- - - - To send a message: RE-wrenches@topica.com Archive of previous messages: http://www.topica.com/lists/RE-wrenches/ List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm Check out participant bios: www.mrsharkey.com/wrenches/index.html Hosted by Home Power magazine Moderator: michael.welch@homepower.com ==^================================================================ EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9 Or send an email To: RE-wrenches-unsubscribe@topica.com This email was sent to: michael.welch@homepower.com T O P I C A -- Register now to manage your mail! http://www.topica.com/partner/tag02/register ==^================================================================ Return-Path: Received: from mailout.pacificglobal.net ([209.84.182.242]) by merlin (EarthLink SMTP Server) with ESMTP id tr5e1e.8n6.37tiu4s for ; Wed, 26 Sep 2001 22:25:01 -0700 (PDT) Received: from micron (ip64-75-146-229.dial.maui.net [64.75.146.229]) by mailout.pacificglobal.net (8.11.0/8.9.3) with SMTP id f8R5PMW98462 for ; Wed, 26 Sep 2001 19:25:23 -1000 (HST) Message-ID: <00ab01c14714$edc80030$0100a8c0@micron> Reply-To: "Michael Pelosi" From: "Michael Pelosi" To: "Joel Davidson" References: <0.1300002502.1186493758-951758591-1001458969@topica.com> <3BB1246E.DEBCC7CB@earthlink.net> Subject: Re: "Real" Sun Hours [RE-wrenches] Date: Wed, 26 Sep 2001 19:26:13 -1000 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 X-Mozilla-Status2: 00000000 Hi Joel and other RE-wrenches, Thank you for including me in this discussion. The best information I can offer in light of the desire to be using "good" solar data is about one of our forthcoming products. For each of the 239 sites in the NREL database, there is a TMY2 file, which is an "average" (and that term is used loosely) of the 30 years of history for the site. There is also a file for each year (1961-1990) for each site. We are preparing a 3 CD set that will contain each of the 30 years for each site, so within PV-DesignPro you can simulate "good", "bad", and "average" years for any of the 239 sites, along with the TMY2 year--which should correspond to "average" annual performance. The 3 CD set should be available by the end of November. Aloha, Michael Pelosi ----- Original Message ----- From: "Joel Davidson" To: Cc: Sent: Tuesday, September 25, 2001 2:42 PM Subject: Re: "Real" Sun Hours [RE-wrenches] > Thanks for jogging my memory about Ron Richmond's 1984 Guidebook on Photovoltaic > Applications in Hawaii. See page 40 for Oahu yearly average peak sun hours per day. A > more recent and excellent source of data is Michael Pelosi's Solar Design Studio > software. Michael's audio tutorial is so good it defies description. Check it out at > http://www.mauisolarsoftware.com/ > > mmangelsdorf@hei.com wrote: > > > My 2 cents. > > > > The NREL red book includes many sites which have less than accurate solar > > data listed. If the site is designated by NREL as "primary" then you can > > have confidence that the data listed is accurate based on actual long-term > > (XX years) monitoring. If it's a "secondary site" then the data listed is > > an extrapolation/estimate of the insolation based on computer modeling and > > the actual data recorded at a "nearby" primary site. For example, here in > > Hawai'i, the only real data listed for our four listed locations (Honolulu, > > Hilo, Kahului and Lihue) is for Honolulu. The other three sites are > > secondary sites where NREL is using the modeling approach based on estimated > > cloud cover, precipitation, etc. Mike Pelosi's very useful Maui Solar > > Software design program uses NREL data to estimate system performance. But > > I have to remind myself that many of the listed cities in the U.S. are > > secondary sites. But hey, you have to put something into the program if you > > want to get some idea of what the system is going to do. > > > > My 2 cents are up. > > > > marco > > > > Carl and Travis, > > Most insolation data provided by folks like NREL and others is in units > > referred to as "peak sun hours". This is kWh/m2/day. Values are often > > published for monthly or yearly averages as in the NREL "Red Book". Goto > > http://rredc.nrel.gov/solar/pubs/redbook/ and look at this. You can also > > order a copy online. > > Measurements are made with pyranometers and the insolation recorded is > > listed in units of peak sun hours. This is an average daily energy delivered > > > > by the sun (averaged over 30 years in the case of the "Red