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Abstract This paper presents a novel approach for optimizing and also improving a flash-binary geothermal power plant whose binary cycle is an organic Rankine cycle (ORC) which is using various combinations of zeotropic mixtures as working fluid. All of the obtained results are optimized with particle swarm optimization (PSO) method for maximum total output power which is the objective function of the problem. First, the optimization is performed in the certain amounts of mixtures’ mass fractions. Then, the optimal values for the mass fractions are found. The results indicate that Pentane containing combinations show better performances. For instance, when the ORC unit is using the mixture of Pentane(0.45)/Butane(0.55) the highest output power is gaining: 1376.87 (kW) from the ORC unit and 5726.44 (kW) from the whole system. Also, the highest improvements in utilization of zeotropic mixture instead of pure fluids are obtained by this mixture which are 18.769 (%) with respect to ORC's output power and 3.950 (%) with respect to total output power. Finally, an investigation on flash chamber pressure effect on the system performance is accomplished and the results reveal that with increasing the pressure, the total output power decreases. Although lower flash chamber pressure seems to be a suitable choice, the investigation on the size parameters (SP) of the turbines shows that it is better to choose a mean amount of pressure for the flash chamber, thereby having the affordable amounts for the size parameters and also obtaining an adequate amount of total output power.

Abstract In this paper, a three-dimensional numerical simulation was carried out to characterize a high-ash coal gasification in a pressurized, oxygen-blown, two-stage E-Gas entrained flow gasifier. The Tabas coal was used as a high-ash feedstock, with 32 wt% ash and was compared with the Illinois #6 low-ash coal, with 10 wt% ash. The computational model was conducted in ANSYS FLUENT 14 based on the conservation equations described in the Eulerian–Lagrangian approach. Also, four heterogeneous combined with seven homogeneous reactions were solved via the finite rate and eddy-dissipation/finite rate model, respectively. Two different parametric analyses were conducted to characterize the gasification process in the E-Gas gasifier. These analyses cover the effects of the O2/Coal ratio and coal slurry water content on the gasifier performance characteristics such as the exit temperature, main species mole fractions, carbon conversion, high heating value, yield syngas fraction and cold gas efficiency. It was found that using the higher ash content coal decreases the cold gas efficiency about 5%, limits the gasifier economical operating range, and reduces the exit temperature, yield syngas and total higher heating value.

In this research, the electro-catalytic activity of nickel-copper (Ni-Cu) alloy towards oxidation of ethanol and its possible redox process were investigated in alkaline solution. For this purpose, cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques were employed. According to the cyclic voltammetry studies, Ni- Cu alloy compared to pure nickel can demonstrate a significantly higher response for ethanol oxidation. So, the enhancement of the anodic peak current corresponding to the oxidation of nickel hydroxide was accompanied with attenuated cathodic current in the presence of ethanol. The anodic peak currents have a linearly dependence on the square root of scan rate which is the characteristic of diffusion-controlled processes. Based on the chronoamperometry measurements, the reaction exhibited a Cottrellian behavior and the diffusion coefficient of ethanol was found to be 1.26 - 10-5 cm2 s-1. The impedance spectroscopy declared electro-catalytic behavior of Ni-Cu electrode for oxidation of ethanol and showed that the charge transfer resistance decreases by increasing the ethanol concentration.

This work investigates the effect of using palm oil based additive on four stroke engine performance and exhaust emission. This investigation focused on the comparison of performances of an internal combustion engine fitted with the fuel additive. Performance tests were conducted for, fuel consumption, engine torque and engine power, while exhaust emissions were analyzed for carbon monoxide (CO), carbon dioxide (CO 2 ), oxygen (O 2 ) and unburned hydrocarbons (HC) at variable engine speed ranging from 1000 to 6000 rpm. The results showed that the effect of the adding fuel addictive gives more power and increases fuel efficiency compared to the fuel without additives.

Abstract Since the discovery of electricity, the demand for effective energy storage methods has increased. Energy storage devices are efficient tools used to manage power supply and produce resilient and cost-effective energy frameworks. Advanced technologies in modern economy and society require the application and design of inexpensive, highly efficient, and various infrastructures for energy storage systems. For instance, fuel cells, batteries, electrochemical capacitors, and conventional capacitors are used as energy storage devices because they can enhance energy or power densities. They can also supply energy within short or long periods. Their performances have also been improved. This review emphasizes carbon nanotubes as electrode materials for lithium-ion batteries and electrochemical capacitors. Different types of substrates and thin films may yield various structural and electrochemical properties of carbon nanotubes. This review also discusses their electrochemical performance observed through cyclic voltammetry and charge-discharge.

