Assessing the outdoor operating temperature of photovoltaic modules

By a careful study of data collected from seven varieties of photovoltaic (PV) module it is demonstrated that a simple modified form of the Hottel-Whillier-Bliss (HWB) equation, familiar from the analysis of flat-plate solar-thermal collectors, can be employed to predict module temperatures within an accuracy comparable to the cell-to-cell temperature differences typically encountered within a module. Furthermore, for modules within the range of construction parameters employed in this study, the actual values of the two modified HWB constants do not appear to depend upon module type. The implication of these results for the accuracy of outdoor module characterization is discussed. Copyright (C) 2008 John Wiley & Sons, Ltd.