密閉水簾式蛋雞舍於入風口增設擋板和出風口增設側排風扇對內部氨氣分布之影響：以雲林某蛋雞舍為例

Abstract

為降低極端氣候和禽流感對蛋雞舍的風險，台灣政府大力推動傳統開放式蛋雞舍改建為密閉水簾式蛋雞舍，但這也使蛋雞舍面臨氨氣等汙染物於末端累積和潮濕環境更有利於氨氣產生等問題，影響工作者健康或蛋雞生產力（大於20 ppm）。本研究以計算流體力學（CFD），模擬「入風口有／無導流擋板」及「出風口有／無側排風扇」4種幾何配置，對蛋雞舍工作者走道呼吸區與蛋雞活動區之氨氣分布影響。本研究首先建立雞籠與蛋雞舍的精確幾何模型，並透過數值風洞獲取雞籠在三個方向軸的壓力差，以建構雞籠Porous Media模型，此模型被應用於4種幾何配置的整體蛋雞舍氨氣分布模擬中，並於兩排走道各6個工作者呼吸區（H = 1.5 m）及兩排雞籠各4個蛋雞活動區進行氨氣模擬採樣。本研究結果顯示，入風口增設擋板將大幅影響蛋雞舍內氨氣分布：僅開啟後排風扇下，「有擋板」模型的整體走道工作者呼吸區平均氨氣濃度為2.6 ppm較「無擋板」模型的 1.8 ppm高 (提升31 %)；開啟側排風扇能局部降低走道末端氨氣濃度：在「有擋板」下，僅開啟後風扇的末端工作者呼吸區平均氨氣濃度為3.9 ppm，而在開啟側排風扇後則降低為3.0 ppm (降低23 %)。在蛋雞活動區中，各模型間平均氨氣濃度相近，然而在「無擋板」模型於蛋雞舍末端的單點模擬採樣點氨氣濃度頻繁超過20 ppm下（最高達27.1 ppm），「有擋板」模型的所有模擬採樣點皆小於20 ppm。本研究結論為，於密閉水簾式蛋雞舍入風口增設導流擋板會提高走道工作者的暴露，但可抑制末端蛋雞活動區的氨氣高峰；側排風扇能有效降低走道末端濃度，建議作業時彈性啟用。

To mitigate risks from extreme weather and avian influenza, Taiwan is converting open layer houses into water-pad type layer house. However, higher humidity and unidirectional airflow result in ammonia accumulation, impacting worker health and layer productivity (>20 ppm). This study used computational fluid dynamics (CFD) to assess four ventilation models—presence/absence of inlet flaps and side exhaust fans—on ammonia distribution in worker breathing zones and layer activity areas. Virtual wind-tunnel experiments measured three-axis pressure drops in the cages, informing a porous-media cage model. This model was integrated into CFD simulations of the layer house under four ventilation models. Ammonia concentrations were virtually sampled at twelve breathing zones (two aisles × six locations) and eight layer activity zones (two aisles × four locations). With only the rear fans running, adding inlet flaps increased aisle mean ammonia concentration from 1.8 ppm to 2.6 ppm (+31%). With flaps installed, activating side exhaust fans lowered end-aisle concentrations by 23% (3.9 ppm → 3.0 ppm). Mean ammonia concentration of layer activity zones was similar across all models, but only flaps-installed models kept every layer activity zones sampling point below 20 ppm, whereas flap-free repeatedly exceeded 20 ppm at the downstream end (maximum 27.1 ppm). Our research suggest that inlet flaps suppress ammonia peaks in layer activity zones—supporting productivity—but raise worker exposure in aisles. Side exhaust fans effectively reduce end-aisle concentrations. We recommend flexible use of side exhaust fans during end-aisle operations.