Abstract Finite Element Analysis is commonly used for product designer to visualize the structural analysis of a product. Not much works done by these designers using Computational Fluid Dynamic, CFD due to the complexity of the application. In this study, the dynamic of the water flow within the turbine had been predicted as the preliminary design steps. Several significant parameters had been reviewed and tested using CFD tool to give better insight of the important components of the turbine on its performance, in terms of the velocity, the pressure and the vorticity of the water. Three different velocities were used which was 5 m/s, 9.9 m/s and 13 m/s. The maximum outlet velocity that can be produced at various inlet velocity were predicted to be 17.09 m/s, 33.79 m/s, and 44.37 m/s. The pressure gradients were 159 kPa, 618 kPa, and 107 kPa. Meanwhile, the vorticities were 48.28 m/s, 91.66 m/s, and 120.5 m/s. Furthermore, the vorticity distribution was observed through the simulated work.

Abstract This paper presents a novel load frequency control (LFC) model for an interconnected thermal two-area power system in the presence of wind turbine generation and redox flow battery (RFB). The study model includes frequency and voltage excitation loops with needed interactions between them along with the power system stabilizer. A two-degree of freedom (2DOF)-based controller called 2DOF-Hybrid controller is developed as secondary controller in automatic generation control (AGC) to adjust the power outputs of generator and RFB. Also, the dynamic performance of the proposed controller in the RFB loop is evaluated. The Hybrid controller comprises a fractional-order proportional-integral-derivative (FOPID) controller and a tilt-integral-derivative (TID) controller. In order to obtain accurate and realistic results, the outputs of thermal power plants are restricted by considering the limitations of the governor dead-band and generation rate constraint. Since the controller performance depends on its parameters, these parameters are optimized using a modified sine–cosine algorithm (MSCA). The dynamic performance of the proposed 2DOF-Hybrid controller as secondary controller of the AGC loop is compared with integral-double-derivative (IDD), integral-tilt-derivative, proportion-integral–derivative (PID)-DD, 2DOF-PID, 2DOF-TID, and 2DOF-FOPID ones under different scenarios. In addition, the superiority of the MSCA is compared with benchmark metaheuristic methods including an SCA, a genetic algorithm, a particle swarm optimization, and a differential evolution. The sensitivity analysis is also carried out to show the robustness of the proposed controller versus the changes of the parameters. The simulation studies on two-area and New England 39-bus power systems are carried out to examine the advantage of the presented LFC scheme. A range of power system signals such as frequencies of areas, terminal voltages, and tie-line power flow is demonstrated to compare the controllers. The results disclose that the proposed LFC scheme provides better dynamic performance compared to other ones. Moreover, RFB modeling based on the proposed controller is superior to conventional RFB modeling in reducing the amplitude of the oscillations.

AbstractThis paper demonstrates the potential of the quartzite as an economic and efficient filler material in thermal oil direct thermocline storage system. This natural rock appears as a good candidate for thermal energy storage by sensible heat up to 350°C.In the present study, many experiences were conducted in order to choose the best rock among five varieties (quartzite, basalt, granite, hornfels and marble) which are found abundant in Morocco. The optimal rock was selected according to various criteria such as surface characteristics, porosity, density, calorific capacity, hardness, mechanical resistance. The chosen rock should also provide a thermal stability during energy exchange with the heat transfer fluid (HTF). It should be noted that choice of the rocks as a filler material may reduce the quantity of the HTF used for charging and discharging the thermal energy. Hence, the shrinkage of tank volume by thermocline sensible heat storage system using rocks as filler materials allows reducing the cost with an increase in the efficiency of the system.

Abstract Current conventional agricultural systems using intensive energy has to be re-vitalized by new integrated approaches relying on renewable energy resources, which can allow farmers to stop depending on fossil resources. The aim of the present study was to compare wheat production in dryland (low input) and irrigated (high input) systems in terms of energy ratio, energy efficiency, benefit/cost ratio and amount of renewable energy use. Data were collected from 50 irrigated and 50 dryland wheat growers by using a face-to-face questionnaire in 2009. The results showed that the total energy requirement under low input was 9354.2 MJ ha −1 , whereas under high input systems it was 45367.6 MJ ha −1 . Total energy input consumed in both dryland and irrigated systems could be classified as direct, indirect, renewable and non-renewable energies which average in two wheat production systems were 47%, 53%, 24% and 76%, respectively. Energy ratios of 3.38 in dryland and 1.44 in irrigated systems were achieved. The benefit–cost ratios were 2.56 in dryland and 1.97 in irrigated wheat production systems. Based on the results of the present study, dry-land farming can have a significant positive effect on energy-related factors especially in dry and semi-dry climates such as Iran.