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Modelling and New Identification Procedures to evaluate Concentrating Photovoltaic Multijunction (MJ) Module Equivalent Parameters and MJ-cells Junction Temperature in operating outdoor conditions

pubblicazioni - Articolo

Modelling and New Identification Procedures to evaluate Concentrating Photovoltaic Multijunction (MJ) Module Equivalent Parameters and MJ-cells Junction Temperature in operating outdoor conditions

A new theoretical approach is presented to: – Model the electrical behaviour of a Concentrating Photovoltaic (CPV) multi-junction (MJ) module, consisting of N- series-connected receivers, each one with M-parallelconnected III-V multi-junction solar cells,- Identify the CPV multi-junction module equivalent parameters, – Evaluate the cells junction temperature of the CPV module in operating outdoor conditions. Keywords: III-V modelling, Semiconductors, Gallium Arsenide Based cells, Multijunction Solar Cells, Concentrator modules, Characterisation, Testing.

Dams provide remarkable benefits to society, such as: renewable hydropower; drinking water; flood protection; irrigation and recreation, but also represent a public safety issue, as dam failures can result in severe loss of life, economic disaster and extensive environmental damage. For this reason, dams must be safely operated and maintained. This represents a crucial challenge from a social and economic point of view, particularly in light of the increasing shortage of available resources due to several concurrent factors, such as the global economic recession, the liberalization of the energy and water supply markets, the climate changes. Dam safety assessment is a complex process based on several technical, socio-economic and environmental factors, which combines information from different sources, such as design and operational data, materials parameters, monitoring systems, numerical simulation results and statistical data, aimed at evaluating the structural integrity of the whole system composed by the dam, its appurtenant structures and the reservoir. Since most of these data are strongly affected by uncertainty, their nominal values are usually assumed deterministically by assigning suitable conservative safety margins. Nevertheless, it has been widely recognized that such assumptions often fail to ensure the required safety level and, instead, a more consistent probabilistic approach should be adopted to properly handle uncertainties. Risk analysis methods have proved their effectiveness in handling a wide range of risks associated to critical infrastructures. In the last decades, particularly in the Anglo-Saxon countries, risk analysis methods have been successfully applied to dam safety assessment. These methods imply that all processes involved in dam safety management are integrated in logic and transparent systems or risk models that are capable of aggregating all risk components inherent to these infrastructures. The resulting information will be of great value to help the decision makers. The process that starts with gathering data and leads to risk quantification implies the consolidation of the existing knowledge on the facility and has to be ensured with procedures to properly store and update such data that will be integrated in a necessarily dynamic management tool. Moreover, risk analysis framework facilitate to share and to transfer the knowledge to new engineers and technicians involved in the dam safety process, to assign and identify responsibilities and to properly communicate risk to all dams’ stakeholders, in particular the downstream populations potentially at risk. That, along with a clear legislation that integrates design standards, safety requirements, risk management and legal responsibilities, are basic requirements of a modern, transparent, efficient and socially accepted procedure for decision making in dam safety. In this paper a proposal of a risk analysis framework for the Italian dams is presented, along with a roadmap for its development and implementation. This activity is funded by the Research Fund for the Italian Electrical System under the Contract Agreement between ERSE SpA and the Italian Ministry of Economic Development.

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