the effect of array azimuth at this tilt angle. The solar radiation per time of day is evaluated to indicate the potential adjustments which might be required based on shading at various times of day but the Path Finder readings from the site should be used for a more accurate assessment. Cheers Carl Adams SunRock Solar, LLC On Mon, Jan 4, 2010 at 6:08 PM, Ryan LeBlanc r...@naturalenergyworks.com wrote: Drake, The SPA software is likely telling you 'close-to-the' optimum tilt for maximum total annual peak production, without telling you WHEN the most valuable power is produced. That's for you to figure out based on the specific utility rate schedule, and is a critical factor. So, it kind of is geared towards off-grid systems, by default, but only because it doesn't have the Holy Grail database of utility rate schedules, (TOU, etc.) that we all wish was available. Though, it may manually allow you some of these features. I haven't looked at Assistant software in a little while, apologies. Solmetric has some resources you may be interested in, http://www.solmetric.com/annualinsolation-us.html. Also, perhaps you should play with PVsyst, for a large fixed ground mount, use the Unlimited Sheds Option. This tool gives you some optimum suggestions as well, but I prefer to run a few production estimates to compare. Each site is specific, so be cautious if someone tells you there is an across-the-board answer to an optimum tilt for grid-tied applications. For rooftops, you'll likely go with the orientation and tilt of the roof due to aesthetics and cost. For ground mounts, we can play with it a little more to find our sweet spots. Ryan J. LeBlanc NABCEPT Certified Solar PV Installer Lead PV Consultant NATURAL ENERGY WORKS 2139 Westland Dr Santa Rosa CA 95407 Cell: 707.591.1950 Direct: 707.536.9839 r...@naturalenergyworks.com http://www.NaturalEnergyWorks.com For your latitude, you see the same max. average yearly peak sun regardless of your fixed array tilted at latitude or latitude -15 degrees. See http://rredc.nrel.gov/solar/pubs/redbook/PDFs/OH.PDF. Being taught old school we always used latitude, but now I use latitude - 5 degrees for optimal fixed tilt. Kirk Herander Vermont Solar Engineering 802.863.1202 NABCEP(tm) Certified Solar Installer NYSERDA-eligible Installer VT Solar Incentive Program Partner _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake Chamberlin Sent: Monday, January 04, 2010 8:30 AM To: RE-wrenches Subject: [RE-wrenches] Best angle - direct grid tie Hello Wrenches, My Solar Pathfinder Assistant (SPA) claims that the optimum tilt angle for the solar modules is latitude. I'm skeptical. The system being designed is a direct grid tie, ground mount. It seems to me that an angle of latitude will give a balanced angle for both summer and winter charging. Since there is far less energy available in the winter, is this balance really the best. Also, a flatter angle in the summer should gain more hours of sun, since the sun goes N of the E-W axis. With ballasted systems, the 15 degree angle is supposed to work just fine, due to better summer charging. Does anyone have an answer to what really is the optimum tilt angle for a direct grid tie system? Is the SPA geared toward off grid systems, or is latitude really the best? Thank you and best wishes for the New Year, Drake Chamberlin Athens Electric OH License 44810 CO License 3773 NABCEP TM Certified PV Installer Office - 740-448-7328 Mobile - 740-856-9648 -- next part -- An HTML attachment was scrubbed... URL: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachme nts/20100104/d0653269/attachment-0001.htm ___ List sponsored by Home Power magazine List Address: 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 Check out participant bios: www.members.re-wrenches.org PVWatts Output as a function of Module Tilt and Azimuth.pdf Description: Adobe PDF document ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List
Re: [RE-wrenches] Best angle - direct grid tie
Drake, I just noticed a new feature with the Pathfinder Assistant called the Optimal Azimuth and Tilt Tool. Find it on the Tools menu. I don't believe this function accounts for snow cover but pretty handy nonetheless. Best regards, Nik From: Drake Chamberlin drake.chamber...@redwoodalliance.org ... what really is the optimum tilt angle for a direct grid tie system? ... ___ List sponsored by Home Power magazine List Address: 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 Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Best angle - direct grid tie
