Sunlight Redirecting Mirror Arrays with Prismatic Sheet
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Solution Overview
Problem
Existing sunlight redirector systems face challenges in achieving efficient light redirection over a wide range of sun angles due to increased complexity and cost, particularly when trying to maintain thinness for building integration, and require a large number of mirrors that increase costs prohibitively.
Innovation Solution
A stationary sunlight redirector system comprising two mirror arrays and a prismatic sheet, where the mirror arrays are interconnected like Venetian blind slats and can be pivotally adjusted to maintain parallel normal vectors, with the prismatic sheet enhancing light redirection efficiency by refracting light rays into a desired direction, especially at problematic angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a large number of small mirrors are used to form a thin mirror array, then the thickness of the array is reduced for building integration, but the cost of constructing the array increases prohibitively
Solution Approach 1:
The mirror array is divided into multiple longitudinal segments that can be independently positioned. Each segment contains multiple mirrors arranged to redirect light from different sun angles. This segmentation allows the array to be thin while using fewer total mirrors, as each segment handles specific angular ranges efficiently.
Solution Approach 2:
The patent introduces longitudinal positioning of mirror segments as a new degree of freedom. Instead of only pivoting mirrors within a single plane, the segments can be positioned at different longitudinal locations along the array. This dimensional addition allows light redirection over a wider angular range with fewer mirrors, reducing both thickness and mirror count.
2Length of moving object
If the mirror array is made thin for building integration, then the array can be mounted on or within building walls, but the complexity and cost increase due to requiring a large number of mirrors
Solution Approach 1:
The array is segmented into longitudinal sections that can be independently adjusted. Each segment handles specific angular ranges, simplifying the control logic. The segmentation allows the thin array to achieve complex light redirection functions through coordinated movement of fewer segment groups rather than individual mirrors.
Solution Approach 2:
The patent employs dynamic positioning of longitudinal segments combined with pivotal mirror adjustment. The segments can be moved to different longitudinal positions and the mirrors within each segment can pivot. This dynamic multi-degree-of-freedom system enables a thin array configuration to achieve sophisticated light redirection with reduced overall complexity.
3Adaptability or versatility
If the mirror array uses a large number of mirrors to cover wide sun angles, then the angular range is improved, but the cost becomes prohibitive
Solution Approach 1:
The mirror array is divided into multiple longitudinal segments, each responsible for redirecting light from specific angular ranges. This segmentation allows the system to cover a wide total angular range using fewer mirrors per segment, reducing the overall mirror count while maintaining versatility across different sun positions.
Solution Approach 2:
By adding longitudinal positioning as an additional degree of freedom, the patent enables mirrors to serve multiple angular ranges. Mirrors can be repositioned longitudinally to handle different sun angles, allowing a smaller number of mirrors to achieve wide angular coverage that would otherwise require many more fixed-position mirrors.
4Measurement precision
If actuators are used to pivot mirrors for tracking the sun, then the light redirection accuracy is improved, but the device complexity increases
Solution Approach 1:
The actuator system is segmented to control longitudinal positions of mirror segments rather than controlling each individual mirror. This reduces the number of actuators required while maintaining positioning accuracy. Each segment group can be controlled by fewer actuators, simplifying the overall actuation system while preserving light redirection precision.
Solution Approach 2:
The patent uses dynamic coordination between longitudinal segment positioning and mirror pivoting. The system optimizes the combination of these two degrees of freedom to achieve accurate sun tracking. This dynamic approach allows the use of fewer actuators compared to systems that rely solely on mirror pivoting, reducing actuator complexity while maintaining redirection accuracy.
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
The system efficiently redirects sunlight over a wide range of angles with reduced complexity and cost by using a combination of mirror arrays and a prismatic sheet, improving light redirection efficiency and minimizing loss of useful light rays, even at challenging sun positions like solar noon.
Implementation Method 1
the prismatic sheet enhancing light redirection efficiency by refracting light rays into a desired direction
Implementation Method 2
the mirrors reflect incident light in a desired direction
Data Source
AI summary
Sunlight redirector (30) incorporates closely proximate mirror arrays (32, 34) having parallel, uniformly spaced, longitudinal mirror segments (38, 44). Prismatic sheet (36) is positioned behind and closely proximate second array (34). Segments (38) extend in first direction (x). Segments (44) extend in second direction (y) perpendicular to direction (x) segments (38, 44)have normal vectors (42, 48). Segments (38) are interconnected for simultaneous pivotal movement (40), such that their normal vectors (42) remain parallel. Segments (44) are interconnected for simultaneous pivotal movement (46), such that their normal vectors (48) remain parallel. Arrays (32, 34) redirect incident light toward sheet (36), which redirects the light into a desired fixed direction, e.g. parallel to the sunlight redirect's normal vectors (50). Segments (38, 44) may have inward and outward segments (60A, 60B) which can be adjustably positioned to maximize redirection of incident sunlight rays in a desired direction.