CFD modeling and optimization of pre-cooling conditions in a cold room located in the South of Tunisia and filled with dates.

Abstract

Thermal and aerodynamic study is performed on a cold store room installed in the south of Tunisia and filled with about 11 tons of dates to be cooled from harvest conditions to about 5°C. The main object of this study is to define the suitable precooling conditions leading to homogeneous storage temperature inside the room. The considered cold room is of about 67m3 of volume and equipped with an evaporator giving the required refrigeration capacity. Three-dimensional CFD model is established taking into consideration the local environmental parameters. The model SST k-ω is used to analyze the air turbulences. For normal design of the cold store room and during a precooling period of 40h, the air velocity and temperature are determined in the different locations inside the room and vary between 0.25-7m/s and 3-6°C. While the product temperature remains higher than the required storage conditions of about 12°C. A new cold store room design is proposed using specific aerodynamic air deflector profiles. That permits to improve the heat transfer between the cold air and product. The precooling period is reduced of about 10h and the average product temperature reaches 6°C.