Sun hours

[J.P.M.]

Is there any such thing a a ballasted ground mount? Was thinking about another trial mount here. There are a dozen tons of rock
piled up here from previous foundation digs. Bruce Roe

Don't see why not. But my guess is it would still require some anchorage against long term creep or seismic movement, although probably/maybe not as robust as a foundation. I could probably make one work from a design/safety standpoint. That's not to say it would be practical, cost effective or pretty.

[bcroe]

Is there any such thing a a ballasted ground mount? Was thinking about another trial mount here. There are a dozen tons of rock
piled up here from previous foundation digs. Bruce Roe

[bcroe]

The April/May/June quarter of my 2016/17 KWH year shows production up 8% from last year, from 95.6 to 103.3 KWH per day. I
am crediting this partly to fewer rainy days, and somewhat reduced shading at day extremes. I expect an increase of at least as
much can be obtained by moving panels to less shaded positions.

KWHs banked for winter are up nearly 17%, 73.3 vs 63.1 KWH per day. I suppose its due to much warmer weather this spring.
That level may not continue, because the air has been running a lot in these 90+ deg days. Work has continued slowly despite
the heat and very high humidity; all the space I need is cleared and unshaded. Bruce Roe

[ButchDeal]

Yes it doesn't change the default. You can select a region of the graph and zoom it to scale as well ( though also not permanent)

[bcroe]

Second bullet.... Random site in image....

Or were you talking about the daily view? If so click on the word efficiency to turn it off

I was doing daily. That does temporarily turn it off, thanks. But they don't rescale energy to fill the page (my real objection)
anyway, and next time its right back. Bruce Roe

[ButchDeal]

I tried all the buttons at the top, but none listed a way to turn off EFFICIENCY. Bruce Roe

Second bullet.... Random site in image....

Or were you talking about the daily view? If so click on the word efficiency to turn it off

[bcroe]

I tried all the buttons at the top, but none listed a way to turn off EFFICIENCY. Bruce Roe

[ButchDeal]

Turn off eficiency if you don't want it.

[bcroe]

I don't really understand my graph on PVOUTPUT, under SUN HOURS. Sometimes they show a sun symbol on that EFFICIENCY
curve. It plots the number of KWH per KW capacity. Today the array managed 9 KWH/KW capacity, but it did't rate a SUN. How
much more can an array put out in a day?

I'm also not pleased that they keep changing the KWH scale, and its scaled so it never goes up up more than half the space. I scale
plots to fill the page. Of course they do it so that it never overlaps the EFFICIENCY curve (that I don't need), entirely above KWH. Bruce Roe

[bcroe]

With heavy clipping, it becomes more complicated.

Exactly

tools like TMY files can help narrow down the range of likely possibilities.

My "tool" here is dependent on clear weather. But it includes things a pure simulation might miss, like temp or shade. Bruce

[sensij]

If its cloudy, it doesn't matter which way the panels face. Sunny, I'm already in clipping at noon, so more south facing panels
won't contribute. Anyway best daily sun here frequently isn't around noon. So I'll try to even out power, to minimize clipping
and maximize my "sun day". Tilt to vertical is in the plan for the snow months only. Bruce Roe

At the end of the year, one azimuth will have outgenerated any of the others. Most likely, that ideal azimuth is something very close to south, unless the cloud patterns are very strong and consistent. The outperformance of a south facing panel is not just during noontime, and even with some clipping, south can still outperform east or west (over the course of the year). With heavy clipping, it becomes more complicated. Certainly, over short periods of time, east or west could be better, but tools like TMY files can help narrow down the range of likely possibilities.

[bcroe]

I hope that if you have the terrain / space for it, you aren't overthinking yourself out of simply putting as many panels facing south as possible. 3 east + 1 west might make sense off-grid, or *severely* inverter limited, but otherwise, putting them south will surely generate the most over the course of the year (especially with adjustable tilt).

If its cloudy, it doesn't matter which way the panels face. Sunny, I'm already in clipping at noon, so more south facing panels
won't contribute. Anyway best daily sun here frequently isn't around noon. So I'll try to even out power, to minimize clipping
and maximize my "sun day". Tilt to vertical is in the plan for the snow months only. Bruce Roe

[DanKegel]

Do any utilities incentivize morning and evening generation yet?

[sensij]

Here are some curves made on recent sunny days. Note the highest curve is the
summation of the (1)W and (3)E facing panels, elevated 58 degrees on 13 June.
The implication is that enough of these will produce excess power at noon without
any help from the (2)S panel. The 17 June curve attempts to level things with an
elevation of 61 degrees; the E-W sum is quite different for a small change. I'm
considering just using E & W facing strings, but some winter curves are still
needed. Bruce Roe

I hope that if you have the terrain / space for it, you aren't overthinking yourself out of simply putting as many panels facing south as possible. 3 east + 1 west might make sense off-grid, or *severely* inverter limited, but otherwise, putting them south will surely generate the most over the course of the year (especially with adjustable tilt).

[bcroe]

MODELING

The array here started as a classic SW desert design. In 3 years of studying
performance, I have a list of things it doesn't deal with very well. Like, CLOUDS,
SHADING, and SNOW. The thought here is to improve these things by changing
the placement of panels. At this stage some model panels could be placed in the
field to compare actual performance to ideas.

3 panels have been set up to model any new design over an operating day, starting
in summer. Maybe they will still be there in winter. In fact about as much energy
can currently be collected on clear day in April, May, or June; this seems to be
because shadowing here increases as the sun moves north. The placement of these 3
test panels will check for any remaining shading. Notice the locating stakes, measured
out within inches. The angle of elevation is adjustable.

Output of a panel recorded over a day will give a curve of power vs time.
Adding together these curves on an hour by hour basis over a clear day, will
show how well total power output is (or is not) maintained at a fairly constant level.
Some fine tuning of the orientation will be involved.

I didn't really want to bother with an MPPT control for each of the 3 test panels,
representing the 3 tilts and locations of a complete array. I decided to just wire
a shunt to each panel (0.1 ohm 10 watt), putting them in the shorted output mode.
This will give a current nearly proportional to the MPPT value. Here is one plugged
into its panel, with meter jacks. Power of a full sized array is just a matter of
estimating the Vmp & Imp, multiplying them together and by the number of panels.

Here are some curves made on recent sunny days. Note the highest curve is the
summation of the (1)W and (3)E facing panels, elevated 58 degrees on 13 June.
The implication is that enough of these will produce excess power at noon without
any help from the (2)S panel. The 17 June curve attempts to level things with an
elevation of 61 degrees; the E-W sum is quite different for a small change. I'm
considering just using E & W facing strings, but some winter curves are still
needed. Bruce Roe