International Journal of Renewable Energy Development
ISSN / EISSN : 2252-4940 / 2252-4940
Published by: Diponegoro University (10.14710)
Total articles ≅ 452
Latest articles in this journal
Published: 5 September 2022
International Journal of Renewable Energy Development, Volume 12, pp 22-34; https://doi.org/10.14710/ijred.2023.46696
Lattice Boltzmann method (LBM) is employed in the current work to simulate two-phase flows of immiscible fluids over a square obstacle in a 2D computational domain using the Rothman-Keller color gradient model. This model is based on the multiphase Rothman-Keller description, it is used to separate two fluids in flow and to assess its efficacy when treating two fluids in flow over a square obstacle with the objective of reducing turbulence by adjusting the viscosities of the two fluids. This turbulence can cause major problems such as interface tracking techniques in gas-liquid flow and upward or downward co-current flows in pipes. So, the purpose of the study is to replace a single fluid with two fluids of different viscosities by varying these viscosities in order to reduce or completely eliminate the turbulence. The results show that to have stable, parallel and non-overlapping flows behind the obstacle, it is necessary that the difference between the viscosities of the fluids be significant. Also, showing that the increase in the viscosity ratio decreases the time corresponding to the disappearance of the vortices behind the obstacle. The results presented in this work have some general conclusions: For M≥2, the increase in the viscosity difference leads to an increasing of friction between fluids, reducing of average velocity of flow and decreasing the time corresponding to the disappearance of the vortices behind the obstacle. However, for M≤1/2, the opposite occurs.
Published: 26 August 2022
International Journal of Renewable Energy Development, Volume 12, pp 11-21; https://doi.org/10.14710/ijred.2023.46328
In this investigation, the effect of replacing the conventional solar absorber with a new solar absorber on the thermal performance of a double-pass solar air heater has been studied experimentally and numerically. Three configurations have been introduced, the first configuration is a double pass solar air heater with a flat plate solar absorber (DPSAHWFP) for the aim of comparison, and the second configuration is a double pass solar air heater with a tubular absorber that includes a set of tubes which are fitted perpendicularly to the direction of airflow (DPSAHWT-1), and the third configuration is double-pass solar air heater with a tubular absorber that involves set of tubes which are fitted in parallel to the direction of airflow (DPSAHWT-2). The experiments have been carried out under indoor conditions at a constant heat flux equal to 1000 W/m2 and different air mass flow rates (0.01– 0.03 kg/s). The results revealed that the air mass flow rate has a substantial impact compared to the rise in air temperature, hence, the thermal performance of solar air heater is directly proportional to increase air mass flow rate. In addition, the experimental and numerical outcomes indicated that for all air flow rates. The (DPSAHWT-2) offers higher thermal performance as compared to other models, where the maximum effective efficiency has been obtained at 0.03 kg/s equal to 80.9 %. Moreover, (DPSAHWT-2) is more efficient than DPSAHWFP and DPSAHWT-1 by 4.2 % and 9.8 % respectively.
Published: 15 August 2022
International Journal of Renewable Energy Development, Volume 11, pp 1134-1141; https://doi.org/10.14710/ijred.2022.46501
Power transmission system stability can be significantly affected due to faults. The fault location accuracy in the transmission lines can make many benefits such as acceleration of the line restoration, reduction in cost, breakdown time, maintenance, and time searching. The methods based on the impedance, including the simple reactance, Takagi, modified Takagi, and double-end, are very much appreciated for locating the fault in transmission lines and especially by estimating the fault distance. This study proposes a comparative case study between these methods. The theoretical basis and the analysis, calculation, and estimation of each method are specifically re-established. To observe the performance of each method, a practical 220kV Quy Nhon - Tuy Hoa transmission line in Vietnam is used to simulate, calculate, evaluate, and compare under the various fault types and resistances. The power system is modeled and simulated in the MATLAB/Simulink software via the time domain. The voltage and current measurements at two ends of the line are used to determine the fault location on the Quy Nhon - Tuy Hoa transmission line. The simulation results show clearly the effectiveness of each fault location method.
