Temperature and thermal stress analysis of parabolic trough receivers

The failure of a parabolic trough receiver has a significant influence on the safety and economic operation of a parabolic trough system. Data from existing commercial parabolic trough power stations show that 55% of the failures were reported to involve broken glass and 29% involved loss of vacuum, in most cases due to the failure of glass to metal seals, but also due to bowing tubes. In this study, three-dimensional numerical simulation of heat transfer and stress in the whole receiver is conducted by combining the Monte-Carlo Ray Tracing (MCRT) method, CFD and FEA stage by stage. The temperature field and stress of the bellows, glass envelope and Kovar ring were specially analyzed for the first time by the numerical simulations. The simulation results agreed with the measurement results. The temperature and thermal induced stresses of the Kovar ring were investigated on a parabolic trough solar collector system. Finally, the effects of DNI, the fluid temperature and flow velocity on the temperature and the stress of the absorber tube are studied.