Performance analysis of a parabolic trough solar collector with non-uniform solar flux conditions

The improvement of the performances of the parabolic trough solar collector system (PTC) plays a vital role in the utilizations of solar energy. In this paper, a solar ray trace (SRI) method and the finite element method (FEM) based numerical simulation method is proposed to solve the complex problem coupled with fluid flow, heat transfer and thermal stress in a PTC system. The profile of the solar energy flux is calculated by the SRI method, and the effects of the key operating parameters on the performances of the receiver are numerically investigated. The distributions of the stress intensity and the thermal deformations of the receiver are numerically studied. Numerical simulation results indicate that the circumferential temperature difference (CTD) of the absorber decreases with the increases of inlet temperature and velocity of the heat transfer fluid (HTF) and increases with the increment of the direct normal irradiance (DNI). When the inlet velocity is in a range of 1.00-4.00 m/s, the DNIs are 500-1250 W/m(2) and the inlet temperature is 373-673 K, the CTD of the absorber can reach 22-94 K. The thermal stress and the deformations of the absorber are higher than that of the glass cover. The promising results will provide a fundamental reference for the development of the parabolic trough solar thermal power plant in China. (C) 2014 Elsevier Ltd. All rights reserved.