Axis Tracking Research Articles

Performance of Solar Module with Presence of Two Types of Reflectors in Concentrator System

Any work to improve the performance of the solar modules could add to their economic competitiveness against fossil fuels. In the present work the performance of PV solar module was improved by using V-Trough concentrator system (CPV) which moved by two axis tracking system. The concentrator consists of two flat reflectors of area 2 m2 for each one with geometric concentration ratio of 2X. To optimize the performance of the V-Trough CPV systems, two types of reflector material, Aluminum and mirror (glass coated by silver nitrate) were used. The results indicated that the temperature of PV reference module was higher than the ambient temperature by 27oC but there is too small difference in temperature between the tracking PV module with the reference which ranged to 2oC, while the temperature of the CPV system was higher than reference by 37oC. The temperature of the PV module under mirror reflectors was lower than module combined with Aluminum reflectors by 3oC. As a result of arising of the temperature of CPV system in compare with PV reference module, the open circuit voltage was droop by 0.7 V, 0.5 V for PV module under mirror and Aluminum reflectors respectively. The reflectors increased the short circuit current values by 2.1 A, 2.6 A for PV module combined with mirror and Aluminum reflectors respectively. Accordingly the performance (as an average daily gain of output power) of the PV solar module was improved by using V-Trough CPV system, 44%, 34% by using Aluminum and mirror reflectors respectively.

A Study on Implementation of PV Tracking for Sites Proximate and Away from the Equator

The performance of photovoltaic (PV) system depends upon the orientation and the site climatic conditions. Solar PV tracking systems align the modules perpendicular to the incoming solar radiation. In this paper, six locations with latitudes 0° through 55° were selected to investigate the PV system performance using single-axis (horizontal and vertical) and two-axis tracking systems compared to the fixed south-oriented PV system. It was found that single-axis (vertical axis) tracker optimally tilted is the most promising for sites near the equator and achieves around 19% more energy output over the fixed south-oriented solar panel system. Moreover, it is considered simpler compared to the two-axis tracking system. It is true that the two-axis tracking system could harvest around 4% more energy than the vertical axis tracker optimally tilted system for sites near and far from the equator. However, such increase in energy may not sound feasible as the two-axis system is consuming more power for tracking and considered more complicated compared to the vertical axis tracking system. The novelty of this work is that, it introduces a new concept for the optimum tilt for the single-axis (vertical axis) tracking system.

Vortex axis tracking by iterative propagation (VATIP): a method for analysing three-dimensional turbulent structures

Vortex is a central concept in the understanding of turbulent dynamics. Objective algorithms for the detection and extraction of vortex structures can facilitate the physical understanding of turbulence regeneration dynamics by enabling automated and quantitative analyses of these structures. Despite the wide availability of vortex identification criteria, they only label spatial regions belonging to vortices, without any information on the identity, topology and shape of individual vortices. This latter information is stored in the axis lines lining the contours of vortex tubes. In this study, a new tracking algorithm is proposed which propagates along the vortex axis lines and iteratively searches for new directions for growth. The method is validated in flow fields from transient simulations where vortices of different shapes are controllably generated. It is then applied to statistical turbulence for the analysis of vortex configurations and distributions. It is shown to reliably extract axis lines for complex three-dimensional vortices generated from the walls. A new procedure is also proposed that classifies vortices into commonly observed shapes, including quasi-streamwise vortices, hairpins, hooks and branches, based on their axis-line topology. Clustering analysis is performed on the extracted axis lines to reveal vortex organization patterns and their potential connection to large-scale motions in turbulence.

Monopulse Comparators [Applicaton Notes

In radar systems, antennas serve two purposes: transmitting and receiving the information required for searching or tracking a target. Various techniques are used for these purposes, including lobe switching, conical switching, and monopulse tracking. Among these, the monopulse tracking technique is useful because it offers high speed, high accuracy, and target estimation using a single pulse [1]. However, it requires a set of two or four similar antennas, depending on the tracking axis, to determine the angular position and distance of a target. A feed network known as a monopulse comparator is required to process the collected information. This makes the monopulse comparator a key element in determining monopulse tracking performance.

