LA REGOLAZIONE DELLA FASCIA OMBREGGIANTE NEI SOLARIMETRI PER RADIAZIONE DIFFUSA

Regulation of shading band of radio1neters used for ,neasuring diffuse radiation «sometimes» requires intervention on site by an operator. It is indeter,nination due to the use of the generic 45 «sometimes» (which continuously changes during the year) ,Nhich leads to the fact that «often» diffuse radiation data are not reliable because the device is hit (for a more or less long period) by direct radiation. In this paper the proposed equations allo\v forecasting, with excellent precision, the day when an operator should go on site to reset the band. This method predicts well also when the devices do not have a mechanical structure n1ade with great precision. The proposed method is particularly helpful for those who 1nust control net\vorks of pyrano,neters for diffuse radiation because it allows to progran1 interventions. In this way it is possible to obtain correct diffuse radiation measurements and consequently, actual sunshine duration measurements. In fact it is particularly difficult to identify errors due to exposition of device parts to the direct component of solar radiation. The proposed n1ethod can be easily implemented on worksheets or can be translated in software for PC. Information regarding software may be obtain fromthe authors.