فهرست مطالب

  • Volume:4 Issue: 1, 2020
  • تاریخ انتشار: 1399/02/21
  • تعداد عناوین: 7
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  • Abdollah Baghaei Daemei *, Mostafa Kazemi, Mahsa Malekfarnoud, Seyed Mostafa Tavakoli Mollasaraei, Ronak Geravandi Pages 1-12

    Energy crises and the continuous fluctuation cost of fossil fuels have moved researchers' attention towards new sustainable and renewable energy sources. The three R-type thinking (i.e., reduce, reuse, and recycle), utilizes three great ways to protect the environment by saving money, energy, and natural resources. The Australian Building Codes Board is considered as a project for energy efficiency. BCA has also identified eight different climate zones within Australia. This paper discusses the climate conditions of the state capital cities of Sydney, Adelaide, and Perth that belong to the same climate zone 5 of the BCA. On this basis, the present paper covered three major aims. At first, we are doing to identifying the similarities and the differences in climate conditions in case studies, as a result of bioclimatic features. Then, the thermal performance of the "green roof" was evaluated in all three cases. The simulation was carried out on a residential building block for one year (four seasons) using the Design Builder software. Finally, based on the findings of this paper, building orientation strategy was chosen to assess natural ventilation through BEopt V. 2.8 software on a residential building in Sydney. The results showed that the green roof in Sydney could be an optimal thermal performance, in comparison with other cases. Also, it can be stated that the findings of natural ventilation simulation show the most optimal building orientation in Sydney is 45 degrees to the southeast in which this among included 17% has better performance to improve wind flow.

    Keywords: Three R-type, sustainable design, passive techniques, green roof, Energy efficiency, Building simulation, Natural Ventilation
  • Younes Noorollahi *, Armin Aligholian, Aminabbas Golshanfard Pages 13-26

    Energy crisis and global warming due to fossil fuel implementation in the energy production sector and in the transportation sector have stimulated global trends to employ the electric vehicles (EVs) in the transportation sector and renewable energy sources (RESs) in the power generation. Coordinated charging of EVs can bring some benefits by itself such as voltage and frequency regulation, spinning reserve, load leveling, peak shaving, RESs support, GHG emission saving and so on. But implementation of this scenario with uncoordinated EV charging which can impose a huge amount of excess load on the grid. In this regard, EVs coordinated energy scheduling is inevitable. This paper comprehensively reviewed the pros and cons of integrating EVs to the grid and recent investigations in EV energy scheduling especially ones that focused on stochastic energy scheduling. Moreover, with knowing this fact that, microgrid with the presence of different distributed generation (DG) such as RESs and a diverse storage system such as EVs would have an important role in the future smart grid, thus, this paper aims to illustrate further research opportunities in this particular field. Also, different types of uncertain variables in recent studies and mathematical methods for optimizing the relevant objective functions of EVs charging are reviewed inclusively. Finally, future trends and investigation occasions in this field of study are discussed.

    Keywords: stochastic optimization, electric vehicles, Renewable Energy Sources, microgrid, heuristic optimization
  • Sassan Azad *, MohammadMehdi Amiri, MohammadTaghi Ameli Pages 27-33

    Given the importance of the power system security and the role of the operator in enhancing this feature, improving the operator’s actions and information in the power system management is critical. The proper tools and available information for the operator can continuously improve the power system security. During power system operation, the operator needs to identify probable hazardous contingencies to assess power network security online. Thus, contingency ranking based on their importance has always been of interest to researchers. In present study, a new method is proposed for appropriate contingency ranking and online power network security assessment based on the Phasor Measurement unit (PMU) data. In the proposed method, unlike the previous methods, two voltage and angle indices were used. Since the variables of load-flow studies are used to calculate the proposed index, this index can provide a comprehensive assessment of the network security. The proposed index is implemented on three IEEE 14-, 30- and 57-bus test systems to evaluate its performance. First, using this index, contingency analysis is carried out in 2000 operational points and the obtained results are compared with a randomly selected operating point. The results indicated the performance and response time of the proposed index.

