Model Of Solar System Research Articles

Simulation model of a new solar laser system of Fresnel lens according to real observed solar radiation data in Helwan of Egypt

A new simulation model of a new solar pumped laser system was tested to be run in Helwan in Egypt (latitude φ=29°52′N, longitude λ=31°21′E and elevation=141m) as an example of an industrial polluted area. The system is based on concentrating the solar radiation using a Fresnel lens on a laser head fixed on a mount tracking the sun during the day and powered by a DC battery. Two cases of this model are tested; the first one is the model consisting of a Fresnel lens and a two-dimensional Compound Parabolic Concentrator (CPC), while the other is the model consisting of a Fresnel lens and a three-dimensional Compound Parabolic Concentrator (CPC). The model is fed by real actual solar radiation data taken in Helwan Solar Radiation Station at NRIAG in the various seasons in order to know the laser power got from such a system in those conditions. For the system of Fresnel lens and 2D-CPC, an average laser output power of 1.27W in Winter, 2W in Spring, 5W in Summer and 4.68W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 3.24W. For the system of Fresnel lens and 3D-CPC, an average laser output power of 3.28W in Winter, 3.55W in Spring, 7.56W in Summer and 7.13W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 5.38W.

Comparative Study of MPPT Methods for Solar PV Driven Induction Motor Load

tracking (MPPT) such as Fuzzy logic controller (FLC) and artificial neural network (ANN) are investigated, and compared with traditional constant voltage (CVC), Perturb & observed (P&O) and Incremental conductance (IC) MPPT methods to achieve maximum power point (MPP) through PV system, in this paper. For transient analysis of MPPT assisted photovoltaic (PV) system powered to the induction motor (IM) in various applications. The system performance is investigated for different irradiation conditions in terms of voltage, current, power and rotor speed response. The detailed study is carried on advantages of advance MPPT techniques over the traditional MPPT techniques. The modeling of solar PV system and considered MPPT techniques have been done in MATLAB/ Simulink environment.

Numerical Modeling, Simulation and Validation of Hybrid Solar Photovoltaic, Wind Turbine and Fuel Cell Power System

The energy conversion equations describing the total power generated by a hybrid system of solar photovoltaic, wind turbine, fuel cell as well as hydrogen storage were presented, and integrated simultaneously. For the purpose of validating, this simulation model, the aforementioned equations were coded with MATLAB V13.2 and used for optimization and design purposes. A block diagram approach was used during the simulation with MATLAB. In order to validate and tune up the predicted output results, on-site data was used to validate the simulation program under various conditions. Comparison between the data and predicted results showed a fair agreement.

Towards a measurement of the half-life of 60Fe for stellar and early Solar System models

Radioisotopes, produced in stars and ejected into the Interstellar Medium, are important for constraining stellar and early Solar System (ESS) models. In particular, the half-life of the radioisotope, 60Fe, can have an impact on calculations for the timing for ESS events, the distance to nearby Supernovae, and the brightness of individual, non-steady-state 60Fe gamma ray sources in the Galaxy. A half-life measurement has been undertaken at the University of Notre Dame and measurements of the 60Fe/56Fe concentration of our samples using Accelerator Mass Spectrometry has begun. This result will be coupled with an activity measurement of the isomeric decay in 60Co, which is the decay product of 60Fe. Preliminary half-life estimates of (2.53±0.24)×106years seem to confirm the recent measurement by Rugel et al. (2009).

Dynamic Modeling and Simulation of Parabolic Trough Solar System

Abstract Solar energy has become increasingly distinguished among the renewable resources and solar parabolic trough solar thermal power plants have proved the most mature solar thermal technology by far. In this paper, a dynamic mathematical collector model is established and verified based on the photo-thermal conversion process of parabolic trough collector. Combined the validated model with pumps, oil-water heat exchanger and other existing models, a parabolic trough solar field system is built on the simulation platform. Furthermore, considering the collector loops and solar collector assemblies (SCA), the solar field layout is optimized according to diverse irradiation conditions. In view of one chosen optimum solar field, its dynamic characteristics are tested by the real-time simulation under the disturbances of different irradiation conditions, changeable working medium parameters, etc.

