Subjects -> ENERGY (Total: 414 journals)
    - ELECTRICAL ENERGY (12 journals)
    - ENERGY (252 journals)
    - ENERGY: GENERAL (7 journals)
    - NUCLEAR ENERGY (40 journals)
    - PETROLEUM AND GAS (58 journals)
    - RENEWABLE ENERGY (45 journals)

ENERGY: GENERAL (7 journals)

Showing 1 - 7 of 7 Journals sorted alphabetically
Energy Research Journal     Open Access   (Followers: 3)
Greenhouse Gases : Science and Technology     Hybrid Journal   (Followers: 4)
International Journal of Energy Optimization and Engineering     Hybrid Journal   (Followers: 3)
International Journal of Powertrains     Hybrid Journal   (Followers: 2)
International Journal of Renewable Energy Development     Open Access   (Followers: 7)
Journal of Power Technologies     Open Access   (Followers: 6)
Journal of Thermophysics and Heat Transfer     Hybrid Journal   (Followers: 94)
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International Journal of Renewable Energy Development
Number of Followers: 7  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2252-4940 - ISSN (Online) 2252-4940
Published by Diponegoro University Homepage  [16 journals]
  • The Effect of Wood Tar and Molasses Composition on Calorific Value and
           Compressive Strength in Bio-coke Briquetting

    • Authors: Erlina Yustanti; Abrar Muharman, Anggoro Tri Mursito
      Abstract: Biomass-based materials have the potential to replace conventional cokes for blast furnaces in the steel manufacturing study. Biomass as a renewable energy source can reduce the consumption of coking coal. The current challenge is saving fossil energy and waste management. The steelmaking industry with environmentally friendly processes and high energy efficiency is expected today. Many researchers have partially developed biomass as an alternative renewable resource to replace fossil fuels. This study aimed to determine the effect of composition the blending ratio of wood tar and molasses as a binder on the calorific value and compressive strength of bio-coke. The carbonization of redwood waste to produce high-quality charcoal was carried out at 500 °C with a kiln rotation speed of 20 rpm and a slope of 5°. The resulting charcoal showed a promising result with a 23.87 MJ/kg calorific value. The carbonization process of the redwood increased the fixed carbon value by up to 130% and the calorific value by 40%. The second part of this study focuses on bio-coke production by blending coking coal with redwood charcoal at 90:10 wt%. The coking coal and the redwood charcoal particle sizes were 40 and 50 mesh, respectively. A 15 wt% binder was added to increase the compressive strength of the bio-coke. The binder composition ratios of molasses: wood tar were 15:0, (12.5:2.5), and 10:5 wt%. The briquette was pressed using a cylinder die with a height: diameter ratio of 2.7:5.0 cm, then compacted up to 20 MPa followed by heating at 1100 °C for four hours. The bio-coke with a binder composition of 2.5 wt% wood tar + 12.5 wt% molasses produced a compressive strength of up to 5.57 MPa with a sulfur content of 0.8 wt% and produced a calorific value of 31.25 MJ/kg with an ash content of 9.6%. The study showed that the bio-coke produced meets some requirements for steelmaking industry.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • MATLAB/Simulink Based Instantaneous Solar Radiation Modeling, Validation
           and Performance Analysis of Fixed and Tracking Surfaces for the Climatic
           Conditions of Lahore City, Pakistan

    • Authors: Naseer Ahmad
      Abstract: Mathematical modeling, simulation and experimental validation of instantaneous solar radiation is conducted in this article. The input parameters of the developed model are solar constant, latitude & longitude of the selected site, collector surface azimuth and elevation angle. The whole model is developed in MATLAB/Simulink and plots global radiation for any selected day of the year. To validate the model, actual data from RETScreen (energy management software) is taken and compared with the predicted data from developed model. During the whole year the predicted specific insolation is 226.65 MJ/m2/day and actual is 202.14 MJ/m2/day. The percentage error of the predicted data is 10.8% higher than the actual data. The validated model is used to calculate the monthly received solar radiation energy for the fixed surface and tracking surface. The yearly harvested solar energy by horizontal, yearly and monthly optimal tilt surfaces are 6828 MJ/m2, 7405 MJ/m2 and 7761 MJ/m2 respectively. Yearly insolation gain of the yearly optimal tilt and monthly optimal tilt collector surface is 8% and 14% as compared to the energy harvested by horizontal surface. For the single and dual axis tracking surfaces, yearly harvested energy is 8843 MJ/m2 and 9374 MJ/m2 respectively and this figure is 30% and 37% more as compared to the horizontal surface. If the insolation received by yearly optimal tilt is considered as reference value, then energy gain for monthly tilt, single and dual axis tracking is recorded as 5%, 19% and 27% respectively
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Operational Planning and Design of Market-Based Virtual Power Plant with
           High Penetration of Renewable Energy Sources

