<p>Solar energy is one of the most viable sources of energy, with well-established technologies and extensive range of applications. The parabolic trough collectors (PTC) are widely used for converting solar energy into thermal energy, especially in industrial and domestic settings. This study is focused on assessing the optical and thermal performance of a PTC with an evacuated tube. A home-built numerical code was developed to calculate the heat flux distribution around the receiver using the Monte Carlo ray tracing method (MCRT), and to determine the average local concentration ratio (LCR). The present work suggests a uniformization of the heat flux in the axial direction based on the LCR. Subsequently, a two-dimensional code based on the optical properties and the thermal model is treated by the finite volume method (FVM). The computational grid is optimized, and the code is validated against available numerical and experimental results. The study evaluates the outlet temperature and thermal efficiency by varying the collector width, flow rate, and rim angle. A 90° rim angle provides higher geometric concentration, more uniform radiation distribution, higher thermal performance, and higher outlet temperatures compared to other angles. Doubling the width of the collector doubles the temperature variation of the working fluid, while a 25% increase in flow rate results in a 20% decrease in temperature variation.</p>