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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Agricultural and Biosystems Engineering

First Advisor

Dr. Erin Cortus


Livestock facilities are a source of aerial pollutants including ammonia, hydrogen sulfide, carbon dioxide (CO2), methane, and nitrous oxide. However, estimating pollutant emission depends on accurate measurements of highly variable pollutant concentrations and ventilation airflow rates. There is a need to refine and validate direct airflow measurements, especially through naturally-ventilated barns, and identify the environmental conditions that provide the best measurement results. The objective of this research was to measure the airflow through naturally-ventilated monoslope beef barns by direct and indirect (CO2 mass balance) methods, and determine filtering conditions when accurate airflow measurements are achievable. An additional objective was to compare perpendicular (to the wall opening) wind velocity between a remotely located weather station and through the south wall opening. Direct airflow measurements were collected using ultrasonic anemometers and depended on wind direction perpendicular to the opening area of the inlet and outlet wall; therefore, some ranges of wind speed and direction were not suitable for accurate airflow measurements. Barn management decisions, such as the north side wall opening also changed and impacted airflow measurement accuracy. The results of this study suggested filtering databased on large north wall opening dimensions, wind speeds between 0.5 m/s to 6 m/s, and wind direction conditions ±45° from due south provide data suitable for predictable airflow measurements for monoslope beef barns. Based on a comparison of airflow through the north and south wall openings, when airflow was 200 - 400 m^/s per pen, the north wall opening airflow was within ±20% of the south wall opening airflow. Carbon dioxide method airflow estimates were generally lower than airspeed-based measurements. Relating airflow through the barn to weather station wind velocity was not recommended because, for the same height, wind velocity at the weather station was almost twice the wind velocity through the south wall.

Library of Congress Subject Headings

Beef cattle -- Housing
Barns -- Heating and ventilation
Air flow


Includes bibliographical references (74-81)



Number of Pages



South Dakota State University


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