    • Authors: Zahid Ullah; Muhammad Baseer
      Abstract: Renewable energy sources (RESs) are becoming more prevalent as a source of clean energy, and their integration into the power market is speeding up. The fundamental reason for this is the growing global concern about climate change. However, their weather-dependent and uncertain nature raise questions about grid reliability particularly, when photovoltaics (PVs) and wind turbines (WTs) technologies are used. As a result, rationally managing Energy Storage Systems (ESSs) under the virtual power plant (VPP) setting is being encouraged as a way of minimizing the impact of the uncertain nature of renewable energies. A VPP is comparatively a new concept that aggregates the capacities of dispatchable and non-dispatchable energy sources, electrical loads, and energy storage systems for the purpose of improving energy supply and demand imbalance. It enables individual consumers and producers to participate in the power markets. In this study, a new market-based (MB)-VPP operational planning model is designed and developed with the aim to evaluate the optimal active power dispatched by (WT, PV, and ESS) operating in the day-ahead power market to maximize the social welfare (SW) of the market. SW can be described as the maximization of the consumer’s benefit function minus the cost of energy generation. The optimization process was carried out by using a scenario-based approach to model the uncertainties of renewable energy sources (i.e, WTs & PVs) and load demand. The proposed model and method performance is validated by simulation studies on a 16-bus UK generic distribution system (UKGDS). The simulation results reveal that the proposed approach maximizes overall system social welfare. The capacity of total active power dispatched by (WT, PV, and ESS) has a positive impact on the VPP profit maximization. This empirical study could be used as a reference baseline model for other energy services providers interested in conducting similar research in the future.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Solar Tracking System with Photovoltaic Cells: Experimental Analysis at
           High Altitudes

    • Authors: Elmer Rodrigo Aquino Larico; Angel Canales Gutierrez
      Abstract: There is currently an urgent need to study the application of solar energy to photovoltaic systems due to the need to produce electricity; indeed, maximizing the performance of solar energy promotes efficient and sustainable energy systems. The objective of this study was to determine the photovoltaic performance of a dual-axis solar tracker based on photovoltaic cells with different inclination angles at high altitudes above 3800 m.a.s.l. A solar tracking system activated by two linear actuators was implemented to automatically follow the trajectory of the sun during the day, and the results were compared with those from a fixed photovoltaic system. In addition, due to the climatic variation in the area, photovoltaic cells installed at different inclination angles were used to maximize electricity production and processed by a programmable logic controller (PLC). Finally, principal component analysis (PCA) was used to determine the factors that influenced the performance of the photovoltaic system during the experimental period. The results showed that the maximum monthly performance of the solar tracker was 37.63% greater than that of the fixed system, reaching 10.66 kWh/m2/d on sunny days in peak sun hours (PSH). On days with frequent rain and clouds, the partial yield was less than 14.38%, with energy production during PSH of 6.54 kWh/m2/d. Therefore, in this high-altitude area, the performance of the solar tracker was greater from July to October; from November to February, the performance was reduced due to the occurrence of rain.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Effect of Different Hydrothermal Temperatures on the Properties on
           Nano-Silica (SiO2) of Rice Husk

    • Authors: Irzaman Irzaman; Irmansyah Irmansyah, Siti Aisyah, Nazopatul Patonah Har, Aminullah Aminullah
      Abstract: Rice husk has high silica (SiO2) content and can be used as the primary material for making nano-silica. One of the methods for synthesizing nano-silica was the hydrothermal method. The objective of this study was to synthesize nano-silica from rice husks by observing the effect of temperature in the hydrothermal process on the structure, electrical and particle properties of nano-silica. The hydrothermal process temperature was 150, 200, and 250 °C for 4 hours. The results showed that all nano-silicas were in the amorphous phase. The particle size was in the range of 0.16-13.49 nm with more uniform size distribution on nano-silicas of 200 °C and 250 °C than nano-silica at 150 °C. These three nano-silicas were included in the semiconductor category by increasing temperature and frequency. In addition, these treatment variations resulted 200 °C for 4 hours and pressure of 2 atm as the optimum treatment for manufacturing nano-silica of rice husk ash. This nano-silica could be used as semiconductor material for electronic industry.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Numerical Investigation of Solidity Effect Based on Variable Diameter on
           Power Performance of H-type Darrieus Vertical Axis Wind Turbine (VAWT)

    • Authors: Muhamad Fadhli Ramlee; Shaikh Zishan, Wan Khairul Muzammil, Ahmad Fazlizan
      Abstract: Renewable energy resources especially wind energy, have seen significant growth in the worldwide energy market as clean energy sources. This has brought attention to areas with low and moderate wind speeds. Small-scale Darrieus vertical axis wind turbine (VAWT) with omnidirectional capability captures potential energy in these areas at a cost-effective scale. Numerous studies have been conducted to optimise their design, hence improving the performance of these turbines. Turbine solidity, σ, representing the ratio of the overall area of the blades over the swept area of the turbine, is one of the influential geometrical factors that significantly affect wind turbine performance. Previous studies on solidity focused on the number of blades and blade length variations, while the study on turbine diameter is limited. Hence, this paper intends to numerically investigate the effect of solidity that corresponds to different turbine diameters. Power performance and flow characteristics are investigated closely according to different solidity, σ and tip speed ratios, λ using high-fidelity computational fluid dynamic (CFD) method, which solves the unsteady Reynolds-Averaged Navier-Stokes (RANS) equations. Solidity and tip speed ratios vary within a wide range of 0.3 – 0.7 and 0.5 – 4.5, respectively. The results show that decreasing the turbine solidity from 0.7 to 0.3 could significantly increase the maximum power coefficient, Cp, by 30%. However, turbine with high solidity (σ = 0.7) generate much higher instantaneous moment coefficient, Cm than the low solidity turbine (σ = 0.3), but at lower λ and a narrower range of λ. The difference in turbine's performance between high and low solidity turbine is attributed to stall experienced by the blade at low λ and the blockage effect experienced by the turbine at moderate to high λ that significantly influence the energy generation at downstream region
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Experimental Investigation of Bladeless Power Generator from Wind-induced

