Solar Panel Angle Considerations and performance implications

Solar Panel Angle Considerations and performance implications


(“The Good, the Bad and the
Ugly Theme” by Ennio Morricone ) – [Instructor] Alright, I
thought I’d do a little follow up on this solar panel angle considerations with a graphic here that
kind of tells the story that might make it easier
for people to understand. So here we are near the spring equinox. What happens there is the
sun, all over the world, regardless of your location, the sun’s gonna come up due east, and it’s gonna set due west. As it’s rising up, at solar noon, the angle that it’ll
be above your location will be equal to your latitude. You’ll have, essentially,
a twelve hour day. Twelve hours of sunlight,
twelve hours of night. If you compare that to the winter, the sun comes up south of
east, is shallower in the sky, and at the winter solstice, December 21st, it’ll be about 23 and a half degrees down, which is the tilt angle of the Earth, below your latitude. At sunset, the sun will
go down south of west in many locations. If you look, the number of
hours that the sun is up in the wintertime is much shorter. Now, if we compare that to
what’s gonna happen this summer, and that’s what we’re setting up for now, see the sun can come up
much more north of east, will end up much higher in the sky, and at the summer solstice, it will be up to 23 and a half degrees
above your normal latitude, and then will set much more north of west. Now if I take a look at my
example here with Minnesota, our sun on the summer solstice
will rise at 55 degrees, which is to the east, north east, travel through the sky,
then it’ll set at 305. So much more north of west. The problem is, if you have
a set of fixed solar panels facing due south like you should, maybe set up at your normal latitude or maybe a little higher
for your summer setting, the panels still will
not be exposed to the sun for many hours. Matter of fact, it will
probably be around seven AM before the angle of the
sun is such that the panels will be exposed to light. The same things happens in
the other part of the day. More like at 14 hours in
is where the sun will stop shining on the panel, and
when you get to due west then you won’t get any of the panel. So that’s a good reason
to consider some strategy to be able to take advantage
of the sun as it’s on the east side as well as on the west side by either having staggered
panels or some kind of tracker set-up. Now if I look at the monocrystalline
solar panel power curve that I drew the other
day, which is basically, this is the kind of
performance you’ll get out of a standard monocrystalline,
polycrystalline kind of solar panel, where it’ll
at solar noon, facing south, will get 100% of its available power. Then either side of that
will get less power. You can tell, I put on
these one hour hash marks, since the Earth rotates
at 15 degrees per hour. You can see one hour before noon, what percent of the
power would be available, two hours before noon, how
much power you’ll get out. You can use this chart to
get an estimate of either how much power you should be getting with an ideally placed solar panel, or a set of panels that
are not exactly aligned with where the sun is,
because this also works east and west as well as north and south. The panel doesn’t really care. The other thing I’ve
added on here is if you, I’ve added some hash marks
where you can determine at the four hour point, how
much power you can get out. In this case, no matter
where you have this panel, if it’s pointing right towards the sun, you can get four hours worth only at above 83% available power. Looking at a six hour perspective, you’ll get up to 63%
of the available power. You can tell that solar panels only have a certain range that
they can capture a lot of the sun power, they’re not ideal. Anyway, I’ll put a version
of this as a graphic in the description area. You can download it for your purposes. It’s a good, handy tool
to use to determine if the kind of power you’re
getting out of your panels is what you expect, because
what might be happening is there’s nothing wrong with
your system other than your panel may not be
pointing exactly towards where the sun is in the
sky on the day you’re doing your measurements. I wanted to put this
chart together for myself. I can also use it to show other people, tell them about how a solar panel works. You’re welcome to use it
for your own purposes. So have a good day.

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