Beam-Down Secondary Mirror Layout for Lower Optical Loss
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Solution Overview
Problem
In solar energy plants, the 'beam-down' configuration faces challenges with optical enlargement and increased maintenance costs due to the use of curved secondary reflectors, which lead to larger receiver surfaces and additional optical losses, and plane mirrors require complex supporting structures and may cause mechanical integrity issues.
Innovation Solution
A secondary optical system comprising multiple plane mirrors arranged at different heights and distances from the vertical axis, each associated with a sub-section of primary heliostats, concentrating solar rays to a single secondary focus, reducing optical enlargement and maintaining high efficiency while minimizing the size of the secondary reflector and its supporting structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If curved secondary reflectors are used to concentrate solar radiation in beam-down configuration, then the receiver surface area is reduced, but optical enlargement occurs leading to larger impression and additional optical losses
Solution Approach 1:
The patent divides the single curved secondary reflector into multiple plane mirror segments arranged in a specific geometric configuration. Each plane mirror segment reflects solar radiation from a corresponding primary heliostat subgroup to the common receiver, eliminating optical enlargement while maintaining concentration efficiency and reducing energy losses.
2Loss of energy
If plane mirrors are used as secondary reflectors to avoid optical enlargement, then optical losses are reduced, but complex supporting structures are required and mechanical integrity issues arise
Solution Approach 1:
The patent merges multiple plane mirror segments into a unified geometric arrangement where all segments share a common focal point and are supported by an integrated structure. This combination reduces the overall complexity compared to supporting a single large curved reflector, while maintaining the optical advantages of plane mirrors.
3Power
If the power of the plant is increased to improve energy generation, then the surface occupied by heliostats and receiver height increase proportionally, but installation and maintenance complexity and costs increase
Solution Approach 1:
The patent inverts the traditional beam-down configuration by placing the receiver at ground level instead of at height, and using plane mirrors at elevated positions to reflect radiation downward. This inversion allows the receiver to be easily accessible for maintenance while the plane mirror segments can be positioned at optimal heights for radiation collection, decoupling plant power scaling from receiver accessibility issues.
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 configuration enhances the collection efficiency of solar radiation, reduces thermal losses, and decreases the size of the secondary reflector and its supporting structure, resulting in lower investment and maintenance costs while ensuring high operating safety.
Implementation Method 1
a secondary optical system suitable to collect the solar radiation collected (reflexed) by a primary optical system arranged at the ground and to direct (reflect) such solar radiation towards a receiver
Data Source
AI summary
The present invention provides a secondary optical system (3) able to increase the efficiency in collecting the solar radiation concentrated by primary mirrors (2) in "beam-down" plant configurations. Such secondary optical system is formed at least by two reflectors (31-38)- preferably in form of plane mirrors arranged at different heights - oriented so as to associate to each one thereof a subsection of a primary field of heliostats. Such plurality of secondary reflectors - each one associated to a different primary focus F1,i (i = l,...,n) corresponding to a subset of primary concentrators - allows concentrating the solar rays towards a single secondary focus F2.