Numerical Investigation and Thermal Performance Analysis of Smooth Absorber Tube in a Parabolic Trough Solar Collector

The thermal efficiency of parabolic trough solar collectors (PTSCs) is highly dependent on the design and material characteristics of the absorber tubes that control the performance of heat transfer and fluid flow. This study used a three-dimensional computational fluid dynamics (CFD) model to examine the thermal and hydrodynamic processes of a smooth circular absorber tube at various inlet velocities between 0.20 and 0.32 m/s. Four candidate materials—stainless steel, iron, copper, and aluminum—were compared using the surface temperature distribution, outlet fluid temperature, and velocity profiles. Water was used as a heat transfer fluid (HTF) and a constant solar flux of 1000 W/m was directed on the tube wall. The findings reveal that an increase in the mass flow rate lowers the surface and outlet temperatures because of the increase in the convectional heat transfer, and copper and aluminum always exhibit better thermal performance because of their high thermal conductivity. However, stainless steel and iron have higher surface temperamres and greater thermal gradients, indicating poorer heat dispersion. These results demonstrate that the optimization of materials and flow rate can contribute to maximizing the efficiency and operational stability* of PTSC systems, and can be used as a reference point in the future to develop new design approaches.