Full-scale CFD simulation of commercial pig building and comparison with porous media approximation of animal occupied zone

Many CFD simulation studies substitute Animal Occupied Zone (AOZ) as porous media to reduce computation time and resources. With the improved computational capacity, it is now possible to include realistic geometric models of individual animals and partition walls. This study presents a CFD model of a large commercial-sized, hybrid ventilated pig building with 1,360 animals. It compares the developed full-scale model (that includes pigs and partition walls) with a simplified model that substitutes AOZ with a porous media approximation. We find that the simplified model with porous media approximation predicts the airflow rates and overall flow characteristics in the building as good as the full-scale model. Full-scale simulations with animals and partition walls give a snapshot of a particular situation in the building and the environmental conditions in the AOZ level; for example, we found that even in a well-ventilated pig building temperatures in the AOZ were, on average, 3 °C - 5 °C higher than at a height 0.5 m above the AOZ. Including the realistic shape of animals and the partition walls is overkill if the aim is to study ventilation configurations’ effects. However, porous media models are not good enough to describe the conditions in the AOZ.