    • Authors: La Ode Ahmad Barata; Kiwata Takahiro, Toshiyuki Ueno, Samhuddin Samhuddin, La Hasanudin
      Abstract: The power harvester unit from flow-induced vibration (FIV) was designed to harness energy from low flow velocity based on the magnetostrictive effect on the galfenol (Fe – Ga alloy) strip induced by the oscillating bluff body. This study aimed to investigate the cross-section variation’s effect on the FIV characteristics and the magnetostrictive material’s performance for the bladeless power generator. The generator model’s vibration characteristics and performance tests were conducted in the wind tunnel test using the wind-receiving unit (WRU) variation. The results showed that the resonance reduced-velocity (Vr) were around 3.7 and 4.0 for rectangular and circular cylinders, respectively. Furthermore, the effect of rectangular depth variation on the power generation output is linear to the test models’ displacement rate and vibration frequency. The harvester’s maximum power generation was 5.25 mW, achieved using the rectangular prism with depth D = 0.4H. The power coefficient was also evaluated for different wind-receiving models. The harvester model lit up 54 LED lamps in the wind tunnel test. The voltage output is sufficient to provide electric power resources for an IoT system, sensor, and wearable or wireless devices. The harvester model successfully generated a voltage signal under the initial field test with an ambient wind velocity of 0.9 – 2.71 m/s. Therefore, this study recommends the development of bladeless power generators in the future.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • A Brief Study on the Implementation of Helical Cross-Flow Hydrokinetic
           Turbines for Small Scale Power Generation in the Indian SHP Sector

    • Authors: Jayaram Vijayan; Bavanish Balac Retnam
      Abstract: This article addresses the simulation and experiments performed on a Gorlov Helical Turbine (GHT) by altering the index of revolution of its helical blades. Gorlov Helical Turbine is a hydrokinetic turbine that generates energy from the perennial/tidal source. The paper serves a two-fold purpose: parametric optimisation of Gorlov Helical Turbine with respect to the index of revolution and viability of installing the turbines in river creeks. Nine models of turbines with a diameter of 0.600 m and a height of 0.600 m were generated with different indices of revolution and then subjected to simulation studies. A significant rise in the output torque of the turbine was not observed with the various indices of revolution, even as the probability of finding a section at every azimuthal position is likely to rise. Gavasheli's solidity ratio formula was used to formulate an expression for the output power. The output power as per analytical formulation is 1.11 W, which is of the order of output power obtained through simulation (0.951 W). The studies suggest that 0.25 remains the optimum value for the index of revolution of the helical blades. A model with 0.25 as the index of revolution was fabricated and tested at a river creek. The results were found to agree with the simulations accounting for the losses. The study results could encourage setting up hydrokinetic turbines in river creeks, thereby increasing the grid capacity of SHPs in India.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Public Support for Feed-in-Tariff and Net Energy Metering Policies in
           Malaysia: The Role of Policy Information

    • Authors: Fatimah Azzahraa' Mohd Sobri; Mariani Ariffin, Amir Hamzah Sharaai, Mohd Amran Radzi
      Abstract: Renewable energy (RE) policies have proven to be an effective tool for implementing RE. Despite various policies introduced, the RE deployment in Malaysia has been weak, especially individual RE uptake. Lack of policy support has been linked with inadequate policy awareness and information based on the knowledge deficit theory. This study investigates the support for the Feed-in-Tariff (FiT) and Net Energy Metering (NEM) policy of individual solar photovoltaic (PV) technology among landed residents in Malaysia and the effect of information provision on policy support. A Solomon-four-group design was employed to measure policy support and test the relationship between information provision and policy support using a set of Likert scale questionnaires and a poster of FiT and NEM policy prepared in layman's terms as an intervention. Results show that majority of the residents agree with the environmental mission of the policy, except for the reduction of fossil fuel usage. For the economic aspect, the residents prefer a fixed rate for RE produced and generally agreed that high electricity consumers should pay for the RE fund. However, residents were less enthusiastic about the percentage deducted from electricity bills and the 'high electricity consumer' baseline.  There was a significant difference between items scores at pre and post-test when given the intervention, in line with the deficit theory. Therefore, policy information should be communicated strategically, focusing on thepolicy's social and economic components that have the greatest influence on Malaysians.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • A Green Heterogeneous Catalyst Production and Characterization for
           Biodiesel Production using RSM and ANN Approach

