This article presents modeling and experimental verification of conversion of solar irradiation from horizontal to sloped surfaces and photovoltaic cell temperature and an analysis of photovoltaic conversion efficiency. Modeling and validation of the models are carried out on the basis of measurements conducted using the experimental system set in a city in southern Turkey. In addition to current, voltage, and cell temperature of the photovoltaic module, environmental variables such as ambient temperature and solar irradiance were measured and used for validation purposes. Correlation of conversion of solar irradiation from horizontal to sloped surfaces indicated that the presently used model is highly successful because of the fitting parameters: the coefficient of determination (R-2) = 0.97, and themean bias error (MBE) = -2.2. Similarly, the cell temperature model used in the present article is validated by the following correlation parameters: (R-2) = 0.97, MBE = 0.7, and root-mean-square error (RMSE) = 2.1. DOI: 10.1061/(ASCE)EY.1943-7897.0000082. (C) 2013 American Society of Civil Engineers.