US 4,223,214 A · Solar tracking device

Abstract

An improved solar tracking arrangement is provided for directing a solar energy collector to face the sun. An electrical control mechanism is provided to detect misalignment of the collector as the sun traverses in relative movement across the sky. When the misalignment exceeds an adjustable limit of tolerance, the tracking system moves the collector to an orientation slightly in advance of the current position of the sun by an amount equal to the limit of tolerance. A threshold light level is required to activate the tracking system, and differential photosensors are employed, the composite signals of which compensate for variations in ambient light level so that the amount of surrounding illumination of the environment does not effect the preset limit of tolerance. The tracking system includes east and west limit switches, which reorient the collector to an eastward facing direction at the end of each day. A high temperature cut off is provided to direct the collector away from the sun when the operating temperature of the collector exceeds a predetermined limit of safety. For self-contained operation, photovoltaic cells are mounted on the collector to provide electricity for the tracking system.

Claims15

Dependent claims

A tracking system for orienting a solar energy collector toward the sun comprising:

unshielded photosensitive means exposed to direct solar radiation for detecting misalignment of a solar energy collector relative to the sun beyond a preselected limit of tolerance and for generating output signals from each of said photosensitive means,
means for providing an error signal proportional to the ratio of the difference between the output signals of said photosensitive means to the sum of the output signals of said photosensitive means,
means responsive to said error signal to realign said collector relative to the sun to a position in advance of the normal orientation of the collector relative to incident radiation to anticipate solar movement, whereby said means responsive to said error signal remains inactive for the duration of an interval during which the sun undergoes relative movement with respect to said collector from a position trailing the orientation of said collector to a position leading the orientation of said collector, and
means for altering said preselected limit of tolerances uniformly relative to a plane perpendicular to said collector.

1 more element

Dependencies are inferred from the claim text.

Solar tracking device

Life of this patent

Solar tracking device

Life of this patent

Abstract

Claims15