    • Authors: Aditya Kolakoti; Muji Setiyo, Muhammad Latifur Rochman
      Abstract: In this work, naturally available moringa oleifera leaves (also known as horseradish trees or drumstick trees) are chosen as a heterogeneous catalyst in the transesterification for biodiesel production from palm oil. The dry moringa oleifera leaves are calcinated at 700 °C for 3 hours to improve their adsorbing property. The calcinated catalyst characterization analysis from XRD and EDX highlights the presence of calcium, potassium, and other elements. Response surface method (RSM) optimization and artificial neural network (ANN) modeling were carried out to elucidate the interaction effect of significant process variables on biodiesel yield. The results show that a maximum biodiesel yield of 92.82% was achieved at optimum conditions of catalyst usage (9 wt.%), molar ratio, methanol to triglyceride (7:1), temperature (50 °C) and reaction time (120 min). The catalyst usage (wt.%) was identified as a significant process variable, followed by the molar ratio. Furthermore, the biodiesel’s significant fuel properties in terms of thermal, physical, chemical, and elemental match the established standards of ASTM. Finally, when the catalyst was reused for five cycles, more than 50% of the biodiesel yield was achieved.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • SWHEI: A New Approach to Measure Policy Effectiveness for Solar Water

    • Authors: Bruno Luis-Badillo; Daniel Guerrero-Hoyos, Gerardo A. Escamilla, Luis Rojas-Solórzano
      Abstract: In the context of the global energy transition, governments design and apply renewable energy policies as tools to replace fossil fuel sources for the heating end-use sector, which represents half of the global total final energy consumption (TFEC). In the last two decades, large deployments of solar thermal technologies, such as solar water heaters (SWH), have helped renewable energy penetrate the heating sector. To be successful, their adoption must be supported by effective policies; however, measuring the effectiveness of a particular policy is a complex task. Some studies design and propose indicators to measure this effectiveness but are difficult to replicate or adapt to specific markets. This work submits a novel policy-outcome effectiveness indicator, the Solar Water Heater Effectiveness Indicator (SWHEI), based on equipment deployment (installed capacity per capita, installed capacity growth) and the solar energy potential of each country, constructed using publicly available data to ensure replicability and universal utilization. The overall SHWEI values for the period 2003–2019 are low, reflecting the current low adoption of solar technologies, but show regional clusters of good performance, such as in Europe. Barbados achieved the maximum value of 6.9, which reflects its outstanding performance, driven by its installed capacity per capita. The analysis shows that the SWHEI is particularly useful to determine policy ineffectiveness while confounding factors could camouflage policy effectiveness. The SWHEI-active SWH policies matrix can help policymakers identify courses of action. Policymakers could 1) use market-entry policy instruments in undeveloped SWH markets (segment C, no policies in place); 2) review and improve failing SWH policies (segment D); 3) propose randomized controlled trials to study causal relationships between SWH policies and large SWHEI (segments A and B with policies in place); and 4) regulate successful markets, allowing for continued organic growth (segment A, no policies). 
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • The Effect of Trailing Edge Profile Modifications to Fluid-Structure
           Interactions of a Vertical Axis Tidal Turbine Blade

    • Authors: Nu Rhahida Arini; Stephen R Turnock, Mingyi Tan
      Abstract: Renewable energy has become an essential energy alternative since the continual depletion of non-renewable energy resources and increasing environmental issues. Tidal energy is a promising future renewable resource which can be extracted using a vertical axis tidal turbine. Since it was proposed, a tidal turbine performance requires improvements which can be obtained by a blade’s trailing edge modification. Modifying the blade’s trailing edge profile is confirmed to be one way to improve a turbine’s work. However, the influence of a trailing edge modifications on a vertical axis tidal turbine blade’s interaction with fluid has not been fully understood, thus the fluid induced vibration as the fluid behaviour working on a vertical axis tidal turbine blade has not been completely discovered. In this paper, 2D fluid-structure interactions of modified vertical axis tidal turbine blades are examined and modelled using OpenFOAM. Three different modified blade profiles are proposed: sharp, rounded, and blunt. The modified profiles are employed to an original NACA 0012 blade and their influences on a vertical axis tidal turbine blade interaction are observed. The result discovers the fluid behaviour and fluid-induced vibrations at all positions (represented by 12 positions) over one turbine’s cycle. The results demonstrate the frequency domain blade velocities and time domain blade displacements for all modified blades. The fluid behaviour around the blade is confirmed by pressure distribution plots over the blade’s upper and lower surfaces. The results show that the blunt profile provides less frequent vibrations due to a reducing vorticity in the downstream fluid regime. However, the vibration amplitude that occurs on the blunt blade is higher than those of rounded and sharp profiles. Based on this research, the blunt trailing edge profile appears to be more favourable to be applied and used for vertical axis tidal turbine blades.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Short Term Solar Irradiation Forecasting using CEEMDAN Decomposition Based
           BiLSTM Model Optimized by Genetic Algorithm Approach

