A solar water heater is a device that captures solar energy and transfers it in the form of heat to water. Solar water heaters are very easy to install and use. They can be adapted to many types of installations. The present work deals with the thermal performance and cost evaluation of a low cost solar water heater. The low cost solar collector designed and fabricated use the date palm fibers as insulation material in replacement of glass wool. To prepare the insulation material the date palm waste has been grinded and used without adding anything. Tests carried out in this work follows the international standard ISO 9806. This standard gives the procedure for the thermal characterization of the solar collector. The results showed that our solar collectors provided good behavior and good performances, close to the performance of a commercial solar collector, with a production cost up to three times cheaper.
Innovations in technologies that rely on electricity have led to an uncontrollable rise in power usage. In order to predict future electricity demand and enhance the power distribution system, analysis and forecasting of energy consumption systems are necessary. Several issues with the present energy consumption prediction methods make it difficult to anticipate actual energy usage with any degree of accuracy. In order to master the energy prediction method, this study examines fourteen years' worth of hourly energy usage data from a Kaggle open source dataset. In addition, a Long Short Term Memory (LSTM) and Convolution Neural Network (CNN) based method for estimating energy consumption based on actual datasets is presented in the research. The empirical findings demonstrate which LSTM and CNN architectures can improve energy consumption forecasting accuracy.
In recent years, the demand for hydrogen trains has increased following the successful commercialisation of hydrogen fuel cell-based trains in Germany. To support the growing business case, an established hydrogen infrastructure for refuelling is required to meet the demand-supply. This paper aims to investigate the techno-economic assessment of hydrogen refuelling stations (HRS) powered by renewable resources and a power grid to supply the trains' hydrogen demand. The HRS sizing is based on the estimated demand loading for a 1-day operations train throughout a regional line in Malaysia and the availability of renewable resources at the proposed facility location. The simulation using MOHRES software resulted to be composed of a 2.0 MW-PEM Electrolyser, producing 900 kg of hydrogen, stored in hydrogen storage. The financial analysis of the total life span cost (TLSC) for the overall system resulted in $36M, indicating the potential hydrogen market for hydrogen infrastructure in Malaysia is feasible.
Accurate and robust aeroelastic modelling is playing an important role in the design of large wind turbines nowadays, due to the dramatical size increasing of the blades which require extra attentions to be paid to flexibility and deformation analysis. Linear Beam Theory (LBT) and Geometrically Exact Beam Theory (GEBT) are introduced in this paper, and coupled with classic Blade Element Momentum Theory (BEMT) to predict the aerodynamic performance and the dynamic responses of wind turbine blades of different sizes. BEMT-LBT model has higher computational efficiency as a linear aeroelastic model while BEMT-GEBT model considers the nonlinear deformation of the blades as a nonlinear model. The results show that the impacts of the linear and nonlinear models on the dynamic responses is more significant on larger blades, and the difference of the flapwise deformation of the blade tip reaches 18.14% at 10MW size. There is no significant difference between dynamic responses of the blades of a 1.5MW wind turbine or less, calculated by two aeroelastic models. For the ultra-long blades of the 5MW and 10MW wind turbines, the BEMT-LBT linear aeroelastic model overestimates their deformations due to the assumption of small blade deflections.
Soil stabilisation is crucial to tackle the problem of land disasters, such-as landslide, slope failure, and debris flow among others, which may occur naturally or as a result of human actions. Many people are displaced from their homes and some even lose their life in such disasters. Mauritius has not been spared by these major issues and, as a Small Island Developing State (SIDS) which is found under the tropics, the island is at a high risk of cyclones and torrential rains which may induce further land disasters. Another problem occurring worldwide is the landfill scarcity to dispose human, commercial, and industrial solid waste. The facilities for recycling municipal solid waste (MSW) in the country are very limited. Chemical stabilisation could potentially help solve both issues by combining binders with waste products to stabilise the soils in landslide-prone areas. The goal of this paper was to investigate the scope for an economically, environmentally, and socially sustainable solution to help mitigate the negative geotechnical events which come with climate change and also reducing the environmental problem of disposal and landfill scarcity. It was found that plastic wastes (14% of MSW), textile wastes (6% of MSW) and glass wastes (3% of MSW) in Mauritius were largely unrecycled and could partially be used in soil stabilisation.
