Heliostat Reflectivity Measurement Using Camera and Thermopile
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Solution Overview
Problem
Measuring the reflectivity of heliostat fields in solar thermal power systems is challenging due to the time-consuming and biased nature of existing methods, which often rely on handheld devices that only sample a subset of the solar spectrum and are prone to user error and contamination issues.
Innovation Solution
A system comprising a thermopile and a high-resolution camera with radiation shielding and a gimbal, connected to a control processing unit that calculates reflectivity estimates based on pixel analysis and energy absorption data, allowing for accurate measurement of reflectivity across a wider solar spectrum and reducing user bias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If handheld reflectometers are used to measure heliostat reflectivity, then the measurement process can be performed with simple equipment, but the measurement is time-consuming and subject to systematic biases
Solution Approach 1:
The patent combines a camera system with a thermopile sensor into an integrated measurement apparatus. The camera captures images of the heliostat and solar disc, while the thermopile simultaneously measures thermal radiation, allowing reflectivity measurement to occur in a single operation rather than requiring manual handheld measurements
Solution Approach 2:
The patent replaces manual mechanical measurement processes with an automated optical-thermal measurement system. The camera and thermopile system automatically captures and processes measurement data, eliminating the need for operators to manually position and read handheld reflectometers
2Ease of operation
If handheld reflectometers are used to measure heliostat reflectivity, then the equipment is simple to operate, but the measurements are subject to user bias and contamination issues
Solution Approach 1:
The measurement system performs self-calibration and self-measurement by using the camera-captured images to determine the solar disc position and the thermopile to measure thermal radiation. The system automatically calculates reflectivity from these measurements, eliminating user bias and the need for manual intervention that could introduce contamination or error
Solution Approach 2:
The patent introduces a camera as an intermediary to capture the solar disc image and determine its position, which then guides the thermopile measurement. This intermediary system ensures that measurements are taken at the correct location and time, preventing user error and systematic biases
3Device complexity
If standard handheld reflectometers are used, then the device is simple and portable, but it only samples a subset of the solar spectrum
Solution Approach 1:
The patent changes the measurement parameter from optical reflection only to thermal radiation measurement. The thermopile sensor detects thermal radiation across a broader spectrum, providing versatility in measuring reflectivity while accounting for different spectral characteristics that affect solar thermal power system performance
4Ease of manufacture
If manual handheld measurement methods are used, then the equipment is simple, but the process is expensive when considering time and labor costs
Solution Approach 1:
The patent enables continuous measurement capability where the camera and thermopile can rapidly capture and process multiple measurements in succession. The automated system eliminates the sequential, time-consuming nature of manual handheld measurements, allowing for efficient assessment of multiple heliostats or repeated measurements of the same target
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 system provides a more efficient and accurate method for measuring heliostat field reflectivity, reducing the need for manual sampling and accounting for systematic biases, thereby improving the assessment of solar flux delivery in solar thermal power systems.
Implementation Method 1
a thermopile, where the thermopile has radiation shielding
Implementation Method 2
the thermopile may have radiation shielding
Implementation Method 3
a camera configured to produce digital imagery
Implementation Method 4
The camera may have a neutral density filter
Implementation Method 5
The device may have at least one gimbal for re-orienting the device
Data Source
AI summary
Methods and systems for measuring heliostat reflectivity with a control processing unit configured to receive an image of a heliostat, receive an image of the Sun, process the received images, and determine a reflectivity estimate based on a comparison of the processed images.