Jumping mechanisms of Trojan asteroids in the planar restricted three- and four-body problems

We explore minimal dynamical mechanisms for the transport of Trojan asteroids between the vicinities of the stable Lagrange points \(L_{4}\) and \(L_{5}\) within the framework of the planar restricted three- and four-body problems. This transport, called “jumping” of Trojan asteroids, has been observed numerically in the sophisticated Solar System models. However its dynamical mechanisms have not been fully explored yet. The present study shows that invariant manifolds emanating from an unstable periodic orbit around the unstable Lagrange point \(L_{3}\) mediate the jumping of Trojan asteroids in the Sun–Jupiter planar restricted three-body problem. These invariant manifolds form homoclinic tangles and lobes when projected onto the configuration space through a discrete mapping. Thus the resulted lobe dynamics explains the mechanism for the jumping of Jupiter’s Trojan asteroids. In the Sun–Earth planar restricted three-body problem, on the other hand, invariant manifolds of an unstable periodic orbit around \(L_{3}\) do not exhibit clear homoclinic tangles nor lobes, indicating that the jumping is very difficult to occur. It is then shown that the effect of perturbation of Venus is important for the onset of the jumping of Earth’s Trojan asteroids within the framework of the Sun–Earth–Venus planar restricted four-body problem. The results presented here could shed new insights into the transport mechanism as well as trajectory design associated with \(L_{3}\), \(L_{4}\), and \(L_5\).

Study of solar regenerated membrane desiccant system to control humidity and decrease energy consumption in office spaces

This paper investigates the feasibility of using a solar regenerated liquid desiccant membrane system to remove humidity from an office space. While conventional vapor compression cycles dehumidify the air before supplying it to the indoor space, through using sub cool–reheat process, the proposed cycle absorbs the humidity directly from indoor space through the dehumidifier. The dehumidifier consists of a set of permeable vertical tubes placed in the indoor space with liquid desiccant flowing through them. Solar energy is used as the source of thermal energy required for the regeneration of the desiccant and sea water is used as heat sink to provide the cooling needs of the liquid desiccant.A mathematical model of the membrane desiccant system was integrated with the internal space model and solar system model to predict the humidity removal capacity from the space at given dehumidification and heat sink temperatures and outdoor environmental conditions. Experiments were performed to validate the model results be comparing exit humidity and temperature of the exit air from the space.The validated model was applied to a case study consisting of an internal office during the month of August in Beirut hot humid climate. A decrease of 10% in indoor relative humidity is observed when the system was used. The cost of the proposed system was compared to the cost of a conventional vapor compression cycle that provides the same indoor conditions. A payback period of 7years and 8month was estimated compared to the investment in the vapor compression cycle.

Erratum to: Constructing ballistic capture orbits in the real Solar System model

Z.-F. Luo · G.-J. Tang College of Aerospace Science and Engineering, National University of Defense Technology, Changsha 410073, People’s Republic of China e-mail: luozongfu200@nudt.edu.cn G.-J. Tang e-mail: tangguojian@nudt.edu.cn F. Topputo (B) · F. Bernelli-Zazzera Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa, 34, 20156 Milan, Italy e-mail: francesco.topputo@polimi.it F. Bernelli-Zazzera e-mail: franco.bernelli@polimi.it

Constructing ballistic capture orbits in the real Solar System model

A method to design ballistic capture orbits in the real Solar System model is presented, so extending previous works using the planar restricted three-body problem. In this generalization a number of issues arise, which are treated in the present work. These involve reformulating the notion of stability in three-dimensions, managing a multi-dimensional space of initial conditions, and implementing a restricted $$n$$ -body model with accurate planetary ephemerides. Initial conditions are categorized into four subsets according to the orbits they generate in forward and backward time. These are labelled weakly stable, unstable, crash, and acrobatic, and their manipulation allows us to derive orbits with prescribed behavior. A post-capture stability index is formulated to extract the ideal orbits, which are those of practical interest. Study cases analyze ballistic capture about Mercury, Europa, and the Earth. These simulations show the effectiveness of the developed method in finding solutions matching mission requirements.

An automated tool for solar power systems

In this paper a novel model of smart grid-connected solar power system is developed. The model is implemented using MatLab/SIMULINK software package. Artificial neural network (ANN) algorithm is used for maximizing the generated power based on maximum power point tracker (MPPT) implementation. The dynamic behavior of the proposed model is examined under different operating conditions. Solar irradiance, and temperature data are gathered from a grid connected, 28.8 kW solar power system located in central Manchester. The developed system and its control strategy exhibit excellent performance with tracking efficiency exceed 94.5%. The proposed model and its control strategy offer a proper tool for smart grid performance optimization.

Physical Design and Modeling of 25V DC-DC Boost Converter for Stand Alone Solar PV Application in Distributed Generation System

As per the present development the shortage in power all over the world seems to be abundance. Renewable energy sources are the capable energy source along with the accessible resources of energy. Among all the renewable resources of energy, solar PV technology is most acceptable due to its considerable advantage over other form of renewable sources. Calculating the output of PV system is a key aspect. The main principle of this paper is to present physical modeling and simulation of solar PV system and DC-DC boost converter in SIMSCAPE library of MATLAB. The benefit by SIMSCAPE library is that it models the system physically and the outcome obtains from it will be considering all the physical result. In this paper the output of solar cell has been interfaced with the boost converter. The system model in SIMSCAPE can be directly converted into hardware for implement for actual time application.