Simulation and performance analysis of concentrating photovoltaic/thermal collector (CPV/T) with three-sided thermal insulation based on coupled optothermal model

The present paper is focused on drawing a high performance modeling and computation of a low concentrating collector combined into a Photovoltaic/Thermal system. A 3-D computational model based on 3D-4Rays technique and volume finite method is developed. The collector consists of a trough parabolic concentrator of a 20× concentration rate and two axis tracking system. The absorber is composed of a square duct in which Triple-junction PV cells are connected in series into its lower surface and a three-sided insulated multi-layer water channel, which acts as a cooling system introducing heat recovery capability.A steady pressure-driven laminar flow of a Newtonian fluid is assumed with constant properties inside water microchannel. This coupled model is initially used to simulate and analyze the temperature distributions within the PV cells, and then the thermal and electrical behavior of the proposed system. The results of the coupled model are compared with the analytical model in terms of thermal and electrical performances, such as PV cell temperature, electrical efficiency, and outlet water temperature. In addition, the impact of non-uniform illumination on the PV solar cells is also investigated. The results of the analysis indicated that a discontinuity of the thermal conductivity along the absorber tube duct, post shading and non-uniformities of PV cells temperature distributions causes a reduction in thermal efficiency of slightly more than 6% while significantly effecting the overall electrical performance.

Sensitivity analysis and propagation of uncertainty for the simulation of vehicle pass-by noise

The study presented in this paper aims at developing an aid to the modeling of the pass-by noise of a vehicle, as called for in regulatory testing. The goal is to accurately predict and evaluate noise emissions earlier in the vehicle development cycle, i.e. before the industrialization stage. For these reasons, a synthesis model is developed. This model combines the acoustic flow of the most influent sources (powertrain, intake, exhaust tail, exhaust line, tire/road noise), with the acoustic transfer between these sources and the microphone located at 7.5 m from the axis of the test track, taking into consideration the motion of the vehicle. The input parameters of these models are considered uncertain; therefore, an uncertainty quantification study is first performed. These uncertainties are then propagated in these models using quasi-Monte Carlo methods. Finally, a sensitivity analysis study is carried out to study the impact of the variability of the input parameters on the variability of the output noise levels of the synthesis models. Influential parameters have been identified and classified by vehicle family.

Design and Structural Analysis of the Sun Ray Double Axis Tracking Device

To improve the solar energy utilization in the photovoltaic power, the sun ray double axis tracking device is designed and its tracking method is introduced. Using the finite element method, the parameterized analysis model is built and the static calculation is performed in different conditions for the device. The design feasibility of the device is verified by evaluating the stress. The lightweight of the device is made on the premise that the design satisfies the intensity and this provides the basis for manufacturing the prototype. The sun's rays tracing experiment is carried out by the prototype. Results show that the device design is reasonable and meets the design requirements; the key working conditions for the solar tracking design are found; the lightweight is obvious and the weight is reduced by 14%; the average errors of azimuth angle and height angle are within 5 deg; compared with the fixed device, the increasing proportion of solar energy one day is up to 52.6%; and the device works steadily and has good mechanical properties.

Design and Performance Evaluation of a Dual-Axis Solar Tracking System for Rural Applications

Most rural dwellers in developing countries do not have access to adequate and regular supply of energy and most of these estimated two billion people are poor with no sustainable means of livelihood and therefore rely on wood fuel for their cooking and heating needs. And due to lack of energy, including electricity, socio-economic development is either absent or at abysmally low level. To foster rural development and improved living conditions among this populace, there is need for a reliable, low cost and environmentally risk-free source of energy. This work designed, implemented and evaluated the performance of a dual axis solar tracking system (DATS) using light dependent resistor (LDR) sensors, direct current (DC) motors and microcontroller to make it capable of uninterruptible electricity supply for rural applications. Results of the experiment show that the proposed system is more cost-effective and produces 31.4 % more energy than the single axis tracking system (SATS) and 67.9 % more than the fixed PV panel system (FPPS). Owing to the unique design of the proposed tracking system, solar energy can be tracked and stored continuously so that there is adequate electricity for the consuming population at all times. Though tested on a rural community in Abia State, Nigeria, the proposed system can be adapted to rural communities anywhere in the world.

