Experimental Comparative Analysis of Fixed-Point Ventilation with Tunnel Ventilation in Multi-Floor Pig Building in Summer

Highlights The environmental conditions in a multi-floor pig building with different ventilation systems were analyzed. Both environmental and physiological conditions were improved in the house with fixed-point ventilation. Energy consumption was reduced by approximately 60% in the house with fixed-point ventilation. Air distribution was most uniform when the duct helix angle was set to 0.26°. ABSTRACT. Ventilation patterns significantly affect the environment in pig houses, thereby affecting pig growth and productivity. To evaluate the impact of different ventilation strategies, this research continuously monitored environmental parameters and physiological responses of pigs in a large-scale mechanically ventilated multi-floor pig building (MFPB), employing both tunnel and fixed-point ventilation systems. Preliminary experiments validated the duct helix angle, which was determined based on the principles of duct design for uniform airflow distribution. The results indicated that fixed-point ventilation significantly enhanced ventilation efficiency in the sows' living area, lowering temperature, relative humidity, and ammonia concentration. Additionally, the effective wind speed increased by 2 to 3 times, while energy consumption decreased by approximately 60%. The average respiratory rate of the pigs also decreased by 17 breaths per minute, and the incidence of abnormal body surface temperatures was significantly reduced. Mortality rates of sows decreased by 8.3%, while the average total number of piglets per litter and the average number of piglets surviving per litter increased by 0.2 and 0.4, respectively. Furthermore, the proportion of weak piglets, stillbirths, and mummified piglets was notably reduced. Moreover, adjusting the duct helix angle to 0.26° resulted in a more even distribution of air velocity in the pig living area. This study provides valuable insights into optimizing ventilation control strategies for MFPBs. Keywords: Environment, Fixed-point ventilation, Multi-floor pig building, Optimization, Physiological, Tunnel ventilation.