Experimental study and exergy analysis of three-fluid tubular heat exchanger with nanofluids

The present study investigates the exergetic performance of a three-fluid heat exchanger employing Al2O3-water nanofluids. Numerical and experimental approaches were applied to investigate the effects of varying flow rates, flow arrangements and nanoparticle volume concentrations on overall performance of the exchanger under study. Reynolds number in the range 2500-10,000 and volume concentration of nanoparticles in the range 0%-3% have been considered to study their effects for four flow arrangements. Numerical results revealed that increasing flow rate and addition of nanoparticles resulted in a reduction of exergy loss of the system. Significant deviation between experimental and numerical results was observed. At a maximum Re = 10,000, a drop in exergy loss by 23.7% for parallel, 11.56% for parallel-counter, 10.6% for counter-parallel, and 25.8% for counter flow arrangements by varying phi from 0% to 3%. Furthermore, minimum exergy loss for all the flow arrangements was found at phi = 3% and Re = 4500.