Numerical analysis of photothermal conversion performance of MXene nanofluid in direct absorption solar collectors

A newly direct absorption solar collector (DASC) based on MXene nanofluid is proposed herein. The excellent optical properties of MXene nanofluids are experimentally determined, and a three-dimensional steady-state numerical model is developed to investigate the synergistic effect of the optical properties of MXene nanofluids and the structural parameters of the DASC. The effects of volume flow rate, working temperature, and solar concentration ratio on the photothermal conversion performance of the DASC are also analyzed. The results show that the transmittance of the MXene nanofluid evidently decreases because of the enhanced absorption of solar radiation of MXene. With the addition of MXene, the photothermal conversion efficiency of the nanofluid rapidly increases and then slightly decreases. The optimal MXene mass fraction is inversely proportional to the collector height. A mere 100 ppm of MXene nanofluid can achieve a maximum intercept efficiency of 77.49%, which is 55.47% higher than that of the base fluid. This work demonstrates the potential for the application of MXene nanofluids in the utilization of solar energy.