Study on Air Mixing Limit in Vertical Inlet/Outlet Diffuser of Temperature-stratified Water Thermal Energy Storage Tank by Three-dimensional CFD

摘要

Water Thermal Energy Storage (TES) system is used to cut down heating and cooling cost in the daytime. In the temperature-stratified water TES tank, a diffuser is used as an inlet/outlet for mixing restrain. The upper diffuser in water tank sucks water near water surface in a storage mode of chilled water, and can entrain air from near water surface. Water could not flow through pipe system smoothly under air-mixing condition. This study aims to show a limit condition of air mixing in vertical inlet/outlet diffuser of water TES tank and to provide a design procedure on the safe side.