Study on ventilation system of naturally ventilated broiler house by aerodynamic approach

Conducting field experiment for the ventilation study of the broiler house is very difficult because of limited measuring points as well as unpredictable and uncontrollable weather conditions. Accordingly, the CFD (Computational fluid dynamics) models were developed to overcome the disadvantages of field experiment. Using these models, the ventilation efficiencies of several upgraded ventilation systems of a naturally ventilated broiler house were quantitatively and qualitatively compared with each other. In this study, the ventilation efficiencies and internal temperature distributions were mainly analyzed for the four different types of the upgraded systems, and Tracer gas decay method was adapted to effectively examine the ventilation efficiencies. The ventilation efficiency of the whole internal volume and broiler zone were compared using several vent opening types compounded with four different types: chimney, sidevent, pipe under the roof, and sideup vent at eave. Referring to the ventilation rates between the cases of chimney-sideup(inlet-outlet) and pipe-chimney, the results indicated that the former case made 10% lower ventilation rate compared to the later while improvement of 58% at the broiler zone(about 0.3m above the ground). Its ventilation rate was also 34% higher at the chicken location than the pipe-sideup case even though showing 5% lower for the whole internal volume. The uniformity of the internal temperature with the case of pipe-chimney was 16.3 times better than the existing broiler house (Lee et a/., 2003). The results indicated that the use of internal curtain and diffuser improved the uniformity of a broiler zone. The TRNSYS results indicated that the chimney-sideup case made 22% lower heating energy than the existing broiler house.