Heat and Flow Analysis of a Chilled Water Storage System using Computational Fluid Dynamics

Abstract

Thermal energy storage cooling system has been used to reduce peak power consumption of air conditioning system in buildings. Low energy cost during night time is utilized to power water chiller to chill water and stores in tank rather than running the chiller directly during daytime at higher tariff rate. This study embarks on Computational Fluid Dynamics (CFD) approach to analyse heat distribution and fluid flow behaviour within a chilled water storage system. Three cases are simulated which are; tank without diffuser, diffuser without tank and tank with diffuser. The results are compared with designer's design calculation for validation purposes. Simulated thermocline thickness is approximately 1.3m and 0.22m/s for nozzle outlet velocity. This study provides better understanding of velocity vectors, magnitudes, and temperature distribution across the tank compared to analytical data. Conclusively, our results show good agreement with analytical data. This study will become validation basis for our future tank and diffuser design optimization.