Measurements and Simulation of Climatic Conditions in the Animal Occupied Zone in a Door Ventilated Room for Piglets

A. V van Wagenberg, B. Bjerg, G. P. A Bot

Abstract


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.

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