In this paper, two 20MW wind turbine permanent-magnet generators are separately designed with concentrated windings and distributed windings, based on the same slot fill ratio, magnetic loading and rotor structure to illustrate the overall performance. The generator efficiency and the mass of the two different winding types are then compared for the same temperature limit. Particular attention is paid to the rotor loss and magnet demagnetisation, due to the space harmonics of flux created by the concentrated windings. Conclusions are drawn that whilst concentrated windings can result in a smaller generator, they require additional measures to reduce magnet losses and may require additional magnet mass.
Renewable energy is seen as the greatest solution for meeting growing energy needs. Wind energy is regarded as a rich energy source, and it frequently coexists alongside solar energy. In comparison to fossil fuels, it is inexhaustible and pollution-free. Based on its purpose and energy producing yield, wind turbines are frequently classified as small or large systems. This paper will present an overview of all possible faults in a wind turbine from structural damage to electrical fault. To improve the system's reliability, sustainable materials and advanced technologies for the development of various parts of wind turbines are being supported. Turbine blades, generators, and other auxiliary parts play an important role in the turbine's smooth functioning. Thus, their material properties are paramount. Hence, an overview of different parts, their yearly corresponding faults and their breakdown causes, are presented in this paper.
In recent years, multicellular power converter, is being studied as one of the latest research topics in high power applications, for their attractive features such as, using minimal rating components, high quality voltage output, ability to integrate in smart grids and renewable energy systems, and higher power conversion efficiency. However, the redundant topology and serial connection makes the multicellular converter more subjected to the occurrence of faults. Therefore, a fault tolerant control (FTC) is necessary to solve this issue. In this paper, an FTC is proposed without changing the structure of multicellular converter during flying capacitors failure. A robust sliding mode control is used for different fault scenarios. Simulation results with Matlab proves the effectiveness of proposed FTC to increase robustness and reliability of multicellular converter.
Due to their inherent capacity to convert solar energy to electrical energy, photovoltaic systems are considered as one of the most promising developing technologies which are gaining a lot of attention these days. In this paper, we propose a novel feedback approach to control the position of two Direct Current servomotors mounted in a solar energy system. Unlike the classical feedback controller, this strategy can handle both of linear and nonlinear models and it is very suitable for underac-tuated systems. The concept of the investigated method consists on dividing the system into individual subsystems and designing a virtual input for each one. Since this strategy processes in iterative algorithm, general formulation is established to provide a standard modeling that can be applied with any order of systems. Simulation results have demontrated the efficiency of the investigated controller in terms of convergence towards the desired references with minimal tracking errors.
In this research paper, an assessment of the rooftop technical solar potential is made to meet the predicted electric vehicle uptake in Mauritius by 2030. A strategic GIS-based approach is adopted to estimate the available rooftop surface of buildings for solar power generation from photovoltaic cells to charge four-wheelers' batteries. The framework has been split into three scenarios of EV uptake namely slow, medium and fast growths in the future EV fleet with an average battery of size of 40 kWh and a daily energy autonomy for 30 km revealed through a survey. Five sites have been identified around the island. Simulation results show that in order to satisfy the demand for EV vehicles, grid-tied PV modules need to be installed on 682,184 m2 of the available rooftops for slow growth, 294,109 $m$2for medium growth, and 511,773 m2 for rapid growth in 5 strategic zones identified around the island. The most optimistic uptake will require only 0.8% of all rooftop surfaces available as residential, commercial and industrial. Finally, it can be deduced that even if 100% of the battery capacity of average EV cars in 2030 is supplied, only about 6.4% of the total available rooftop surface needs to be covered with grid-tied PV modules to meet the demand.
