Sun hours

[Naptown]

Is that for tracking, or for vertical angle, or for anything past vertical? Here nothing is under warrantee
for very long, interferes with activities. Bruce Roe

If it exposes the back to the sky going beyond vertical would do that.

[PNjunction]

Instead of a tracker, just use more panels to take advantage of the prime solar-insolation hours you do have. Off-prime hours when the sun is low during the early morning and late afternoon are weak, so that's why it may seem incredible in places where there are 8 hours of daylight, that according to calculations only has 2 hours of *quality* usable sunlight power.

Increasing your stationary panel wattage would probably be cheaper and easier to implement.

[inetdog]

I
Increasing your stationary panel wattage would probably be cheaper and easier to implement.

Except for the part about getting the snow off....

[bcroe]

Instead of a tracker, just use more panels to take advantage of the prime solar-insolation hours you do have. Off-prime hours when the sun is low during the early morning and late afternoon are weak, so that's why it may seem incredible in places where there are 8 hours of daylight, that according to calculations only has 2 hours of *quality* usable sunlight power.

Increasing your stationary panel wattage would probably be cheaper and easier to implement.

Yes it only took me 5 months to increase panels that way. Here in northern IL, with snow and E-W panels, Monday production calculated out to 7.8 equivalent sun hours (117 KWH). Solving the snow issues may take years, but getting all panels near vertical should help.
Bruce Roe

[bcroe]

quote who?

That is interesting. My post is missing, but SOMEBODY else quoted part of it, commented
on it, and its all credited to me. Bruce Roe

[inetdog]

That is interesting. My post is missing, but SOMEBODY else quoted part of it, commented
on it, and its all credited to me. Bruce Roe

Mea Culpa. I hit the wrong button when trying to comment/reply.
Not sure how to fix it up again, but I will try.

OK, I think it is all better now.
Sorry about that....

[inetdog]

Yes it only took me 5 months to increase panels that way. Here in northern IL, with snow and E-W panels, Monday production calculated out to 7.8 equivalent sun hours (117 KWH). Solving the snow issues may take years, but getting all panels near vertical should help.
Bruce Roe

Very impressive and giving some additional hope to those who are not all that far north.

[FUN4ME]

Solving the snow issues may take years, but getting all panels near vertical should help.
Bruce Roe

Me again trying to think outside the box,
Have you looked into radiant heating flooring coils to see if they could be mounted under or around your panels?
I have no idea how efficient they are or even if they could be used outside.

[bcroe]

Melting snow

Me again trying to think outside the box,
Have you looked into radiant heating flooring coils to see if they could be mounted under or around your panels?
I have no idea how efficient they are or even if they could be used outside.

My intuitive feeling, this would be hopelessly complex & energy inefficient. The approach
being considered (another thread, Panel Sensitivity) is to directly heat the panels with
external power to them. I have some doubt that even that will be efficient enough to
be justified. Next year i might set up a couple panels and try this, the second panel
for comparison. Following summer, see if the heating experiment reduced the
performance of the heated panel, compared to the reference panel. Meantime, the
immediate change will be to get panels mostly vertical, later this year.

Bruce Roe

[bcroe]

Yes it only took me 5 months to increase panels that way. Here in northern IL, with snow and E-W panels, Monday production calculated out to 7.8 equivalent sun hours (117 KWH). Solving the snow issues may take years, but getting all panels near vertical should help.
Bruce Roe

Decided to graph the level of my AC energy output over a sunny + cool day.
Clipping is minimal, probably will stop with warmer weather & snow melted.

This doesn't look much like the usual "bell curve". Power rises very fast as
sun hits the east facing panels. Toward mid day the main power comes from
south facing, and then transfers to west facing approaching sunset. It would
be even closer to "rectangular" if I didn't have any shading issues at
extremes of the sun day. Best day so far is 125 KWH.

The selection of non south panel orientations was chosen by guess & by golly,
no proper simulation. It was based on the panels and space I had, and what
one guy might be able to throw up in a month. For all that, it is working very
well. In addition, output in cloudy weather (light dispersed) is way up; a
typical overcast day produces 60 to 90 KWH.

There is probably room for improvement here. Need to understand some
serious simulation tools. Generally goals are to set panels to: minimize snow
accumulation; minimize clipping in good sun all year; and bring up power for
sun day beginning & end times. Using additional panels "inefficiently" to do
this, will bring up power during clouds, etc, rather common here. Bruce Roe

[bcroe]

Last year the sun was beaming down, but the power co didn't put in my net
meter till Aug. This year everything is running, but clouds just won't go away.
On Monday I saw SNOW falling????

Despite that, had mostly sunny today, spotty dark clouds. If we ever have
a clear day this summer, I do hope to see a day of 150 KWH. Regardless,
it did produce a new record today, 144 KWH squeezed through 15 KW of
inverters, 9.6 SUN HOURS in a day. Bruce Roe

[gregvet]

Last year the sun was beaming down, but the power co didn't put in my net
meter till Aug. This year everything is running, but clouds just won't go away.
On Monday I saw SNOW falling????

