Solar Radiation Estimation Using Data Mining Techniques for Remote Areas-A Case Study in Ethiopia

High quality of solar radiation data is essential for solar resource assessment. For remote areas this is a challenge, as often only satellite data with low spatial resolution are available. This paper presents an interpolation method based on topographic data in digital elevation model format to improve the resolution of solar radiation maps. The refinement is performed with a data mining method based on first-order Sugeno type Adaptive Neuro-Fuzzy Inference System. The training set contains topographic characteristics such as terrain aspect, slope and elevation which may influence the solar radiation distribution. An efficient sampling method is proposed to obtain representative training sets from digital elevation model data. The proposed geographic information system based approach makes this method reproducible and adaptable for any region. A case study is presented on the remote Amhara region in North Shewa, Ethiopia. Results are shown for interpolation of solar radiation data from 10 km x 10 km to a resolution of 1 km x 1 km and are validated with data from the PVGIS and SWERA projects

Development of a simplified analytical model for a passive inertial system solicited by wave motion

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThis paper presents a theoretical and experimental investigation about the modelling of a 1:45 scale prototype Wave Energy Converter (WEC). An analytical model is implemented to describe its behaviour in a wave tank. The aim is to provide a contribution to modelling tools used for WEC characterisation and design. Hydrodynamic characterisation software is avoided in favour of a simpler and more versatile design tool destined to a wider range of users. Therefore, an alternative approach is presented, based on mechanical analogies and the use of Matlab/Simulink/SimMechanics environment. This analytical model was constructed using linear wave theory, coupled with a non-linear model for the device and its power take-off system (PTO). Assumptions on incident waves and geometric properties of the device were required and implemented on the basis of literature of naval architecture, ships stabilization and control issues. Simulation results were compared and validated with those obtained in the same range of experimental tests of the prototype in wave tank. Trends and values of both investigation techniques show a good agreement, indicating the validity of the methodology adopted and leaving space for future improvements of the same. Finally, as example of application, the model was applied in a show case in order to estimate the energy yield by the WEC if scaled to real size, using Froude scaling. Results are encouraging and show the viability of the proposed design

Numerical Investigation of the Performance of Three Hinge Designs of Bileaflet Mechanical Heart Valves

Thromboembolic complications (TECs) of bileaflet mechanical heart valves (BMHVs) are believed to be due to the nonphysiologic mechanical stresses imposed on blood elements by the hinge flows. Relating hinge flow features to design features is, therefore, essential to ultimately design BMHVs with lower TEC rates. This study aims at simulating the pulsatile three-dimensional hinge flows of three BMHVs and estimating the TEC potential associated with each hinge design. Hinge geometries are constructed from micro-computed tomography scans of BMHVs. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Leaflet motion and flow boundary conditions are extracted from fluid–structure-interaction simulations of BMHV bulk flow. The numerical results are analyzed using a particle-tracking approach coupled with existing blood damage models. The gap width and, more importantly, the shape of the recess and leaflet are found to impact the flow distribution and TEC potential. Smooth, streamlined surfaces appear to be more favorable than sharp corners or sudden shape transitions. The developed framework will enable pragmatic and cost-efficient preclinical evaluation of BMHV prototypes prior to valve manufacturing. Application to a wide range of hinges with varying design parameters will eventually help in determining the optimal hinge design

Planning of power systems with distributed generation and storage

Abstract. A high penetration of distributed generation in electricity networks makes it necessary to adapt the network to the new conditions of generation and consumption. Storage units can be converted within a few years in another element of power grids. Therefore, it is necessary to analyze the network to determine the optimal location of distributed generation, which lines need to be built or where to install the storage units. This paper presents a model of power network planning which takes into account the effect of the expansion of distributed generation. The results obtained show the continuing replacement of conventional generation by distributed generation and the importance of storage units in this process of replacement

Control structure for optimal demand-side management with a multi-technology battery storage system

Demand-side management (DSM) is proposed as a key solution to increase electric system flexibility, essential for large-scale deployment of renewable energy generation. System flexibility is required to avoid congestions in electric systems and reduce costs for network operators and consumers. IoT deployment, real-time pricing and cost reductions for electric energy storage opens new opportunities for DSM tools, which help matching demand with variable renewable generation. This paper describes the control structure developed, implemented and tested in real demonstrators to deploy demand management programs to reduce energy bills of industrial customers. This structure operates at two stages: remotely, to calculate economically optimal consumption and ESS operation set points and locally to adapt the forecast-based economic program to real-time conditions. The described DSM structure has been developed within a national Spanish research project called EV-OPTIMANAGER

Development of a simplified analytical model for a passive inertial system solicited by wave motion

This paper presents a theoretical and experimental investigation about the modelling of a 1:45 scale prototype Wave Energy Converter (WEC). An analytical model is implemented to describe its behaviour in a wave tank. The aim is to provide a contribution to modelling tools used for WEC characterisation and design. Hydrodynamic characterisation software is avoided in favour of a simpler and more versatile design tool destined to a wider range of users. Therefore, an alternative approach is presented, based on mechanical analogies and the use of Matlab/Simulink/ SimMechanics environment. This analytical model was constructed using linear wave theory, coupled with a non-linear model for the device and its power take-off system (PTO). Assumptions on incident waves and geometric properties of the device were required and implemented on the basis of literature of naval architecture, ships stabilization and control issues. Simulation results were compared and validated with those obtained in the same range of experimental tests of the prototype in wave tank. Trends and values of both investigation techniques show a good agreement, indicating the validity of the methodology adopted and leaving space for future improvements of the same. Finally, as example of application, the model was applied in a show case in order to estimate the energy yield by the WEC if scaled to real size, using Froude scaling. Results are encouraging and show the viability of the proposed design