Bifacial Solar Module Orientation Using Sky and Ground Luminance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional solar tracker control methods based on direct sun orientation fail to maximize energy efficiency, especially in cloudy conditions and when considering diffuse solar radiation and albedo radiation, leading to performance deficits.
Innovation Solution
A method for controlling the orientation of a solar module that measures and accounts for both direct and diffuse solar radiation from the sky, as well as albedo radiation from the ground, using a single-axis solar tracker with photovoltaic devices on both faces, incorporating past measurements, forecasting, and energy consumption considerations to determine an optimal orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct orientation control based on sun position is used, then the solar module can track the sun's movement, but energy efficiency is reduced under cloudy conditions with diffuse radiation
Solution Approach 1:
The system uses luminance sensors to measure actual incident radiation from the sky and ground, providing feedback to the control unit. This feedback loop allows the system to adjust the module orientation based on real-time radiation conditions rather than relying solely on pre-calculated sun position, thereby maintaining high energy efficiency under both clear and cloudy conditions.
Solution Approach 2:
The control unit stores historical luminance measurements and forecasts future radiation trends in advance. By predicting upcoming radiation patterns and pre-adjusting the module orientation accordingly, the system proactively optimizes energy capture rather than reactively responding to changing conditions, improving overall productivity.
2Use of energy by moving object
If direct orientation towards the sun is used, then the upper face receives maximum direct radiation, but the lower face does not necessarily maximize albedo radiation
Solution Approach 1:
The system employs separate luminance measurement for both the sky (incident radiation) and ground (reflected albedo radiation). The control unit processes both measurements simultaneously to determine an optimal orientation that maximizes the combined energy production from both the upper and lower faces, rather than optimizing for only one face.
Solution Approach 2:
The system dynamically changes the orientation parameter (module tilt angle) based on real-time luminance measurements from both sky and ground sensors. By adjusting this parameter to optimize the sum of energy production from both faces rather than fixing it for direct sun tracking, the system simultaneously improves both upper face and lower face productivity.
3Productivity
If frequent orientation changes are made to follow optimal position, then energy capture is maximized, but mechanical wear and energy consumption increase
Solution Approach 1:
The control unit forecasts future radiation trends and determines optimal orientation in advance. By predicting when significant radiation changes will occur and only adjusting orientation when necessary to capture meaningful energy gains, the system reduces unnecessary mechanical movements, thereby decreasing wear and energy consumption while maintaining high energy capture.
Solution Approach 2:
Instead of continuously adjusting the module orientation to track every minor change in optimal position, the system applies partial action by making adjustments only when the predicted energy gain exceeds a threshold. This selective approach captures sufficient energy while significantly reducing mechanical operations and associated wear and energy consumption.
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 approach enhances energy production by optimizing the solar module's orientation based on comprehensive radiation analysis, reducing energy losses and improving efficiency across varying weather conditions.
Implementation Method 1
a photo-active upper face facing the sky and equipped with photovoltaic cells
Implementation Method 2
a photo-active lower face facing the ground and equipped with photovoltaic cells
Implementation Method 3
measurement of a distribution of solar luminance called incident emanating from solar radiation called incident
Implementation Method 4
measurement of a distribution of solar luminance called reflective emanating from solar radiation called albedo which corresponds to the reflection of solar radiation on the ground
Data Source
Figure 1(a)~2
Figure 3a~4
Figure 5~6
AI summary
Method for controlling the orientation of a solar module (1) comprising a single-axis solar tracker (2) orientable around an axis of rotation (A), and a photovoltaic device (3) supported by said tracker and having photoactive upper and lower faces, comprising the following steps: - measurement of a distribution of the solar luminance called incident solar radiation from the sky to reach the upper face, said distribution being established according to several angles of elevation; - measurement of a distribution of the solar luminance called reflective solar radiation from the albedo solar radiation corresponding to the reflection of solar radiation on the ground to reach the lower face, said distribution being established according to several angles of elevation; - determination of an optimal orientation taking into account the measurements of said distributions of the incident and reflective solar luminance;- controlling the module's orientation based on said optimal orientation.