Measuring and simulating climatic conditions in the animal occupied zone in a door ventilated room for piglets

Climatic conditions in the animal occupied zone (AOZ) of a pig room are important for animal health, comfort and performance. Both practical measurements and numerical simulations could be used to assess the climatic conditions in the AOZ. The objective was to test the possibilities for using pig location patterns based on the real time monitoring as a thermal boundary condition in a numerical simulation model and to gain insight in the distribution of air velocity, air temperature and CO2 concentration in the AOZ. Measurements were performed in a door ventilated room for weaned piglets. Animal lying locations were recorded. The geometry of the air space including models for the pigs was constructed in AutoCad and imported in the numerical simulation program (Fluent 5). The measurements of three 1-hour periods were considered to be static situations, and are compared with numerical simulations. Measured and simulated airflow direction in the AOZ did correspond, but in air velocity magnitude there were differences. The simulations agree with measurements in a preceding study, that show that the height above the solid floor is of crucial importance for the local air velocity. Both measurements and simulations showed a tendency for decreasing pen temperature when the distance to the door increased, but the measured temperatures were in general higher than the simulated. Adding radiation heat transfer in the simulations might decrease the difference. The differences between measured and simulated CO2 concentration were relatively large, this could be caused by chosen simplifications in the simulations that influence the calculated airflow pattern and CO2 distribution, such as not including the feeders in the model and assuming homogeneous conditions in the air inlet. In the study it is proved to be possible to include boundary conditions obtained from conditions with live pigs, but some adaptations in the presented simulation model are necessary. Regarding the door ventilation system, the study confirmed that the air distribution is inhomogeneous especially at high ventilation rates. The study confirms the expectation that numerical simulation has the potential to become an important tool for designing and improving ventilation systems for livestock rooms.