Thermo-mathematical model for parabolic trough collector using a complete radiation heat transfer model - A new approach

Solar Parabolic Trough Collectors (PTC) are alternative clean solution for the thermal power plants to generate electricity and thermal energy. It can be configured to support small, medium and high temperature applications. In PTC, solar radiation is concentrated to a pipe coated selectively and enclosed in a glass tube with vacuum maintained in the annulus, through which a heat transfer fluid is circulated. Heat transfer analysis of PTC is important to determine the operating characteristics as well as for optimization of the parameters under different operating conditions. In this paper a heat transfer model is developed for receiver tube with the focus on a complete radiation heat transfer model for the annulus. For the analysis the receiver tube is divided into severe elements where the governing energy equations are discretized using Finite Volume Method. Gerhart factor is used for modelling the radiation heat transfer. View factors are computed using contour integration technique and analytical solutions. Heat transfer results are then validated with the test results obtained from Sandia National Laboratory. The results obtained show close agreement with the test results. Also the result is compared with other four published models. Based on the RMSE analysis, it is proven that our model is the best among all the four models compared.