Ben Goren via EV wrote:
...and it's worse than even that. The angle from the Sun to the
panels matters a great deal. A panel at right angles to the incoming
light receives the maximum amount of energy; a panel parallel to the
light receives zero energy.
Agreed. There are some tricks, though.
Some solar car designs had aerodynamic shapes that were *mostly* flat,
to maximize the panel area presented to the sun. Some had panels that
folded out when parked, to get more area when wind resistance wasn't an
issue.
Conceptually, a vehicle could be very long or very tall, to get
additional area while staying within the "footprint" of a normal
vehicle. A vehicle could even change its shape dynamically, depending on
how the car was positioned relative to the sun. Or use movable panels
inside a fixed transparent aerodynamic shell, or use adjustable mirrors
to concentrate the light on the cells.
But overall, the amount of power you can get from the sun in a
normal-sized is very limited. That pretty much forces you to concentrate
on vehicle efficiency. Extremely light, with exceptionally good
aerodynamics and very high efficiency components (tires, motor,
controller, etc. At least, that's how the solar cars have all done it.
You don't have much choice about the angles the panels of a car make
with the light. Fixed panels, on the other hand, can either be
statically positioned for an optimum annual average production or, if
money isn't an object and space is at a premium, you can dynamically
tilt the panels to follow the Sun.
For the car...well, ideal geometry for the panels is going to be a
flat top parallel to the ground, but that's a geometry bordering on
the pathological for aerodynamics.
It works well for airplane wing, though. :-)
--
Sometimes when you innovate, you make mistakes. It is best to admit
them quickly and get on with improving your other innovations.
(Steve Jobs)
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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