Heliostat Array Tracking Using Polarization and Intensity Ratios
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Solution Overview
Problem
Existing solar tracking systems fail to accurately determine the sun's position using a combination of light intensity, polarization, and color ratios, as they typically ignore polarization and treat all light colors uniformly, leading to inefficiencies in aligning heliostat mirrors with the sun.
Innovation Solution
A solar tracking system employing multiple cameras to capture images of polarized light and intensity ratios, using radial lines generated from polarization data and light intensity gradients to accurately determine the sun's position and reorient heliostat mirrors for optimal energy capture, incorporating both light intensity and polarization tracking methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor arrays integrate the entire spectrum of light without differentiating between colors, then the system structure is simple, but the measurement precision of sun position is insufficient
Solution Approach 1:
The patent divides the light spectrum into multiple color channels (red, green, blue) using separate sensors or filters for each channel. This segmentation allows the system to measure color ratios and intensity distributions across different wavelengths, enabling more precise sun position determination through chromatic aberration analysis and polarization detection.
Solution Approach 2:
The patent adds spectral dimension by measuring light intensity across multiple color channels (wavelengths) in addition to spatial dimension. By analyzing the ratio of intensities at different wavelengths and the polarization state of light, the system extracts additional information about the sun's position, transforming a 2D spatial measurement problem into a multi-dimensional measurement that includes spectral and polarization characteristics.
2Measurement precision
If sensor arrays ignore light polarization, then the device complexity is reduced, but the measurement precision of sun position deteriorates
Solution Approach 1:
The patent introduces polarization filters or polarizing beam splitters as intermediary components between the incoming light and the sensors. These intermediaries separate light based on polarization states, allowing the system to measure the polarization angle and degree of polarized light. This additional measurement dimension provides more accurate sun position determination, especially when combined with color ratio analysis.
3Productivity
If heliostat mirrors are not properly aligned with the sun, then the system operation is simpler, but the energy capture efficiency decreases
Solution Approach 1:
The patent implements a feedback control system where the measured color ratios and polarization angles from the sensor array are continuously compared with reference values corresponding to optimal sun alignment. The system automatically adjusts the heliostat mirror angles based on these measurements, creating a closed-loop control mechanism that maintains high energy capture efficiency by keeping the mirrors properly aligned with the sun throughout the day.
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
Enhances the accuracy and efficiency of solar tracking by ensuring heliostat mirrors are properly aligned with the sun, improving energy capture by utilizing a combination of light intensity and polarization data to center sunlight on the receiver aperture.
Implementation Method 1
determine orientations of maximal intensity of polarized light received from the at least one heliostat mirror
Implementation Method 2
track the sun based on the intensity of light, preferably the ratio of white light intensity to blue light intensity
Implementation Method 3
re-orient the at least one heliostat mirror based on the determined position of the sun
Data Source
AI summary
A tracking system for a solar collector is disclosed. The tracking system includes at least two polarization cameras and a tracking controller configured to: determine orientations of maximal intensity of polarized light received from the at least one heliostat mirror; generate radial lines based on the orientation of maximal intensity of polarized light from the at least one heliostat mirror; determine a position of the sun based on an intersection of the radial lines; and re-orient the at least one heliostat mirror based on the determined position of the sun. In the preferred embodiment, the sun position may be determined based on radial lines corresponding to three or more cameras mounted around the receiver aperture.