Effects of glass cover on heat flux distribution for tube receiver with parabolic trough collector system

A solar receiver is designed for operation under extremely uneven heat flux distribution, cyclic weather, and cloud transient cycle conditions, which can induce large thermal stress and even receiver failure. In this study, the effects of a glass cover (GC) on heat flux distribution are analyzed by Monte Carlo Ray Tracing (MCRT) method. In order to minimize the heat flux gradient, which in turn can reduce the thermal stress of tube receiver, a GC with elliptic-circular cross section is proposed in this study. The effects of refractivity and characteristic parameters on the heat flux distribution are also investigated. The numerical results indicate that the magnitude and distribution of heat flux are affected only slightly when concentrated sunlight passes through the GC with circular cross section, and adopting a GC with elliptic-circular cross section for the tube receiver can effectively decrease the heat flux gradient, the peak heat flux reduction is up to 32.3%. (C) 2014 Elsevier Ltd. All rights reserved.