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Abstract In the current study, an integrated renewable based energy system consisting of a solar flat plate collector is employed to generate electricity while providing cooling load and hydrogen. A parametric study is carried out in order to determine the main design parameters and their effects on the objective functions of the system. The outlet temperature of generator, inlet temperature to organic Rankine cycle turbine, solar irradiation intensity ( I ) , collector mass flow rate ( m ˙ c o l ) and flat plate collector area ( A P ) are considered as five decision variables. The results of parametric study show that the variation of collector mass flow rate between 3 kg/s and 8 kg/s has different effects on exergy efficiency and total cost rate of the system. In addition, the result shows that increment of inlet temperature to the ORC evaporator has a negative effect on cooling capacity of the system. It can lead to a decrease the cooling capacity from 44.29 kW to 22.6 kW, while the electricity generation and hydrogen production rate of the system increase. Therefore, a multi objective optimization is performed in order to introduce the optimal design conditions based on an evolutionary genetic algorithm. Optimization results show that exergy efficiency of the system can be enhanced from 1.72% to 3.2% and simultaneously the cost of the system can increase from 19.59 $/h to 22.28 $/h in optimal states.

Abstract A three dimensional numerical model of the northwest (NW) Sabalan geothermal system was developed on the basis of the designed conceptual model from available field data. A numerical model of the reservoir was expressed with a grid system of a rectangular prism of 12 km × 8 km with 4.6 km height, giving a total area of 96 km2. The model has 14 horizontal layers ranging in thickness between 100 m to 1000 m extending from a maximum of 3600 to −1000 m a.s.l. Fifteen rock types were used in the model to assign different horizontal permeabilities from 5.0 × 10−18 to 4.0 × 10−13 m2 based on the conceptual model. Natural state modeling of the reservoir was performed, and the results indicated good agreements with measured temperature and pressure in wells. Numerical simulations were conducted for predicting reservoir performances by allocating production and reinjection wells at specified locations. Three different exploitation scenarios were examined for sustainability of reservoir for the next 30 years. Effects of reinjection location and required number of makeup wells to maintain the specified fluid production were evaluated. The results showed that reinjecting at Site B, immediate adjacent to production zone, is most effective for pressure maintenance of the system. On the base of existing data and assumptions the reservoir can sustain producing fluid equivalent to 50 MWe of electricity for more than 30 years. The reservoir can produce the maximum amount of fluids equivalent to 90–100 MWe for only 5 years, but the production capacity decreases to 50 MWe after 20 years of operation because of pressure and enthalpy drop. The reservoir can sustain 50 MWe over 100 years that can be defined as a sustainable production level of the field.

Abstract In the present study, enhancing the heat transfer is experimentally investigated by the electro-hydrodynamics (EHD) through a single-pass air-cooled PV/T (Photovoltaic/Thermal System). The corona wind increases the heat transfer coefficient by producing a secondary flow and vortex, and consequently, increases the PV/T system efficiency. The effects of the corona wind are studied by changing the voltage values and the flow rates in the air channel. The results show that the corona wind is effective on enhancing the system performance; so that the heat transfer coefficient increases by 65% in natural flow regime by applying 11 kV voltage in the pilot setup. Totally, the thermal efficiency of the PV/T system increases up to 28.9%. Also, the effects of corona wind are studied by changing the amount of the applied high voltages and flow rates.

With the spotlight on smart grid development around the world, it is critical to recognize the key factors contributing to changing power system characteristics. This is more apparent in distribution systems with the integration of renewable energy sources, energy storage, and microgrid development. Utilities are also focusing on the reliability and resiliency of the grid. These activities require distribution automation (DA) strategies that take advantage of available technologies while promoting newer solutions. It is necessary to create a roadmap for holistic DA strategies in a smarter grid. Sustainable and resilient grid development is a paradigm shift requiring a new line of thinking in the engineering, operation, and maintenance of the power system. International perspectives on DA are also addressed, with the understanding that one solution will not fit all. Integrating technical, business, and policy decisions into the challenges will generate the development of technologies, standards, and implementation of the overall solution. The challenges in the development of industry standards are also discussed. This paper explores the challenges and opportunities in the changing landscape of the distribution systems. Evolution of technologies and the business case for infrastructure investment in distribution systems are covered in another paper by the same authors.

