نشریه انرژی ایران
سال هجدهم شماره 4 (پیاپی 69، زمستان 1394)

Liquid natural gas is mentioned to a type of gas that is converted to liquid gas for the purpose of storage or transportation at the large volumes. In this work it has been tried to analyze the LNG cycle with the aid of thermodynamical analysis and parametric investigations on the liquefaction of natural gas cycle. With these investigations it was known that some parameters such as isentropic efficiency of compressor, efficiency of heat exchangers, pressure ratio of compressors and methane temperature have a significant influence on the general efficiency of the liquefaction of natural gas cycle. Finally for having the best efficiency of the related cycle, the optimized results of the investigation is provided.

Daily solar radiation is an important element in the application of solar energy. Measuring solar radiation requires advanced tools and equipment. Hence, solar radiation measured data are not always available in the all the meteorological stations. Generally it needs to be estimated by empirical models based on frequently available meteorological records such as hours of sunshine or temperature. This paper evaluates the behavior of five empirical models based on the difference between maximum and minimum temperatures (the models of Bristow & Campbell, Hargreaves, Samani, Chen and Li). With statistical error tests, the performance of the models is validated by comparing together against the measured data at 12 meteorological stations in Iran located in four region climate humid, semi-humid, semi-arid and arid. Results show that the models are more accurate in the arid regions as compared to humid regions. Hence, these models can be recommended for estimating daily solar radiation in arid regions where only air temperature data are available in Iran.

One of the optimal methods for conversion of waste plastic to fuel is pyrolysis process.There catalyst can improve the conversion process and minimize the temperature and time needed to process the breakage of polymeric macromolecules into smaller molecules to be followed.Using this approach can be madeto protect environment and can be replaced by burning fossil fuels.In this paper for a developed mathematical model has be presented by using two approach of response surface methodology (RSM) and imperialist competitive algorithm (ICA) that has been studied on parameters and influenced model factors to explorer optimum conditions of catalytic pyrolysis.Accordingly optimal condition for liquid fuel achieved 561.92 ̊C for reactor temperature and 1.33 gr catalyst weight.For gas fuel this condition are 560.74 ̊C for reactor temperature and 1gr catalyst weight. As well as nearby results of two way confirm the convergence and accuracy of the methods and the final answers. So that the correlation between the results of the analysis of variance (ANOVA) 98.8% for liquid fuel and liquid fuel 96.5% is obtained.

Application of distributed generation particularly wind power plants in power systems, is rapidly increasing due to their various advantages. Considering the effects of these new resource impacts in power system planning, particularly TEP problem is inevitable, due to their essential role in changing the optimal plans. In this paper, a multi-objective optimization method is presented using DC load-flow in order to present a strong model for solving TEP problem. Considering uncertainties of wind farms generation and network load in the form of probabilistic variables, as well as the investment and maintenance costs in the objective function are the main advantages of the proposed algorithm. Multi-objective optimization problem has been analyzed using Imperialist Competitive Algorithm (ICA) which is one of the newest evolutionary optimization algorithms applied to power systems. To study the effects of wind farms on TEP problem and validate the proposed method, necessary changes have been made in RTS-IEEE 24-bus network and the presented algorithm has been applied to them. The results have been compared to optimum plans which were searched by GA Algorithm

Providing suitable solutions to optimize energy consumption in buildings is very important in all countries, it should become a universal determination so in this way can maintained fossil fuels for next generation. Due to the large share of energy consumption in buildings, there are irreparable damages entered to the environment. Therefore knowing causes of energy consumption and plans to remove them, are the important priorities in buildings design. Optimal uses of passive solar systems in order to achieve two important aspects of sustainability, including economic and environmental considerations are an important feature of this research. In this study, has been examined and tested the impact of different forms of residential units as the independent variable on the energy consumption of buildings as the dependent variable. At every stage of the investigation, Housing units with different values of the parameters are examined and analyzed. The houses in this study are three floors in the small scale and Ecotect Software is used for simulation and calculation of solar potential. Finally, based on simulation, results that L shape units with a depth of two to three (2 to 3) had the highest rates of energy efficiency in a year.

In this work, a compression type HVAC (heating, ventilating, and air conditioning) system has been studied. The aim of the work was improving the cooling operation and performance of the system, elimination of the freezing problem of the compressor, increasing the efficiency, decreasing the energy consumption and reducing the working duration of the compressor. The results of numerical solution of the computational fluid dynamics has been crosschecked with and interpreted according to the experimental data. The results of the exploited modifications based on the numerical solution have been presented in the form of contours and velocity-temperature plots. Eventually, troubleshooting of the HVAC system resulted in the elimination of the compressor freezing accompanied with convenient air conditioning and ventilation. The temperature and flow of the provided air, decreased 7 oC and increased by %13, respectively.

