This is the principle of a North / South oriented cylindroparabolic mirror
Morning: 90 ° angle to the local horizontal to the East
Noon: 0 ° angle
Evening: 90 ° angle to the West.
Or a 180 ° angular movement to manage.
The angle does not vary linearly, and as the concentration systems require a very precise aiming (less than 1 °), you cannot run a motor on the 50Hz with gears which go well as for orienting a large PV panel.
"We know how to do that" with small photovoltaic cells which generate a voltage which passes through a relay and will supply the motor, or by direct programming of the angle.
The only one I know of is a 4-quadrant tracker that has a pointing accuracy of 0,1 °. It is marketed by Cimel for a star spectrometer.
http://www.cimel.fr/photo/pdf/ce318_fr.pdf
It is a "4 quadrant", that means that there are 4 PV cells from which we take the vertical / horizontal potential differences to go to supply the motors of azimuth and height. As long as it is not aligned, the 4 cells give different voltages and the motors run for alignment, then the more it is aligned, the less the ddps are strong: auto-control on the position of the sun.
Joyjoy recently said that he made something with a thermistor or something. This is what he explained to me in MP.
joyjoy wrote:well this is how I solved the problem, it's quite expensive anyway,
I use stepper motors.
the principle for each axis:
an impulse is given a little ahead of one step and from one axis to the other at 90 °, a rise in temperature then makes sense, otherwise it changes direction and sees if the temperature rises.
the control is simple, based on L297 and L298.
all with logics, and a single bpw54 which points to the focus
just the servo but for the return of the evening no meter is yet installed, remains to interface it with a measurement of the motors.
to make it a wind control: my parabola "bends" but does not break, rather it makes the weather vane ..;)
I can give the plans but for the moment they are others that interest me. and then via this debate question losses by IR retransmission of the hearth that it is also very interesting to go in this direction
and see from this point of view if a white glass (a kind of pyrex)
in front of the fireplace if it would decrease the direct energy will let less go
by incidence in the afterlife ...; the greenhouse effect, because this fireplace is still less hot than the sun's rays ...
I'm going to do these tests because the idea is good,
as well as rethinking effective insulation ... the wind is particularly responsible.
here are some pictures: see you soon ..
But solar tracking for concentrating systems is an area where few professionals venture and there are, to my knowledge, no consumer products.
Either it's home-made DIY, or it's hyper-product, or both.