Experimental investigation of 16 square meter Scheffler concentrator system and its performance assessments for various regions of India

An experimental investigation of 16 square meter Scheffler concentrator system with automatic polar axis tracking has been carried out. Various test sequences were performed under quasi-steady-state to analyze various parameters like optical efficiency and thermal characteristics of the system. The paper mainly focuses on the experimental analysis of 16 square meter Scheffler concentrator system and its performance assessment for various regions of India such as New Delhi, Leh-Ladhak, Madurai, and Mumbai. It is studied that, the optical efficiency of the system is achieved up to 59% and the convection heat losses (W/m2K), radiation heat losses coefficient (W/m2K2) are 2.2 and 0.001 respectively. The performance of the system was also studied based on various reflectivity (i.e. 84% and 95%) of the solar-grade mirror and various selective coating (i.e. Silicon based high-temperature coating and black paint). The performance characteristic of the system is also investigated on a seasonal basis i.e. equinox, winter and summer solstice.

Kinematic Measurement of the Railway Track Centerline Position by GNSS/INS/Odometer Integration

Accurate absolute measurement of existing lines is a task of fundamental importance to provide scientific basis for reconstruction. Traditional railway track survey methods in combination with classical geodetic surveying apparatus such as total stations cannot meet the requirements of surveying efficiency. Accurate, reliable and fast existing railway surveying applications call for an innovative method that can obtain high-precision, continuous and uniform railway track axis position in short time without interrupting the railway traffic. This paper provides an innovative solution to track axis surveying based on the integrated technique of global navigation satellite system (GNSS), inertial navigation system (INS) and odometer. GNSS/INS/odometer system does not depend on a high-precision track control network, which can operate in mobile surveying mode and significantly improve the measuring speed from 0.15 km/h to 5 km/h compared to conventional methods. Compared with satellite surveying methods, this solution for the measurement of existing line axis can obtain continuous and high-precision results in the absence of satellite signals. The results of field tests on the Zhengzhou-Xuzhou high-speed railway track show that the measurement errors are less than 0.6 cm and 1.1 cm in horizontal and vertical directions, respectively, and this measuring system is able to maintain high precision of 5 cm with a GNSS outage of 700 s, which can meet the accuracy requirements of China Specifications for Survey Engineering of High-speed Railway and serve visualization, assessment and design process of existing railways.

Dynamic Characteristics and Experimental Research of a Two‐Span Rotor‐Bearing System with Rub‐Impact Fault

Rotor rub‐impact has a great influence on the stability and safety of a rotating machine. This study develops a dynamic model of a two‐span rotor‐bearing system with rubbing faults, and numerical simulation is carried out. Moreover, frictional screws are used to simulate a rubbing state by establishing a set of experimental devices that can simulate rotor‐stator friction in the rotor system. Through the experimental platform and its analysis system, the rubbing experiment was conducted, and the vibration of the rotor‐bearing system before and after the critical speed is observed. Rotors running under normal condition, local slight rubbing, and severe rubbing throughout the entire cycle are simulated. Dynamic trajectories, frequency spectrum diagrams, chart of axis track, and Poincare maps are used to analyze the features of the rotor‐bearing system with rub‐impact faults under various parameters. The vibration characteristics of rub impact are obtained. Results show that the dynamic characteristics of the rotor‐bearing system are affected by the change in velocity and degree of impact friction. The findings are helpful in further understanding the dynamic characteristics of the rub‐impact fault of the two‐span rotor‐bearing system and provide reference for fault diagnosis.

Review of dual axis solar tracking and development of its functional model

The use of solar energy is in the upswing due to its environmental friendliness and abundance. That notwithstanding, efficiency remains a major problem in many of the applications. Mitigation is normally in the form of tracking systems. This paper therefore investigates dual axis solar tracking systems from two dimensions. Firstly, a review of extant literature was conducted to draw up a trajectory of where we are in the efficiency map, Therefore it was found that the current efficiency of dual axis tracking configuration is about 35-43%. Secondly, from the above review, a generic functional model of how an efficient and effective tracking system should be is presented. The two components, coevolving, shall be used to inform the design and development of an efficient solar tracker.

A Review on Solar Tracking System: A Technique of Solar Power Output Enhancement

The renewable energy is a source of energy that does not deplete with time, because of this most of the research focused on this source of energy. Solar energy is among the renewable energy that is free in nature and clean from pollution, but harnessing this energy has limitation due to some environmental conditions. To solve this problem, solar tracking is used. This paper intended to review different solar tracking system that increases the solar power output. The result revealed the solar system with tracking is more efficient compared to that fixed solar system. Furthermore, dual axis tracking system is also more efficient than single axis tracking system due to the fact that dual axis tracking system have ability to track the solar irradiant on both axes. Finally, it is not recommended to use solar trackers with small PV arrays because of the energy consumption of the driving systems, which vary from 2% to 3% of the energy increase delivered by the solar trackers.

