农业工程学报
農業工程學報
농업공정학보
2014年
8期
126-134
,共9页
程琼仪%刘继军%靳薇%穆钰%陈昭辉%刘善斋
程瓊儀%劉繼軍%靳薇%穆鈺%陳昭輝%劉善齋
정경의%류계군%근미%목옥%진소휘%류선재
降温%湿度控制%射流%湿帘冷风机-纤维风管%开放式牛舍
降溫%濕度控製%射流%濕簾冷風機-纖維風管%開放式牛捨
강온%습도공제%사류%습렴랭풍궤-섬유풍관%개방식우사
cooling%humidity control%jets%wet curtain cooling fan-fiber duct%open-sided beef barn
为改善南方夏季开放式肉牛舍环境条件，该文设计湿帘冷风机-纤维风管系统，采用风管定点送风、孔口射流高速出风的模式，将冷风均匀送至肉牛活动区域进行局部降温。该研究以栓系饲养西门塔尔牛为试验对象，对环境、肉牛生理及增质量进行测定。结果表明：测定期间，在肉牛站立（1.3 m高度）和躺卧背部高度（0.7 m高度），与对照舍相比，处理舍的平均温度分别降低2.0和1.8℃，平均相对湿度皆增加10%，平均风速分别增加0.69和0.47 m/s（P＜0.01）；试验舍内氨气和二氧化碳平均质量浓度比对照舍分别降低0.17和81 mg/m3，热负荷指数（heat load index，HLI）均值降低2.84（P＜0.01）；试验牛的呼吸频率降低22次/min、直肠温度降低0.35℃、皮温降低1.04℃，差异均极显著（P＜0.01）。在整个试验期间，处理舍肉牛未出现患病情况，日增质量为0.92 kg/d；对照舍肉牛患病率高达47%，日增质量为0.54 kg/d，差异极显著（P＜0.01）。该研究表明在开放式牛舍中进行湿帘冷风机-纤维风管局部降温，有助于缓解肉牛热应激，应用于南方夏季高温高湿天气下技术和经济可行。
為改善南方夏季開放式肉牛捨環境條件，該文設計濕簾冷風機-纖維風管繫統，採用風管定點送風、孔口射流高速齣風的模式，將冷風均勻送至肉牛活動區域進行跼部降溫。該研究以栓繫飼養西門塔爾牛為試驗對象，對環境、肉牛生理及增質量進行測定。結果錶明：測定期間，在肉牛站立（1.3 m高度）和躺臥揹部高度（0.7 m高度），與對照捨相比，處理捨的平均溫度分彆降低2.0和1.8℃，平均相對濕度皆增加10%，平均風速分彆增加0.69和0.47 m/s（P＜0.01）；試驗捨內氨氣和二氧化碳平均質量濃度比對照捨分彆降低0.17和81 mg/m3，熱負荷指數（heat load index，HLI）均值降低2.84（P＜0.01）；試驗牛的呼吸頻率降低22次/min、直腸溫度降低0.35℃、皮溫降低1.04℃，差異均極顯著（P＜0.01）。在整箇試驗期間，處理捨肉牛未齣現患病情況，日增質量為0.92 kg/d；對照捨肉牛患病率高達47%，日增質量為0.54 kg/d，差異極顯著（P＜0.01）。該研究錶明在開放式牛捨中進行濕簾冷風機-纖維風管跼部降溫，有助于緩解肉牛熱應激，應用于南方夏季高溫高濕天氣下技術和經濟可行。
위개선남방하계개방식육우사배경조건，해문설계습렴랭풍궤-섬유풍관계통，채용풍관정점송풍、공구사류고속출풍적모식，장랭풍균균송지육우활동구역진행국부강온。해연구이전계사양서문탑이우위시험대상，대배경、육우생리급증질량진행측정。결과표명：측정기간，재육우참립（1.3 m고도）화당와배부고도（0.7 m고도），여대조사상비，처리사적평균온도분별강저2.0화1.8℃，평균상대습도개증가10%，평균풍속분별증가0.69화0.47 m/s（P＜0.01）；시험사내안기화이양화탄평균질량농도비대조사분별강저0.17화81 mg/m3，열부하지수（heat load index，HLI）균치강저2.84（P＜0.01）；시험우적호흡빈솔강저22차/min、직장온도강저0.35℃、피온강저1.04℃，차이균겁현저（P＜0.01）。재정개시험기간，처리사육우미출현환병정황，일증질량위0.92 kg/d；대조사육우환병솔고체47%，일증질량위0.54 kg/d，차이겁현저（P＜0.01）。해연구표명재개방식우사중진행습렴랭풍궤-섬유풍관국부강온，유조우완해육우열응격，응용우남방하계고온고습천기하기술화경제가행。
To improve the summer environmental conditions for open-sided beef barns in Southern China, a wet curtain cooling fan-fiber duct system was designed to locally cool the barns based on air jet distribution. The wet curtain cooling fan was used as a cooling source with air volume at 13 000 m3/h and 150 Pa of total pressure. A fiber duct was used as the end of the duct of the air distribution system to deliver cold air evenly to the beef activity area for local cooling. The duct was 0.8 m in diameter and designed with four rows of holes at the bottom with diameters of 20.0 mm and 22.0 mm, respectively;the spacing between two adjacent holes along the axial direction of the duct was 58.0 mm and 60.0 mm, respectively. The air dispensing mode of the system was jetting. The duct was hung above the stalls, and bottom of it was 1.75 m from the floor, and 0.96 m from the manger. Considering the local environmental conditions and farm management, the operation time of the cooling system was from 08:00 to 20:00. The study was conducted with Simmental beef in an open-sided barn with feed and water available ad libitum. Data of wind speed along the duct in the axial direction, the cooling effect of the wet curtain cooling fan, the environmental parameters of the barns, and the physiology and body weight gain of beef were collected. Air speed was 8.39 m/s at the head of the fiber duct and 8.21 m/s at the end of the duct. The variation coefficient of wind speed among 10 cross profiles was 0.0153, which showed that the air duct could be considered uniform in air supply, with rational design and layout of holes. The outlet temperature of the wet curtain cooling fan increased with ambient temperature and humidity rising. During the measurement period, at beef standing height (1.3 m from floor) and at reclining back height (0.7 m from floor), compared with the control barn, average wind speed increased by 0.69 and 0.47 m/s, respectively (P<0.01);the average temperature of the treatment barn decreased by 2.0 and 1.8℃, respectively; and, the average relative humidity increased by 10 percent at two heights. However, humidity was still within the appropriate range of 55-85 percent. Compared with the control barn, the average mass concentration of ammonia and carbon dioxide in the treatment barn decreased by 0.17 and 81 mg/m3, respectively;and the average HLI decreased by 2.84 (P<0.01). Compared with beef in the control barn, the respiratory rate of the experimental beef was decreased by 22 beats/min, rectal temperature was decreased by 0.35℃, and skin temperature was decreased by 1.04℃ (P<0.01). Throughout the experimental period, the beef in the treatment barn never experienced any sickness, and daily weight gain was 0.92 kg/d;while the morbidity rate of beef in control barn was up to 47 percent, and daily weight gain was 0.54 kg/d (P<0.01). Operation of this system for two months could earn 13 564.96 Yuan of profit. The results showed that the application of a wet curtain cooling fan-fiber duct in an open-sided beef barn was effective in relieving heat stress of beef. The application of this system in Southern China, which is hot and humid, is technically and economically feasible.