    • Authors: Anuj Gupta; Kapil Gupta, Sumit Saroha
      Abstract: An accurate short-term solar irradiation forecasting is requiredregarding smart grid stability and to conduct bilateral contract negotiations between suppliers and customers. Traditional machine learning models are unable to acquire and to rectify nonlinear properties from solar datasets, which  not only complicate  model formation but also lower prediction accuracy. The present research paper develops a deep learningbased architecture with a predictive analytic technique to address these difficulties. Using a sophisticated signal decomposition technique, the original solar irradiation sequences are decomposed  into multiple intrinsic mode functions to build a prospective feature set. Then, using an iteration strategy, a potential range of frequency associated to the deep learning model is generated. This method is  developed utilizing a linked algorithm and a deep learning network. In comparison with conventional models, the suggested model utilizes sequences generated through preprocessing methods, significantly improving prediction accuracywhen  confronted with a high resolution dataset created from a big dataset.On the other hand, the chosen dataset not only performs a massive data reduction, but also improves forecasting accuracy by up to 20.74 percent across a range of evaluation measures. The proposed model achieves lowest annual average RMSE (1.45W/m2), MAPE (2.23%) and MAE (1.34W/m2) among the other developed models for 1-hr ahead solar GHI, respectively, whereas forecast-skill obtained by the proposed model is 59% with respect to benchmark model. As a result, the proposed method might be used to predict short-term solar irradiation with greater accuracy using a solar dataset
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Energy Management Strategy Based on Marine Predators Algorithm for
           Grid-Connected Microgrid

    • Authors: Amel Kheiter; Slimane Souag, Abdellah Chaouch, Abdelkader Boukortt, Benaissa Bekkouche, Mohammed Guezgouz
      Abstract: This work aims to optimize the economic dispatch problem of a microgrid system in order to cover the load of a commercial building in Algeria. The analyzed microgrid system is connected to the power grid and composed of photovoltaic panels (PV), wind turbine, battery energy storage system (BESS) and diesel generator. To ensure energy balance and the flow of energy, we have implemented an energy management strategy based on Marine Predator Algorithm (MPA) and Multilayer Perceptron Neural Network (MLPNN), which guarantee an optimal economic operation of the system. First, using historical meteorological data, the power generation is forecasted a day-ahead using MLPNN, which allows the optimization of the microgrid operation. Second, the proposed strategy has been studied under three different microgrid configurations. Eventually, the performances of MPA are compared against well-known algorithms. The results indicate that the integration of the PV-BESS microgrid system significantly reduces the daily operating cost up to 34.5%. Due to the availability of wind resources in the studied area, the addition of a wind turbine to the microgrid minimizes the operating cost by 43.96% compared to the operating cost of the power grid. In the case of selling excess energy to the main power grid, the operating cost could be decreased as much as 49.33%.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Numerical Investigation of Convective Heat Transfer and Fluid Flow Past a
           Three Square Cylinders Controlled by a Partition in Channel

    • Authors: Youssef Admi; Mohammed Amine Moussaoui, Ahmed Mezrhab
      Abstract: This document presents a research article on the control of fluid flow around three heated square cylinders placed side by side in a 2D horizontal channel using a flat plate. The objective of this research is to examine the effect of the position, length and height of a flat plate on fluid flow and heat transfer. For this purpose, numerical simulations are performed by using the Boltzmann double relaxation time multiple network method (DMRT-LBM). The MRT-D2Q9 and MRT-D2Q5 models are used to treat the flow and temperature fields respectively. In contrast to several existing investigations in the literature in this domain which study the passive control of the flow using a horizontal or vertical plate around a single cylinder, this work presents a numerical study on the effect of the position, length and height of a flat plate (horizontal and vertical) on three heated square cylinders on the flow and temperature fields. First, the effect of the position and length of the horizontal flat plate is examined. This study shows that the implementation of a flat plate of length Lp = 4D at a position g=3 behind the central cylinder reduces the amplitude of the Von Karman Street and allows large and regular heat exchange.  Thus, in the second part, the effect of the position and height of the vertical flat plate is studied. The results obtained show that the implementation of a flat plate of height h=2D at a position g=3 behind the central cylinder improves the thermal exchange between the incoming fluid and the heated cylinders. This numerical work could lead to the prediction of the cooling of the electronic components: The cooling of the obstacles is all the better when the control plate is arranged at g = 3 and its height h = 2D in the case of the vertical plate or its length Lp equal to 4D in the case where the plate is implemented horizontally
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Ultrathin Film Amorphous Silicon Solar Cell Performance using Rigorous
           Coupled Wave Analysis Method

