Effects of rotational flow on energy efficiency of a novel parabolic through solar collector equipped with elliptical ribbed absorber tube filled with non-Newtonian two-phase nanofluid

The main purpose of this study is to investigate the effect of using an elliptical absorber system with helical ribbed tube on the energy efficiency of linear parabolic collectors. For this purpose, energy efficiency has been measured and presented for different modes, and finally different optimal models are introduced in terms of having the highest energy efficiency, and finally the best model is determined. Based on the obtained results, the highest energy efficiency in different Reynolds is related to the new collector and single-phase model. According to the results of this dissertation, the use of grooved pipe has an effect on increasing the efficiency of the collector. As the number of grooves increases from 1 to 3, the collector efficiency increases. It was also found that the collector efficiency increases with increasing step and slope amplitude. by increasing the groove angle from 10 ° to 50 °, the collector efficiency increases and the maximum value of η is obtained at ° ξ = 60. However, by increasing the groove angle from 50 ° to 60 °, the collector efficiency decreases.