Numerical predictions of air temperature and velocity to assist in the design of free ventilation piggeries

Abstract

Pigs are subjected to intensive environmental control and management for higher productivity due to their sensitivity to climatic variation. The climate affects pigs’ growth and impacts greatly on the profitability of this industry. The aim of the current work is to numerically model the air velocity and temperature in a free ventilation piggery for grower pigs (32-52 kg) and to investigate the effect of variation in the design on the environment inside the piggery and more specifically at the pigs’ level. These variations were reducing the height of the outer wall of the piggery to the same level as the pens and changing the type of fence used in the pens as well as adding louvers in the air opening, changing the shape of the roof and adding insulation to the roof. A steady twodimensional numerical model based on the integral volume method including the effect of buoyancy, turbulence and heat generated by the pigs was solved using the computational fluid dynamics software Fluent. The results suggest that varying the type of fence from a solid internal fence to one made of separated bars (new fence) did not have much impact on the environment inside the piggery. When this change was combined with the other variation such as lowering the outer walls it made some improvements. Combining the new fence, lowering the outer walls and changing the shape of the roof resulted in the highest increase in the air speed of about 0.2-0.4 m/s at the pigs’ level. These improvements would be only sufficient in milder climate. If these variations were combined with appropriate water sprayers it will help to meet the pigs’ thermal comfort limit at that hot climate.