    • Authors: Raghvendra Sarvjeet Dubey; Sigamani Saravanan
      Abstract: The issues related to global energy needs and environmental safeties as well as health crisis are some of the major challenges faced by the human, which make us to generate new pollution-free and sustainable energy sources. For that the optical functional nanostructures can be manipulated the confined light at the nanoscale level. These characteristics are emerging and leading candidate for the solar energy conversion. The combination of photonic (dielectric) and plasmonic (metallic) nanostructures are responsible for the development of better optical performance in solar cells. Here, the enhancement of light trapping within the thin active region is the primary goal. In this work, we have studied the influence of front-ITO (rectangular) and back-Ag (triangular) nanogratings were incorporated with ultrathin film amorphous silicon (a-Si) solar cell by using rigorous coupled wave analysis (RCWA) method. The improvement of light absorption, scattering (large angle), diffraction and field distributions (TE/TM) were demonstrated by the addition of single and dual nanogratings structures. Significantly, the plasmonic (noble metal) nanogratings are located at the bottom of the cell structure as a backside reflector which is helpful for the omni-directional reflection and increased the path length (life time) of the photons due to that the collection of the charge carriers were enhanced. Further, the proposed solar cell structure has optimized and compared to a back-Ag, front-ITO and dual nanogratings based ultrathin film amorphous silicon solar cell. Finally, the obtained results were evidenced for the assistance of photonic and plasmonic modes and achieved the highest current density (Jsc) of 23.82 mA/cm2(TE) and 22.75 mA/cm2 (TM) with in 50 nm thin active layers by integration of (dual) cell structures.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Optimum Control of Grid-Connected Solar Power System Under Asymmetrical
           Voltage Drop

    • Authors: Van Binh Nguyen
      Abstract: Solar power systems are now gradually dominating in providing clean, environmentally friendly energy and human health. In areas with a large share of solar power, grid connection control plays a key role in ensuring operational quality and stability, especially in the event of a grid failure. In case of asymmetrical voltage drop, the control system needs to maintain operation and create a function to assist in restoring the power grid. This study proposes a method to control the solar power system in the condition of asymmetric grid voltage drop based on the method of controlling symmetrical components. Controllers for each of the forward and inverse components are built to limit the effects of failures. The optimal control parameter calculation method is also proposed to improve the overall quality and minimize the undesired variation of the electromagnetic quantities. The simulation and experimental results are verified to evaluate the effectiveness of the grid-connected control method in converting DC power to three-phase power.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Decision Support for Investments in Sustainable Energy Sources Under

    • Authors: Kenneth Ian Talosig Batac; Angelie Azcuna Collera, Resy Ordona Villanueva, Casper Boongaling Agaton
      Abstract: Investment in sustainable energy sources is one of the climate mitigation strategies that can significantly reduce greenhouse gas emissions in the energy sector. However, in developing countries, investment is challenged by high capital expenditures and several uncertainties. This paper aims to provide decision support for investment in sustainable energy projects by evaluating the comparative attractiveness of shifting energy sources from fossil fuels to renewables and nuclear. Applying the real options approach (ROA), this paper calculates the value of the flexibility to postpone the investment decision and identifies the optimal timing (described here as the trigger price of coal) for shifting to sustainable energy sources. Then, various uncertainties are considered, such as coal and electricity prices, negative externality of using fossil fuels, and the risk of a nuclear accident, which are modelled using geometric Brownian motion, Poisson process, and Bernoulli probability. Applying the ROA model in the case of the Philippines, results find that investing in sustainable energy is a better option than continuing to use coal for electricity generation. However, contrary to conventional option valuation result that waiting is a better strategy, this study found that delaying or postponing the investment decisions may lead to possible opportunity losses. Among the available sustainable energy sources, geothermal is the most attractive with trigger prices of coal equal to USD 49.95/ton, followed by nuclear (USD 58.55/ton), wind (USD 69.48/ton), solar photovoltaic (USD 72.04/ton), and hydropower (USD 111.14/ton). Also, the occurrence of jump (extreme) prices of coal, raising the current feed-in-tariff, and considering negative externalities can decrease the trigger prices, which favor investments in sustainable energies. Moreover, the risk of a nuclear disaster favors investment in renewable energy sources over nuclear due to the huge damage costs once an accident occurs. Results provide bases for policy recommendations toward achieving a more secure and sustainable energy sector for developing countries that are highly dependent on imported fossil fuels.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Univariate and Multivariate LSTM Models for One Step and Multistep PV
           Power Forecasting

    • Authors: Tariq Limouni; Reda Yaagoubi, Khalid Bouziane, Khalid Guissi, El Houssain Baali
      Abstract: The energy demand is increasing due to population growth and economic development. To satisfy this energy demand, the use of renewable energy is essential to face global warming and the depletion of fossil fuels. Photovoltaic energy is one of the renewable energy sources, widely used by several countries over the world. The integration of PV energy into the grid brings significant benefits to the economy and environment, however, high penetration of this energy also brings some challenges to the stability of the electrical grid, due to the intermittency of solar energy. To overcome this issue, the use of a forecasting system is one of the solutions to guarantee an effective integration of PV plants in the electrical grid. In this paper, a PV power ultra short term forecasting has been done by using univariate and multivariate LSTM models. Different combinations of input variables of the models and different timesteps forecasting were tested and compared. The main aim of this work is to study the influence of the different combinations of variables on the accuracy of the LSTM models for one-step forecasting and multistep forecasting and comparing the univariate and multivariate LSTM models with MLP and CNN models  . The results show that for one step forecasting, the use of a univariate model based on historical data of PV output power is sufficient to get accurate forecasting with 28.98W in MAE compared to multivariate models that can reach 35.39W. Meanwhile, for multistep forecasting, it is mandatory to use a multivariate model that has historical data of meteorological variables and PV output power in the input of LSTM model. Moreover, The LSTM model shows great accuracy compared to MLP and CNN especially in multistep PV power forecasting.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Kinetic and Thermodynamic Analysis of Thermal Decomposition of Waste
           Virgin PE and Waste Recycled PE

