Sun Azimuth Angle Research Articles

Design of double axis solar automatic light tracing device based on cloud platform

Solar energy is a widely distributed and inexhaustible "green" renewable new energy, which is one of the best solutions to the energy crisis in the world. However, the conversion efficiency of photovoltaic cells in large-scale solar applications is not high, and the cost is very high. Therefore, in order to increase the power generation capacity and efficiency of solar power generation, automatic tracking power generation devices should be used to replace fixed solar photovoltaic panels and other solar equipment. This design proposes a two axis solar tracking system based on the Internet of Things cloud platform. This system uses the sun viewing motion tracking method to drive photovoltaic panels in horizontal and vertical directions to track the sun. The preset tracking angle of the system is based on the sun azimuth angle and altitude angle operation rules calculated and collected by the sun angle calculation software, and combined with weather data to find the best angle for real-time tracking. This design will elaborate the design process from the aspects of system overall scheme design, hardware circuit design and host computer software development.

Fotovoltaiklerin ve Güneş Kollektörlerinin Özel Aletler ve Yöntem ile Konumlandırılması ve Gölge Faktörünün Jeodezik Yöntemle Araştırılması

In order to be able to be injured from the PV panel at an inclined angle with a horizontal plane at a certain incline, they must be turned approximately to the south. But, it is difficult to obtain maximum efficiency from November to March when the sun's rays are more oblique than in the summer. In order to benefit from the sun in the given months, the solar PV panel must be positioned between the maximum and minimum values of the sun azimuth angle. In addition, shadow analysis should also be done in the panel setup. In this work, how to position the PV panel from 150g to 250g in solar azimuth angle to achieve maximum benefit, it was researched how to do shadow analysis in order to prevent the fragmented lake situation, the related numerical application was made, the findings obtained were indicated and the suggestions were presented.

The comparison of dual axis photovoltaic tracking system using artificial intelligence techniques

<span>In this paper, the efficiency of photovoltaic panels is improved by adding a sun tracking system. The solar tracking system is used for tracking the sun so that photovoltaic always faces the sun. This system uses a dual axis consisting of horizontal rotation axis and a vertical rotation axis. The horizontal rotational axis motion is to follow the azimuth angle of the sun from north to south. Then, to follow the sun's azimuth angle from east to west is the vertical axis motion. Both types of movements are controlled using a PID controller that is optimized with an artificial intelligence approach, namely particle swarm optimization (PID-PSO), firefly algorithm (PID-FA), imperialist competitive algorithm (PID-ICA), bat algorithm (PID-BA), and ant colony optimization (PID-ACO). Experiments of various approaches were carried out and the corresponding performance compared. The experimental results show that PID-BA performs best in terms of settling time and overshoot. The results also allow the comparison of different PID controller and the calculation of the fastest completion time.</span>

HYBRID SYSTEM OF DUAL AXIS PHOTOVOLTAIC TRACKING SYSTEM USING PID-CES-ACO

In this paper, the efficiency of photovoltaic panels is improved by adding two solar tracking systems. The solar tracking system is used to track the sun so that the photovoltaic always faces the sun. This system uses a dual axis consisting of a horizontal rotation axis and a vertical rotation axis. The motion of the horizontal axis of rotation follows the sun's azimuth angle from north to south. The motion of the vertical axis of rotation following the sun's azimuth angle from east to west is the vertical axis motion. Both types of movement are controlled using PID and Fuzzy controllers which are optimized with an artificial intelligence approach, namely Ant Colony Optimization (ACO). Experiments with PID control approach and CES control were optimized using the ACO method (Hybrid PID-CES-ACO method). In this research, PID-CES-ACO was the best model, obtained on the horizontal axis of overshot 1328 pu, the smallest undershot was 0.116, and the fastest settling time was 0.183 s, on the vertical axis the smallest overshot was 1.246 pu, the smallest undershot was 0.044, the fastest settling time was 0.163 s