Book"), not an > > instantaneous irradiance measurement. > > I hope this helps. > > Bill. > > > > > -----Original Message----- > > > From: Carl Emerson [mailto:freepower@freepower.co.nz] > > > Sent: Tuesday, September 25, 2001 2:10 PM > > > To: RE-wrenches@topica.com > > > Subject: Re: "Real" Sun Hours [RE-wrenches] > > > > > > > > > Travis, > > > > > > I'll stick my neck out on this one... > > > > > > Real sun hours is very complicated to measure and requires very > > > sophisticated > > > recorders that can integrate the varying insolation levels during > > > the day and > > > come out with an index for 1000 watts/SqM. > > > Very early recorders used a magnifying glass to burn a track in a > > > paper roll and > > > could therefore only record a threshold. > > > Using a C40 might indicate a threshold and you could relate this > > > to a current > > > reading and an insolation level, but this will not be able to account for > > > integrating the intensity variations. > > > Personally I have gone away from using 'sun hours' in my design > > > calculations and > > > use the irradiance data. I find this much more useful and accurate partly > > > because even today the sun hour recordings in our country are > > > useful only to > > > tourists who might want to calculate the gallons of sun cream > > > required for their > > > holiday... > > > > > > "Travis Creswell, Ozark Solar" wrote: > > > > > > > My second question of the day. > > > > > > > > Noticing the high module temps I am seeing even on cool days I > > > am wondering > > > > about the accuracy of Sun Hour numbers. > > > > > > > > I use the DVM on my C40 to make a crude calculation of the > > > daily sun hours I > > > > am getting. Of course, it's accuracy is questionable and > > > commonly I have > > > > found the C40 DVM's that I've installed to read amps about 10% > > > low. Voltage > > > > is usually right on. Mine is no different. Simply, I divide > > > the rated amps > > > > of my array into the amp hours for that day and that tells me > > > how Sun Hours > > > > I got. Currently I have only part of my array installed so I > > > only have 7.1 > > > > amps (Four Astro power 120's at 48 volts). > > > > > > > > But what I just realized about this number is that it factors > > > everything in, > > > > including a de-rate for heat and actual insolation. Are these things > > > > already factored in to the commonly published Sun Hours numbers? > > > > > > > > Travis Creswell > > > > Ozark Solar > > > > > > > > - - - - > > > > To send a message: RE-wrenches@topica.com > > > > > > > > Archive of previous messages: http://www.topica.com/lists/RE-wrenches/ > > > > > > > > List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm > > > > > > > > Check out participant bios: www.mrsharkey.com/wrenches/index.html > > > > > > > > Hosted by Home Power magazine > > > > > > > > Moderator: michael.welch@homepower.com > > > > > > > > > > -- > > > Regards, > > > > > > > > > Carl Emerson > > > Manager > > > FREEPOWER LTD. "Harnessing Natural Energy" > > > P.O. Box 10-1207 N.S.M.C. Auckland, NEW ZEALAND. > > > Ph. 09 4275206 fax 09 4275208 cell 021-633999 web www.freepower.co.nz > > > > > > - - - - > > > To send a message: RE-wrenches@topica.com > > > > > > Archive of previous messages: http://www.topica.com/lists/RE-wrenches/ > > > > > > List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm > > > > > > Check out participant bios: www.mrsharkey.com/wrenches/index.html > > > > > > Hosted by Home Power magazine > > > > > > Moderator: michael.welch@homepower.com > > > > > > > > > > > > > > - - - - > > To send a message: RE-wrenches@topica.com > > Archive of previous messages: http://www.topica.com/lists/RE-wrenches/ > > List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm > > Check out participant bios: www.mrsharkey.com/wrenches/index.html > > Hosted by Home Power magazine > > Moderator: michael.welch@homepower.com > > > > - - - - > > To send a message: RE-wrenches@topica.com > > > > Archive of previous messages: http://www.topica.com/lists/RE-wrenches/ > > > > List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm > > > > Check out participant bios: www.mrsharkey.com/wrenches/index.html > > > > Hosted by Home Power magazine > > > > Moderator: michael.welch@homepower.com > > > > > ------------------------------------------------------------------------ > > Name: winmail.dat > > winmail.dat Type: DAT File (application/x-unknown-content-type-DAT_auto_file) > > Encoding: base64 > >