Modeling and CFD study of heat transfer within the circulation pipes of solar water heating systems

The main objective of this work is to study numerically the thermal behavior of solar collectors. In particularly, we performed a detailed design and parametric study of the circulation pipe of an evacuated tube collector. Indeed, we altered the geometry of the anodes by adopting three configurations: circular, rectangular and triangular. In each configuration, we changed the inlet position of cold water and the outlet of hot water: either at the top, middle or bottom. The obtained results show that rectangular shape is most optimal due to the large exchange area. On the other hand, the water inlet must be positioned at the bottom and the outlet at the top in order to take profit of the stratification of the hot water and subsequently obtain high efficiency.