肉牛棚舍温热环境及围护结构隔热性能评价

Environmental Evaluation and Heat Insulation Performance of Beef Cattle Shed in Lingbi Region of Anhui Province

为了解亚热带双坡隔热棚舍拴系饲养模式下的环境特征和隔热性能,在灵璧测定了肉牛舍的温度、湿度、风速、PM10等指标,计算了棚舍围护结构的总热阻、总衰减度、总延迟时间,并同设计要求的参考值进行比较。结果表明:夏季牛舍内温度范围23.0℃～29.5℃,考虑了气流影响的体感温度范围为23.3℃～26.8℃,降低了近3℃,气流有利于降温,畜舍满足最大换气量的需求。冬季牛舍内温度范围为-1.3℃～9.7℃,舍内外温差小于1℃。湿度变化范围很大,平均值在55%～85%之间。PM10浓度均低于卫生学标准。牛舍棚顶外表面温度随时间的变化有较大的波动。夏季最高温度可达近60℃,早晚温度低,中午温度高。而棚内表面温度的变化幅度较小,尤其在棚外温度最高的中午,棚内、外表面的温差可达19℃。冬季最低温度可以降到-12.3℃。而棚内温度最低也只降到-1℃。棚顶冬季总热阻为0.372 m2.k/W,夏季总热阻为0.411 m2.k/W,总衰减度为4.3,总延迟时间为0.2 h。棚顶隔热层降低了棚外向舍内的辐射热,有效的降低了舍内的温度,有利于夏季的防暑降温。

To investigate the environmental characteristics and heat insulation performance of the open ridge shed with insulating layer in the subtropical region,the determination of temperature,relative humidity,wind velocity and PM10 index in the beef cattle shed were conducted in Lingbi region of Anhui province.The thermal resistance value,decay rate and delay time of the roof were calculated and compared with the reference value.The result indicated that the temperature of shed ranged from 23.0℃ to 29.5℃,but the THVI was from 23.3℃ to 26.8℃,dropped by 3℃ in summer.The wind velocity reduced the impact of high temperature evidently.The ventilation rate of the shed met and exceeded the requirement of the maximal ventilation rate.In winter,the temperature inside the shed was from-1.3℃ to 9.7℃.The temperatures between the inside and outside of the shed were smaller than 1℃.The relative humidity inside the shed was from 55% to 85%.The concentration of PM10 in the shed was better than the standard of environmental sanitation.The highest temperature of the surface outside roof was 60℃,19℃ higher than the inside surface in summer.The lowest temperature of the surface outside roof was-12.3℃,and the temperature inside at the same time was-1℃ in winter.The thermal resistance value was 0.372 m2·k/W in winter,and 0.411 m2·k/W in summer.The decay rate and delay time were 4.3 and 0.2h.The insulating layer stopped radiant heat partly.The temperature in the shed was reduced.Our finding suggested that this system was beneficial for heat resistence.