Abstract: The dual tank single tube water heater has the advantages of small volume and low cost due to its unique dual tank structure. However, due to the fact that the heating tube only exists in the lower tank, there is a temperature difference between the upper and lower tanks during heating. The stability and efficiency of the outlet water temperature have become a hot topic in the research of dual tank single tube water heaters. To study the temperature conduction problem of a dual tank water heater during single pipe heating, simulates the heating situation of the water heater under different connecting pipe diameters and lengths. The temperature field changes at the middle section of the dual tank are studied, and the variation law of the temperature difference between the upper and lower tanks is analyzed, providing guidance for improving the structure of the dual tank single pipe water heater.

Key words: Water heater, Convection, CFD, Temperature difference optimization