[RE-wrenches] Best angle - direct grid tie

[Kirk Herander, VSE]

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-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at 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 

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