Authors: Long Chen, Eileen Fabian
Download file: https://library.csbe-scgab.ca/docs/meetings/2021/CSBE21383.pdf
Published in: CSBE-SCGAB Technical Conferences » 5th CIGR and AGM Quebec City 2021 » Regular Sessions
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Description: A shift to cage-free eggs is underway worldwide that contributes to the most significant evolution that poultry facilities have been faced with in decades. However, the lack of unified guidelines and various definitions of cage-free housing options have left egg producers with many uncertainties about cage-free housing. This work aims to investigate alternative ventilation schemes to refining proper ventilation system design in cage-free hen houses with the goal of assuring bird welfare through comfortable conditions and improving the capacity of containing contaminants, such as a virus. This study uses computational fluid dynamics (CFD) that simulates airflows to quantify the effectiveness of ventilation systems in maintaining suitable, uniform living conditions at the bird level and the capacity of containing any contaminant. Four three-dimensional CFD models were developed on the basis of a full-scale floor-raised hen house, corresponding to ventilation configurations of the standard top-wall inlet sidewall exhaust (TISE), and three alternatives: mid-wall inlet ceiling exhaust (MICE), mid-wall inlet ridge exhaust (MIRE), and mid-wall inlet attic exhaust (MIAE). In addition, 2,365 birds were individually modeled with simplified shapes. One-eighth of a real commercial hen house was modelled make full use of symmetry and save computer resource.. The simulated ventilation rate for the hen house in each model was 1.97 m3/s (4174 ft3/min), 1.93 m3/s (4089 ft3/min), 1.96 m3/s (4153 ft3/min), and 1.91 m3/s (4047ft3/min), which all fell in the desired range for cold weather (0 oC). The three alternative models showed comparable performance in maintaining desirable microclimate at the bird level, compared to the standard TISE model. The simulation output of MIRE and MIAE demonstrated both models could provide airflows about 0.35 m/s (69 ft/min) on average at the bird level, which had no statistically significant difference with the standard TISE model. The temperature at the bird level was maintained between 20 and 24 oC on average by all models, which was acceptable in the cold weather. The indoor static pressure was stabilized at -25 to -21 Pa, which fell in the normal range for a hen house with the negative-pressure ventilation. Simulation results also revealed three models, TISE, MIRE, and MIAE had indistinguishable performance in containing the contaminant, while the average contaminant level in the model of MICE was discovered 19% lower than the others within the majority of the indoor space. Considerable simulation results and subsequent analyses substantially demonstrated these alternative models had the capacity to create satisfactory indoor conditions for the cage-free hen house. In addition, statistical analyses were conducted to confirm the significance of vital factors and verify significant differences for particular comparisons.
Conference name: 5th CIGR International Conference and CSBE-SCGAB AGM 2021, Quebec City,QC, 11-14 May 2021.
Session name: Animal Systems 3 - Ventilation
Publication type: Presentation
Coverage: United States
Language 1: en
Rights: Canadian Society for Bioengineering