    • Authors: Nurameylia Rasaidi; Ahmad Rafizan Mohamad Daud, Siti Norazian Ismail
      Abstract: Polyethylene is one of the key components of plastic wastes that can be utilized for resource recovery through pyrolysis method. Understanding of thermal decomposition properties and reaction mechanism of pyrolysis are necessary in designing an efficient reactor system. This study investigated the kinetics and thermodynamics parameters for individual waste virgin polyethylene (WVPE) and waste recycled polyethylene (WRPE) by using distributed activation energy model (DAEM). The calculated kinetic parameters (activation energy (Ea) and pre-exponential factor (A) were used to determine thermodynamic parameters (enthalpy (ΔH), Gibbs free energy (ΔG) and entropy (ΔS). The activation energy (Ea) values for the WVPE estimated at conversion interval of 5%-95% were in the range of 180.62 to 268.04 kJ/mol while for the WRPE, the values were between 125.58 to 243.08 kJ/mol. This indicates the influence of exposure to weathering and mechanical stress during recycling on the course of the WRPE degradation. It was also found that the pyrolysis reaction for both WVPE and WRPE were best fitted using the two-dimensional diffusion (D2) model. The WVPE exhibited higher enthalpy and lower ΔG compared to WRPE, suggesting that less energy is required to thermally degrade recycled waste PE into products of char, gases and pyro-oils.  Both kinetics and thermodynamics analyses were useful for the development of the plastic waste management through pyrolysis process.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Daily Solar Radiation Forecasting based on a Hybrid NARX-GRU Network in
           Dumaguete, Philippines

    • Authors: Al Diego Pega Fuselero; Hannah Mae San Agustin Portus, Bonifacio Tobias Doma Jr
      Abstract: In recent years, solar radiation forecasting has become highly important worldwide as solar energy increases its contribution to electricity grids. However, due to the intermittent nature of solar radiation caused by meteorological parameters, forecasting errors arise, and fluctuations in the power output of photovoltaic (PV) systems become a severe issue. This paper aims to introduce a forecasting hybrid model of daily global solar radiation time series. Meteorological data and solar radiation samples from Dumaguete, Philippines, are used to assess the forecasting accuracy of the proposed nonlinear autoregressive network with exogenous inputs (NARX) – gated recurrent unit (GRU) hybrid model. Four different models were trained using the meteorological and solar radiation data, which are the Optimizable Gaussian Process Regression (GPR), Nonlinear Autoregressive Network (NAR), NARX, and the proposed Hybrid NARX-GRU Network.  Results show that the hybrid NARX-GRU model has a root mean square error (RMSE) of ~0.05 and a training time of 33 seconds. The proposed hybrid model has better forecasting performance compared to the three models which obtained RMSE values of 27.741, 39.82, and 28.92, for the GPR, NAR, and NARX, respectively. The simulation results demonstrate that the NARX-GRU model significantly outperforms the regression and single models in terms of statistical metrics and training efficiency. Furthermore, this study shows that the hybridized NARX-GRU model is able to provide an effective estimation for daily global solar radiation, which is important in the operation of PV plants in the country, specifically for unit commitment purposes
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Electrical Energy Management According to Pricing Policy: A Case in

    • Authors: Thi Tuyet Mai Nguyen; Pham Nguyen Dang Khoa, Ngoc Anh Huynh
      Abstract: Electrical equipment is increasingly diversified in both types and capacity to meet the maximum needs of people in the 4th industrial revolution. This development has helped people to achieve many great scientific achievements, but this development has led to a rapid increase in the demand for electric energy in recent years. The traditional electricity supply from fossil fuels is gradually depleting, which has prompted the search for clean and renewable energy sources to gradually replace the dependence on this energy source. Prosumer, HEMS (home energy management system), and other solutions have been researched and applied to optimize electrical energy sources. However, for countries that mainly use fossil energy sources like Vietnam, these solutions are not effective. Policy on the management could help to solve this problem, in particular, the price policy is the solution that Vietnam has used to effectively manage this energy source. This article analyzes the issues of applicable pricing policy in Vietnam, proposes potential policies to improve and protect the electric energy system, as well as enhances the rate of renewable energy use in the electricity system in Vietnam
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Investigation of the Impact of Large-Scale Wind Power and Solar Power
           Plants on a Vietnamese Transmission Network

