Photodetector Array Alignment for Solar Concentrator Mirrors
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Solution Overview
Problem
Solar concentrators require precise orientation towards the sun to maintain high efficiency, but existing solutions that integrate shadow-casting means into the detector structure are prone to errors due to misalignment of the housing, complicating optimal alignment.
Innovation Solution
A photodetector array is mounted across the centerline of a curved mirror to detect the shadow cast by an energy collector, creating an energy profile that indicates optimal alignment when the mirror is correctly oriented, allowing for correction of any misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If shadow-casting means are integrated into the detector structure, then alignment detection is enabled, but misalignment of the housing causes errors in alignment detection
Solution Approach 1:
The system separates the shadow-casting function from the detection function by using the energy collector (which casts the shadow) as a distinct component from the photodetector array (which detects the shadow). This segmentation eliminates the housing misalignment problem because the photodetectors only need to detect shadows cast by the energy collector, not generate shadows themselves.
Solution Approach 2:
The shadow cast by the energy collector serves as an intermediary between the sun's position and the photodetector array. Instead of the housing structure directly participating in shadow generation (which causes alignment errors), the shadow acts as a mediator that carries alignment information to the detectors without requiring precise housing alignment.
2Quantity of substance
If solar concentrators use curved mirrors to focus sunlight, then fewer photocells are required, but precise orientation toward the sun becomes critical
Solution Approach 1:
The system uses the energy collector itself (the same component that needs to be aligned) to cast the shadow for detection. This self-referential approach allows the system to automatically detect its own alignment status without requiring external reference structures or complex housing alignment mechanisms.
Solution Approach 2:
The system detects changes in light intensity distribution (analogous to color changes) across the photodetector array. When the concentrator is misaligned, the shadow position shifts, creating a detectable pattern of light intensity variations that indicate the direction and magnitude of misalignment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables precise and accurate alignment of solar concentrators with the sun, minimizing errors and maintaining high efficiency by using a sensor array to detect and correct deviations from the optimal energy profile.
Implementation Method 1
a first array of at least three light sensitive elements arranged successively one after another along a first linear direction, wherein each respective one of said elements has an output adapted to provide a respective output signal responsive to light impinging on said respective element
Implementation Method 2
uses curved mirrors to reflect and focus incident sunlight onto a solar converter
Implementation Method 3
curved mirrors to reflect and focus incident sunlight onto a solar converter such as a photocell or fluid pipe coupled to a heat exchanger
Implementation Method 4
The solar energy collector is configured to cast a shadow along a central axis of the curved mirror when the mirror is at an optimum orientation with respect to the sun
Data Source
AI summary
In a solar concentrator of a type having a curved mirror adapted to focus light onto an energy collecting body mounted at the mirror's focal axis, an alignment correction apparatus and method includes a linear array of light detectors adapted to be mounted at a bottom of and across a centerline of the curved mirror so as to intercept the shadow cast by the energy collecting body mounted along the focal axis. Outputs of each of the detectors are measured and plotted according to an order of arrangement of the light detectors on the array. The output results in a dip across adjacent detectors when a shadow falls across the array. A shadow detection means is adapted to determine a center point of the dip and correction means are configured to output a correction command if the center point is different from an optimal position.