Flow structure in a water-in-glass evacuated tube solar water heater

Abstract

The solar powered membrane distillation technology is applied to deal with brackish water desalination in the west of China, and this research work has laid the foundation for application of the solar membrane distillation system. This paper evaluates the characteristics of water-in-glass evacuated tube solar water heaters including assessment of fluid flow of a single ended evacuated solar collector tube and a storage tank in order to further improve the system design and to increase its performance of the complicated fluid flow and heat transfer in the system components is necessary. The most promising solution to this challenge is the use of computational fluid dynamics (CFD) in combination with the experiment investigation. The numerical simulation result is consistent with the result acquired by the experiment method. It is shown that fluid flow in the connection of the tube and reservoir becomes stochastic and turbulent. The flow instability leads to mixing of the warm uprising flow and the cold downward flow, which decreases the efficiency of heat exchange process. It is necessary to take effective methods to prevent the flow instability and secure the flow circulation in the tube.