Hybrid System of Dual Axis Photovoltaic Tracking System Using ANFIS-ACO

In this paper, the efficiency of the photovoltaic panels is improved by adding two solar tracking systems. The solar tracking system is used to track the sun so that the photovoltaic always faces the sun. This system uses a dual axis consisting of a horizontal rotation axis and a vertical rotation axis. The motion of the horizontal axis of rotation follows the sun's azimuth angle from north to south. Then to follow the sun's azimuth angle from east to west is the vertical axis motion. Both types of movements are controlled using PID and Fuzzy controllers, which are optimized with an artificial intelligence approach, namely Ant Colony Optimization (ACO). Experiments with PID control, Fuzzy control, and ANFIS control approaches optimized by the ACO method (ANFIS-ACO Hybrid method). The experimental results show that ANFIS-ACO has the best performance in terms of settling time and overshoot.

Sensorless dual axis solar tracker using improved sun position algorithm

This paper presents development of a prototype sensorless dual axis solar tracker for maximum extraction of solar energy. To prove the concept and evaluate the proposed algorithm, a low cost widely availabe materials were used which was programmed based on Arduino microcontroller. The porposed algorithm works based on two search methods namely the global search that approximates the best point location in a region, and local search that further determines the actual sun’s position. Experimental results showed that the proposed algorithm gives better performance compared to the existing sun position algorithm (SPA) - based method as well as the fixed panel system. In terms of total output power, the proposed algorithm gives 17.96% more efficient than the fixed system and 6.38% better than the SPA-based system. Furthermore, the percentage error of the experimental measured angle to the actual sun azimuth angle was relatively minimal (less than 3%) during clear day operation. The system was proven to be effective in tracking the sun for improved energy production of solar PV panels and the proposed algorithm also can be used for designing the tracker with larger size of solar PV systems.

A Spherical Temperature Sensor Array Design for Near-Surface Atmospheric Temperature Studies

AbstractThe observation accuracy of the surface air temperature less than 0.1 K is a requirement, stated by the meteorological and climatological community. However, the accuracy of a temperature sensor inside a shield is affected by a number of factors including solar radiation, wind speed, upwelling longwave radiation, air density, sun elevation angle, sun azimuth angle, underlying surface, precipitation, moisture, structure, and coating of the radiation shield. Due to these factors, the temperature error of the temperature sensor may be much larger than 1 K under adverse conditions. To improve the observation accuracy, this paper proposed a spherical temperature sensor array. A series of analytical calculations based on a computational fluid dynamics (CFD) method is performed to verify the design principle of this sensor array. The calculation results show that the temperature error ratio can be assumed as a constant. To verify the accuracy of this sensor array, simulations and observation experiments are conducted. The simulation results show that the mean difference between the temperature provided by this sensor array and the reference air temperature is 0.072 K. The field experiment results show that a root-mean-square error (RMSE) and a mean absolute error (MAE) between the temperature provided by this sensor array and the reference air temperature are 0.173 and 0.153 K, respectively.

Evaluation of Topographic Correction on Subpixel Impervious Cover Mapping With CBERS-2B Data

This study compared the effectiveness of six commonly used topographic correction methods for subpixel impervious surface mapping in selected mountainous areas of Southwest Virginia. One 2008 China–Brazil Earth Remote Sensing 2B (CBERS-2B) image was processed using selected topographic algorithms and then used as input for subpixel impervious cover mapping. High-resolution National Agriculture Imagery Program (1-m resolution) images were used to build proportional subpixel impervious cover as training/validation data. We then applied a classification and regression tree algorithm to establish relationships between CBERS signals and impervious surfaces. Accuracy assessment showed that both $R^{2} $ (0.644–0.767) and RMSE (0.118–0.150, reported as proportion of impervious surface) values vary across different topographic correction algorithms. The accuracy differences ( $R^{2} $ : 0.448–0.771; RMSE: 0.118–0.247) were most pronounced for areas facing away from the sun azimuth angle, suggesting aspect–sun azimuth-dependent map accuracy. For terrain shadowing areas, the Minnaert method, the minslope method, and the C-correction substantially outperformed the cosine and improved cosine correction. These findings indicate that users should apply caution in using topographic correction algorithms and that aspect-stratified accuracy assessment needs to be conducted for detailed comparisons. We also repeated the analyses using Landsat TM and obtained better overall results compared to the CBERS-2B data. The differences in $R^{2} $ (or RMSE) for two data sources were not substantial, suggesting the high potential of CBERS data for subpixel impervious surface mapping.

