Light Guide Facet Layout for Low-Loss Solar Concentration
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Solution Overview
Problem
Concentrated photovoltaic (CPV) systems face inefficiencies in light collection and emission due to interactions with light injection elements, leading to light loss through absorption, scattering, and out-coupling, which hinders the effective concentration and redirection of solar radiation for optimal energy conversion.
Innovation Solution
A light guide apparatus with a dimple layer and a primary light concentrator array, where the dimple layer features transverse cuts forming facets that redirect incident light through total internal reflection, allowing for efficient light propagation and concentration towards an output aperture, and an optional secondary concentrator enhances light coupling into a PV cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If light injection elements are used to concentrate solar radiation, then light concentration is improved, but light loss occurs through absorption, scattering, and out-coupling
Solution Approach 1:
The light injection element is divided into multiple discrete facets arranged in a specific geometric pattern. Each facet independently redirects light through total internal reflection, distributing the concentration function across multiple segments to reduce cumulative losses compared to a single large injection element.
Solution Approach 2:
Different regions of the light guide apparatus have optimized properties: the facets have specific orientations for optimal light redirection, the core has a higher index of refraction than the cladding to enable total internal reflection, and the output aperture is positioned and sized to maximize light delivery to the PV cell while minimizing losses.
2Quantity of substance
If PV material is reduced to lower cost, then system cost is improved, but light concentration efficiency may be compromised
Solution Approach 1:
The light guide apparatus performs preliminary concentration and directional control of solar radiation before it reaches the PV cell. The facets pre-redirect light into the core, and the total internal reflection mechanisms pre-concentrate the light along the light path, delivering highly concentrated light to the reduced PV material area, thereby maintaining efficiency despite reduced PV material quantity.
3Weight of moving object
If component weights and thicknesses are minimized, then system weight is improved, but light propagation efficiency may be reduced
Solution Approach 1:
The light guide apparatus uses a thin-walled tubular or planar structure with a core-cladding configuration similar to optical fibers. The thin walls and compact geometry minimize weight and thickness while the total internal reflection mechanism ensures efficient light propagation through the thin structure, maintaining reliability despite reduced dimensions.
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 solution achieves higher light concentration and redirection efficiency, reducing component and system weights, and costs, while maintaining manufacturing feasibility, resulting in improved performance and cost-effectiveness for CPV systems.
Implementation Method 1
the light injection elements are disposed outwardly at a rotation angle Δz bout the y-axis... each light injection element is disposed outwardly at a rotation angle Δz bout the y-axis... light propagation through the transport structure is hindered by interactions with downstream light injection elements. Light loss can occur by absorption or scattering at a light injection element, out-coupling of light at a light injection element
Data Source
AI summary
A light guide apparatus includes a light guide layer having a top surface and a bottom surface, and a transversely oriented side-end surface that forms an output aperture of the light guide, characterized by an index of refraction, n1, and further characterized by a length dimension in an intended light propagation direction towards the output aperture, where the intended light propagation direction is a z-axis direction of a Cartesian coordinate system; and a plurality of light injection elements disposed in the form of at least one linear strip in at least one of the top and bottom surfaces of the light guide layer, wherein some of the plurality of light injection elements are disposed on one lateral side of the strip and some other of the plurality of light injection elements are disposed on an opposing lateral side of the strip at a rotation angle Δz about the y-axis.