Morteza Khalaji Assadi

Comparative analysis of three numerical methods for estimating the onshore wind power in a coastal area

ABSTRACT Although there are many studies concerning the estimation of wind potential in different locations of Iran, an adequate evaluation of wind power for onshore locations of this country has not been investigated yet. The purpose of this research is to evaluate the potential of onshore wind in the south of Iran along the Gulf of Oman by comparing three Weibull numerical methods. In the first step, it became clear that the maximum likelihood method (MLM) compared to other methods represented the actual wind data with the lowest error rate and therefore it was selected as an accurate statistical distribution to model the wind speed of the investigated location. Using the MLM, the estimation of wind speed characteristics as well as the techno-economic evaluation of different wind turbines has been investigated. It was concluded that both technically and economically the studied area does not have sufficient wind power for the development of large-scale or grid-connected wind turbines. However, it may have enough power for non-grid-connected mechanical applications, such as wind generators for water pumping. Therefore, in the last part of this paper, an investigation of water pumping potential of the studied site by using adequate and modern wind turbines with lower start-up wind speed was recommended for future studies. Furthermore, it was suggested that the current methodology used in this research could be employed and extended in future studies to evaluate the wind potential of all onshore locations of Iran including onshore locations along the Persian Gulf and Caspian Sea.

Transparent Carbon Nanotubes (CNTs) as Antireflection and Self-cleaning Solar Cell Coating

Carbon nanotubes have fascinating chemical and physical properties as indicated by graphite and diamond characteristics, and the reason is their individual atomic structure. They have acquired critical achievements in various fields such as materials, electronic devices, energy storage, separation, and sensors. Recently, antireflective coatings with self-cleaning properties attract critical consideration for their theoretical characteristics and their wide-ranging applications. In this chapter, the benefits of using CNTs as an antireflection and self-cleaning thin coating layer have been discussed to improve mechanical and electrical behavior of solar cells. Transfer-matrix method (TMM) and finite-difference time-domain (FDTD) method were studied as most suitable technique for thin films.

Integration of Computer Simulation, Design of Experiments and ParticleSwarm Optimization to Optimize the Production Line Efficiency

The goal of this paper is to optimize the productivity of manufacturing system by integrating computer simulation, design of experiments (DOE) and particle swarm optimization (PSO) algorithm. Optimizing productivity of colour factory was considered as the case of this study. To evaluate and estimate the effect of main factors, 2n factorial design with higher and upper levels and centre points was considered. After obtaining the significant factors, the local optimum setting of the significant factors was determined using the steepest ascent method and response surface methodology (RSM) approach. Finally, the global optimum productivity was achieved by computer programing of PSO method. Base on the final result, maximum productivity occurs in the point of 87.23 that is relevant to number of labour (B) = 26 and failure time of lifter (C) = 78.04 min. In addition, other two factors A (Service rate of Delpak mixer) and D (Number of permil) should be located at low level to obtain maximum productivity.

Simulation of Dynamical Performance of Solar Desiccant Cooling Cycle

In this research, solar desiccant cooling cycles in ventilation and hybrid mode are simulated. To simulate cycles, at first a model for desiccant wheel simulation is presented and a computer code based on experimental correlations is used to solve equations. Then by TRNSYS software a model for solar hot water system is simulated, and eventually by representing a suitable algorithm, computer program for simulating solar desiccant cooling cycles by EES software is developed. For all components of desiccant cycle, the dynamic optimum were based on regeneration temperature and solar fraction, and after optimum, dynamic cycle performance in an office building with an area of 115 m2 located in Bushehr city, capacity of cooling 3 ton refrigeration were analyzed. The results show that solar desiccant cooling cycles in comparison with compression refrigeration cycles with 40% saving in energy consumption and also during the day and in office buildings have a better performance.

Comparison of Different Neural Network Training Algorithms for Wind Velocity Forecasting

In this paper the wind speed is predicted by the use of data provided from the Mehrabad meteorological station located in Tehran, Iran, Collected between 2003 and 2008. A comprehensive analogy study is presented on Comparison of various Back Propagation neural networks methods in wind velocity forecasting. Four types of activation functions, namely, BFGS quasi-Newton, Bayesian regularized, Levenberg-Marquardt, and conjugate gradient algorithm, werestudied. The data was investigated by correlation coefficient and characterizing the amount of dependency between the wind speed and other input data. The meteorological parameters (pressure, direction, temperature and humidity) were used as input data, while the wind velocity is used as the output of the network.The results demonstrate that for the similar wind dataset, Bayesian Regularized algorithm can accurately predict compared with other method. In addition, choosing the type of activation function is dependent on the amount of input data, which should be acceptably large.

Solar Energy Potential Estimation in Perak Using Clearness Index and Artificial Neural Network

In this paper solar energy potential has been estimated by two methods which are clearness index and artificial network (ANN) methods. The selected region is Seri Iskandar, Perak (4°24´latitude, 100°58´E longitude, 24 m altitude). Experimental data (monthly average daily radiation on horizontal surface) was obtained from UTP solar research site in UTP campus. The data include the period of 2010 to 2012 and were used for testing the artificial neural network model and also for determination of clearness index. Also the experimental data of the three meteorological, Ipoh, Bayan Lepas & KLIA were used in calculating the clearness index and for training the neural network. Result shows that clearness index for Seri Iskandar is 0.52, the highest radiation is on February (20.45 MJ/m 2 /day), annual average is 18.25 MJ/m 2 /day and clearness index is more accurate than ANN when there is limited data supply. In general, Perak states show strong potential for solar energy application.

Technical-Economic Analysis of Steam Double Effect Absorption Chiller-Heaters Equipped with Solar Heat Pipe System

The aim of this research is to indicate a steam double effect chiller-heater equipped with solar heat pipe in a certain space with the area of 975 m2 located in Tehran, which is currently equipped with a direct-fired single effect absorption chiller-heater. Thereafter , the most obvious differences of the two chiller-heater systems are compared: the solar cooling system increases coefficient of performance as high as 0.54, decreases CO2 dissemination by 829 tons in each year, and reduces energy consumption by 1552.42 MWh/Yr. Economic analysis of the two systems using break-even-point showed that the use of solar system is attractive in applications that have excess thermal energy, and the conversion of this energy to higher value energy markets is to be more profitable than absorption gas-fired system from 13th year on. Keywords: Technical-economic analysis, energy optimization, solar chiller, absorption chiller-heater, solar heat pipe.