Based on the I- V curves of a photovoltaic (PV) module, a novel and simple model is proposed in this paper to predict the PV module performance for engineering applications. Five parameters are introduced in this model to account for the complex dependence of the PV module performance upon solar-irradiance intensity and PV module temperature. Accordingly, the most important parameters, i.e. the short-circuit current, open-circuit voltage, fill factor and maximum power-output of the PV module, may be determined under different solar irradiance intensities and module temperatures. To validate the developed model, field measured data from one existing building-integrated photovoltaic system (BIPV) in Hong Kong was studied, and good agreements between the simulated results and the field data are found. This model is simple and especially useful for engineers to calculate the actual performances of the PV modules under operating conditions, with limited data provided by the PV module manufacturers needed. (C) 2007 Elsevier Ltd. All rights reserved.