Building Reserve and Using KWH

[ButchDeal]

Sounds like a good plan to utilize some of that 4 gWhrs of energy your system produces over and above your consumption..

I think you mean 4MWhs not 4GWhs

4000kWh = 4MWh
4000MWh = 4GWh

[Ampster]

Sounds like a good plan to utilize some of that 4 MWhrs of energy your system produces over and above your consumption..

[bcroe]

Meantime the car shop is well along in the installation of a 16,000 BTU mini-split
heat pump, pictures soon. This 15RLS3H has a -25F degree operational capability,
achieved with some internal supplemental resistive heat at the very lowest outside
temps. This luxury will attempt to keep inside temps at least 40 F year around, as
opposed to just being really cold in Feb. This will make quick jobs (oil change) easy
and a quick blast from the propane furnace will get me 65 F for a transmission
overhaul. The occasional, automatic use of some resistance heat at extreme lows
is a huge improvement over using it continuously and manually.

The shop is 1080 sq ft, with basic level insulation. Bruce Roe

Here is the state of the 15RLS3H installation in the car shop, the inside work is
already finished. My house mini splits past winter left me with a generation
surplus of over 4000 KWH, so this winter will attempt to use some of it up on
this semi insulated building, which used to sit with no heat in winter. Damaging
levels of ice and snow slide off the high metal roof, so a small roof/shield will
be placed a foot or so above this equipment for protection.

The 15RLS3H will be the main energy experiment for the next winter. I do not see
it as being in its sweet spot, trying to maintain 40 F in a substantial area with
outside temps down to -25F, so it will be a test. It has more capacity than my
first minis, and the heater supplement will take energy, but nothing like a pure
resistance heater. Bruce Roe

RLS3H1.JPG

[Ampster]

..........but many of us were not happy to see suggestions of here putting them on some of the best farm land, in direct violation of existing zoning......

In California there are a number of large commercial solar farms in the desert. At other locations I have observed smaller installations on hillside pasture land and adjacent to flat farm land in the Central Valley. In the case of the hillside pasture land I occasionally see sheep grazing under the panels. In the Central Valley water is an issue and not all land appears to be utilized for farming for reasons that may relate to water allocations or cost of transporting water. I don;t know what the zoning issues are in California with respect to agriculturally zoned land either.

In looking at some of these smaller installations I also notice that the panel angles are sometimes closer to horizontal than I would have suspected. On further research I understand that the power density per acre can be increased by using these lower angles and thereby reducing the spacing between arrays. This appears to result in a configuration that produces more AC power per acre. I would guess that these systems run higher AC to DC ratios.to optimize system performance. . I can understand that if someone looked only at the array configuration it could be argued that they are suboptimal. However from a system standpoint (array, inverter and land), they may be optimizing the ROI.

[bcroe]

The first results are in for the attempt to expand commercial solar in IL. Those I
reviewed were in the 2MW to 20MW (AC rating) range. Of 900 project submissions,
100 were approved, I do not yet know more details of the approval process. I do not
yet know of anything close by, but many of us were not happy to see suggestions of
here putting them on some of the best farm land, in direct violation of existing zoning
Comprehensive Plans, by some sort of slight of hand. And I was additionally unhappy
to see proposals where clouds and snow are so prominent. Bruce Roe

[Ampster]

You guys ought to just stick to the facts. Bruce Roe

The facts are that large scale solar farms average a DC to AC ratio of 1:25 to 1.That number has been increasing over the years. I don't recall your AC to DC ratio but I believe it is greater than 1 to 1.

Perhaps the misunderstanding is whether we are talking about optimizing the array or optimizing the entire system. I won't speak for J.P.M. but he consistently refers to arrays (the panels) and I interpret your discussion on this thread to mean the entire system, including the panels, inverters and racking.
EDIT
As you point out in the following post, most commercial solar farms are described by their AC rating. My point in the above is that an array centric methodology is not always used by professionals to optimize systems.

[bcroe]

You guys ought to just stick to the facts. Bruce Roe

[Ampster]

I agree with Bruce because he is optimizing his system. Perhaps you might want to try to attack the argument instead of attacking someone else.

[J.P.M.]

Indeed it is the system as a whole that is optimized. It is easy for someone to cherry pick the individual components output and try to infer that your system is suboptimal.

Ampster, if you think I'm cherry picking Bruce's array, you're exhibiting an example of your ignorance of the basics of PV and solar energy in general, and I have no inclination to instruct you.

Bruce's array is optimized for what his goals and intentions are. Big AMEN on that. I share more than a bit of what appear to be his eccentricities.

