Hemisphere Diffuse Solar Irradiance Sensor With Uniform Aperture Shading
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Solution Overview
Problem
Existing solar radiation sensors struggle to accurately separate and measure diffuse solar irradiance due to complex shading patterns and require multiple calibrations, leading to diminished accuracy in total solar irradiance measurement, especially for assessing photovoltaic system performance.
Innovation Solution
A sensor with a well-defined, easily reproducible shading pattern and transparent apertures on a hemisphere, allowing near-uniform transmission of diffuse radiation, combined with light-sensitive sensors arranged near the center to ensure consistent shading from direct sunlight, facilitating accurate separation of diffuse and direct irradiance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a complex irregular shading pattern is used to ensure both shaded and lighted sensor conditions, then measurement capability is improved, but manufacturing complexity increases and measurement accuracy diminishes
Solution Approach 1:
The sensor array is segmented into multiple individual sensors arranged in a grid pattern, with each sensor independently measuring radiation through apertures. This segmentation allows the system to achieve both shaded and unshaded measurement conditions without requiring a complex irregular shading pattern, as the aperture geometry itself provides the necessary measurement differentiation.
Solution Approach 2:
Instead of using an irregular opaque shading pattern to create measurement conditions, the invention inverts the approach by using a regular transparent aperture pattern with opaque background. This inversion simplifies manufacturing while maintaining the ability to distinguish between direct and diffuse radiation through geometric relationships between apertures and sensors.
2Adaptability or versatility
If both shaded and lighted sensor conditions are required simultaneously, then measurement versatility is improved, but calibration complexity increases
Solution Approach 1:
The sensor array is positioned at a specific distance from the aperture plane where all sensors experience equivalent measurement conditions. This equipotential positioning ensures that each sensor receives a consistent ratio of direct to diffuse radiation, simplifying calibration while maintaining the ability to measure both radiation types through the regular aperture pattern.
Solution Approach 2:
The regular grid pattern of apertures and sensors creates homogeneous measurement conditions across the sensor array. Each sensor operates under similar geometric relationships with the aperture plane, allowing for simplified uniform calibration procedures while still enabling differentiation between direct and diffuse radiation measurements.
3Ease of manufacture
If a regular aperture pattern is used instead of irregular shading, then manufacturing ease is improved, but measurement precision must be maintained
Solution Approach 1:
The measurement precision is maintained by transitioning to a three-dimensional geometric relationship between the aperture plane, sensor array, and radiation sources. The specific spacing and positioning in the third dimension (distance from aperture plane) create unique viewing angles that preserve measurement accuracy for diffuse irradiance while allowing regular two-dimensional aperture patterns for simplified manufacturing.
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
Enables precise measurement of diffuse solar irradiance with improved accuracy and ease of calibration, allowing reliable assessment of photovoltaic system performance by separating direct and diffuse components.
Implementation Method 1
a transparent aperture pattern providing a near-uniform transmission of the diffuse radiation as seen from near a center of the hemisphere
Implementation Method 2
under any position of the sun relative to the sensor at least one of the two or more light-sensitive sensors is shaded from direct solar radiation by the hemisphere with aperture pattern
Implementation Method 3
two or more light-sensitive sensors arranged in an array near the center of the hemisphere
Data Source
AI summary
The invention shows a sensor for measuring diffuse solar irradiance including: an hemisphere having an approximately 2π steradian solid opening angle with a non-transparent layer and a transparent aperture pattern, the transparent aperture pattern providing a near-uniform transmission of the diffuse radiation as seen from near a center of the hemisphere, an aperture being an area occupying a part of the hemisphere surface area that is smaller than 2% and two or more light-sensitive sensors arranged in an array near the center of the hemisphere such that under any position of the sun relative to the sensor at least one of the two or more light-sensitive sensors is shaded from direct solar radiation by the hemisphere with aperture pattern.