Abstract

Thermal stratification in large warehouses is a common phenomenon in winter, especially in regions with cold climates. Natural buoyancy causes warmer air to move upwards towards the ceiling. The relatively high temperature beneath the roof leads to a large amount of heating energy loss. Nowadays, mixing the air is one of the effective methods for reducing thermal stratification which have started to be used in industrial warehouses. This thesis aims to determine thermal stratification conditions in five warehouses via field measurement. Furthermore, this thesis also aims to investigate the effects of mechanical mixing of indoor air with fans using CFD-based numerical simulations. For these objectives, field measurement of thermal stratification in five warehouses was conducted and used to validate CFD models. Meanwhile, two warehouses were simulated in CFD. ANSYS FLUENT, a commercial CFD package, was used to the indoor air flow in this thesis. The numerical temperature results were validated by comparison with the on-site measurement data. The vertical temperature profiles and rate of heat flow from different cases were compared. The effectiveness of different fan configurations in reducing thermal stratification was evaluated.