Carlos Andrés Arredondo

Design and implementation of sun tracker prototype for solar module positioning

This paper describes the design process and implementation of a two-axis sun tracker prototype for solar modules positioning by sensing the point of maximum brightness of the sky with the building of a sensor based on a geodesic dome and using a structure motion on horizontal celestial coordinates. The developed prototype system performs a continuous sampling of the entire sky; allowing it to identify the brightest point of the firmament, even with a partly cloudy sky, and guiding the solar module to that point by using a two-axis drive system, and running a new sampling of the sky every five minutes to reposition the solar module if the brightest point has changed its location. This sun tracker system uses as sensor element a Light Dependent Resistor (LDR) or a photoresistor to find the brightest point in the sky. The data and signal processing of the lightning sensor (using LDR matrix) and solar modules are performed by a microcontroller-based system. The energy obtained from the solar module is bigger and remains stable when the two-axis sun tracker prototype is used.

Comparison of two grid connected photovoltaic systems GCPVS with different dimensioning factor DF during three years operation in Bogotá - Colombia

This paper shows the comparison of two grid connected photovoltaic systems GCPVS that are operating in the city of Bogotá - Colombia for more than three years. The systems are constituted by one of 0.8 kWp and the other of 3.6 kWp, they were designed with different dimensioning factor FD. The results revealed that the systems has different performance ratio PR, one of 0,78 for the one of 3,6 kW and 0,5 for the other of 0,8 kW.

Methodology for technical analysis to massify PV systems as an option for distributed energy generation in low-voltage systems

This work presents the results for the use of a methodology to predict in a statistically reliable way, the impact of the behavior in steady-state of the massification of Grid-connected photovoltaic system to a low-voltage system. The methodology can be implemented either in common using programming software or using any commercial electric system simulation software. First, a grid-connected photovoltaic model was determined and verified for comparing its behavior with output measured on a real installed system 3.6 kWp. Parallel, atmospheric parameters which affect the PV systems behavior were characterized in statistically way from actual measurements. The solar resource characterized and the photovoltaic system model are integrated in a non-deterministic approach using the stochastic method to estimate the electrical parameters in steady- state, describing the influence of massification of the Grid-connected PV systems in low-voltage grid.

In(O,OH)S/AgInS 2 absorbent layer/buffer layer system for thin film solar cells

In this work In(O,OH)S thin films were deposited on AgInS2 thin films for the system absorbent-layer/buffer-layer to be used in two junctions tandem and/or in single junction solar cells. AgInS2 layers were grown by co-evaporation from metal precursors in a two stage process, and In(O,OH)S thin films were deposited by chemical bath deposition. X-ray diffraction measurements indicated that AgInS2 thin films grown with chalcopyrite structure; and In(O,OH)S films grown with polycrystalline structure. It was also found that the AgInS2 films presented p-type conductivity, a high absorption coefficient (greater than 104 cm-1) and an energy band gap (Eg) of 1.95 eV, and In(O,OH),S thin films presented Eg about 3.01 eV. The results indicate that the developed system can be used in single junction solar cells, and in two junctions tandem solar cell as top cell.

Physicochemical study of synthetic dyes adsorption on TiO2 thin films for dye sensitized solar cells

In this work we study equilibrium and kinetic adsorption process of Methylene Blue (MB) and Copper phthalocyanine (CuPhTh) dyes on TiO2 thin films. We synthesized phthalocyanines through Achar method; dyes were characterized by Fourier-Transform Infrared spectroscopy (FTIR) and Diffuse reflectance. TiO2 thin films were fabricated by Doctor Blade method for using Degussa P25 as TiO2 source. We used Langmuir and Freundlich adsorption models to describe adsorption equilibrium, and besides, we used Largergren model to describe kinetic adsorption process. Characterization results reveal typical signals of phthalocyaninaes, and besides, TiO2 thin films had a polycrystalline structure. Results indicated dyes adsorption to occur through chemisorption process and Langmuir adsorption model describes suitably dye adsorption process on TiO2 thin films.

Technical potential of some Colombian cities for the development of grid connected PV systems through virtual instrumentation

This paper briefly describes the operation curves of some PV modules under actual irradiance conditions and temperature in 10 Colombian cities. Those curves were obtained from a Virtual Instrument (VI) developed in LabVIEW®. With the collected information from the VI, the cities were classified taking into account 5 parameters: solar irradiance, temperature, variability of solar resource, maximum power point and Photovoltaic (PV) modules efficiency in the cities. From the VI, an analytical methodology was developed to identify the technical potential of some regions for the implementation and development of grid connected PV systems. Additionally, users were able to get information on the solar irradiance potential, helping to achieve an accurate design of the PV systems.

Sistema fotovoltaico para abastecimiento energético rural residencial

Nowadays, the cost reduction of photovoltaic panels allows an economically implementation of autonomous energy systems, granting viability. This paper presents the design, analysis and implementation of an energy supply system for residential use based on solar energy, functional for rural or remote areas of conventional electrical grid. Calculation of the average energy consumption of a two floors residence, based on use of conventional home-electronics appliances, it is calculated the energy consumption of the lighting system, obtaining the average total consumption for system dimensioning. It is obtained an energy consumption of 5822 W corresponding to 11 solar panels of 120 W each, with the possibility of a system interconnection to electrical grid so as to deliver unused energy.

Development and implementation of a hybrid photovoltaic system for energy back-up

The purpose of this work is to introduce a novel system developed to be used as back-up of a conventional UPS, in order to increase its autonomy and to warrant continue operation for long periods of time in the case of a power failure in the public grid. The system is constituted by a conventional UPS connected in parallel to a standalone PV system and a electronic system with facilities to control the charge and discharge of the battery bank of the PV system and to keep the UPS functioning when power cut occur. These elements are interconnected through relays which are activated by digital signals from a control that was developed using virtual instrumentation.