    • Authors: Ngo Minh Khoa; Nguyen Thi Hai Van, Le Kim Hung, Doan Anh Tuan
      Abstract: Integrating wind power and solar power plants into a power system has significantly grown over the past decade and is expected to grow to unprecedented levels in the coming years. In Vietnam, much large-scale wind power and solar power plants have been built and connected to the power system in recent years. To investigate and evaluate the impact of these power plants on system power operation, the 110kV power transmission network of Binh Dinh province in Vietnam is used in this paper. In the system, the Phuong Mai 3 wind power plant with a capacity of 21MW, the Fujiwara solar power plant with a peak capacity of 50MWp, and the Cat Hiep solar power plant with a peak capacity of 49.5MWp are modeled by using the PSS/E software to simulate and analyze their impacts on power system stability of the 110kV transmission network in Binh Dinh province, Vietnam. Besides, the control strategies of these power plants are also established to investigate their impacts on the network. In addition, this paper proposes three typical scenarios for the wind power and solar power plants in the system. For each scenario, the grid's operating parameters such as voltage variations and frequency variations are acquired for analyzing and evaluating their impacts on the frequency and voltage variations of the network. The simulation results show that the 110kV power transmission network remains in a stable operation mode after the fault scenarios for the wind and solar power plants. Furthermore, these simulation results provide some guidance for the actual operation
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Effect of Adding Combustion Air on Emission in a Diesel Dual-Fuel Engine
           with Crude Palm Oil Biodiesel Compressed Natural Gas Fuels

    • Authors: Dori Yuvenda; Bambang Sudarmanta, Arif Wahjudi, Rozy Aini Hirowati
      Abstract: A diesel dual-fuel engine uses two fuels designed to reduce the consumption of fossil fuels. Generally, the specific fuel consumption of diesel dual-fuel engines has increased.  However, in   combination with alternative fuels, namely compressed natural gas injected through air intake, the use of diesel fuel can be reduced. However, using two fuels in a diesel dual-fuel engine increases the equivalent ratio; therefore, the air and fuel mixture becomes richer because the air entering the cylinder during the intake stroke is partially replaced by compressed natural gas. This results in incomplete combustion and increases exhaust emissions, particularly hydrocarbon (HC) and carbon monoxide (CO) emissions. This study aims to improve the combustion process in dual-fuel diesel engines by improving the air-fuel ratio; thus, it can approach the stoichiometric mixture by adding combustion air forcibly to produce complete combustion to reduce CO and HC emissions. An experimental approach using a single-cylinder diesel engine modified into a diesel dual-fuel engine powered by crude palm oil biodiesel and compressed natural gas was adopted. The combustion air was forcibly added to the cylinder using an electric supercharger at different air mass flow rates ranging from 0.007074 to 0.007836 kg/s and different engine loads (1000 to 4000 watts). The results indicated that adding more air to the cylinder could produce complete combustion, reducing the emission levels produced by a diesel dual-fuel engine. An air mass flow rate of 0.007836 kg/s can reduce CO, HC, and particulate matter emissions by averages of 60.55%, 49.63%, and 86.87%, respectively, from the standard diesel dual-fuel engine. Increasing in the amount of oxygen concentration improves the quality of the air-fuel ratio, which results in improved combustion and thereby reducing emissions.
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
  • Optimization of Aeration for Accelerating Municipal Solid Waste Biodrying

    • Authors: Panida Payomthip; Sirintornthep Towprayoon, Chart Chiemchaisri, Suthum Patumsawad, Komsilp Wangyao
      Abstract: Biodrying technology is commonly used in Thailand to produce refuse-derived fuel (RDF), however, this technology remains ineffective on high-moisture waste. Air supply is key to ensuring homogenous temperature development within the waste matrix during biodrying, increasing RDF quality. This study investigated negative aeration during local municipal solid waste biodrying to meet RDF standards in reduced time. Lysimeter experiments were performed on pre-shredded waste (300 kg/m3) using different aeration patterns. The temperature, vent gas oxygen level, weight loss, and leachate volume during the biodrying process were monitored. In addition, the treated waste’s temperature, moisture, and heating values were evaluated to determine the biodrying process efficiency. The results indicate that shorter heating phases can be achieved during continuous aeration. No significant temperature variation was observed in the waste layers, with a low standard deviation of 1.96% during constant air supply, indicating homogeneous temperature development during the biodrying process. The vent gas contained 15–20% oxygen and non-detectable methane, evidencing sufficient air supply. The total heat development was independent of aeration pattern; therefore, biodrying was unaffected by excess air supply at a 95% confidence level. The highest weight loss and moisture content reduction were 25% and 66%, respectively. The optimal aeration was continuous mode with non-excessive aeration, increasing the lower heating value from 2,884.0 to 4,938.0 kCal/kg, and reducing the moisture content from 48.5% to 22.2%. RDF quality can be improved 1.7 times to meet Thailand’s standards within a short biodrying period of 7 days using homogeneous temperature distribution operated under continuous aeration
      PubDate: Thu, 04 Aug 2022 00:00:00 +000
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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