西北地区纵墙湿帘山墙排风系统改善夏季蛋鸡舍内热环境

    Vertical walls-evaporative cooling pad and gable-exhaust-air-ventilation system improving poultry house thermal environment in Northwest region of China

    • 摘要: 为研究应用于中国西北地区的纵墙湿帘山墙排风系统对蛋鸡舍内热环境的改善状况,该试验选取了西北地区纵墙湿帘山墙排风与传统纵向通风2种通风系统的蛋鸡舍,通过对舍内热环境的连续监测,探究了2种通风系统下蛋鸡舍内的热环境及热应激状况,并比较了2种通风系统的经济投入成本。结果表明:纵墙湿帘山墙排风与传统纵向通风系统蛋鸡舍内温度最大波动幅度分别为2.7、10.3 ℃,纵墙湿帘山墙排风系统舍内水平与垂直方向温度差异不显著(P>0.05),传统纵向通风蛋鸡舍内水平与垂直方向温湿度差异显著(P<0.05);传统纵向通风蛋鸡舍内无热应激状态比试验舍低9.9%,轻度、中度、高度热应激状态分别比纵墙湿帘山墙排风系统舍内高2.7%、7.2%、0.1%;但相同饲养条件下蛋鸡舍采用纵墙湿帘山墙排风降温系统的经济投入成本是传统纵向通风降温系统成本的1.6倍。综合2栋蛋鸡舍内热环境空间分布、温湿指数等认为,纵墙湿帘山墙排风系统应用于中国西北炎热干旱地区蛋鸡舍可降低舍内温差及热应激程度,为更好的缓解舍内局部热应激并将该降温系统在西北地区蛋鸡养殖中推广,建议在风机相对侧山墙上也安装湿帘小窗。

       

      Abstract: Abstract: Large temperature variations and non-uniformity of air distribution are founded in the poultry houses by using tunnel ventilation and evaporative cooling systems. Poultry suffer from large variations of temperatures, cold stress near the evaporative cooling pads region and heat stress near fans region. These adverse factors negatively influence poultry health, production performance, mortality rate, and consequently resulting in significant economic losses. In order to improve the welfare of the poultry and mitigate the large variations of air temperatures, heat stress in the poultry occupied zones. The poultry houses were equipped with a new ventilation system-vertical walls intake air and gable exhaust air ventilation system in China Northwest region. The evaporative cooling pads separately and uniformly on both vertical walls and exhausting air through fans located on the gable. When the indoor air temperature was higher than the set-point, the fans created a slightly negative pressure to draw fresh air through the evaporative cooling pad into the poultry houses. This was in contrast to other time in poultry houses which have fresh air directly entering into the poultry houses without cooling through the wall inlets. In order to determine the environmental condition of the poultry house that was equipped with the new ventilation system and its existing problems, this study had been conducted to detect and analyze the thermal environment. The performance of the new ventilation system in an experimental poultry house was evaluated in comparison with the tunnel ventilation and evaporative cooling systems in control poultry house by measuring the thermal environment. Results showed that the maximum air temperature fluctuation in the experimental poultry house and in control poultry house was 2.7 and 10.3 ℃, respectively. The air temperature and relative humidity difference were not significantly different (P>0.05) along the horizontal and vertical direction in the experimental poultry house, and the air temperatures and relative humidity difference were significantly different (P<0.05) along the horizontal and vertical direction in control poultry house. The heat stress degree in control poultry house was larger than that in the experimental poultry house, and the normal level of no heat stress in the control poultry house was lower by 9.9% compared with in the experimental poultry house, alert level was higher by 2.7%, danger level was higher by 7.2% and emergency level was higher by 0.1%. There was no emergency heat stress in experiment poultry house but the control poultry house was suffered from different degrees of heat stress. The economic cost of using the new ventilation system-sidewall intake air and gable exhaust air ventilation system in the experimental poultry house is 1.6 times the cost of the traditional tunnel ventilation cooling system in control poultry house. Comprehensive evaluation, the new ventilation system can mitigate the large variations of air temperatures, heat stress in the poultry occupied zones in China Northwest region poultry houses. Thus, this new ventilation system of the poultry house is suitable to be promoted and applied in China Northwest region and it is necessary to equipped with evaporative cooling pads in gable wall of the opposite side of the fans. The study expectation was to develop a guideline on ventilation and cooling systems design and automation control for poultry houses under continental climate zones.

       

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