نشریه انرژی ایران
سال نوزدهم شماره 2 (پیاپی 71، تابستان 1395)

Analysis of players behavior and electricity markets conditions through simulation can assist market decision-makers in appropriate designing and policy-making before actual implementation and can reduce costs and possible future problems. Considering ancillary service markets in addition to the energy market in simulations makes possible to compare and evaluate different market auction and commodity allocation models more efficiently. In this article, impacts of implementing different models of sequential and simultaneous allocation of energy, spinning reserve and replacement reserve on players behavior, possibility of price reversal, and payments in the markets are evaluated. In this regard, first, an approach based on the multi-agent system and the reinforcement learning algorithm is presented for simulating players behavior in the energy, spinning reserve and replacement reserve markets. Then, this approach is applied on a sample system including 17 generators, with various sizes and supply costs, under sequential and simultaneous allocation models. The analysis and evaluation results obtained about price reversal conditions and payments under different models will be useful for electricity markets policy- and decision-makers.

One of the major challenges for power system operators and administrators who are involved with the electricity market, reduce the uncertainty of wind power in a competitive market. In this study an integrated partnership model wind and pumped storage power plants in the energy and reserve market clearing Different aspects of the operating costs compared. Also, the role of pumped storage plants as storage for the increased penetration of wind power in the power network has been compiled. In addition, reduced operating costs, reducing the need to store the rotating and nonrotating joint exploitation of wind and storage are discussed. To simplicity of the problem, Three-bus system, the presence of a pumped storage unit and an wind unit during the simulation period of 4 hours is considered.

Aerodynamic analysis of wind turbine tower is one of the most important in structual design of wind turbines. Usually, dynamic response of the wind turbine tower under aerodynamic forces is calculated using the finite element method. FEM has high accuracy but it can considerably increases the computational works depending on the modeling type of foundation and modeling axial force variations. In this paper, transfer matrix method is used to reduce computational works and increase the speed of analysis instead of the FEM. For this purpose, the wind turbine foundation is modeled using CS model and required relations are extracted to determine of wind turbine response.Then, the transfer matrix method obtained results are compared with the results of the analytical method and experimental data in several case study which show good agreement in spite of low computational cost.

This study aimed to analysis of barriers and solutions for use of solar energy in Hekmatane district in order to protect the environment as one of the dimensions of sustainability. The research type was the applied-descriptive that data were gathered by survey method. Statistical population of research was farmers of Hekmatane district (N=34070) that 153 person selected through Cochran formula with random sampling method. The questionnaires validity was confirmed by a panel of specialist and faculty members. Reliability was measured after pre-test by Cronbachs alpha and it was 0.867 that was acceptable. The results of factor analysis showed barriers for use of solar energy in Hekmatane district categorized in four factors such as information-protection, policy, technology-cost and attitude that upper ingredients to say 72/273 % of total variance. Thus results of factor analysis showed solutions for use of solar energy in Hekmatane district in tree factors such as psychological, protection and education-cost that upper ingredients to say 75/546 % of total variance.

Rational and efficient energy production and distribution is one of the main issues of sustainable development. ‘’Combined Cooling, Heating and Power (CCHP)’’, has significant environmental benefits by increasing energy efficiency, reducing environmental pollution and consumption of thermal energy from fossil fuels. However, these systems have also higher cost of investment and more maintenance complexity. Therefore, In order to select the best CCHP system, these systems must investigated from the technical and sustainable aspects. In this paper, a hybrid model is developed for selecting and assessing the prime movers of CCHP which is using fuzzy multi criteria decision making (FMCDM), fuzzy TOPSIS method (FTOPSIS) and modified digital logic method (MDL). Thus, fuzzy theory, modified digital logic method and FMCDM model are explained and the various types of prime movers of CCHP systems, including Stirling engines, gas turbines, solid oxide fuel cells and micro-turbines and gas engine are studied according to the objectives of sustainable development and also are compared with a separate production system. To select the optimal system, the proposed decision model is implemented at Taleghani hospital in Tehran regarding to technical, economic, social and environmental aspects and its effectiveness has been analyzed. The results show that the best choice among the alternatives is reciprocating gas engine.

In this study, the energy and economic analysis of irrigated lentil production was done through investigation of different energetic and econometric indices. The required data were collected randomly by questionnaire method from 50 sesame farms in Mazandaran province of Iran. Chemical fertilizers and pesticides had the highest and lowest contribution on energy input equivalents, respectively. The values of energetic indices energy ratio, energy productivity, specific energy and net energy gain of sesame production were calculated as 1.81, 0.07 kg/ MJ, 13.80 MJ/kg, and 19949/34 MJ/ha, respectively. Econometric indices net return, gross return, economical productivity and benefit to cost ratio were obtained as 18925718 Rials/ha, 30020718 Rials/ha, 0.037 kg/1000 Rials and 1.51,respectively.