Research on Analysis Method of Shading and Blocking of LFR Field

Shading and blocking problem is the main element restricting efficiency of a LFR system. The traditional analysis methods often need to build the models by using SolTrace, which results in the low efficiency. According to characteristics of single axis tracking of the LFR field, a plane right-angle coordinate system was established, and coordinate equations of reflectors at any time were deduced. Lengths of shading and blocking were got by tracking sun rays which fell on the reflectors and reflected the receiver passing through the adjacent reflector endpoints at any time. Offset caused by the solar azimuth in the shading and blocking area was got by geometrical optics. And then, the shading and blocking efficiency could be calculated. For the Puerto Errado 1 solar thermal plant, the shading and blocking efficiencies on vernal equinox hardly changed; on summer solstice, they were smaller at sunrise and sunset, and gradually stable and close to the value of spring equinox with the increase of solar altitude angle; they were smaller on winter solstice and the change with time were larger. The results of the calculations were good agreement with the simulation dates of SolTrace, and validity of the method was proved.

ПРИМЕНЕНИЕ БЕСПИЛОТНЫХ ЛЕТАТЕЛЬНЫХ АППАРАТОВ ДЛЯ ИСПОЛНИТЕЛЬНОЙ СЪЕМКИ ЖЕЛЕЗНЫХ ДОРОГ

The as-built survey of railways is one of unmanned aerial vehicle (UAV) application fields. Digital surface models (DSM) are the results of UAV survey data processing. Concerning railways, they are used for receiving information about railway track position and distance between tracks, obstruction clearance, for generating longitudinal and cross profiles. For generating high accuracy DSM, regularly distributed control and check points within a survey area are necessary to be used. As these points rail track axis points, measured during a hardware-software system «Profile-M» movement, can be used. The goal of the article is the accuracy study of DSM generation whose ex-ternal orientation was carried out with railway track axis points measured with this hardware-software system.

Analysis of the possibilities in railways shape assessing using GNSS mobile measurements

In recent years, a dynamic development of satellite positioning techniques using both static and mobile GNSS coordinates register mode can be observed. In addition, still developing Real-time GNSS Networks, post-processing algorithms and another measurement signal analysis algorithms, make the satellite measurements increasingly used in railway industry sector. In the article the possibilities which follows from the mobile satellite measurements in railway engineering are briefly presented. In the years 2009-2015, the authors conducted a series of field investigations on operated railway lines. The obtained results of these measurements led to the development of a number of algorithms that increase the range of applicability of GNSS measurements. The analysis of obtained results also showed how the accuracy of the measurements have increased since 2009. The achieved accuracy has been increased due to a development of GNSS positioning systems as well as improvement of the measurement methodology, i.e. configurations of satellite receivers and layouts of their placement on a mobile measuring platform. It was also found that the development of data analysis algorithms contributed to the increase in the obtained accuracy in assessment of a railway track axis shape. The authors indicate the possibilities of applying GNSS techniques at various stages of construction and operation of railways. According to the authors, the most important advantage of both the presented measurement technique and computational methodology is the ability to effectively and relatively low-cost data acquisition regarding the existing state of the railway line. These data can be successfully used to design changes to the geometry of railway lines, and therefore satellite positioning has enormous application potential in the process of modernization of operated railway lines.

Design and Implementation of a Dual Axis Solar Tracker Using Arduino Microcontroller

Energy is pivotal to the human and capital development of any nation; hence, the ever growing quest to discover reliable and sustainable energy sources. Researches on renewable energy sources ranging from wind, tidal, hydro power and solar energy is on-going; all geared towards providing better electrical energy source. Solar energy, however, holds a very promising future as far as sustainable energy solution is concerned. It is silent, green, with zero negative impact to the globe and no pollution. Unlike the conventional energy sources from fossil fuel, it reduces greatly the impact of global warming and remains endless. The developed solar tracker has two automatic tracking axis for both the zenith daily and the azimuth annually as well as displaying in real-time solar irradiation and tilt angles on the mounted LCD. The self-controlled tracking is achieved by using a MEGA2560 microcontroller board, programmed to read analog values from an array of LDRs, convert them to digital values, compare them and drive the stepper motors in the desired direction until equal light is sensed by alternate LDRs. At this point, the panel is aligned perpendicular to the sun rays to capture the maximum possible energy. A working prototype is successfully designed and constructed. The testing revealed very precise tracking made possible by using micro-stepping modes of the stepper motors. This also gave a very high tracking accuracy of about ±0.0560.

