scholarly journals Solar Tracking Error Analysis of Fresnel Reflector

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Jiantao Zheng ◽  
Junjie Yan ◽  
Jie Pei ◽  
Guanjie Liu
Keyword(s):  
Rotation Angle ◽  
Rotation Axis ◽  
Tracking Error ◽  
The Sun ◽  
Angle Error ◽  
Tracking Errors ◽  
Solar Altitude ◽  
Solar Tracking ◽  
Main Factors ◽  
The Difference

Depending on the rotational structure of Fresnel reflector, the rotation angle of the mirror was deduced under the eccentric condition. By analyzing the influence of the sun tracking rotation angle error caused by main factors, the change rule and extent of the influence were revealed. It is concluded that the tracking errors caused by the difference between the rotation axis and true north meridian, at noon, were maximum under certain conditions and reduced at morning and afternoon gradually. The tracking error caused by other deviations such as rotating eccentric, latitude, and solar altitude was positive at morning, negative at afternoon, and zero at a certain moment of noon.

scholarly journals The Impacts of Tracking System Inaccuracy on CPV Module Power

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1278
Author(s):  
Henrik Zsiborács ◽  
Nóra Baranyai ◽  
András Vincze ◽  
Philipp Weihs ◽  
Stefan Schreier ◽  
...  
Keyword(s):  
Tracking System ◽  
Tracking Error ◽  
Weather Conditions ◽  
Cell Diameter ◽  
Tracking Accuracy ◽  
Optimal Position ◽  
Climate Conditions ◽  
Solar Tracking ◽  
Power Yield ◽  
The Difference

The accuracy and reliability of solar tracking greatly impacts the performance of concentrator photovoltaic modules (CPV). Thus, it is of utmost significance to know how deviations in tracking influence CPV module power. In this work, the positioning characteristics of CPV modules compared to the focus points were investigated. The performance of CPV modules mounted on a dual-axis tracking system was analysed as a function of their orientation and inclination. The actual experiment was carried out with CPV cells of 3 mm in diameter. By using a dual tracking system under real weather conditions, the module’s position was gradually modified until the inclination differed by 5° relative to the optimal position of the focus point of the CPV module. The difference in inclination was established by the perfect perpendicularity to the Sun’s rays. The results obtained specifically for CPV technology help determine the level of accuracy that solar tracking photovoltaic systems are required to have to keep the loss in power yield under a certain level. Moreover, this power yield loss also demonstrated that the performance insensitivity thresholds of the CPV modules did not depend on the directions of the alterations in azimuthal alignment. The novelty of the research lies in the fact that earlier, no information had been found regarding the tracking insensitivity point in CPV technologies. A further analysis was carried out to compare the yield of CPV to other, conventional photovoltaic technologies under real Central European climate conditions. It was shown that CPV needs a sun tracking accuracy of at least 0.5° in order to surpass the yield of other PV technologies. Besides providing an insight into the tracking error values of solar tracking sensors, it is believed that the results might facilitate the planning of solar tracking sensor investments as well as the economic calculations related to 3 mm cell diameter CPV system investments.

scholarly journals Connecting measurements of solar and stellar brightness variations

2020 ◽  
Vol 638 ◽  
pp. A56
Author(s):  
N.-E. Nèmec ◽  
E. Işık ◽  
A. I. Shapiro ◽  
S. K. Solanki ◽  
N. A. Krivova ◽  
...  
Keyword(s):  
Transport Model ◽  
Rotation Axis ◽  
Surface Flux ◽  
Light Curves ◽  
The Sun ◽  
Solar Cycles ◽  
Stellar Rotation ◽  
Flux Transport ◽  
Surface Distribution ◽  
The Difference

Context. A comparison of solar and stellar brightness variations is hampered by the difference in spectral passbands that are used in observations, and also by the possible difference in the inclination of the solar and stellar rotation axes from the line of sight. Aims. We calculate the rotational variability of the Sun as it would be measured in passbands used for stellar observations. In particular, we consider the filter systems used by the CoRoT, Kepler, TESS, and Gaia space missions. We also quantify the effect of the inclination of the rotation axis on the solar rotational variability. Methods. We employed the spectral and total irradiance reconstruction (SATIRE) model to calculate solar brightness variations in different filter systems as observed from the ecliptic plane. We then combined the simulations of the surface distribution of the magnetic features at different inclinations using a surface flux transport model with the SATIRE calculations to compute the dependence of the variability on the inclination. Results. For an ecliptic-bound observer, the amplitude of the solar rotational variability, as observed in the total solar irradiance (TSI), is 0.68 mmag (averaged over solar cycles 21–24). We obtained corresponding amplitudes in the Kepler (0.74 mmag), CoRoT (0.73 mmag), TESS (0.62 mmag), Gaia G (0.74 mmag), Gaia GRP (0.62 mmag), and Gaia GBP (0.86 mmag) passbands. Decreasing the inclination of the rotation axis decreases the rotational variability. For a sample of randomly inclined stars, the variability is on average 15% lower in all filter systems we considered. This almost compensates for the difference in amplitudes of the variability in TSI and Kepler passbands, making the amplitudes derived from the TSI records an ideal representation of the solar rotational variability for comparison to Kepler stars with unknown inclinations. Conclusions. The TSI appears to be a relatively good measure of solar variability for comparisons with stellar measurements in the CoRoT, Kepler, TESS Gaia G, and Gaia GRP filters. Whereas the correction factors can be used to convert the variability amplitude from solar measurements into the values expected for stellar missions, the inclination affects the shapes of the light curves so that a much more sophisticated correction than simple scaling is needed to obtain light curves out of the ecliptic for the Sun.

