钟楼式单层彩钢瓦屋面肉牛棚舍的环境评价

为了解亚热带无隔热层钟楼式单层彩钢瓦屋面棚舍栓系饲养模式下的环境特征,在凤阳测定了肉牛舍的温度、湿度、气流、PM10、NH3等指标。结果:夏季,棚舍内外温湿度几乎相同,换气量超过了最大换气量,PM10优于卫生标准,温湿指数范围为78～87,肉牛处于热应激状态。考虑了气流影响的体感温度范围为25.1～32.2℃,气流显著地减少了高温的影响。晴天棚顶内外表面温度最大相差1.2℃,棚顶隔热能力差,棚顶内表面最高可达48.3℃,此时的舍内气温仅为33.1℃,棚舍自然换气调节是环境控制的主体,适当架高棚顶,开设钟楼换气口有利于畜舍通风换气。冬季,舍内温度范围为-1～7.5℃,舍外温度范围-3.3～5.5℃,温差仅2℃,舍内风速为0.2～0.4 m/s,舍外风速为1.01～2.53 m/s。舍内湿度高于舍外,超过了肉牛生长的适宜湿度范围,NH3浓度优于卫生标准,冬季棚舍四周围挡塑料薄膜,减少了换气量,保温作用弱,空气质量下降。

Environmental evaluation on single layer of metal-plate roof housing cowshed for beef cattle

In order to investigate the environmental characteristics of the belfried open ridge shed in the subtropical region,the determination of temperature,relative humidity,wind velocity,PM10,and NH3 index in the beef cattle shed were carried out in the district of Fengyang.The result indicated that the temperature and relative humidity were almost the same inside and outside the shed in the summer.The ventilation rate of the shed met and exceeded the requirement of the maximal ventilation rate.The concentration of PM10 in the shed was better than the standard of environmental sanitation.The THI ranged from 78 to 87,and the beef cattle were in heat stress.The THVI which considered the influence of wind ranged was from 25.1℃ to 32.2℃.The wind reduced the impact of high temperature evidently.The temperatures between the inside and outside roof surface during the testing period were all smaller than 1.2℃,therefore,the ability of heat insulation was not strong.The highest temperature of the inside roof was 48.3℃,and the temperature in the shed at the same time was only 33.1℃.The main part of the environmental control was the natural ventilation of the shed.It is advantaged to make the roof higher and sent a belfried shed.In the winter,the temperature inside the shed was from-1℃ to 7.5℃,and from-3℃ to 5.5℃ outside the shed.The temperatures between the inside and outside were smaller than 2℃.The wind velocity was between 0.2m/s and 0.4m/s.The relative humidity inside the shed was higher than outside,exceeded the standard of environmental sanitation.The concentration of NH3in the shed was better than the standard of environmental sanitation.Therefore,the shed surrounded by plastic film is unnecessarily in winter.