    Keywords: power systems, Security assessment, Contingency rating, Phasor measurement units, Voltage-angle index
  • Amir Amini, Hamid Falaghi *, Majid Oloomi Buygi Pages 34-45
    The transmission network expansion planning is necessary for supplying the future needs, considering load growth. Furthermore, in restructured environments, transmission lines provide the required infrastructure for creating a competitive environment. In recent years, there has been a significant advancement in storage technologies. This advancement leads to using energy storage systems to postpone the construction or replacement of transmission lines. Therefore, in this paper, the problems of transmission expansion planning and energy storage systems deployment are investigated simultaneously. Considering the presence of storage devices and their effect on network operation cost, in this paper, the operation cost is modeled as an independent objective function along with investment cost. Moreover, the problems of transmission and storage expansion planning are modeled as a tri-objective optimization problem with the objectives of reducing costs and increasing the social welfare index in the power market. The multi-objective shuffled frog leaping evolutionary algorithm is used to solve these problems. The presented model for expansion planning is implemented and analyzed on IEEE 24-bus test system in the presence and absence of energy storage systems, and the effect of change in the price of energy storage systems is studied. The results of this research show that as the technology advances and the storage costs decrease, energy storage systems can play a pivotal role in reducing expansion planning costs of the power network and improving market-based indices in the restructured environment.
    Keywords: Energy storage systems, Locational marginal price, Multi-Objective Optimization, power market, Transmission expansion planning
  • Ghaleb Mostafaee, Reza Ghandehari * Pages 46-51
    Dynamic reconfiguration of photovoltaic arrays is one of the effective ways to decrease partial shading effects. In this paper, by using auxiliary modules and after a suitable fixed reconfiguration, an optimizer and economic method based on dynamic reconfiguration is presented. In this method, Auxiliary modules are arranged next to the photovoltaic array and replaced with shaded modules to maximize the energy delivery. The best connection between the auxiliary modules and the array is determined by an optimal decision process. The objective function for this decision process is energy delivery of the solar array in shadow conditions which is maximized by the genetic algorithm. Significant improvement in the output power of the photovoltaic array and smaller number of switches than the other dynamic reconfiguration methods are the main advantages of the proposed method. Benefits and effectiveness of this method are compared with other recently dynamic configuration approaches, and the results confirm power enhancement of the photovoltaic arrays in various shadow patterns.
    Keywords: Photovoltaic array, partial shading, dynamic reconfiguration, Power Enhancement
  • Hadi Sadeghi, Masoud Rashidinejad *, Moein Moeini Aghtaie, Amir Abdollahi Pages 52-66

    Following increases in interdependencies of gas and electricity energy systems (G&ES) in parallel with the incremental growth of demands for the relevant energy carriers, the need for a more optimal capacity expansion planning approach, in particular in developing countries, is felt more than before. By considering the most important factors that can affect expansion strategies of the Iranian G&ES, the present paper proposes a comprehensive planning model for the expansion of the G&ES using an integrated approach. The interactions between the energy systems (ESs), environmental issues, renewables penetration rate under the implementation of supportive energy policies in a semi-deregulated environment, and the possibility of employing the salt caverns and/or depleted fields for storing natural gas, are included the aforementioned factors. Formulated as a mixed-integer linear programming problem in the GAMS software environment, the model aims to identify the least-cost planning schedule of candidate infrastructures, while applied techno-economic constraints are satisfied. Two different scenarios are conducted to investigate the superiority of employed planning methodology. The simulation results demonstrate that in order to cope with the challenges, co-expansion planning of the G&ES in a coordinated framework can reach more optimal and realistic strategies compared with the traditional separate expansion planning models. In addition, analysis shows that the integrated expansion planning of the ESs gives the opportunity of exploring the impact of different aspects on each other and better perception of the interactions with planners.

    Keywords: Integrated expansion planning, Iranian gas, electricity systems, Gas storage systems
  • Muluken GETIE *, Mehare DEGEFA Pages 67-74
    The major energy consuming sector in Ethiopia is the domestic usage. Cooking takes the major share from household energy consumption. Although urban areas of Ethiopia are mainly accessible to electricity, most households still mainly depend on biomass-based energy sources, which are very traditional and associated with inefficient technologies. The primary objective of this study is to assess the general trend of household energy utilization and the factors that affect the choice of energy sources and the associated energy technologies in urban areas of Eastern Amhara. The study analyzes the primary and secondary data collected from the selected sample of households and experts in the study area. The study covers the determinant factors for household energy choice, especially for cooking application; the community awareness level, the energy appliance types in use, the energy experts’ contribution, and the future energy/energy technology demand. The analysis is conducted mainly based on demographic variables such as residence type, educational status, and availability of technology. The result shows that the energy sources type and the energy technology preference at the household level are largely depend on the education level of house heads and type of residence they live in. For instance; 76.3%, 34.1%, and 22.5% of the households are who are living in the condominium, own apartment, and rented houses respectively are using electricity for injera baking. Model to validate the findings of the descriptive statistics, to estimate the trend and relations among different factors for the whole population of the study region has been developed.
    Keywords: Household energy, Injera baking, Stew cooking, Utilization trend, Eastern Amhara