[Greenbuilding] Solar microFIT installations

[Frank Tettemer]

/Just for reference: normally on single-axis tracking collector systems, 
the axis is E-W, not N-S. Are you CERTAIN it's N-S? Also, single-axis is 
generally good for more like 20% performance improvement, not 30-40%. 
But at those far north latitudes it may be that my rules of thumb suck 
(terrible pun on thumb-sucking, for those who missed it).

K/
............................................................................................................
I agree with Derek and Kieth that these trackers, at best, will improve 
productivity, by (perhaps) 30%.  However, for a gambling man, this means 
their added initial cost will pay off the installation costs about as 
quick or quicker than the fixed mounts.  The carrot to this is that 
after the installation is paid off, the daily production is greater and 
thus the owner's income per month is also greater.

Yes, I've seen quite a few of these North-Southhorizontal pole mount 
trackers.  They've become quite common trackers in the Ottawa Valley, 
Ontario. Talking to an installer/purveyor of these devices from 
Pembroke, and he says they cost 50% less than a Dager tracker, which 
seems to be the other common microFIT tracker in this rural area.

The Dager tracker is a single pole mount, holding 10kw, mounted on a 
monstrous concrete base, and the actuators are two axis tracking, thus 
keeping the PV's at 90 degrees to the sun shine from early AM to late 
PM. They are definitely the most productive of the tracking devices, 
compared to the North-South horizontal pipe mounted thingies.

My wife and I have built and installed our own microFIT, using eight 
steel poles, no tracker. These mounts can be adjusted seasonally, to 
optimize production but definitely have a production curve that begins 
low in the morning, goes to full production mid-day and drops off in 
afternoon.
What we've done is mount 13,000 watts of PV's, to sell 10,000 
watts/hours.  As Derek has talked about, we've spent our money on more 
fixed mounted PV's, to get a greater daily yield, without the 
difficulties of maintenance of a tracking device.

Two Reasons being:  I've seen one of these North-South horizontal pole 
mounts tipped to the East, and stuck there, for a full month, because 
the installer was too busy installing more of them to come back and fix 
the broken one.  This was a turn-off.

And secondly, a Dager tracker holds 10Kw on one pole. That is One Huge 
Sail.  The one I'm aware of in Southern Ontario was blown over in a huge 
wind, and I'm told it wasn't a pretty site. (PV's contain very large 
sheets of glass.) Yes, they broke.  And how did they re-erect that huge 
tracker?

I like the simplicity of a fixed mount, where I can go out four times a 
year, with a pair of wrenches, and manually adjust my mounts.  It adds , 
maybe, eight total hours of labour per year. I can do that.

Frank

Frank Tettemer
Living Sol ~ Building and Design
www.livingsol.com
613 756 3884



On Fri, Jul 29, 2011 at 3:00 PM, 
<greenbuilding-request at lists.bioenergylists.org> wrote:

 >> His panels are attached to a 12 metre (40 ft) long horizontal pipe
 >> oriented with it's long axis running North-South, suspended about 3
 >> metres
 >> (10 ft) off of the ground.
 >>
 >> The pipe rotates to follow the arc of the sun over the course of the
 >> day.
 >>
 >
 > I'm trying to visualize this array. Does the North end of the pipe angle
 > up by XY degrees? Or are the individual panels tilted up?
 > Is the array 2x26 panels (I got that from the first graphic found at the
 > Enphase link)?
 > Does the XY angle above change over the course of the year?




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