For your latitude, you see the same max. average yearly peak sun regardless of your fixed array tilted at latitude or latitude -15 degrees. See http://rredc.nrel.gov/solar/pubs/redbook/PDFs/OH.PDF. Being taught old school we always used latitude, but now I use latitude - 5 degrees for optimal fixed tilt. Kirk Herander Vermont Solar Engineering 802.863.1202 NABCEP(tm) Certified Solar Installer NYSERDA-eligible Installer VT Solar Incentive Program Partner _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake Chamberlin Sent: Monday, January 04, 2010 8:30 AM To: RE-wrenches Subject: [RE-wrenches] Best angle - direct grid tie Hello Wrenches, My Solar Pathfinder Assistant (SPA) claims that the optimum tilt angle for the solar modules is latitude. I'm skeptical. The system being designed is a direct grid tie, ground mount. It seems to me that an angle of latitude will give a balanced angle for both summer and winter charging. Since there is far less energy available in the winter, is this balance really the best. Also, a flatter angle in the summer should gain more hours of sun, since the sun goes N of the E-W axis. With ballasted systems, the 15 degree angle is supposed to work just fine, due to better summer charging. Does anyone have an answer to what really is the optimum tilt angle for a direct grid tie system? Is the SPA geared toward off grid systems, or is latitude really the best? Thank you and best wishes for the New Year, Drake Chamberlin Athens Electric OH License 44810 CO License 3773 NABCEP TM Certified PV Installer Office - 740-448-7328 Mobile - 740-856-9648 ___ List sponsored by Home Power magazine List Address: 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 Check out participant bios: www.members.re-wrenches.org
Re: [RE-wrenches] Best angle - direct grid tie
Drake, The SPA software is likely telling you 'close-to-the' optimum tilt for maximum total annual peak production, without telling you WHEN the most valuable power is produced. That's for you to figure out based on the specific utility rate schedule, and is a critical factor. So, it kind of is geared towards off-grid systems, by default, but only because it doesn't have the Holy Grail database of utility rate schedules, (TOU, etc.) that we all wish was available. Though, it may manually allow you some of these features. I haven't looked at Assistant software in a little while, apologies. Solmetric has some resources you may be interested in, http://www.solmetric.com/annualinsolation-us.html. Also, perhaps you should play with PVsyst, for a large fixed ground mount, use the Unlimited Sheds Option. This tool gives you some optimum suggestions as well, but I prefer to run a few production estimates to compare. Each site is specific, so be cautious if someone tells you there is an across-the-board answer to an optimum tilt for grid-tied applications. For rooftops, you'll likely go with the orientation and tilt of the roof due to aesthetics and cost. For ground mounts, we can play with it a little more to find our sweet spots. Ryan J. LeBlanc NABCEPT Certified Solar PV Installer Lead PV Consultant NATURAL ENERGY WORKS 2139 Westland Dr Santa Rosa CA 95407 Cell: 707.591.1950 Direct: 707.536.9839 r...@naturalenergyworks.com http://www.NaturalEnergyWorks.com For your latitude, you see the same max. average yearly peak sun regardless of your fixed array tilted at latitude or latitude -15 degrees. See http://rredc.nrel.gov/solar/pubs/redbook/PDFs/OH.PDF. Being taught old school we always used latitude, but now I use latitude - 5 degrees for optimal fixed tilt. Kirk Herander Vermont Solar Engineering 802.863.1202 NABCEP(tm) Certified Solar Installer NYSERDA-eligible Installer VT Solar Incentive Program Partner _ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake Chamberlin Sent: Monday, January 04, 2010 8:30 AM To: RE-wrenches Subject: [RE-wrenches] Best angle - direct grid tie Hello Wrenches, My Solar Pathfinder Assistant (SPA) claims that the optimum tilt angle for the solar modules is latitude. I'm skeptical. The system being designed is a direct grid tie, ground mount. It seems to me that an angle of latitude will give a balanced angle for both summer and winter charging. Since there is far less energy available in the winter, is this balance really the best. Also, a flatter angle in the summer should gain more hours of sun, since the sun goes N of the E-W axis. With ballasted systems, the 15 degree angle is supposed to work just fine, due to better summer charging. Does anyone have an answer to what really is the optimum tilt angle for a direct grid tie system? Is the SPA geared toward off grid systems, or is latitude really the best? Thank you and best wishes for the New Year, Drake Chamberlin Athens Electric OH License 44810 CO License 3773 NABCEP TM Certified PV Installer Office - 740-448-7328 Mobile - 740-856-9648 -- next part -- An HTML attachment was scrubbed... URL: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachme nts/20100104/d0653269/attachment-0001.htm ___ List sponsored by Home Power magazine List Address: 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 Check out participant bios: www.members.re-wrenches.org
