The present paper is focused on drawing a high performance modeling and computation of a low concentrating collector combined into a Photovoltaic/Thermal system. A 3-D computational model based on 3D-4Rays technique and volume finite method is developed. The collector consists of a trough parabolic concentrator of a 20 x concentration rate and two axis tracking system. The absorber is composed of a square duct in which Triple junction PV cells are connected in series into its lower surface and a three-sided insulated multi-layer water channel, which acts as a cooling system introducing heat recovery capability. A steady pressure-driven laminar flow of a Newtonian fluid is assumed with constant properties inside water microchannel. This coupled model is initially used to simulate and analyze the temperature distributions within the PV cells, and then the thermal and electrical behavior of the proposed system. The results of the coupled model are compared with the analytical model in terms of thermal and electrical performances, such as PV cell temperature, electrical efficiency, and outlet water temperature. In addition, the impact of non-uniform illumination on the PV solar cells is also investigated. The results of the analysis indicated that a discontinuity of the thermal conductivity along the absorber tube duct, post shading and non-uniformities of PV cells temperature distributions causes a reduction in thermal efficiency of slightly more than 6% while significantly effecting the overall electrical performance.