Journal of Renewable Energies

Transition Energétique - Remplacement d’une Microcentrale Diesel par un Système Renouvelable Hybride : Etude de cas.

2023-12-04T16:40:39+00:00

This paper aims to study the replacement of a Diesel Generator based plant by a hybrid renewable system. To overcome both source and load fluctuations, a battery-based storage system is used. The renewable energy resources available in southern Algeria is considerable. Actually, this region has one of the largest wind capacity in the country with wind speeds up to 4 to 6 m/sec, the wind energy density is 280-Watt/m2/ day. Meanwhile, the solar potential is characterized by an average duration of sunshine above 11 hours/day and the energy they can provide for a large-scale industry can change the development of the region and of the whole country.
Genetic algorithms under optimtool is used to size hybrid systems. The resulting levelized cost of electricity (LPSP) of $0.262/kWh, is competitive and economical if a large-scale electricity production is undertaken. The loss of power supply probability or customer dissatisfaction rate (LPSP) of 1.2545 %, which is within standard limits.

Particulate matter air pollution in the Republic of Slovenia and its national spatial emissions release

2023-12-05T09:09:29+00:00

In this work, an impact of particulate matter (PM) on air pollution and its emissions released is investigated. Concentration levels of PM10 and PM2.5 in the Republic of Slovenia (RS) were analyzed on daily, weekly, monthly, quartile, and annual data and then compared. The study was conducted from January 1, 2020 to December 31, 2020 at two monitoring stations, so-called urban traffic and urban industrial. Obtained results showed that the highest concentrations of PM in air were during the cold months of the year when the temperatures are lower (< 6%). Results from heating seasons (from October 1, 2019 and March 31, 2020 and from October 1, 2020 to March 31, 2021) showed the highest concentration levels of PM10 between 9:00 and 14:00 and between 18:00 and 22:00, with highest concentrations recorded during the winter months (January and February). Additionally, emission building inventory was built based on PM10 and PM2.5 emissions released. The study includes yearly spatial building emissions release model considering currently installed high PM emitted stoves. The building model for the Republic of Slovenia has been developed by using 500 x 500 m model grid. Obtained results showed that changing currently low efficient appliance with advanced appliance would result in significant lower PM emissions released from building sector.

The thermal and stored heat energy driving a Stirling engine for power generation

2023-12-05T10:18:55+00:00

South Africa’s national power grid is currently in dire straits. The lack of a dependable power supplier and rising electricity costs force the public and businesses to look for alternatives to meet their energy needs. These alternatives are costly to implement and beyond the financial reach of most South Africans. The most common alternative energy source is solar photovoltaic systems with large battery banks to survive Eskom's long, regular load-shedding schedules. This research aims to design and simulate a combined solar-thermal and stored heat energy-powered Stirling engine for power generation. The output of the research simulation was compared to a standard photovoltaic installation of similar power output. The results for this paper were generated from the simulation software package MATLAB. Such a system must have a lower capital cost to compete with solar photovoltaic systems with battery backup. The Stirling system was found to be cheaper than the deep-cycle gel system and about 11% cheaper than the PV system using lithium iron phosphate.

Biodiesel production feedstocks: current state in Algeria

2023-12-04T11:59:49+00:00

Research and development of affordable, sustainable, and low-carbon energy sources capable of reducing dependence on fossil fuels, contributing to social and economic development, and improving environmental and health skills have become a global priority. In recent decades, biodiesel produced from oilseeds has received significant attention as an alternative biofuel. However, the use of first-generation oilseed crops has sparked controversy, and the use of local non-edible feedstocks is considered a promising alternative. The motivation behind this review is to provide an alternative and enlightening perspective on the use of non-edible vegetable oils for biodiesel production, with a particular focus on the current state of biodiesel production in Algeria. The objective is to assess the conditions under which this production could be sustainable and environmentally friendly while maintaining a balance between energy needs, economic stability, and environmental impact.

CFD study of active flow control around a wind turbine profile using synthetic jet

2023-12-04T14:39:55+00:00

In this study, numerical simulations are performed to investigate the effect of the position and jet angle of the synthetic jet on the aerodynamic characteristics of a wind turbine blade profile. The study is applied to the NREL S809 profile with a 1m chord, set at an angle of attack of 15.2° in a flow at a Reynolds number Re=10⁶. The synthetic jet is placed on the extrados of the profile and modeled by a sinusoidal function. The flow around the blade profile is simulated by solving Navier–Stokes equations using the commercial software ANSYS Fluent based on the finite volume method. Turbulence is simulated using the two-equation SST model. The results show that the considered jet parameters have a strong effect on the aerodynamic characteristics of the profile. Applying an optimal combination of synthetic jet parameters significantly improves the aerodynamic performance of the profile.

Efficient model for solar steam generation

2023-12-05T10:35:10+00:00

In this research, an advanced hybrid steam generation system using solar energy was designed, with higher performance and lower cost compared to other systems and researches. It's an ideal system where fossil fuels are still plentiful. The selected system units with the innovative automatic control allows the absorption of all levels of solar radiation and its exploitation in steam generation. The boiler is a classic fire tube one and the solar collector is a modified linear parabolic collector that tracks the sun in one of three tracking modes. A proper Matlab program has been prepared to determine and demonstrate the performance of the system and the optimal characteristic values of the collector that provide the maximum seasonal solar fraction of the plant. It was found that the average monthly daily solar fraction of the plant in Antalya, Mediterranean region, is 0.85 in June and 0.28 in January with the collector optimal characteristics and east-west tracking within 12 hours stable daily steam generation. It is demonstrated that the deviation in an optimum characteristic value of the collector causes a reduction in solar fraction. This study forms the basis for a similar plant construction project to test it in practice under real climatic conditions.

Comparative study between PI, FLC, SMC and Fuzzy sliding mode controllers of DFIG wind turbine

2023-12-04T15:35:19+00:00

In speed control, double-fed-induction generator (DFIG) has attracted attention in wind energy conversion systems (WECs). These systems can offer higher performances by controlling converters that connect the generator windings to the grid network. Therefore, different control strategies have been used. We can find the proportional integral (PI) and sliding mode control (SMC) which offer better performances. However, PI has constant gains that can’t change with the external variation and SMC has a chattering problem. Therefore, a hybrid control system that combines fuzzy logic control (FLC) and SMC to perform fuzzy sliding mode control (FSMC) is proposed. The hybrid system can improve the FLC and SMC robustness. The DFIG modeling and each of the control strategies have been detailed. To demonstrate the effectiveness of the control strategies, a comparative study of different control strategies (PI, FLC, SMC and FSMC) is described and performed using MATLAB/Simulink software. The results obtained from the present study show that FSMC is more robust and efficient than the other controllers (PI, FLC and SMC). It has high performances (low settling time, high steady state accuracy) assuring a perfect power decoupling with minimal ripples and errors.