EXPERIMENTAL AND MODEL ANALYSIS OF MECHANICAL VENTILATION OF A MILKING PARLOR IN SUMMER

摘要

The aim of this study was an experimental and model analysis of the ventilation rates with mechanical ventilation of a side-by-side milking parlor during milking in summer. The study showed that a direct increase in air temperature and relative humidity, exceeding the optimum values for cows, was mainly due to the ambient air temperature and the presence of animals. Each milking of a group of 24 cows on hot days (temperature above 25 degrees C) was associated with an increase in air temperature of 1.5 degrees C to 2 degrees C in the milking parlor and with a decrease in humidity of 3% to 5%. On cooler days (temperature below 25 degrees C), the air temperature increased by 5 degrees C to 6 degrees C and the humidity decreased by approximately 10%. Based on observations of ventilation in the milking parlor, substantial differences in airflow were revealed. The airflow velocity strongly differed from the optimal value (0.2 to 0.5 m s(-1)) and adversely affected the welfare of the cows and the dairy workers. A model analysis of the ventilation system, performed in PyroSim software, showed strong similarity to the results of the observations. Therefore, the accuracy of the simulation and its usefulness in the design and analysis of ventilation systems in milking parlors were shown. In addition, the computer model showed that cows occupying the milking parlor during milking significantly affected the airflow and could change the airflow direction.