Numerical study of tube arrangement and fin effects on improving the ice formation in ice-on-coil thermal storage systems

Heat storage systems are used as a method for transferring and controlling the cold load in hot seasons. In this paper, to analyze the phase changes of an ice-on-coil thermal storage tank, the process of ice formation in a cavity with refrigerant carrier tubes is carried out using numerical simulation. Moreover, performance of some heat transfer enhancement methods including usage of fins around tubes with various dimensions and numbers and various tube number and arrangement, are compared. In this study, the inlet temperature is considered to be 275 K, which the temperature decrease up to 10 K due to freezing is observed. According to the results, the fin height is a very effective parameter in increasing the freezing rate. Also, upon increasing the tube number with smaller diameter, ice is formed with a higher speed due to their uniform distribution. So, with the tube number increasing from 9 to 16 in these systems at the same time interval, the fluid temperature drops from about 275 to 269 K, as well as the volume fraction of liquid decrease from about 0.4 to 0.22. Finally, by changing the tube arrangement from rectangular to triangular, faster rate of ice formation are observed.