Numerical Study of Thermal Performance Influence on Design Parameter and Fe3O4 Nanofluid of Flat Plate Direct Absorption Solar Collector

Abstract

In this study, the influence of design factors (concentration of Fe3O4 nanofluid (NF), mass flow rate, FPDASC height, and emissivity of the receiver) of flat plate direct absorption solar collector (FPDASC) using Fe3O4 NF was investigated using the CFD (computational fluid dynamics) method. As a result, when the concentration of Fe3O4 NF increases up to 0.1 wt%, the thermal and exergy efficiencies increase by 0.773 and 0.0293, respectively, due to the increased optical absorbance. Increasing the mass flow rate of Fe3O4, NF decreases the outlet temperature; however, thermal efficiency increases due to reduced heat loss and improved heat transfer. Moreover, there is little effect on the irreversibility of the FPDASC due to the Bejan number with almost one, although the mass flow rate increases the pressure loss. The increasing height of the FPDASC and the emissivity of the receiver improve the thermal and exergy efficiencies in the case of water with low optical absorbance. In contrast, the increasing height of the FPDASC and the emissivity of the receiver decrease the thermal and exergy efficiencies when the optical absorbance is high (0.1 wt% Fe3O4 NF).