In this study, a solar collector was considered with a cylindrical cavity receiver. The receiver was a type of coated copper closed-tube open cylindrical cavity. Thermal oil was used as the working fluid in the cavity receiver. The affecting parameters including the concentrator shape, concentrator reflectivity, concentrator optical error, solar tracking error, receiver aperture area, receiver tube diameter, cavity receiver depth, inlet temperature and the mass flow rate of the thermal oil through the receiver were investigated. Also, R141b was considered as the Working fluid of the ORC system in the condition of saturated vapor. The main focus of this study was on the thermal modeling and optimization of cylindrical cavity receiver. With the help of the ray-tracing software, SolTrace, and the receiver modeling techniques, the optimum aspect ratios are identified. It is conducted that for attaining higher collector efficiency, higher overall efficiency and higher network smaller tube diameter, optimum height of cavity and lower thermal oil inlet temperature are necessary. (C) 2016 Elsevier Ltd. All rights reserved.