The rate of using plugin hybrid electric vehicles (PHEV) will be increased in near future in Iran. In the present article, a comparison between existing electricity pricing method (BR) and time of use (TOU) demand response program was made in order to study whether consumers would be motivated purchasing PHEVs or not. The total monthly electricity consumption and the monthly electricity bill utilizing both methods are calculated. Aimed at economic viability evaluation, rate of return (ROR) and net present value (NPV) are calculated in different cases. A motivating loan is entered to cost and benefit analysis and further economic analysis is made.

Refrigerators have considerable share of residential consumption. They can be, however, flexible loads because their operating time and consumption patterns can be changed to some extent. Accordingly, they can be selected as a target for the study of Demand Side Management plans. In this paper, two experimental models for a refrigerator are derived. In obtaining the first model, following assumptions are made: the ambient temperature of refrigerator is assumed to be constant and the refrigerator door is remained closed. However, in the second model the variation of ambient temperature and door-opening effects are considered according to some general patterns. Further, two strategies are proposed to reduce the annual electricity cost and electric power consumption at peak-load times. These strategies together with the aforementioned models form an optimization problem which is, then, solved by Particle Swarm Optimization algorithm. Simulation results indicate a reduction of more than 28.61% in the annual cost. Also, the annual electricity consumption has decreased more than 20.46% and load shifting from the peak periods has achieved about 40%. In addition, these approaches are implemented in laboratory and their performance is confirmed by experimental results.

AbstractEstablishment of demand security is a key incentive to boosting oil and gas investments in countries, thus, making the study of demand security also critical. In the present research, the primary aim is to explore the capacity of Caspian Markets in establishing energy demand security in the Caspian region and investigate its impact on oil and gas exports from the region. Therefore, additional factors such as political issues, international support and geographical limitations should also be considered for the determination of energy demand security. To address this need, a hybrid index is proposed that characterizes energy demand security in the Caspian region. In this research, we have looked at the countries of the Caspian region as a collective identity and we have avoided looking at the particular country of the Caspian region. In this study, we have used analytic hierarchy process (AHP method) to make hybrid index (Caspian energy demand security index). Results produced by the hybrid index demonstrate the superior state of Iran and Russia’s swap markets in establishing demand security in the Caspian region in the years 2020 and 2030 when compared to the markets of China, European Union (EU) and India that follow, respectively. The exception to this trend is that in 2030, the European Union will demand more Caspian gas than China.

In this study, nitrogen oxides emission reduction is investigated with humid combustion in a non-premixed combustion chamber of a gas turbine that burns natural gas using computational fluid dynamics. For humidification of the combustion chamber, two methods are studied: direct water injection into the combustion chamber and increasing the inlet air humidity. The mathematical model of combustion, governing equations, numerical method, and the combustion chamber properties are extensively discussed. The mathematical model is first validated. The two approaches are then simulated and compared for low water and steam flow rates. The results show that at the water to fuel ratio of about 1, direct water injection is 1.69 times more efficient than increasing inlet air humidity in reducing nitrogen oxide emission. Finally, it is concluded that direct water injection is appropriate at low flow rates (up to the fuel flow rate) and for situations where reducing nitrogen oxide emission is highly relevant. Furthermore, increasing the humidity of the inlet air up to 25% is suitable and increases the combustion efficiency and reduces pollutants, while the outlet temperature is not decreased too much.

Feed in tariff (FiT) is one of the most efficient ways that many governments throughout the world use to stimulate investment in renewable energies (REs) technology. For governments, financial management of the policy is very challenging as that it needs a considerable amount of budget to support RE producers during the long remuneration period. In this paper, we illuminate that the early growth of REs capacity could be a temporary boost and the system elements would backlash the policy if financial circumstances are not handled well. To show this, we chose Iran as the case, which is in the infancy period of FiT implementation. Iran started the implementation of FiT policy in 2015 aiming to achieve 5 GW of renewable capacity until 2021. Analyses show that the probable financial crisis will not only lead to inefficient REs development after the target time (2021), but may also cause the existing plants to fail. Social tolerance for paying REs tax and potential investors trust emanated from budget related mechanisms are taken into consideration in the system dynamics model developed in this research to reflect those financial effects, which have rarely been considered in the previous researches. To prevent the financial crisis of the FiT funding and to maintain the stable growth in long term, three policy scenarios are analyzed: continuation of the current program with higher FiT rates, adjusting the FiT rates based on the budget status, and adjusting the tax on electricity consumption for the development of REs based on the budget status. The results demonstrate that adjusting the tax on electricity consumption for the development of REs based on budget status leads to the best policy result for a desired installed capacity development without any negative social effects and financial crises.