The use of high concentration ratio parabolic trough systems
is emerging as one of the ways to further reduce the cost of
energy from these systems. This paper reports on the thermal
efficiency of a parabolic trough system and entropy generation
in the parabolic trough receiver at different concentration ratios.
In this study, the geometric concentration ratios considered were
in the range 88-113, while the collector rim angle was taken as
80o. A combined Monte Carlo ray tracing and computational
fluid dynamics procedure was implemented to obtain the
numerical solution of the thermal and thermodynamic
performance of the system. Results show that the thermal
efficiency reduces by about 4.5% as the concentration ratio
increases from 88 to 113 at a given flow rate, while the entropy
generation rate is shown to increase with increasing
concentration ratio. Results further show that there is potential
for improved performance with heat transfer enhancement using
Cu-Therminol®VP-1 nanofluid as the heat transfer fluid in the
receiver’s absorber tube. For a system with a concentration ratio
of 113 using Cu-Therminol®VP-1 nanofluid as the heat transfer
fluid, the thermal efficiency increases by about 12% as the
nanoparticle volume fraction increases from 0 to 6%.
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.