Design and Implementation of an Automatic Control for Two Axis Tracking System for Applications of Concentrated Solar Thermal Power

The present work presents design and implementation of an automated two-axis solar tracking system using local materials with minimum cost, light weight and reliable structure. The tracking system consists of two parts, mechanical units (fixed and moving parts) and control units (four LDR sensors and Arduino UNO microcontroller to control two DC servomotors). The tracking system was fitted and assembled together with a parabolic trough solar concentrator (PTSC) system to move it according to information come from the sensors so as to keep the PTSC always perpendicular to sun rays. The experimental tests have been done on the PTSC system to investigate its thermal performance in two cases, with tracking system (case 1) and without tracking system (case 2). The experimental results showed that the average solar radiation falling on the PTSC prototype in the two cases during the same time was 854 and 701 watt/m2, respectively, which means an increase in the solar radiation about 21.8 % when using tracking system. It was found that the average useful heat gain output of solar collector was equal to (376.2, 252.6 watt) for the two cases, respectively, so there was an increase of about 48.9 % when using the tracking system. Also, the average thermal efficiency of the PTSC was found to be (20.7, 26.5 %) for the two cases, respectively, which means an increase in the average efficiency by 28% with use of tracking system compared to the fixed case.

Simultaneous Influence of the Track Axis Curvature and the Support Line Obliquity at Railway Bridge Superstructures with Steel Beams Embedded in Concrete

Abstract For new railway bridges with small spans (L ≤ 35.00 m) superstructures with steel beams embedded in concrete are recommended and used, which can ensure the requirements of strength and especially stiffness, regardless of velocity. In all the design prescriptions used so far for superstructures with steel beams embedded in concrete, and even in the technical literature, there is little information and data on the influence of the support line obliquity and the track axis curvature in the design and calculation of these types of structures. In the design code, if certain conditions related to the geometry of the superstructure are met (obliquity, curvature) the calculation is a simplified one, made on a single isolated longitudinal beam of the deck; otherwise, if the conditions are not met, finite element program analysis is recommended. The article aims to study the situations in which the requirements of the design prescriptions are not met.

KINEMATICS OF MOVEMENT OF A WHEEL PAIR AFTER ITS DERAILMENT

The work is devoted to a deep study of the kinematics of a wheeled pair at the derailment of a railroad car. Attention to this subject is increased, since the damage caused by the descent of passenger and freight trains is sufficiently great. Currently available technical means do not allow timely identification of the car wagon, and the data presented in the literature, sufficiently, do not allow to create the necessary equipment for its detection.In order to solve this problem, the work of studying the movement of the wheeled car after the derailment. A trajectory and a kinematic model of the motion of a wheel along a tie lattice are constructed.The wheel pair after its descent from the rail moves, as a rule, along the sleeper grille. Accordingly, its trajectory of motion depends on the upper structure of the path in this section. In this case, the wheels continue to move along the axis of the path. In this paper, for the initial simplification, only the movement of the wheel in a plane parallel to the vertical plane of the track axis is considered. Also, the inelastic deformation of sleepers at low speeds is not taken into account.The kinematics of the movement of the wheel along the sleepers, that is, after the derailment, has been analyzed. Analytic dependencies of the connection between the movement of the wheel and the parameters of the upper structure of the path are made. It is shown that the amplitude and frequency of oscillations of a wheel pair at its descent depend on the diameter of the wheel, the width of the horizontal surface of the sleeper and the distance between the axes of the sleepers. Instantaneous centers of wheel velocities at characteristic points are determined. The developed kinematic model determines the main diagnostic signs of the derailment of wagons from the rail. This will make it possible to create a reliable descent recognition algorithm for constructing the hardware and software of the technical control system for car wagons from the rail. This model allows us to use it later to create the sensors of the descent.