Heliostat Beam Target Using Pyranometer Arrays for Long-Range Evaluation
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Solution Overview
Problem
Conventional methods for evaluating the beam reflected by a heliostat in solar power towers face challenges in accurately measuring irradiance at large distances due to beam divergence and ambient light interference, making it difficult to assess the beam's quality effectively.
Innovation Solution
A portable target equipped with a plurality of sensors, such as silicon-detector-based collimated pyranometers or pyrheliometers, is used to capture and measure the beam's characteristics, including irradiance, allowing for precise evaluation even at distances of up to a mile or more from the heliostat, with a computing device generating data on peak irradiance, total power, and irradiance distribution for performance analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the distance between the heliostat and the target surface increases, then the evaluation range is expanded, but the irradiance received at the camera decreases making it difficult to distinguish the beam from ambient light
Solution Approach 1:
The target surface is segmented into multiple photodetector elements arranged in an array, allowing the beam profile to be divided into discrete measurement zones. This segmentation enables accurate measurement of irradiance distribution even at large distances where the beam is highly divergent, as each detector element can independently measure local irradiance without being overwhelmed by ambient light.
Solution Approach 2:
A portable target equipped with photodetector elements serves as an intermediary device between the heliostat and the camera. This intermediary captures the beam characteristics directly through the photodetectors, which are sensitive enough to measure low irradiance levels at large distances, and then transmits this information to the camera system for visualization and analysis.
2Length of stationary object
If the distance between the heliostat and the target surface increases, then the evaluation range is expanded, but the beam divergence increases resulting in lower irradiance on the central collector
Solution Approach 1:
The measurement approach transitions from point-based irradiance measurement to a two-dimensional array of photodetectors that capture the spatial distribution of the beam profile. This dimensional expansion allows accurate characterization of divergent beams at large distances by measuring irradiance across multiple spatial zones simultaneously, maintaining evaluation accuracy despite beam divergence.
Solution Approach 2:
The traditional mechanical flux gauge measurement system is replaced with an electronic photodetector array that directly converts light intensity into electrical signals. This substitution enables more sensitive and accurate measurement of low irradiance levels at large distances, where mechanical gauges would be insufficient.
3Device complexity
If traditional photographic flux image technique is used, then the equipment is simple, but the ability to evaluate the beam deteriorates at large distances due to low irradiance and ambient light interference
Solution Approach 1:
The system merges the advantages of direct photodetector measurement with optical imaging by combining a photodetector array with a camera. The photodetectors provide precise quantitative irradiance measurements, while the camera captures the visual beam profile, creating a hybrid system that maintains measurement precision at large distances while preserving ease of operation.
Solution Approach 2:
The portable target with photodetector array serves multiple functions: it acts as a beam profiler, an irradiance meter, and a positioning reference simultaneously. This multi-functionality replaces the need for multiple separate measurement devices, maintaining equipment simplicity while significantly improving measurement precision at large distances.
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 accurate characterization of the beam's quality at greater distances than traditional methods, providing sensitive and reliable data for heliostat performance evaluation, facilitating adjustments and improving tracking accuracy.
Implementation Method 1
A portable target that includes a plurality of sensors is configured to capture the beam reflected by the heliostat... The plurality of sensors can include substantially any number of sensors. According to an example, the sensors can be silicon-detector-based collimated pyranometers or silicon-detector-based pyrheliometers.
Data Source
AI summary
Various technologies described herein pertain to evaluating a beam reflected by a heliostat. A portable target that has an array of sensors mounted thereupon is configured to capture the beam reflected by the heliostat. The sensors in the array output measured values indicative of a characteristic of the beam reflected by the heliostat. Moreover, a computing device can generate and output data corresponding to the beam reflected by the heliostat based on the measured values indicative of the characteristic of the beam received from the sensors in the array.