The New Method of Solar Power Generation Using Spin Angle and Elevation Angle Program Control with LabVIEW

2013 ◽  
Vol 756-759 ◽  
pp. 650-654
Author(s):  
Qi Rong Lu ◽  
Lei Wang ◽  
Qi Lin Tang ◽  
Yu Jian Yang
Keyword(s):  
Tracking Control ◽  
Tracking Error ◽  
Elevation Angle ◽  
Control Mode ◽  
The Sun ◽  
Main Method ◽  
Solar Power Generation ◽  
Photovoltaic Efficiency ◽  
Solar Tracking ◽  
Angle Deviation

In order to reduce the power consumption of traditional tracking control, this article according to the tracking theory of spin new angle of elevation design of high precision two-axis solar tracking controller based on LabVIEW programming. The main method of control mode to calculate the position of the sun, using the S1337-1010BQ sensor to track the sun angle deviation automatic proofreading. According to the light intensity automatically adjust the reset program, can maximize the more light. After the test, a new tracking method tracking error is reduced, the photovoltaic efficiency is further improved.

scholarly journals Prototype System of Solar Tracking Design to Optimize the Energy Absorption Based on Arduino

2020 ◽  
Vol 3 ◽  
pp. 251-254
Author(s):  
Alex Wenda ◽  
Rendy Dwi Putra
Keyword(s):  
Solar Energy ◽  
Rotation Axis ◽  
Tracking System ◽  
Prototype System ◽  
The Sun ◽  
Test Results ◽  
Solar Panels ◽  
Tilt Axis ◽  
Solar Tracking ◽  
Microcontroller Unit

This research optimizes the absorption of solar energy in solar panels by designing mechanical systems that can move solar panels in the direction of incoming sunlight. Light-sensitive sensors are used to track the sun. The solar tracking system is designed using two axes, namely rotation axis and the tilt axis. Both axes are driven by servo motors based on light-sensitive sensors. The system was developed using an ATmega328 microcontroller unit. The test results found that using solar tracking the amount of energy produced was greater than static solar panels. Radiation generated between solar tracking and static sun can increase by 55.2%.

On the Tracking Error of a Self-Contained Solar Tracking System

1984 ◽  
Vol 106 (4) ◽  
pp. 416-422 ◽  
Author(s):  
A. Baz ◽  
A. Sabry ◽  
A. Mobarak ◽  
S. Morcos
Keyword(s):  
Solar Energy ◽  
Tracking System ◽  
Tracking Error ◽  
Design Parameters ◽  
Tracking Errors ◽  
Solar Tracking

This paper deals with the analysis of the tracking errors of a self-contained solar tracking system that is totally powered by solar energy. The effect of the different design parameters of the system on its tracking error is studied in detail, in an attempt to define the important factors that influence the system’s performance. The obtained results present valuable design guides for this class of tracking system.

The Sun as a Magnetic Star

1976 ◽  
Vol 32 ◽  
pp. 457-463
Author(s):  
John M. Wilcox ◽  
Leif Svalgaard
Keyword(s):  
Recent Work ◽  
Rotation Axis ◽  
Polar Field ◽  
Magnetic Star ◽  
Rotational Axis ◽  
Field Variation ◽  
The Sun ◽  
Arbitrary Angle ◽  
Solar Magnetism ◽  
Oblique Rotator

SummaryThe sun as a magnetic star is described on the basis of recent work on solar magnetism. Observations at an arbitrary angle to the rotation axis would show a 22-year polar field variation and a 25-day equatorial sector variation. The sector variation would be similar to an oblique rotator with an angle of 90° between the magnetic and rotational axis.

scholarly journals Window dressing in the Active Share scores in publicly reported portfolios

2021 ◽  
pp. 234094442110246
Author(s):  
Laura Andreu ◽  
Carlos Forner ◽  
José Luis Sarto
Keyword(s):  
Positive Relationship ◽  
Tracking Error ◽  
Jel Classification ◽  
Tracking Errors ◽  
Window Dressing ◽  
Future Performance ◽  
Money Flows

