Impact of Inlet Flaps on Ammonia Distribution in a Water-Pad Layer House: A Case Study in Yunlin, Taiwan

To reduce the risks of extreme climate and avian influenza to laying hen houses, the Taiwanese government has vigorously promoted the reconstruction of open-type laying hen houses into closed-type water-pad cooling laying hen houses. This has led to problems for laying hen houses, such as a high humid environment that is more conducive to ammonia generation, and the accumulation of pollutants like ammonia and particulates indoors, which negatively impacts worker health and laying hen productivity. This study used Computational Fluid Dynamics (CFD) to simulate the effect of two geometric configurations—with or without a guide flap at the air inlet—on ammonia distribution in the worker' breathing zones and the laying hen activity areas. This study constructed a Porous Media model of the chicken cages through a numerical wind tunnel, applying it to the overall simulation of ammonia distribution in the laying hen house. Ammonia sampling was simulated at 6 worker breathing zones (H = 1.5 m) in each of the two rows of aisle, and at 4 laying hen activity areas in each of the two rows of chicken cages. The results of this study show that adding a flap at the air inlet significantly affects the ammonia distribution inside the laying hen house. The average ammonia concentration in the overall worker aisle' breathing zones for the "with flap" model was found to be 0.8 ppm higher than the "without flap" model. In the laying hen activity areas, while the "without flaps" model frequently exceeded 20 ppm (up to 27.1 ppm) at single-point simulation sampling points