책임운영기관 농촌진흥청 국립축산과학원

Naturally ventilated (NV) cattle barns contribute significantly to national ammonia emissions, which are precursors to secondary particulate matter in the atmosphere. However, accurately estimating ammonia emissions from NV buildings is challenging due to variations in ventilation rates caused by fluctuating nature of the wind. This study developed a cost-efficient ultrasonic anemometer for direct measurement of ventilation rates in NV cattle barns. The device underwent wind tunnel testing for accuracy validation and used for field experiments conducted in the studied cattle barn for three months. Measured ventilation rates were compared with estimates obtained from the CO2 tracer gas method and the wind pressure-thermal buoyancy (WT) method to assess measurement reliability. The results indicated that ventilation rates were strongly influenced by external wind speed, with peak values occurring between 12:00 PM and 3:00 PM. The ultrasonic anemometer demonstrated a high correlation with direct wind speed measurements. The CO2 tracer gas method showed close agreement with direct measurements, with only a 4% difference, indicating its reliability under specific conditions. In contrast, the WT method tended to underestimate ventilation rates, highlighting the need for further calibration. The findings provide valuable insights into ventilation characteristics in NV cattle barns and offer a foundation for improving ammonia emission measurement in NV buildings.