Performance study on a dye-sensitized solar cell and thermoelectric hybrid power system

A theoretical model of the dye-sensitized solar cell-thermoelectric hybrid power system is established, which is composed of the dye-sensitized solar cell module and thermoelectric generator module. Based on the theory of non-equilibrium thermodynamics, the expressions for the power output and efficiency of the hybrid power generator system are derived. The general performance characteristics of the hybrid system are analyzed. The optimally operating conditions of the hybrid system at the maximum output power and efficiency are determined. The influence of some main performance parameters on the performance characteristics of the hybrid system are discussed in detail. The results show that the low grade waste heat of the dye-sensitized solar cell module can be effectively used by the thermoelectric generator and the power output and efficiency of the hybrid system can be improved. The results obtained in this paper may provide theoretical significances for the design and optimal operation of practical dye-sensitized solar cell-thermoelectric hybrid power generator system.

Modeling and optimal control of an energy-efficient hybrid solar air conditioning system

Abstract The paper addresses the modeling and optimal control problem of a new hybrid solar-assisted air conditioning system developed for performance enhancement and energy efficiency improvement. To regulate the mass flow rate of the refrigerant vapor passing through a water storage tank for increasing the refrigerant's sub-cooling process at partial loads, we propose a new discharge bypass line together with an inline solenoid valve, installed after the compressor. In addition, to control the air flow rate, a variable speed drive is coupled with the condenser fan. For the control purpose, a lumped parameter model is first developed to describe the system dynamics in an explicit input–output relationship; then, a linear optimal control scheme is applied for the system's multivariable control. The system has been fully-instrumented to examine its performance under different operation conditions. The system model is then validated by extensive experimental tests. Based on the obtained dynamic model, an optimal controller is designed to minimize a quadratic cost function. Numerical algorithms, implemented in a simulation tool, are then employed to predict the energy performance of the system under transient loads. The experimental results obtained from implementation with PLC demonstrate that the newly-developed system can deliver higher system efficiency owing to amelioration of the refrigeration effect in the direct expansion evaporator and adjustment of its air flow rate. The development is thus promising for improvement of energy efficiency, enhancement of the system performance while fulfilling the cooling demand.

A novel algorithm for generating libration point orbits about the collinear points

This paper presents a numerical algorithm that can generate long-term libration points orbits (LPOs) and the transfer orbits from the parking orbits to the LPOs in the circular-restricted three-body problem (CR3BP) and the full solar system model without initial guesses. The families of the quasi-periodic LPOs in the CR3BP can also be constructed with this algorithm. By using the dynamical behavior of LPO, the transfer orbit from the parking orbit to the LPO is generated using a bisection method. At the same time, a short segment of the target LPO connected with the transfer orbit is obtained, then the short segment of LPO is extended by correcting the state towards its adjacent point on the stable manifold of the target LPO with differential evolution algorithm. By implementing the correction strategy repeatedly, the LPOs can be extended to any length as needed. Moreover, combining with the continuation procedure, this algorithm can be used to generate the families of the quasi-periodic LPOs in the CR3BP.

Performance comparison of solar parabolic trough system with glass and film reflector

This paper considers the refractive surface error transfer process to present an optical performance model of solar trough system as well as the reflective surface error. We validate the optical model through comparing the calculation results with the experimental data. The optimized design parameters are presented based on the maximization of the annual average net heat efficiency. The results show that maximum relative error of 20% for the optical efficiency may produce if the refractive surface error transfer process is ignored. It indicates that the refractive surface error should be considered in predicting the performance of the solar trough system especially for the glass reflector as well as the reflective surface error.We apply the model to compare the performance of solar parabolic trough system with vacuum tube receiver under two kinds of reflectors, which are glass mirror and film mirror. The results indicate that both parabolic trough systems with a vacuum tube receiver and a north–south axis tracking system are relatively inefficient in winter days, and the net energy output in the winter solstice is less than one sixth of the summer. The net heat efficiency of solar trough system with film mirror is 50% less than that of the system with the glass mirror at noon of the winter solstice and latitude 40 if the design and parameter of the two systems are the same. The results indicate that film reflector is more preferable than glass reflector especially in high latitude if they have the same optical property.

