Cylindrical Cassegrain Solar Collector With One-Axis Sun Tracking
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Solution Overview
Problem
Existing solar concentrators for photovoltaic systems either require costly two-axis tracking mechanisms or suffer from inefficiencies due to limited concentration factors and complex optical requirements, making them impractical for residential applications and costly to manufacture.
Innovation Solution
A cylindrical Cassegrain optical system with planar symmetry is used to concentrate sunlight onto a line of photovoltaic cells, allowing for simple one-axis tracking and achieving high concentration factors exceeding 20× with modest optical quality requirements, thus reducing manufacturing costs and maintaining high electrical conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two-axis tracking mechanisms are used to focus concentrated light on photovoltaic cells, then light concentration and electrical energy production are improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent employs asymmetric optical geometry where the抛物面 reflector focuses sunlight onto a linear photovoltaic cell array rather than a point, enabling one-axis tracking to achieve sufficient concentration. This asymmetric arrangement decouples the tracking complexity from the focusing requirement, resolving the contradiction between high productivity and low device complexity
Solution Approach 2:
The invention transitions from point-focus (0D) to line-focus (1D) geometry, adding a dimensional aspect to the photovoltaic cell arrangement. This dimensional change allows the system to achieve high concentration factors with simpler one-axis tracking, maintaining electrical energy production while reducing tracking mechanism complexity
2Device complexity
If simple solar concentrators without tracking are used, then device complexity and manufacturing cost are reduced, but concentration factors are limited to 2-3× and light focusing efficiency deteriorates
Solution Approach 1:
The patent introduces dynamic one-axis tracking capability to an otherwise simple concentrator design. The rotational degree of freedom allows the抛物面 reflector to continuously adjust its orientation, maintaining optimal sunlight concentration throughout the day. This dynamic element enables concentration factors exceeding 20× while keeping the overall device complexity low
Solution Approach 2:
The invention optimizes geometric parameters of the抛物面 reflector and linear cell array arrangement to achieve high concentration factors. By carefully selecting the focal length, aperture size, and cell spacing parameters, the system attains concentration factors >20× with modest optical tolerances, resolving the contradiction between simplicity and productivity
3Productivity
If high concentration factors are achieved with complex optical systems, then photovoltaic cell area savings increase, but manufacturing precision requirements and cost increase
Solution Approach 1:
The patent segments the photovoltaic cells into a linear array positioned along the focal line of the抛物面 reflector. This segmentation allows the optical system to distribute concentrated sunlight along a line rather than requiring a single point focus, reducing the stringency of optical precision requirements while maintaining high concentration factors and achieving significant cell area savings
Solution Approach 2:
The invention accepts modest optical tolerances in the抛物面 reflector construction, prioritizing cost-effective manufacturing over perfect optical precision. By designing the system to function effectively with less precise optics, the patent reduces manufacturing costs while still achieving concentration factors >20× and substantial photovoltaic cell area reduction
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 efficient and cost-effective solar energy conversion by leveraging a smaller area of photovoltaic cells with excellent light focusing and tracking, suitable for residential, commercial, and industrial applications, while maintaining low maintenance costs and aesthetic considerations.
Implementation Method 1
The bottom of the collector has a cross section that is substantially that of an upward facing parabola... The inner surface of the top of the collector has a bulge... The cross section of the inner surface of this bulge is a parabola... A reflective coating is applied to the inner surface of this bulge which forms a convex mirror surface... A reflective coating is also applied to the inner surface of the bottom of the collector except for the region directly below the convex mirror... which forms a gap in the reflective coating
Implementation Method 2
concentrate the sunlight on a line of photovoltaic cells... focusing of the concentrated light onto surfaces of the photovoltaic cells... electrical conversion efficiency
Data Source
AI summary
A low-cost solar collector employs a concave reflecting surface and a convex reflecting surface configured as a cylindrical Cassegrain optical system with planar symmetry to concentrate sunlight for photovoltaic solar panels. The collector achieves high concentration factors exceeding 20× and maintains focus of concentrated sunlight on the photovoltaic cells using a simple mechanical means to rotate the collector. A plurality of solar collectors is arranged in parallel in a conventional solar panel form factor and driven by a single drive system to maintain the sun continuously in the plane of symmetry of each of the solar collectors that comprise the solar panel. This reduces the area of photovoltaic cells required to convert a given quantity of light energy to electrical energy. Cost of electrical energy generated is reduced significantly because the cost per unit area of the solar collectors is much less than the cost of photovoltaic cells.