Off-axis cassegrain solar collector
Assignee3M Innovative Properties Company
InventorsDavid G. Freier, Timothy L. Quinn, Thomas R. Corrigan, Byron E. Trotter
Life of this patent
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Abstract
The disclosure generally relates to concentrating daylight collectors and in particular to concentrating daylight collectors useful for interior lighting of a building. The concentrating daylight collectors generally include a cassegrain-type concentrator section that provides for a full-tracking solar collector with one moving part and with a high efficiency of coupling of collected solar irradiation to a stationary duct. In some cases, the disclosed concentrating daylight collectors can be used more conventionally, such as for directing sunlight onto a photovoltaic cell for generation of electrical power, or an absorbing surface for extraction of thermal energy.
Claims21
A solar collector, comprising:
- a parabolic reflector having a vertex, a parabolic focal point, and a first axis therebetween;
- and
- a hyperbolic reflector having a first focal point coincident with the parabolic focal point, a second focal point, and a second axis including the first and second focal points;
- wherein the first axis can be aligned at an elevation angle and an azimuth angle without movement of the second axis, such that solar radiation incident upon the parabolic reflector and reflecting from the hyperbolic reflector, propagates within an output collimation angle of the second axis,
- further comprising an exit aperture disposed in the parabolic reflector, along a line passing through the vertex of the parabolic reflector, wherein the exit aperture comprises a slot that extends to a rim of the parabolic reflector.
A solar collector, comprising:
- a parabolic reflector having a vertex, a parabolic focal point, and a first axis therebetween;
- a hyperbolic reflector having a first focal point coincident with the parabolic focal point, a second focal point, and a second axis including the first and second focal points;
- an exit aperture disposed in the parabolic reflector and on a plane defined by the first and second axis;
- and
- a light duct disposed along the second axis;
- wherein the first axis can be aligned at an elevation angle and an azimuth angle without movement of the hyperbolic reflector or the light duct,
- wherein the exit aperture comprises a slot that extends to a rim of the parabolic reflector.
A solar collector, comprising:
- a parabolic reflector having a vertex, a parabolic focal point, and a first axis therebetween;
- a hyperbolic reflector having a first focal point coincident with the parabolic focal point, a second focal point, and a second axis including the first and second focal points;
- an exit aperture disposed in the parabolic reflector and on a plane defined by the first and second axis;
- and
- a light duct disposed along the second axis;
- wherein the first axis can be aligned at an elevation angle and an azimuth angle, and at least one of the hyperbolic reflector and the light duct rotates around the second axis,
- wherein the exit aperture comprises a slot that extends to a rim of the parabolic reflector.
Dependencies are inferred from the claim text.