Modeling of Grid-connected Solar Photovoltaic Energy Generation System

This paper coversthe design and modelling of a grid-connected solar photovoltaic energy generation system. Solar-PV system with MPPT (maximum power point tracking) controller to track maximum power point is designed with a dc-dc converter. The output of PV array is fed to the VSI converter through a dc-dc converter. For regulating the output voltage and current under varying conditions,a VSI is designed with closed loop controllers. Simulation model for this designed system is developed in Simulink/Matlab platform and simulated results are presented to demonstrate its performance under steady and dynamic conditions.

Solar photovoltaic system modeling and performance prediction

Abstract A simulation model for modeling photovoltaic (PV) system power generation and performance prediction is described in this paper. First, a comprehensive literature review of simulation models for PV devices and determination methods was conducted. The well-known five-parameter model was selected for the present study, and solved using a novel combination technique which integrated an algebraic simultaneous calculation of the parameters at standard test conditions (STC) with an analytical determination of the parameters under real operating conditions. In addition, the simulation performance of the model was compared with other models, and further validated by outdoor tests, which indicate that the proposed model fits well the entire set of experimental field test I–V curves of the PV module, especially at the characteristic points. After validation, this model was employed to predict the PV system power output under real conditions. The results show that the predictions agree very well with the PV plant field collected data. Thus, the operating performance of a standalone PV system located on a remote island in Hong Kong has been further evaluated with the aid of this model. It is found that the PV array power output is restricted by the status of the battery bank. This research demonstrates that the PV simulation model developed during the study is simple, but very helpful to PV system engineers in understanding the I–V curves and for accurately predicting PV system power production under outdoor conditions.

Station-keeping of real Earth–Moon libration point orbits using discrete-time sliding mode control

In this work, station-keeping of real Earth–Moon libration point orbits is studied using discrete-time sliding mode control (DSMC). For comparison, a discrete linear quadratic regulator (DLQR) controller is also considered. The libration orbits are termed “real” in the sense that they are obtained in a complete Solar System model, taking into account all the gravitational forces of the planets, the Moon, and the Sun. This is a key point for any station-keeping study, that the use of far from real orbits as nominal ones increases unnecessarily the station-keeping cost. The resulting controlled system, linearised with respect to some nominal orbit, takes a discrete-time form suitable for applying impulsive maneuvers. The DSMC controller is designed by the reaching law with the parameters chosen in an adaptive way. A method for designing the sliding surface is proposed. In order to assess and compare the performance of the two controllers, simulations are done for six libration point orbits around the L2 point (three halo orbits and three Lissajous ones) during a time span of 10years. Several practical constraints are also considered in the simulations. Extensive Monte Carlo results show that the proposed DSMC approach is able to maintain the spacecraft within a close vicinity of the nominal orbits with a maneuver cost less than 2m/s per year, and it outperforms the DLQR approach in terms of the position controllability. Some comparison with previous results obtained by other authors with different procedures is also given.

An approach to urban tree daylight permeability simulation using models based on louvers

In oasis cities urban forestation shades the lower level facades of buildings. It is thus crucial to analyze the distributional patterns of sun radiation produced by trees on facades. Nevertheless, the complexity of the canopies requires simplified representations for its study through simulation techniques. On the assumption that lighting behavior of trees, as sun control elements, more closely resembles a louver system rather than other frequently used solar control systems (e.g. perforated obstruction), the present study seeks to verify which of these formal simplifications adjusts better to the real case. The methodology used in this study relies on raytrace simulation of solar control system models generated with hemispherical images. Comparisons are made between measured data of vertical illuminance (lux) in situ and those obtained through simulation for each of the models. Louvers model showed a high degree of adjustment (RMSE 9%). This study may be useful to streamline the analysis of urban trees impact in daylight availability on building facades through simulation.

Modeling and simulations of a micro solar power system

SUMMARY In this paper, the mathematical modeling and simulations of a concentrating solar power system located at the Middle East Technical University Northern Cyprus Campus are presented. The system consists of parabolic trough collectors (PTCs), a propane boiler, an organic Rankine cycle (ORC), and a wet cooling tower. Presently, the PTC field is severely undersized with respect to the ORC making the system impossible to operate without burning significant propane. Expanding the solar field could result in better system performance. Hourly, daily and seasonal variations in the performance of this system are simulated using hourly meteorological data for Larnaca, Cyprus, over an entire year. Because the ORC is driven using a relatively low-temperature heat source rather than PTCs, the usage of nonconcentrating evacuated tube collectors that collect both beam and diffuse radiation is explored. The performance of east–west and north–south–tracking axis PTCs and the entire inventory of nonconcentrating evacuated tube collectors that were rated by the Solar Rating and Certification Corporation are compared in terms of annual performance metrics. Based on the simulations, several nonconcentrating evacuated tube collectors are identified with better thermal performance than PTCs, and the feasibility of using these collectors should be explored further. Copyright © 2013 John Wiley & Sons, Ltd.