The numerical simulation and experimental validation of a compound parabolic concentrator (CPC) are presented. The solar device had an aperture area of 1.33?m2, a real concentration ratio of 3.5, an acceptance half angle of 15 degrees, and a carbon steel (or aluminum) tubular receiver with an outer diameter of 0.0603?m and coated with a commercial selective surface. Experimental tests were performed using water as working fluid at solar noon; the inlet temperatures used varied from 30 degrees C to 70 degrees C and the mass flow rates from 0.05?kg/s to 0.25?kg/s. A comparison of the experimental results with the numerical model developed was carried out. The results of the thermal efficiency, outlet temperature, and pressure drop were compared and found to be in close agreement with the experimental data. Therefore, the model is a reliable tool for the design and optimization of compound parabolic concentrators. Because the numerical model is based on the application of physical laws, it is possible to extrapolate its use with confidence to other fluids, mixtures, and operating conditions. Copyright (C) 2011 John Wiley & Sons, Ltd.