Experimental study of inlet structure on the discharging performance of a solar water storage tank

• New simple inlet structure was proposed for solar storage tank—slotting-type inlet.
• Experiments were carried out to analyze the performance of different inlets.
• Effective discharging efficiency and effective discharging time were introduced to compare the discharging performance.

The utilization of the solar water heating system can reduce the conventional energy consumption of a building. A good inlet of the solar storage tank can enhance the thermal stratification and improve the thermal storage efficiency and discharging efficiency. Experiments were carried out to investigate the discharging performance of a rectangular storage tank with different inlet structures which were slotting-type inlet, direct inlet and shower-type inlet. This study aimed to provide guidance for the optimization of the inlet structure of water tank so that the efficiency of solar water heating system (SWHS) could be improved further. The effective discharging efficiency and effective discharging time were introduced to evaluate the performance of water tank with different inlet structures. The results showed that the slotting-type inlet exhibited the best thermal stratification and improved the discharging performance of the tank more effectively than the other two inlets. Energy saving potential of new inlet was also presented.