Effect of different deflector structures on temperature stratification of a passive solar water heater

ABSTRACT

This paper focuses on the optimization of the deflector structures and effect of four different deflectors within the tank on the temperature stratification. Four different deflectors inside the tank are numerically studied and analyzed through computational fluid dynamics simulation, which are: (a) A type deflector (a lamina), (b) B type deflector (a lamina with two fins 90 degree apart), (c) C type deflector (a lamina with four fins 90 degree apart) and (d) D type deflector (a lamina with four fins 120 degree apart). The comparison of the tanks with different deflectors and without deflector are proposed in terms of the temperature distribution of the tank, the flow pattern of the tank, the velocity distribution of the tube opening, Stratification number and natural convection Grashof number. The temperature stratification is enhanced by placing the different deflectors inside the tank. Results illustrate that the temperature stratification depends on the effect of different deflectors on the natural convection. The Stratification number improves with the increase of the natural convection Grashof number. Compared to the tank without the deflector, the Stratification number and natural convection Grashof number of the solar water heater improve by 18.90% and 13.95%, respectively, are reported for the tank with the B type deflector or C type deflector.

KEYWORDS:

• Passive solar water heater
• temperature stratification
• the tank
• different deflector structures

List of symbols

Table

Additional information

Funding

This research is supported by the Major Science and Technology Project of the Xinjiang Production and Construction Corps (No.2018AA003).

Notes on contributors

Yunze Shen

Yunze Shen is a current PhD candidate at the College of Civil Engineering and Architecture, Zhejiang University. His main research field is computational fluid dynamics.

Zhilin Sun

Zhilin Sun is a professor at the College of Civil Engineering and Architecture, Zhejiang University. His main research field is mechanics of sediment transport and computational fluid dynamics.

Leilei Fan

Leilei Fan is a current PhD candidate at the College of Civil Engineering and Architecture, Zhejiang University. His main research field is computational fluid dynamics.