The accurate estimation of irradiance and PV electricity output necessitate costly equipment that need regular maintenance, thereby inflating the capital cost of investment of solar PV system. In this paper, a cloud-based regression model is implemented to estimate irradiance and electricity parameters using cloud cover data. Testing the model in a site having sky regimes characterized as clear sky with scattered clouds revealed the accurate performance of the model. Daily estimations of irradiance were performed to acceptable levels of accuracies, with root mean square error of 90.2 W/m 2 and correlation coefficient value of 0.77. Even higher accuracies were reported for monthly mean estimations of irradiance, with root mean square error of 60.9 W/m 2 and correlation coefficient value of 0.94. Using the monthly mean irradiance estimates, the PV electricity generation output was estimated and compared to simulated performance on NREL PV Watts for a 20 kW DC system at Universite des Mascareignes. Relatively high levels of accuracies have been reported for the Black model with root mean square error of about 149 Wh and correlation of 0.92.
This paper focuses on the options for replacing the heating system at Hillhead Halls at the University of Aberdeen with the goal of providing adequate heat load whilst enabling carbon emissions reduction in line with University and Government carbon emission goals. Hillhead primarily uses gas-fired boilers to heat a local heat network. These gas boilers are now at the end of their design life and a near-term replacement is required. The study focuses on improving the current heat network and reviewing options to replace the existing gas boilers with low-carbon heat technologies. This study concludes that the pipework for the network should be upgraded as this would allow the heat network to move from the current 3G District Network (high temperature) to a 4G District Network (lower temperature). This reduces carbon emissions but also enables the use of low-carbon technology. It also concludes that heat pumps, biomass, and extension of other nearby heat networks are heat technologies that meet the main objective of reducing carbon emissions and which could be a practical solution at Hillhead given further study.
The present work aimed to model the general stages of solid biofuel production, using an automated mechatronic system (AMS) for manufacturing pellets from wood residue and a Petri net. Based on the pellets characteristics a scheme of AMS for processing biomass raw matter was designed and a generalized Petri net was developed. The work was carried out considering the technological and auxiliary operations, performed by the systems' structural units. The technological process of biomass pellets production was determined and expressed in terms of nine global stages. The main nodes and states, and the transition tacts during the operation of the modeled Petri net for the AMS were proposed along with a schematic interpretation of the envisaged mechatronic pellet production system.
In India preserving food is traditionally done by the effective drying method. The heat of the sun and the air are being used for several years to dry food to preserve it. Due to depleting fossil fuels and high prices lead to the use of non-conventional energy sources. Drying of products using solar energy has gained importance as it is environmentally friendly and has little impact on the environment. Natural flexible solar dryers and mandatory solar dryers are the two main phases of drying. In natural convection solar systems, air flow is stopped by air flow caused by buoyancy while in a solar convection dryer forced air flow is supplied using an operating fan either solar / residual module or residual fuel. In this project we are trying to build a hybrid solar dryer. The hybrid solar dryer is designed and constructed using direct solar power and a temperature changer.
Renewable energy is being more widely used, and its usage in transportation is becoming a need to minimize pollution. India produces a large number of scooters, and manufacturers are interested in producing electric scooters and emphasizing the need for charging stations along roads so that e-scooters can travel longer distances. The design of an escooter charging hub based on PV renewable energy systems is presented in this paper. A detailed simulation model with results is provided to analyze the station's efficient performance. Four chargers of different ratings are designed on a charging station, and a backup system with a large backup battery is connected to the circuit to provide energy on rainy or cloudy days as well as at night. Finally, a comparison is given to show the impacts of charging schemes impacting the overall e-scooter battery life span.
This paper explores the steady-state analysis of a Brushless Doubly Fed Reluctance Generator (BDFRG) as an alternative to a doubly-fed induction generator (DFIG) for variable-speed wind power applications. The steady-state equations describing the model of the DFIG and the BDFRG are presented. Furthermore, the effect of the rotor/secondary voltage on the both machines control in the motor and generator mode of operation is studied. The results of steady-state analysis based on equivalent circuits of the two machines having the same rated power and the number of rotor poles show a great deal of similarity in the behavior. But, when the generators are running sub-synchronously in the case of wind speed drop, the BDFRG produces higher active power than the DFIG. However, the copper losses of the DFIG are less.
