One year-round tilt vs seasonal tilts
> > > > We can adjust the altitude tilt-angle of
the modules for maximum intake of sun,
with these options (note- if a module was
standing 'straight up & down', that would
be 90 degrees, and if were laying flat on
most sidewalks, that would be 0°):
> > > > . . . for one best year-round average setting,
we can adjust all modules to a 34-degree tilt
(the latitude in L.A. area) from horizontal zero.
> > > > . . . for maximum output in summer months,
we can adjust tilt-angle back 10 to 15 degrees
from 34° to 19-24°, because the sun is higher
in the sky for that part of the year. This summer
adjustment is known as 'summer bias'.
> > > > . . . for maximum output in winter months,
we can adjust tilt-angle forward 10-15 degrees
from 34° to 44-49°, because the sun is lower
in the sky for that part of the year. This winter
adjustment is known as 'winter bias'.
(see example of tilt-angles 24°, 34°, and 44° below)
The goal of these changes: keeping the sun-to-
solar-panel's 'incidence angle' (a measure of
deviation of something from being "straight on"),
as close to 90° as possible as the sun changes
its place in the sky as the seasons change.
Many people have never noticed this:
At noon in the summer,
the sun is almost directly above you.
At noon in the spring and winter,
the sun is more south from being above you.
At noon in the winter,
the sun is even further south from being above you.
This should explain it:
Summer noon sun is high in the mid-sky,
Spring & fall noon sun is a bit lower,
Winter noon sun is low in the southern sky.
For those that want to make 4 adjustments per
year as to get the highest output: in spring the
tilt angle should be adjusted to equal your latitude;
in summer the tilt angle to equal your latitude,
minus 10 degrees; in fall the tilt angle to equal
your latitude; and in winter the tilt angle equal
to your latitude, plus 10 degrees.
With such adjustments, the maximal efficiency
could be continually obtained throughout the year.
This involves work, time, and expense;
so, most homeowners choose to instead
use just the one average setting of
their location's latitude, right in the middle.
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