Solar photovoltaic tree multi aspects analysis − a review

The generation of photovoltaic solar energy worldwide has increased significantly in recent years. This is mainly due to the growing demand of society for electricity, the need to reduce environmental impacts, and costs of such technology. The installation of a photovoltaic system with horizontally fixed panels requires a significant unshaded area, which has become increasingly scarce, especially in urban centers. The photovoltaic solar tree is a strategy used to increase the efficiency of photovoltaic systems by reducing the occupied area and optimizing the orientation angles of the panels. The originality of this work was that, through a literature review in different researches, seven relevant parameters related to solar photovoltaic trees were analyzed: (i) modeling and simulation, (ii) tree topology, (iii) orientation of the panels, (iv) constructive characteristics, (v) solar tracking, (vi) occupied area and (vii) site multiple uses. It was found that the photovoltaic solar tree is an interesting alternative to generate renewable energy for places without large enough areas, which can be used for other purposes, such as crop production and parking. Finally, it was concluded that, to date, there are no studies available in the literature on the optimization of photovoltaic generation per area for different topologies of known solar trees

Estado-da-arte da simulação da taxa de fixação de carbono de ecossistemas tropicais State-of-the-art of the simulation of carbon fixation rates by tropical ecosystems

Este trabalho avalia o estado-da-arte de modelos de simulação da taxa de fixação de carbono, ou produção primária liquida (NPP), de ecossistemas tropicais em duas configurações diagnósticas (simulação em sítios micrometeorológicos e simulação forçada por dados climáticos e por produtos de sensoriamento remoto) e uma prognóstica (simulação por um modelo acoplado clima-vegetação). Os resultados indicam que os modelos de estimativa de NPP atingiram capacidade de fazer estimativas não-viesadas de valores médios regionais de NPP, tanto no modo diagnóstico, quanto no modo prognóstico, com erros inferiores a 5%, enquanto o valor esperado do erro em cada sítio é inferior a 10% no modo diagnóstico e inferior a 20% no modo prognóstico. Os modelos estado-da-arte são capazes de monitorar a taxa de fixação de carbono por ecossistemas tropicais de maneira rotineira, sendo esperados baixos erros para essas estimativas.<br>This work evaluates the state-of-the-art of the simulation of carbon fixation rates, or net primary production (NPP) by tropical ecosystems in two diagnostic configurations (simulation at micrometeorological sites and simulation forced by climate datasets and remote sensing products) and one prognostic (simulation by a coupled climate-biosphere model). The results indicate that the NPP simulation models are capable of unbiased estimates of average regional values of NPP, both in diagnostic and in prognostic mode, with errors smaller than 5%, while the expected value of the error in each site is smaller than 10% in the diagnostic mode and smaller than 20% in the prognostic mode. State-of-the-art models are capable of routinely monitoring the net primary production of tropical ecosystems, with low errors expected for these estimates