In recent years, environmental concerns are the greatest challenge in vehicle design. Electric vehicles seem to be a suitable solution to this problem. Therefore, numerous measures have been taken to increase the efficiency, reduce losses, and improve the performance of these vehicles. Aerodynamic characteristics improvement is a key issue that should be considered in vehicle design. In this paper, the effects of improving the aerodynamic characteristics on the electric vehicles are analyzed. For this purpose, installing movable rear spoiler along with a controller and covering the rear wheels have been proposed. In order to evaluate the proposed solutions, their effects on an electric vehicle prototype that has been constructed and developed by the authors have been modeled in MATLAB SIMULINK environment. The flow around the electric vehicle has been studied in ANSYS in order to calculate the drag and lift coefficients. The flow has been numerically solved using the Computational Fluid Dynamics (CFD). The standard k-ε turbulence model has been utilized in this study. The results show that improvement of aerodynamic characteristics in electric vehicles not only increases the stability of the vehicle, but also has a significant impact on the energy storage system, mileage, and the electric motor efficiency.

Due to the global understanding and the requirements on the use of renewable energy sources, solar energy has been lacoated in the focus of many research centers. The decline in the price of building next to the efficiency is the goal important of the solar cell industry. The application of thin film technology in these cells that used from photovoltaic effects is one way to reduce prices. Among these thin films, Cu(In Ga)Se has the highest efficiency and cost-effective among the thin films. In this paper the CIGS nanostructures solar cells is simulated by using Comsol and Sivaco-Tcad softwares and then to increase the efficiency, width and thickness of the ZnO: Al are optimized. The maximum efficiency is obtained 19.1% with Comsol in optimized thickness, and 19.702% with T-CAD software in 0.3 mm of thickness for this layer. Then, by optimizing the width of the layer in this optimized thickness, efficiency at 3mm width increase to 19.9%.

Due to the Finitude and the environmental effects of the use of fossil fuels in power generation, many countries are looking for alternative methods in the industry, including biomass that is one of the main sources of renewable energy, Despite the success and promote the use of biomass in electricity production in most parts of the world, Share of the electricity industry in the country is very small, Agricultral waste is a major source of it. The researchers can change the physical and chemical properties so that their combustion behavior the seme as fossil fuels , So in this article, the authors review the procedures to determine the quality biomass fuels ,such as divice analysis CHNOS, TG and using of firecad software for cotton stalk sample that Based on research conducted by the authors in connection with agricultural wastes fuel Ardabil province reported more occasions, the amount of pollutants produced by the combustion parameters are obtained.

HVAC systems and associated equipment consume a relatively large fraction of total building energy consumption, a significant portion of which is attributed to fan operation. The operation of dampers when installed can cause low energy consumption in supply and/or return fans if they are functioning in proper and optimal manner. In this study, mathematical experessions of individual components of HVAC systems are presented to model secondary HVAC systems based on the knowledge of the underlying physical phenomenon. A life-cycle cost analysis using detailed system modeling and initial and operating costs is applied to evaluate the economic feasibilities of constant air volume (CAV) and variable air volume (VAV) air conditioning systems. Several factors such as the building locations, system characteristics, resistance in the duct and dampers, supply air temperature, damper control, and minimum ventilation requirements are also considered during the evaluations. The results show that the way of the dampers been controlled has a significant effect on fan performance and its energy use. The VAV strategy if properly implemented can provide fan energy saving about 13%. It is found that payback period of VAV is suitable particularly by considering cooling and heating system altogether.

One of the crucial issues designers should pay particular attention to is to take thermal comfort into consideration in order to prevent the indiscriminate loss of energy. In this naturalistic research conducted in Shiraz, Iran, an old (Vakil Bazaar) and a new market (Mollasdra Commercial Street), as one of the most crowded urban place, were chosen and examined from the perspective of thermal comfort. Using questionnaires regarding the times when there is sunshine and shade, 120 shopkeepers and customers of two case studies were surveyed, and by employing Ecotect Analysis 2011 the surfaces with shade and sunshine in winter and summer were simulated. The results indicate 73.3% of Mollasadra street customers are dissatisfied with existing shade especially in the summer afternoon, and 93.3% of shopkeepers use cooling and heating equipment because of congruently of orientation and quality in sunshades with climate it showed a sharp contrast with the results obtained from Bazaar Vakil in which the customers were shopping with ease most of the times thanks to its roof. At the end, in order to reach thermal comfort and resolve the problem of Mollasadra Street, some suggestion have been proposed.