Thermal Enhancement of Parabolic Trough Collectors using Absorber Tubes with Internally longitudinal Round Edge Fins

Abstract

In this paper, the heat transfer characteristics of the absorber tube with the module of LS-2 parabolic trough collector with internal longitudinal fins with rectangular cross-section are investigated using ANSYS CFD and oil syltherm 800 type as a heat transfer fluid. The simulation is conducted using the internal longitudinal fins with sharp edge and round edge over a wide range of the heat transfer fluid inlet temperature (300 :600K), flow rate (9 :27 m 3 /h) and direct normal irradiance (800:1100W/m 2) at fin thickness of 4 mm, fin length of 25 mm, radius of round edge of 4 mm and angle between fins of 45⁰. The thermal efficiency, Nusselt Number, pressure losses, and thermal enhancement index are calculated at different operating conditions. The results showed that the heat transfer characteristics of rectangular fins with round edge are better than those with sharp edge in solar parabolic trough collector. The round edge fins yield higher Nusselt number and lower pressure losses than those of the sharp edge fins by 5.6% and 9.32%; respectively, at inlet temperature of 600 K, oil flow rate of 9 m 3 /h., and direct normal irradiance of 1000W/m 2 .