Solar Heliostat: A device capable of reflecting sunshine in a constant direction throughout the day. |
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We build solar heliostats
that are guided by dual axis optical solar tracking electronics. The analog solar tracking circuit
controls two mechanical actuators that move a mirror plane in two axes. The mirror plane will reflect the sun to a stationary target during the day and then
return to a preset morning position after sunset. The tracking electronics are capable of tracking the sun with sub degree accuracy. This heliostat has nine 1' sq programmable mirrors delivering 9X concentrated solar power (CSP) to a fixed target. The sun delivers approximately 1000 watts/m2 so a one sq-ft mirror can be expected to redirect around 80 watts of power after reflective losses. This heliostat can direct around 700 watts of CSP to a 1 square foot target. This energy can be used for heating, lighting and electric generation. |
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After an 80 Mph sand storm at Burning Man the heliostat is still tracking. It is clear from this photo that heliostat fields in the dessert present the real issue of dirty mirrors decreasing reflectivity and efficiency, just like in the movie Sahara. This heliostat is being powered by a small 12 volt garden tractor battery being recharged by a 5 watt solar battery charger. The dual axis solar tracking circuitry consumes only 8 milliamps of current , each actuator draws about 500 milliamps at 12 volts. In 8 hours each actuator operates for about 3 minutes tracking the sun and then returning to the morning preset position. On average each heliostat consumes about .2 watts. This suggests that a five watt solar panel could provide enough power for a field of 25 of these heliostats. |