Despite that, had mostly sunny today, spotty dark clouds. If we ever have
a clear day this summer, I do hope to see a day of 150 KWH. Regardless,
it did produce a new record today, 144 KWH squeezed through 15 KW of
inverters, 9.6 SUN HOURS in a day. Bruce Roe

Bruce, that is impressive. That gives the PVOutput.org definition of efficiency (kWh divided by kW DC) of approximately 7.68 kWh/kW to 8.64 kWh/kW (assuming inverter efficiency of between 80-90%) putting you at the top 1% of the efficient pv systems in PVOutput. Do you have a PVOutput account and if so, may I look at that account?

[SunEagle]

Bruce, that is impressive. That gives the PVOutput.org definition of efficiency (kWh divided by kW DC) of approximately 7.68 kWh/kW to 8.64 kWh/kW (assuming inverter efficiency of between 80-90%) putting you at the top 1% of the efficient pv systems in PVOutput. Do you have a PVOutput account and if so, may I look at that account?

Of course the reason the Bruce gets some many hours of "producing sunlight" in one day is due the way he has set up his panels. One group is facing East, another South and a third West. So for most of the day at least one group is producing.

It is a very impressive system. Great job Bruce.

[bcroe]

Bruce, that is impressive. That gives the PVOutput.org definition of efficiency (kWh divided by kW DC) of approximately 7.68 kWh/kW to 8.64 kWh/kW (assuming inverter efficiency of between 80-90%) putting you at the top 1% of the efficient pv systems in PVOutput. Do you have a PVOutput account and if so, may I look at that account?

As the longest day gets closer, the next 3 predicted clear days might get me that
10 SUN HOUR day. I suppose that means my inverters will only last 5 years instead
of 10, maybe can learn to fix them. I have a spare.

I don't have an account on line, the numbers appear on a pair of 7.5 KW Fronius
inverters, logged regularly in a notebook. If you click bcroe, view profile, about me,
you can find my PHOTOBUCKET link showing details in sub albums under album
ENERGY CONSERVATION.

With the most straightforward PV system located in sunny southern Cal, it might be
fine to list a system as so many KW. I prefer to list DC and AC limits. That starts
to matter when adding panel strings to compensate for the weather here in cloud
land. So a simple ratio of those numbers isn't the whole story.

I have ENOUGH AC capacity, and no way to expand it without replacing EVERYTHING.
The OBJECTIVE is to keep the inverters loaded as much of the time as possible. So
panels aimed at rising, midday, and setting sun do it, and bring mild overcast output
up to 60% to 80% of max. I have seen 4KW during a rain storm. A year will do at
least 25 Megawatt hour.

BUT if you take my DC capacity (29 KW & counting) against AC output, its a very low
number. That because the sun never hits all panels at the same time, and if it did,
there is no way to invert it all. So PVOutput using DC installation might put me in
the basement, I don't care. I'm not sure how your calculation worked.

I don't see a really good rating system for this sort of design, never heard this type
discussion before construction. But minimum panels initially were only a quarter of
the system cost, and more are a really good investment in cloud land. Bruce Roe

[J.P.M.]

As the longest day gets closer, the next 3 predicted clear days might get me that
10 SUN HOUR day. I suppose that means my inverters will only last 5 years instead
of 10, maybe can learn to fix them. I have a spare.

I don't have an account on line, the numbers appear on a pair of 7.5 KW Fronius
inverters, logged regularly in a notebook. If you click bcroe, view profile, about me,
you can find my PHOTOBUCKET link showing details in sub albums under album
ENERGY CONSERVATION.

With the most straightforward PV system located in sunny southern Cal, it might be
fine to list a system as so many KW. I prefer to list DC and AC limits. That starts
to matter when adding panel strings to compensate for the weather here in cloud
land. So a simple ratio of those numbers isn't the whole story.

I have ENOUGH AC capacity, and no way to expand it without replacing EVERYTHING.
The OBJECTIVE is to keep the inverters loaded as much of the time as possible. So
panels aimed at rising, midday, and setting sun do it, and bring mild overcast output
up to 60% to 80% of max. I have seen 4KW during a rain storm. A year will do at
least 25 Megawatt hour.

BUT if you take my DC capacity (29 KW & counting) against AC output, its a very low
number. That because the sun never hits all panels at the same time, and if it did,
there is no way to invert it all. So PVOutput using DC installation might put me in
the basement, I don't care. I'm not sure how your calculation worked.

I don't see a really good rating system for this sort of design, never heard this type
discussion before construction. But minimum panels initially were only a quarter of
the system cost, and more are a really good investment in cloud land. Bruce Roe

Bruce: Are your panels fixed or moveable ?