On the improvement of temperature uniformity and energy efficiency by auxiliary ducts for cooling air in a semi-low temperature warehouse

In this study, the improvement of temperature uniformity and energy efficiency was investigated by installing auxiliary ducts connected to a unit cooler in a low-temperature warehouse for long-term cold storage of cabbage. Based on the empirical data for the refrigeration system of a real storage, numerical simulations were conducted for the 3D unsteady flows inside the storage. Then, the distributions of temperature and velocity fields were compared according to the presence of the duct and the porosity of the duct slit. The results show that at the lower the porosity of the duct slit, the larger the space in the warehouse that remains in the proper temperature band owing to the heat balance during one cooling operation cycle. The auxiliary duct leads to the effective circulation of cooling flows; hence, the temperature uniformity improves and the consumption of cooling energy decreases when the duct is installed.