Finite element based computational analysis to study the effects of baffle and fin on the performance assessment of solar collector

Abstract

The present work aims to develop an ideal solar collector layout through a finite element-based parametric study. The thermohydraulic performance factor of the solar collector was investigated with the placement of baffles and fins on the absorber plate. The cross-flow, channel, and twist designs of three alternative baffle/fin configurations were parametrised, and the heat transfer throughout the collector was analysed using COMSOL Multiphysics software. The parametrised design for cross-flow was the angle of solid baffle as 30°, 35° and 40°; whereas, for channel and twist design, the distance between the fins was varied at 50, 100 and 150 mm. The simulated result manifested that channel design had highest convective heat transfer coefficient of 21–27 W m−2 K−1, followed by cross-flow and twist design. Contrarily, twist and cross-flow design had lowest pressure drops of 0.6–1.27 Pa and 0.60–1.06 Pa, respectively, while channel design showed maximum pressure loss (35–467 Pa). The average overall thermal efficiency for cross-flow, channel, and twist design was 76.16 %, 74.26 %, and 70.65 %, respectively. The average thermohydraulic performance factor for cross flow and twist design was 11.25 % and 0.48 % higher, whereas 248.22 % lower for channel design compared to flat plate collector. The performance of the cross-flow 30 design was best out of all the designs in terms of the thermohydraulic performance factor, outlet temperature, pressure drop, and flow homogeneity inside the collector. Cross-flow 30 demonstrated a minimum friction factor of 0.004, comparable to a flat plate collector and had a double heat transfer coefficient.