Even though research papers discussed increasing fossil fuel costs, it is proven in today's scenario. Therefore, it is confirmed that Renewable Energy (RE) technologies will take a primary role in generating electricity in this era. This has created real operational challenges for the grid operators. With technology transfer and new technology development, capacity building is potentially focused on through grants. The power system was preferred to have large inertia for its smooth operations. With the latest technologies and speedy responses, the modernized systems could create inertia by properly and instantly coordinating and controlling many small plants. Further, accurate prediction algorithms release stress by giving advanced information about the system. It is a new direction of modernized control, and it always starts with a small design. It then integrates with an extensive system through a supervisory control loop. These incorporated technologies are opening several new opportunities for RE-based technologies. The research on micro-grid was initiated about two decades ago. It has been developed parallel with the possible development of RE technologies and prediction algorithms. The recent hike in fossil fuel costs pushes the micro-grid-based RE power generation to the front. Accordingly, this paper presents the coordinated control of a few RE power plants, using a micro-grid concept while integrating the micro-grid with the primary grid through the supervisory control concept. The proposed idea is simulated using the EMTDC/PSCAD, and it shows an excellent result. Furthermore, it will become more attractive over expensive fossil fuel systems in this era.
An investigation of five meteorologically-distinct regions based on topography and wind directions is performed, to classify day-to-day variations of solar irradiances into physically-sensible regimes. Descriptive statistical tools which include standard deviation, coefficient of variation, quartiles, minimum, maximum, skewness, and kurtosis are utilized to measure the central tendency and variability of recorded global solar irradiance values for the regions of Barkly, Flacq, Plaine Sophie, Reduit, and Richelieu. Seasonal analysis is performed and reveals that the summer season witnesses on average, higher insolation values at all sites while the winter season reflects a relatively stable solar climate, characteristic of constant solar energy resource for efficient energy conversion. An inter-comparison study on annual scale indicates that the North-West regions of Barkly and Richelieu have inherently higher solar energy potentials with clear to lightly scattered sky cover for about 275 days with global solar irradiance above a threshold value of 300 W/m2• The annual average daily irradiance at Barkly and Richelieu are 371.8 W/m2 and 374.2 W/m2, respectively, favoring the development of solar energy projects.
In this paper, we present a novel speed-sensorless flux observer design methodology for induction machines based on the measurements of the stator currents and voltages. We start with the well-known $\alpha-\beta$ model of induction motors. We utilise a change of coordinates to transform the $\alpha-\beta$ model into a reduced order $(3^{rd})$ model expressed in terms of complex differential equations. As results, the analysis of the model and the synthesis of observers are made simpler. After that, we formulate a behavioural model of the rotor speed of the induction motor which we use for the synthesis of the flux observer. The potential and practicality of the proposed flux observer is demonstrated via various simulation results
Energy policies are developed to drive the energy sector objectives and targets by countries or regions. As the global push for energy transition to carbon-neutral energy sources continues, developing countries such as Nigeria need to formulate incentive policies to drive the growth and increase the share of hybrid renewable energy systems (HRES). Nigeria experiences diverse energy challenges such as inadequate power supply with only about 13 GW of installed capacity to serve over 200 million people. The average per capita electricity consumption in the country in 2019 stood at 133 kWh. Therefore, for Nigeria, HRES is needed not just for energy transition but more importantly to bridge the huge electricity demand-supply gap. There are existing policies for the energy sector of the country such as the National Energy Policy and the National Renewable Energy and Energy Efficiency Policy, but these policies have failed to achieve their key objectives hence the need for a review with a view to developing a policy that will incentivize renewable energy in the country. Therefore, this research examines the power situation in Nigeria and causes of failure of existing energy policies to drive the needed growth in renewable energy in the country and recommends how incentive policies can be developed and implemented to promote HRES in Nigeria. Incentives such as feed in tariffs, net-metering schemes amongst others have proven to stimulate the growth of renewable energy in some countries and can be adapted in Nigeria.
