Determination of energy efficiency and exergy of solar collector bed, operating plate under turbulent nanoscale flow with molybdenum disulfide nanoparticles in different morphologies for tropical regions of Iran

This investigation evaluates the first and second laws of thermodynamics for a flat plate sheet and tube based solar collector located in Abu-Musa Island (in Persian Gulf) in Hormozgan province, Iran where a suspension of molybdenum disulfide (MoS2) nanoparticles with different shapes in water is the working fluid. The main aim of this study is to analyze morphology effects of MoS2 nanoparticles on heat transfer and entropy generation and due to fulfill this demand, analysis four different nanoparticles shapes (blades, platelets, bricks, and cylinders) are chosen. The results of Nusselt number, outlet fluid temperature, pressure drop, friction factor, performance evaluation criterion (PEC) and entropy generation are calculated and reported for different shapes of nanoparticles and also nanoparticles volume fractions up to 4% in turbulent flow with two different mass flow rates of 0.50 and 0.75 kg/s. According to obtained results, the PEC of model with ϕ=3% and bricks nanoparticle shape in ṁ=0.5 kg/s is found to be the best among all models and its value is around 1.269. But in case with ṁ=0.75 kg/s this value for nanofluid with ϕ=4% and bricks nanoparticle shape is found to be the best among all models and is about 1.182. It was also found that for mass flow rate of 0.50 kg/s, adding the bricks and blade shaped nanoparticles to base fluid is not advantageous from the second law viewpoint, whereas for mass flow rate of 0.75 kg/s it was seen that using volume fractions of 1% and 4% of bricks and blade can reduce the entropy generation rate compared to base fluid till 8%