Tracker efficiencies, etc. [RE-wrenches]

[sunwise at cheqnet.net]

Carl Emerson wrote:
I think we are saying that the nearer the equator the more advantage from dual vs.  single axis tracking ??


Hey Carl,

In regards to single axis trackers, I think the farther you are from the equator, the greater the seasonal disparity in a tracker's increased performance.  Trackers increase the solar gain to an array more during the summer than during the winter (unless the array is located within the Tropics of Cancer and Capricorn), and this seasonal disparity increases with latitude.

This was my point regarding trackers on stand-alone systems at latitudes similar to Wisconsin.  The low arc of the winter sun, as well as the shortened days, place the greatest demands on the system at the same time of the year that a tracker offers the least amount of increased output.

In such scenerios I believe it makes more sense to utilize a seasonally adjustable (two to four times/yr), non-tracking array.  Invest the bucks you would have spent on a tracker in a couple extra panels.  The panels will increase the output of the array in December (when you really need it) much more than the tracker.  And although I've had pretty good luck with Wattsun trackers and their service, PVs are less vulnerable to wear and tear and things like lightning than a tracker.

I usually recommend trackers in grid-tie system with a good solar site (and in stand-alone systems with heavier summer loads than normal). Might as well spin the meter backwards as much as you can during the long summer days when the tracker has a much longer arc to follow and greater gain.

The only dual axis tracker I ever did had manual controls and a computer linked OmniMeter (School space station, was that HP42?).  Just by graphing some data logs with the OmniLink software and playing with the angle of incidence a bit, I doubt that there is much increased performance in a dual axis tracker over single axis if the quarterly elevation adjustments Richard mentioned are easily made.  Like I said before, the snow dump is kind of cool though.

I hope I made my point a bit clearer than the ramble I posted the other night.

Kurt Nelson


--------------------------------------------------------------------
mail2web - Check your email from the web at
http://mail2web.com/ .

- - - -
To send a message: RE-wrenches at 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 at homepower.com

==^================================================================
This email was sent to: michael.welch at homepower.com

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9
Or send an email to: RE-wrenches-unsubscribe at topica.com

T O P I C A -- Register now to manage your mail!
http://www.topica.com/partner/tag02/register
==^================================================================