Sandy Rodrigues

Performance comparison of ANN training algorithms for classification

The Artificial Neural Network research community has been actively working since the beginning of the 80s. Since then many existing algorithm were adapted, many new algorithms were created and many times the set of algorithms was revisited and reinvented. As a result an enormous set of algorithms exists and, even for the experienced user it is not easy to choose the best algorithm for a given task or dataset, even though many of the algorithms are available in implementations of existing tools. In this work we have chosen a set of algorithms which are tested with a few datasets and tested several times for different initial sets of weights and different numbers of hidden neurons while keeping one hidden layer for all the Feedforward Artificial Neural Networks.

Analysis of the Self-Consumption Regulation for Photovoltaic Systems with Battery Banks in the Portuguese Residential Sector

Following recent trends in the developed countries, Portugal recently cut down the Feed-in tariffs for photovoltaic energy. They are now based on the Iberian market average (around 0.04€/kWh) while the final consumer electricity price is 0.16€/kWh. In this view, the PV system should be dimensioned for self-consumption since injecting into the grid produces less revenue. The motivation for the current work was to analyse the changes due to this new regulation, through the analysis of the economic feasibility of different size PV systems (1kW, 3kW, and 5kW), considering the selfconsumption regime with a battery bank as an option. We also compare the most profitable cities in Portugal with and without the use of a battery bank. The results show that the PV systems with battery banks are not as profitable as standalone PV systems in the Portuguese self-consumption regime. This is mainly due to the high price of the battery bank. In general, the mainland results are better than the islands for the 1kW and 3kW PV systems. In spite of the higher initial investment cost, the islands present better results for the 5kW PV system. In general, it can be stated that the investment in PV systems is highly conditioned by external economical factors that continuously change and the current work analyses the current situation in Portugal for different installed powers with or without battery banks.