Nowadays, internal combustion vehicles are the main reason of air pollution in urban areas. Reducing the emissions, energy optimization, and fuel economy are the main goals of vehicle manufacturers. Design and development of clean vehicle including electric vehicles (EVs), hybrid electric vehicles (HEVs), and fuel cell vehicles (FCVs) are the mid and long term strategies to capture the above goals. Unfortunately, these technology in spite of development the clean vehicles in advanced countries, are not the objectives in our country. This paper in order to develop of hybrid electric vehicle technology and using the available resources in Iran, proposes the design and manufacturing steps of the first HEV based on Pride platform. Hybrid Prides that is named Shaheb2 has been manufactured by a joint group student of electrical and mechanical engineering at University of Kashan and prepared for third national competition for manufacturing of hybrid vehicles. Due to some cost and time limitations, Trough-To-Road (TTR) or separated-axle parallel hybrid electric vehicle topology has been chosen. Internal combustion engine of Shaheb2 is 1300CC engine of Pride vehicle that as well as mechanical transmission components such as gearbox, differential are implemented on the front axle. Electric propulsion including electric motor (EM) and drive, energy storage system are located on the rear axle. Employed EM is a 22 kW PMSM that is controlled via field oriented scheme based on space vector modulation inverter and works in two modes torque control and speed control. To store of electrical energy, a set of Li-Ion-Polymer batteries with 192 dc volt has been used. To have an optimum performance for the vehicle, Hybrid Control Unit (HCU) has been developed in which the vehicle can work in different modes only motor, only engine, hybrid and regenerative braking. Employed control method in HCU is based on On/Off strategy that has been implemented by using AVR microcontroller. Due to extra weight of electric propulsion system and so the change of center of mass and total weight of the vehicle, and to increase the stability of the vehicle, the vehicle’s chassis has been enforced and the results have been confirmed via finite element analysis in ANSYS. Suspension system and other auxiliary systems of the vehicle have been recalculated and verified. Aerodynamic performance of the vehicle’s body has been analyzed in Gambit and Fluent and some changes have been made on the body.

High levels of energy consumption in buildings has emerged energy efficient design and optimization strategies. Due to high investment costs there is an increasing need for tools to accurately assess energy conservation measures (ECMs). Whole building energy simulations (BES) play an important role in energy efficient design and post occupancy assessment of buildings. In this study DesignBuilder and Ecotect, with an extensive use in both educational and architectural practice, have been used to model and simulate the energy consumption of an educational building. The results have been compared to on site audits. Both the energy consumption over a whole year and the thermal condition in indoor spaces for a day has been compared with simulation outputs. The study attempts to determine the main input parameters causing the discrepancies between building simulation and the real world performance. To validate and refine the simulation outputs, corrected inputs were applied. It has been concluded input parameters such as the infiltration rate, weather data, efficiency of cooling and heating systems and occupant behavior are the main causes of the discrepancies that should be considered carefully in simulations.

Development and deployment of renewable AnrzhyHay would help to achieve the goals of economic, social and environmental impacts of which are the most important factors in achieving sustainable development in each country. VazhhAy in renewable energy and renewable energy to meet literacy and use them to reduce the use of fossil SvkhtHay, which is the protection of the environment and environmental behavior. This study examines the energy literacy training in the operation of the environmental behavior among high school female students in Maragheh concerns. Applied research methods Barvykrd descriptive survey method to collect information through a questionnaire. -32) -Atfy (21-5) and behavioral (31-22) is designed. Validity to valid standards and professionalism. Assess the reliability of the questionnaire was analyzed using Cronbachs alpha. The Cronbachs alpha was equal to 79/0, indicating the relevance of the questions. The results showed that 21.9% of students with low energy literacy, 9/68 percent and 1.9 percent average energy literacy literacy good energy. In fact, the amount of energy literacy among students is greater than the amount available Anrzhhay saving and environmental protection in their environmental behavior and more.

Objective of this research is to Efficieny Enhancement and Polutant Gas Emission Reduction in a Benchmark Turbo-Compressor Gas Engine. Using Heat Recirculation of Flue Gas are studied and using a shell&tube and plate finn heat exchanger for simple gas cycle is considered and optimized. Thermodynamic modeling of the cycle is performed using energy and exergy analysis. Thermo-hydraulic modeling of the recuperators is performed using the modified heat transfer analysis and ε-NTU method in order to estimate the heat exchangers area, effectiveness and pressure drop. Optimization is considered as the multi-objective evolutionary algorithm in which one objective is maximizing the cycle exergetic efficiency, the second is minimizing the capital payback time of the recuperator and the other one is minimizing the Polutant Gas Emission for both of heat exchangers. A set of optimal solutions namely as the Pareto frontier are obtained and a final optimal solution are selected using the Bellman-Zadeh fuzzy decision-making approach, TOPSIS and LINMAP methods and the best solutions are reported. In final by comparing the heat exchangers, The best of heat exchanger was selected. Finally, by comparing optimal shell&tube and plate finn heat exchanger, The best heat exchanger has been chosen for Turbo-Compressor. The final improvement Heat Recirculation, Resulted in a 19.1 percent increase in exergy efficiency and reduce NOx emissions rate is 17.93 percent.