Soiling Ratio Measurement Using Segmented PV Test Jig
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Solution Overview
Problem
Existing methods for measuring the effect of soiling on photovoltaic devices are prone to high uncertainty due to inherent differences between PV devices, leading to errors such as 4.5% in power loss calculations, and require intensive periodic assessments, making them impractical for long-term monitoring.
Innovation Solution
A device and method using a test jig with three measurement stations to measure a PV device under full exposure, clean conditions, and soiled conditions, employing electro-optical techniques to calculate a Soiling Ratio, which minimizes measurement errors and allows for accurate monitoring of power loss due to soiling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two PV devices are used to measure soiling by comparing power output, then direct measurement of power loss is achieved, but measurement uncertainty increases due to intrinsic differences between devices
Solution Approach 1:
The measurement process is segmented into three distinct states: (1) reference measurement with direct unobstructed light exposure, (2) clean cover measurement with transparent cover in place, and (3) soiled cover measurement with contaminated transparent cover. This segmentation allows systematic isolation and measurement of soiling effects while controlling for other variables.
Solution Approach 2:
A transparent cover is introduced as an intermediary element between the light source and the PV device. This cover can be maintained in clean condition for reference measurements and allowed to soil for soiling measurements, serving as a controllable mediator that isolates the soiling variable from other sources of measurement uncertainty.
2Measurement precision
If periodic in-lab PV assessment is performed to account for device differences, then measurement accuracy improves, but operational complexity and time requirements increase significantly
Solution Approach 1:
All necessary PV device assessments and characterizations are performed preliminarily in the laboratory before field deployment. Device-specific parameters such as quantum efficiency, angular response, thermal response, and parasitic resistances are measured and stored. This preliminary action eliminates the need for repeated complex assessments during field operations.
Solution Approach 2:
The laboratory assessment creates a digital copy or model of each PV device's electrical characteristics. This copied information is then used during field measurements to correct and interpret data, eliminating the need to physically handle and reassess the actual devices during monitoring operations.
3Measurement precision
If comprehensive PV device parameters are measured and corrected for in the field, then measurement accuracy improves, but operational time and resource requirements increase
Solution Approach 1:
All time-consuming PV device parameter measurements are performed in advance in the laboratory setting. The collected device-specific parameters are stored and automatically applied during field measurements through correction algorithms, reducing field operations to simple power output measurements under the three defined states.
Solution Approach 2:
Complex mechanical and procedural field assessments are replaced by computational corrections using pre-measured parameters. Instead of physically reassessing device characteristics in the field, the system uses stored electrical parameters and mathematical models to account for device-specific variations, substituting mechanical assessment procedures with computational methods.
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
The method provides accurate and practical in-field monitoring of soiling effects on PV devices, reducing uncertainties and operational costs, and is applicable to a wide range of mono-facial PV technologies, optimizing cleaning cycles and energy production assessments.
Implementation Method 1
the conversion of sunlight to electricity using a photovoltaic (PV) module that consists of electrically connected solar cells
Implementation Method 2
The transparent cover of the second compartment is adapted for a wide range of cleaning frequency (minutely, hourly, daily, etc.)
Data Source
AI summary
The device and method for measuring effect of soiling on a photovoltaic device includes a device in which a photovoltaic device (reference solar cell, solar cells, PV module, etc.) may be shifted between partially and fully enclosed compartments in quick succession for measurements of the same device (1) when directly exposed to illumination or solar radiation; (2) when placed under a glass or transparent cover maintained cleared or cleaned of soil; and (3) when placed under glass or transparent cover left exposed to natural outdoor soiling, or attenuated using simulated soil that is not periodically cleaned. The measurements may be of short circuit current (Isc), maximum power (Pmax), which are used to calculate the to soiling ratio. If the transparent covers have substantially identical optical properties and meet identical requirements for positioning relative to the DUT, only measurements (2) and (3) are required, and calculations of the soiling ratio are simplified.