M. Cucumo

Data bank Experimental data of the Linke Turbidity factor and estimates of the Ångström turbidity coefficient for two Italian localities

Experimental data of the Linke turbidity factor and estimations of the dngstrom turbidity coefficient are presented. This data has been obtained starting from beam solar radiation measurements performed at Arcavacata di Rende (Cosenza) and at Casaccia (Rome). Comparisons have also been carried out with some calculation methods.

A calculation method for the estimation of the Linke turbidity factor

A general calculation model is presented to determine the Linke turbidity factor, starting from the experimental datum of global daily solar radiation on the horizontal plane. The model was validated using experimental data for the turbidity factor obtained at Arcavacata di Rende (Cosenza) and at Casaccia (Rome). Moreover, polynomial relations are presented for quick calculation of this parameter on different days of the year for those localities for which the European Solar Radiation Atlas supplies the maximum solar radiation values on clear days.

Estimating effective solar absorptance in rooms

Abstract A model capable of calculating the redistribution of solar energy inside a buildings rooms and the rooms effective solar absorptance was developed and implemented in a computer code. Best-fit curves of a rooms effective solar absorptance are provided as a function of the ratio between the window area and the internal surface area and of the wall absorptance. Moreover, model predictions are compared with an approximate theoretical equation.

General calculation methods for solar trajectories

Two calculation methods for solar trajectories are considered, being of general validity and applicable to all latitudes. In addition, some polar and Cartesian solar trajectory diagrams are presented.

Predictive methods to estimate the producibility of PV/T solar collectors

In this work a simple predictive model to estimate PV/T collector performance is presented. The model is based on an equivalent electrical circuit of the collector, whose solution allows evaluation of its thermal and electrical power produced. The electrical circuit is modified according to whether the problem is solved in stationary or transient conditions. As regards the stationary approach, two different circuits can be schematized: the first allows evaluation of the magnitudes at different points along the motion direction of the fluid; the resolution of the second electric circuit allows direct evaluation of the average magnitudes between the inlet and outlet collector section. With the transient model, instead, it is possible to estimate the behaviour of the collector by adding, to the previous circuit, a capacitor of capacity equal to those of the thermal collector. Obviously, when the transient condition is exhausted, the various determined quantities are identical to those measured in stationary conditions. Finally, the study shows that the electrical circuit used for this type of collector is similar to that of the solar thermal collector, with the difference that some circuit components also contain electrical quantities.