Avaliação de diferentes técnicas para o melhor aproveitamento das energias elétrica e térmica em usinas fotovoltaicas

Abstract

The growing demands for electric energy have called attention of several nations about the environmental pollution caused by the sources of generation. In order to soften environmental these influences, many investments and incentives to the research, development and implementation of the generation of electric energy using natural resources, mainly wind, hydroelectric and solar. Photovoltaic technology is an increasingly and promising way to directly convert solar radiation into electrical energy without harming the environment in any sense. The insertion of this technology in large scales in several countries encouraged the expansion of studies trying to increase the performance of this technology, in terms of both construction and operating conditions. UFSM research group CEESP has developed a versatile prototype for this type research mostly related to photovoltaic modules. This prototype aims to increase the electrical performance of the photovoltaic modules, as well as the thermal utilization during its operation. This prototype allows experiments with fixed modules in adjustable positions, solar tracking in one and two axes, flat solar concentration and cooling with thermal storage either in water tanks or in with geothermal technology. This central is a completely automated installation, modular and reprogrammable. Based on the potentiality of this prototype, six lines of experimental research are proposed in this dissertation. The first one analyses the influence of the orientation and inclination angles on the electrical performance of the photovoltaic modules in monthly, seasonal and annual periods. The second line of study evaluates the performance of the photovoltaic modules installed on roofs to verify the influence of the operating temperature variation caused by the restrictions of natural thermal exchange due to proximity of the installation of the panel nearby or in direct contact with the roof. In the third line of research, are studied the effects of dirtiness from the photovoltaic power plant's location on the performance of modules conditioned to different cleaning routines were evaluated. The fourth line of research presents solar tracking under the condition of mostly cloudy skies, such as rainy and very cloudy weather. In the fifth line of study, it is investigated the influence of the mover step for solar tracking on one axis (East – West). The last line of research in this dissertation brought together solar tracking, solar concentration and panel cooling with thermal utilization as a means of enhancing the performance of photovoltaic modules. The experimental results of all these researches contribute technically to enhance the performance of photovoltaic modules. In addition, such results also can assist in decision making for the installation and use of photovoltaic modules, such as, for example, cleaning routine or positioning angle of fixed installations that aim to prioritize electrical performance at any specific period of the year.