Algorithm for Removing Thick Clouds in TM Image Based on Spectral and Geometric Information

A new cloud removal algorithm based on spectral and geometric information is proposed for generating cloud free and cloud-shadow free mosaic image from multi-temporal TM images.At first,single image and multi-temporal images of thick cloud and cloud-shadow multi-spectral detection models are built based on TM spectral characteristics analysis.Secondly,cloud is detected according to spectral characteristics,and then a technique is applied based on coupled geometrical relationship between the cloud and its shadow by using sun azimuth angle,sun elevation angle and statistical distance between cloud and its shadow so as to automatically predict the approximate location of cloud-shadow.After that,erosion filtering and dilation filtering are used sequentially in the cloud and cloud-shadow fraction image to eliminate the small bits and generate the exact zones contaminated by cloud and cloud-shadow.At last,the cloud and cloud-shadow zones of the target image are replaced by the same-location cloud-free zones on reference images whose spectral information is matched with the target image by the linear regression method.The results show that this algorithm is capable of eliminating the cloud influence from TM image significantly.Moreover,it can effectively eliminate the influence of water body and hill shadow on cloud-shadow.This method can therefore support producing cloud removal images in a quick,simple and applicable way.

Correction of aircraft pyranometer measurements for diffuse radiance and alignment errors

A method is outlined whereby the orientation of upward pointing pyranometers on an aircraft is fully characterized. The incoming solar flux is corrected by means of a method that incorporates the fact that the flux is composed of partly diffuse and partly direct radiation. After the angle correction is found, a practical method is outlined to find the pyranometer normal with respect to the aircraft normal. It uses the heading of the aircraft and the position of the sun to adjust the pyranometer to the aircraft horizontal level. While the method is general enough to be used for any aircraft, it is applied here specifically for the National Center for Atmospheric Research C‐130 aircraft in the configuration flown during the First Aerosol Characterization Experiment (ACE 1). It was found that when the difference between the sun azimuth angle and the aircraft heading is near either 0° or 180°, special care has to be taken in interpreting the incoming flux, as it is enhanced by a few percent due to reflections off elements of the aircraft frame.

Model evaluation and optimum collector slope for a tropical country

Various models proposed in the literature, viz. the Beam method, proposed by Morse & Czarnecki; two methods proposed by Liu & Jordan, using hourly values and average daily values of solar radiation: and Klucher's method are compared in this paper using measured hourly values of global and diffuse radiation on a horizontal surface and the total radiation on a tilted surface. It was observed that the model proposed by Klucher estimates the radiation more consistently with the experimental observations for clear as well as cloudy sky conditions. This method was used for predicting the year round radiation availability on (i) a fixed collector inclined at an optimum tilt, (ii) a partially tracking collector in which the slope is fixed but following the sun's azimuth angle, and (iii) a fully tracking collector. In this analysis, measured values of hourly global and diffuse solar radiation on a horizontal plane for four widely separated Indian stations, viz. Delhi (28°38′N), Poona (18°29′N), Calcutta (22°36′N), and Madras (13°8′N) as per India Meteorological Department classification for climatic analysis, have been used. With the model proposed, the radiation availability on different slopes for all the twelve months of the year for a fixed and partially tracking collector have been evaluated and optimum tilts for various seasons of a year for different solar energy applications for all the four Indian stations have been determined. For a typical winter month at New Delhi in the semi-arid zone of India, a fixed collector, a partially tracking collector and a fully tracking collector receive 60, 80 and 95% more radiation compared to that received on a horizontal plane respectively. Another observation is that the variation of the insolation received on inclined surfaces is not at all sensitive to the angle of tilt in the neighbourhood of the optimum angle of operation.