Heat loss modelling and analysis of parabolic trough solar collector using computational approach

Abstract

ABSTRACTThe objective of this paper is to study and analyse heat losses from the absorber tube of a parabolic trough solar collector (PTSC) system and development of heat loss correlation. Computational fluid dynamics has been employed to obtain the convective and radiative heat losses. Heat loss model is simulated by employing the discrete ordinate (DO) radiation model to account for the radiation exchange in an enclosure between steel tube and glass cover, which is maintained as vacuum. Heat losses from the glass cover due to forced convection and radiation have been modelled and simulated. The effect of different emissivity on the absorber tube, different diameter ratio between absorber tube and glass cover, different heat transfer coefficients due to wind effects are studied in the considered PTSC system. Results are mentioned in dimensionless numbers for wider applicability. The result indicates that by varying the emissivity of the tube wall from 0.2 to 0.8, Nusselt number increases from 5.66 to 18.6. Similarly, when the heat transfer coefficient is changed from 6.89 to 19.49 W/m2K, Nusselt number increased from 5.66 to 5.81. Effect of vacuum has been studied as well. Finally, the correlation between Nusselt number and its influencing parameters has been obtained for the PTSC.