A comparison of two methods for the ventilation rate estimation of a naturally ventilated buffalo barn

Abstract In recent years, there has been a concerted effort to identify optimal techniques for quantifying NH3 emissions from livestock activities for updating national emission inventories and implementing mitigation techniques. The measurement of ammonia emissions from livestock buildings remains challenging and is further complicated in naturally ventilated buildings characterized by considerable structural variability, where external environmental factors have a significant influence on the emission process. In general, to calculate an emission factor from a livestock building, it is necessary to establish a mass balance in which ventilation rates and the difference between inlet and outlet concentrations are key measurements. Numerous studies in the literature have investigated the natural ventilation of dairy farms, but this is more difficult when considering the Mediterranean climate, where dairy barns, and especially buffalo dairy farms, are characterized by very large openings. Based on the framework presented, the purpose of this paper is bibliographic research on the best way to evaluate the ventilation rate, for a possible application in a typical buffalo farm. The literature review showed that, despite the variety of methods available, no method has emerged as an undisputed and universally accepted reference. To this end, the direct method using anemometers and the indirect method using CO2 mass balance were investigated in terms of accuracy and uncertainty, ease of use and continuous real-time monitoring for estimating and measuring airflow.