Published: 4 August 2022
International Journal of Renewable Energy Development, Volume 11, pp 713-724; https://doi.org/10.14710/ijred.2022.44173
Heat is the largest energy end-use globally, accounting for 50% of the total energy consumed and 40% of total global carbon dioxide emissions in 2018. Nevertheless, despite the notable efforts to increase renewables and sustainability, the global share of renewables in heat end-uses has not improved in two decades. Under this context, solar thermal technologies such as solar water heaters (SWH) are crucial in the clean energy transition. Governments react to such efforts by enacting public policies to enlarge and sustain SWH markets. However, current methods to measure these policies' effectiveness restrict the SWH policy analysis and design usefulness.This work proposes a novel policy-outcome effectiveness indicator: The Solar Water Heater Effectiveness Indicator (SWHEI) based on equipment deployment and the solar-energy potential for each country. Policymakers could use this indicator, constructed with publicly available data, to test solar water heating policy options' feasibility, as the SWHEI identifies cases where policies are not adequate to solve market failures.
Published: 4 August 2022
International Journal of Renewable Energy Development, Volume 11, pp 703-712; https://doi.org/10.14710/ijred.2022.43627
In this work, naturally available moringa oleifera leaves are chosen as a heterogeneous catalyst for biodiesel production from palm oil. The dry moringa oleifera leaves are calcinated up to 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 (7:1), temperature (50 °C) and reaction time (120 min). The catalyst usage (wt.%) was identified as a significant process variable followed by molar ratio. Furthermore, the significant fuel properties of the biodiesel related to thermal, physical, chemical, and elemental match with the established standards of ASTM. The reutilization analysis of the catalyst reveals that more than 50% of the biodiesel yield was achieved after five cycles of reuse.
Published: 4 August 2022
International Journal of Renewable Energy Development, Volume 11, pp 782-788; https://doi.org/10.14710/ijred.2022.46009
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.
Published: 4 August 2022
International Journal of Renewable Energy Development, Volume 11, pp 676-693; https://doi.org/10.14710/ijred.2022.45249
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.
Published: 4 August 2022
International Journal of Renewable Energy Development, Volume 11, pp 766-781; https://doi.org/10.14710/ijred.2022.43790
In this paper, a numerical investigation was performed to simulate laminar flow and heat transfer characteristics in a two-dimensional horizontal channel, comprising three heated square cylinders placed side-by-side and controlled by a downstream detached partition. The Double Multiple Relaxation Time Lattice Boltzmann Method (MRT-LBM) is applied as the numerical method was using the MRT-D2Q9 model and the MRT-D2Q5 model to treat the flow and the temperature fields respectively. The problem considered is a laminar and incompressible flow. The air (Pr = 0.71) is the fluid circulating in the channel, its physical properties, except the density, are assumed to be constant. The top and bottom channel walls are supposed to be adiabatic, the airflow incoming with cold temperature which is fixed to θc = - 0.5, each cylinder at a constant hot temperature equal to θh= 0,5. The flow is fully developed with a parabolic velocity profile at the inlet and at the outlet of the channel. Also, in the outlet, the temperature and velocity gradients are assumed to be zero. The effects of horizontal and vertical plate position and length on the fluid flow and the heat transfer are examined in terms of streamlines and isotherms contours visualizations.
Published: 4 August 2022
International Journal of Renewable Energy Development; https://doi.org/10.14710/ijred.2022.45913
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.
Published: 22 June 2022
International Journal of Renewable Energy Development, Volume 11, pp 963-972; https://doi.org/10.14710/ijred.2022.45306
The use of hybrid photovoltaic/thermal (PV/T) and low concentrating photovoltaic/thermal (LCPV/T) systems can significantly enhance the overall solar energy conversion efficiency by delivering electricity and thermal energy. This paper presents a case study using a standing PV system's theoretical and modeling approach that can be modified to adapt to the hybrid technology. Firstly, a single-pass conventional PV/T air-cooled collector is investigated based on heat transfer and electrical models under the climatic conditions of Zarqa, Jordan. The performance parameters are evaluated using thermal and electrical properties of the considered PV installation and measured meteorological data. Results show that the total energy produced varies between a maximum of 134.6 kWh/m2 in July and a minimum of 81.7 kWh/m2 in January. The annual average hourly variation of overall energy efficiency ranges between 79.2% and 88.4%. Moreover, the dissipated thermal energy can meet 63.6% of the total energy required to ventilate the Hashemite University Presidency Building during the winter months. Finally, the performance of the modeled PV/T system air system coupled with flat boosters to provide a low irradiation concentration ratio (CR) is explored. The maximum electric output of the resulting LCPV/T system is compared with the uncooled system. It is found that the percentage improvement due to air cooling ranges between 0.72% at CR=1 and 2.77% at CR=2.5