Using a unique database that includes publicly disclosed fund holdings at the end of the quarter as well as the holdings in all non-publicly disclosed months, we found that some funds could alter their portfolios in publicly disclosed months to artificially increase their Active Share scores and consequently appear more active and take advantage of the positive relationship between Active Share and money flows. We show how, consistent with non-informed trades, these funds erode their future performance. However, these funds reach their objective of increasing future money flows. Moreover, we find that window-dresser funds can be identified by controlling the level of tracking error. The funds with high Active Share scores and low tracking errors have the highest levels of Active Share window dressing and the worst future returns. However, compared with less active funds, they are able to capture higher money flows. JEL CLASSIFICATION G23; G11

Research on Physical MPPT of Photovoltaic Array System Based on Image Processing

2013 ◽  
Vol 321-324 ◽  
pp. 1138-1144
Author(s):  
Chao Liu ◽  
Jing Hui
Keyword(s):  
Image Processing ◽  
Tracking Error ◽  
Elevation Angle ◽  
Image Sensor ◽  
Azimuth Angle ◽  
Field Of View ◽  
The Sun ◽  
Photovoltaic Array ◽  
Point Tracking ◽  
Power Point

Based on analyzing the development and the performance feature of existing solar tracker, we propose a solar Maximum Power Point Tracking (MPPT) strategy which combines photoelectric sensor and image processing. Firstly, photoelectric tracking mode positions the sun in the field of view of the image sensor. Then, the position of the sun image is captured by the image sensor. After that, we can find the coordinates of the sun spot in the field of view through image binarization processing. According to the number of steps of stepper motor rotation which is calculated by the deviation of coordinates, the controller drives the biaxial photosensitive (PV) array tracking device, making the sun spot always fall in the centre of the image. Tests show that the elevation angle and azimuth angle of the tracking range of the photovoltaic array are both 0～270°.The average tracking error of elevation angle is less than 0.7°, and the average tracking error of azimuth angle is less than 0.5°.

On the factorization of rotations with examples in diffractometry

1990 ◽  
Vol 428 (1875) ◽  
pp. 451-472 ◽  
Keyword(s):  
Rotation Angle ◽  
Rotation Axis ◽  
Axial Direction ◽  
The Other ◽  
Rotation Vector ◽  
Coordinate Transformations ◽  
Rotation Axes ◽  
Analytic Expressions ◽  
Direction Cosines

An analysis of compound rotations, such as occur in eulerian cradles, is presented in terms of a calculus of rotation axes, without reference to the associated coordinate transformations. The general case of three rotation shafts mounted on one another, with any relation between them at datum zero, is presented. The problem and its solution may be represented entirely in terms of a plane octagon in which four sides have directions that are instrumental constants and the other four sides have lengths that are instrumental constants. When the first four sides are given lengths that express both the rotation angle and the axial direction of the required rotation, then the remaining four sides have directions that directly express the rotations in the drive shafts, that will generate the required rotation. Analytic expressions are given for the shaft setting angles in the general case. If the first and third axes are parallel and the intermediate one perpendicular to these at datum zero (as in the four-circle diffractometer) then these reduce to θ 1 = arctan ( μ, σ ) + [arctan ( λ , v ) - ψ -½8π], θ 2 = 2 s arcsin ( λ 2 + v 2 )½, θ 3 = ( μ, σ ) - [arctan ( λ , v ) - ψ - ½8π], s = ± 1, 0 ≤ arcsin ( λ 2 + v 2)½ ≤ ½π, in which λ, μ, v and σ are the four components of a rotation vector constructed such that λ, μ and v are the direction cosines of the rotation axis multiplied by sin½ θ for a rotation angle θ and σ is cos½ θ . ψ is a constant determined by the choice of directions to which λ and v are measured. The results for the general case are also expressed in terms of more conventional variables.

Data Fusion of Total Solar Irradiance Composite Time Series Using 40 years of Satellite Measurements: First Results 

2021 ◽  
Author(s):  
Jean-Philippe Montillet ◽  
Wolfgang Finsterle ◽  
Werner Schmutz ◽  
Margit Haberreiter ◽  
Rok Sikonja
Keyword(s):  
Time Series ◽  
Data Fusion ◽  
Solar Irradiance ◽  
Total Solar Irradiance ◽  
Maunder Minimum ◽  
The Sun ◽  
Climate Reconstructions ◽  
The Earth ◽  
First Results ◽  
The Difference

<p><span>Since the late 70’s, successive satellite missions have been monitoring the sun’s activity, recording total solar irradiance observations. These measurements are important to estimate the Earth’s energy imbalance, </span><span>i.e. the difference of energy absorbed and emitted by our planet. Climate modelers need the solar forcing time series in their models in order to study the influence of the Sun on the Earth’s climate. With this amount of TSI data, solar irradiance reconstruction models  can be better validated which can also improve studies looking at past climate reconstructions (e.g., Maunder minimum). V</span><span>arious algorithms have been proposed in the last decade to merge the various TSI measurements over the 40 years of recording period. We have developed a new statistical algorithm based on data fusion.  The stochastic noise processes of the measurements are modeled via a dual kernel including white and coloured noise.  We show our first results and compare it with previous releases (PMOD,ACRIM, ... ). </span></p>

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