Role of honeycomb structure in improving the melting process of a phase change material inside a latent heat storage unit

In this work, a numerical study is performed to analyze the impact of honeycomb structure on heat transfer within the PCM. The modeling is based on a transient calculation making it possible to analyze the phase change of the paraffin using the commercial software "Fluent" based on the enthalpy-porosity model. The results showed that the impregnation of a metal matrix in a rectangular enclosure helps to decrease the melting time and thus improve the heat transfer within the PCM.

Determination PV Module Technical Condition

The paper focuses on the determination of technical conditions and degradation of photovoltaic modules installed in grid-on operated photovoltaic systems in Ukraine and the Czech Republic. Detected malfunctions of PV modules are classified and Fault Tree Analyses (FTA) is created for particular PV modules. For assessment of the technical condition of the PV modules it is proposed to use residual resource index (RRI), that is being successfully used for determination of technical condition of transformers, breakers and synchronous generators. The main contribution is the method for the detection of photovoltaic modules condition with the use of a neuro-fuzzy network based on the experience of operational (maintenance) staff of particular plants.

Airfoil optimization for small horizontal axis wind turbine

In order to take advantage of the low wind speed found in the Colombian territory, a gradient-based optimization process (GBA) of 2 airfoils is carried out, using the Xfoil software to evaluate the interactions. The shapes chosen will be destined for the root and for the middle zone of a blade for a small horizontal axis wind turbine (sHAWT). The blade will be created from the calculation of the chord and pitch angle with the blade element momentum methodology (BEM) and the SHAWT will be tested by CFD software to check its performance. As a preliminary result, a root-bound airfoil has been obtained with a higher performance than the airfoil used as a bases.

IoT Monitoring System for Applications with Renewable Energy Generation and Electric Drives

nternet of Things IoT developed for monitoring, control, and management of sectors such as Smart Cities, Energy, Environment, Transport, Manufacture, Industrial Automation, Maritime, Healthcare, Education, etc, by interconnecting devices over internet. New sectors emerged in renewable energy systems, industrial motion drives, sensors and actuators. This article presents the design, and development of specific IoT applications for wind energy generating units, and electric drives. IoT technologies in the control systems of electric machines, mainly in applications of motor drives, and wind energy generating systems, contribute to improved monitoring, and management of performance, and to possible savings of energy. The experimental configurations upgrade laboratory infrastructure and offer new teaching and research perspectives to engineering education.

Real-Time Experimental Assessment of a New MPPT Algorithm Based on the Direct Detection of the Short-Circuit Current for a PV System

To substantially increase the efficiency of photovoltaic (PV) systems, it is important that the Maximum Power Point Tracking (MPPT) system has an output close to 100%.This process is handled by MPPT algorithms such as Fractional Open-Circuit Voltage (FOCV), Perturb and Observe (P&O), Fractional Short-Circuit Current (FSCC), Incremental Conductance (INC), Fuzzy Logic Controller (FLC) and Neural Network (NN) controllers. The FSCC algorithm is simple to be implemented and uses only one current sensor. This method is based on the unique existence of the linear approximation between the Maximum Power Point (MPP) current and the short-circuit current in standard conditions. The speed of this MPPT optimization technic is fast, however this algorithm needs to short-circuit the PV panel each time in order to obtain the short circuit current. This process leads to energy losses and high oscillations. In order to improve the FSCC algorithm, we propose a method based on the direct detection of the shortcircuit current by simply reading the output current of the PV panel. This value allows directly calculating the short circuit current by incrementing or decrementing the solar irradiation. Experimental results show time response attenuation, little oscillations, power losses reduction and better MPPT accuracy of the enhanced algorithm compared to the conventional FSCC method.

Wind Energy Education through Low-Power Wind Turbines and Advanced Software Tools

Wind energy has become a major source of power generation in recent years. This fact, along with the growing expectations for future decades, makes the study of renewable generation systems based on wind energy a subject of great importance for engineers from different disciplines. Although there are numerous research articles that deal with the technoeconomic aspects of this type of system, there are few works focused on the development of new didactic strategies to improve the academic excellence of undergraduate engineering students. This paper describes how to boost the student understanding regarding wind power generation by combining the use of advanced software tools normally used in the design of wind farms, such as System Advisor Model (National Renewable Energy Laboratory, NREL) and WindFarm (RESOFT) with lowpower wind turbines operating in self-consumption and gridconnected modes. Moreover, it is also described how wind turbines constitute an interesting option for distributed generation system in microgrids.

Energy planning tools applied into urban photovoltaic: the importance of compatibilizing with the constructions

The necessity for an efficient way to develop energy planning in urban environments is increasingly part of the reality of cities. In this sense, tools with the ability to evaluate the installation of distributed generation systems become widely necessary for the elaboration of efficient projects. In this sense, our article aims to evaluate 20 tools from the point of view of urban photovoltaic (PV) planning, considering functionalities such as simulation, scenario generation, bottom-up, availability and application in urban PV; PV is the most widespread power plant in urban environments, with great dissemination capacity.

Modelling of solar thermal energy for household use in equatorial latitude by using the F-Chart model

The Andean Equatorial Region, due to its geographic location, shows great potential for using solar energy. Solar thermal energy is of interest in the residential sector in Ecuador and other Andean countries as a method to avoid fossilderived fuels consumption. However, previous learnings of the operation of solar water heating systems in other latitudes cannot be used in the conditions of Ecuador. Thus, the performance of the solar thermal energy systems in this geographic region deserves further study that consider typical high levels of cloudiness and fast climate oscillations. The objective of this work was to investigate the effect of the orientation of solar thermal plates on their energy efficiency and model the behaviour of these systems to predict their operation under Equatorial Andean climate conditions. For the F-Chart calibration different slopes angles were used, according to the typical roofs slopes in Cuenca, Ecuador. Results showed a monthly solar fraction, contributed by an evacuated tube collector is 26% higher than the flat plate collectors. The results also depict that, in the conditions of Cuenca, the greater solar water heating occurs when the collector is inclined 14° and facing towards the south. These findings can be used to predict the best operational conditions for using solar thermal energy collectors to produce hot water in the residential sector under equatorial highland altitude conditions.

Software for calculating the optimum tilt angle of PV modules in different latitudes of the Southern hemisphere and solar plant sizing

Through the development of photovoltaic technologies, the market related to this type of renewable energy grows constantly. In Brazil, the generated power through photovoltaic (PV) power stations approximates to 2.3 GW representing 1.3% of the total Brazilian energy mix. To supply the public it is necessary to offer tools that facilitate consumer decision making or even the work of a solar farm designer. By analyzing the user’s necessity, it is possible to determine that a great parcel needs a quick and simple response to help them with their questions, and programs that are already well established in the marketplace are complex for inexperienced users. For this reason, a software that calculates the best inclination for PV modules using the method proposed by Liu and Jordan in 1962 is developed. It also determines the number of modules that can be installed without any shading between arrays within a user-defined area. This calculation is possible through the standard dimensions provided by the module manufacturers and the solar height and declination study. Through a simple interface, the user quickly receives the optimum tilt angle of installation, the number of PV modules and the maximum generated power.