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Only few manufactures provide the wide set of graphical data that are necessary to use high performance predictive tools for PV systems. On the other hand, reliable graphical data require accurate laboratory measurements that increase manufacturing costs. For this reason PV system designers have to choose between the use of cheap PV modules, lacking in technical data, and the reliable energy predictions that are possible only if the current–voltage characteristics are provided by the PV module manufacturers.\ud This paper describes the procedure to evaluate the parameters of a one-diode equivalent circuit able to accurately epresent the electrical behaviour of a PV panel by means of the minimum set of technical data that are usually provided by all manufacturers. To reach the purpose some correlations based on the survey of more than one hundred PV module characteristics were defined to make up for the lack of technical\ud information. The computer routines used to evaluate the values of the model parameters are listed; the routines are written in BASIC and can be easily implemented, even like VBA macros in Microsoft Excel.\ud The capability of the new model to calculate the current–voltage characteristics was tested by comparing the results with data measured by four different manufacturers. The results of the application of the new model confirm the reliability of the proposed procedure. The differences between the calculated and the measured data are always less than the data tolerance usually declared by the manufacturers

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Nowadays the achievement of a comfortable environment in aircraft cabins is a factor of paramount importance in air travel business competition; on the other hand, the need of reducing the propulsion fuel cost has driven the airline companies to adopt air handling systems that may reduce the levels of thermal comfort and air quality inside the cabins of commercial airliners. With the aim of contributing to a better knowledge of this matter, this paper reports the results of an experimental study upon the indoor air quality aboard commercial aircrafts for 14 domestic flights less than 1 h and half long. The parameters monitored were temperature, relative humidity and carbon dioxide concentration; the measurements were performed during the whole flight from the takeoff to the landing. The relative humidity inside the cabin was also calculated using the rates of outside air and the carbon dioxide as a ventilation tracer; the theoretical results were compared with the measured data. The relationship between relative humidity and carbon dioxide concentration during fights was highlighted in order to define the environmental conditions that may provide acceptable levels of both the air quality and hygrometric comfort to the crew and passengers. The results of calculations confirmed the possibility of improving the hygrometric conditions in aircraft cabins without the need of using humidification systems.

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