Bruce and I do not share all opinions about the best way to apply solar energy.

IMO, Bruce's array is most likely not something that a knowledgeable PV designer would come up with in most any common semirural, grid tie application if cost effectiveness or optimal use of materials or resources were design goals.

You want to be helpful, buy a decent textbook and find out what solar energy is really all about before you criticize and misconstrue and attempt to twist what I write. You might be able to contribute something technical rather than repeat what you read or heard someplace that fits your view of things. You also might begin to understand some of what Bruce and I respectfully disagree about rather than more of the same blather that doesn't contribute much of anything to the discourse except that you agree with someone and disagree with someone else for unspecified reasons.

[bcroe]

Indeed it is the system as a whole that is optimized. It is easy for someone to cherry pick the
individual components output and try to infer that your system is suboptimal.

Oh, critical analysis is welcomed. If I can not answer that, its time to go back to the drawing
board. Have had to explain that to some new guys on the job. I have stories....
Bruce Roe

[Ampster]

......

Better to design a PV system that does well every day, sunny or not. A close look at my actual numbers reveals more output on EVERY day than a pure south facing array. My original south facing array would have much deeper valleys than this
chart.

Indeed it is the system as a whole that is optimized. It is easy for someone to cherry pick the individual components output and try to infer that your system is suboptimal.

[bcroe]

Yea, it is. And I don't have data or literature to comment one way or the other, so I'll not do so.

NOMB or concern, but to be clear, your inverters may be running to capacity but because of your less than optimal array orientations the panel portion of your system is not. If you had ~ 25-26 STC kW of south facing panels at a 45 deg. tilt, instead of ~ 35 STC kW you do have spread in varying orientations as you have, you'd produce about the same output on a sunny May day. You'd probably need bigger/more inverter capacity and that would cost a bit, but I'd wager you'd save a lot more than that cost by having only about 75 % as much STC kW in panels to pay for. But I do appreciate the reasons behind what your doing and the fun you're having.

Also, humidity is the amount of water vapor in the atmosphere or in a gas. What you see is condensed water vapor, or simply condensate.

Respectfully,

PV15May19.png

Will try to say condensate next time.

That is fine for the one fully sunny day on this chart of my recent daily outputs. Better to design a PV system
that does well every day, sunny or not. A close look at my actual numbers reveals more output on EVERY
day than a pure south facing array. My original south facing array would have much deeper valleys than this
chart. Just so any comparisons make sense, there needs to be a common element. Since I cannot change
my 15 KW inverter capacity, I am declaring that the fixed point. It may be used with a DC/AC ratio. Bruce Roe

[J.P.M.]

Its all a guess of course. I can run at capacity even with very light clouds, an ideal sunny
day may do 158 KWH. When our weather person says no clouds, but smoke from Canada
is causing the haze, I credit the 135-140 KWH lessor day production to the smoke.

I see a heat pump automatic switch over to cooling today, humidity is dripping out the other
(inside unit) drain. Bruce Roe

Yea, it is. And I don't have data or literature to comment one way or the other, so I'll not do so.

NOMB or concern, but to be clear, your inverters may be running to capacity but because of your less than optimal array orientations the panel portion of your system is not. If you had ~ 25-26 STC kW of south facing panels at a 45 deg. tilt, instead of ~ 35 STC kW you do have spread in varying orientations as you have, you'd produce about the same output on a sunny May day. You'd probably need bigger/more inverter capacity and that would cost a bit, but I'd wager you'd save a lot more than that cost by having only about 75 % as much STC kW in panels to pay for. But I do appreciate the reasons behind what your doing and the fun you're having.

Also, humidity is the amount of water vapor in the atmosphere or in a gas. What you see is condensed water vapor, or simply condensate.

Respectfully,

[SunEagle]

I didn't hear/read of any big fires west or NW of you, but I'm curious, how do you do the estimating of losses due to atmospheric turbidity/smoke ?

As Bruce mentioned, I have seen a number of weather forecasts that show the smoke from Canadian fires drifting South on the satellite radar images..

[bcroe]

I didn't hear/read of any big fires west or NW of you, but I'm curious, how do you do the estimating of losses due to atmospheric turbidity/smoke ?

Its all a guess of course. I can run at capacity even with very light clouds, an ideal sunny
day may do 158 KWH. When our weather person says no clouds, but smoke from Canada
is causing the haze, I credit the 135-140 KWH lessor day production to the smoke.

I see a heat pump automatic switch over to cooling today, humidity is dripping out the other
(inside unit) drain. Bruce Roe