南方夏季肉牛舍湿帘风机负压通风系统降温效果
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摘要
为改善南方夏季肉牛舍环境条件,该文对湿帘风机负压通风系统在肉牛舍的降温效果进行了探究。试验以栓系饲养西门塔尔公牛为试验对象,对环境、肉牛生理及增重情况进行测定。结果表明:降温后,试验舍平均温度降低3.2℃(P<0.01),相对湿度增加21.3%(P<0.01),肉牛附近风速增加0.30 m/s(P<0.01),肉牛体感温度降低1.8℃(P<0.01);试验牛呼吸频率平均降低13次/min(P<0.01),皮温降低0.92℃(P<0.01),平均日增质量提高0.13 kg/d(P>0.05)。由此可知,在肉牛舍中采用湿帘风机负压通风系统进行降温,能够有效改善舍内热环境,有助于缓解肉牛热应激,具有技术可行性。
Although fan-pad evaporative cooling system is a kind of energy-saving and environment-friendly cooling method, its application in beef cattle barn is still very rare. A negative pressure ventilation system for wet curtain fan was tested in this study to improve the summer environmental conditions of beef cattle barn in Southern China and find out its suitability for hot and humid climates. The study was conducted in 2 cattle beef barns located at Gao'an, Jiangxi Province, where is hot and humid in summer. The system consists of a cellulosic cooling pad and 4 axial flow fans with an air volume of 38 048 m3/h and an electric power of 1.1 kW. According to the results of the preliminary experiment, the operation time of the cooling system was from 09:00 to 19:00. In this study, simmental beef cattle were randomly allotted in 2 confined barns where feed and water were freely available. The data of environmental factors and beef physiology were collected. Temperature-humidity-velocity index(THVI) and heat load index(HLI) value were calculated to estimate the effects of climatic variable and heat accumulation. The cooling effect of the system was affected by the ambient temperature and relative humidity. With the ambient temperature increased by 1 ℃, the cooling effect increased by 0.6 ℃; with the relative humidity increased by 10%, the cooling effect decreased by 1.6 ℃ There was a temperature gradient along the airflow direction, and the temperature increased 0.033 ℃ for every 1 meter increase in the distance from the cooling pad. The air velocity parallel to the direction of the airflow was also inconsistent. The air velocity near the cooling pad was higher than that at the fan outlet and the middle area(P<0.01), and the air velocity of the outlet of the fan was higher than that at the middle area(P<0.01). During the measurement period, the average temperature in the experiment barn was(29.7±0.5) ℃, compared with the control barn, decreased by 3.2 ℃(P<0.01); the average relative humidity was(89.9±1.9)%, increased by 21.3%(P<0.01); the average air velocity near the cow was(0.75±0.02) m/s, increased by 0.30 m/s(P<0.01); the average effective temperature was(29.1± 0.4) ℃, decreased by 1.8 ℃(P<0.01); the average concentration of CO2 was(498±14) ?10-6, deceased by 44 ?10-6(P<0.01); and the average concentration of NH3 was(3.63±0.33) ?10-6. However, because of the high relative humidity, HLI value of the experiment barn was slightly higher than that of the control barn(P>0.05). The average respiration rate in the experiment barn was(57±1)breaths/min, compared with the control barn, decreased by 13 breaths/min(P<0.01); the average skin temperature was(35.54±0.09) ℃, decreased by 0.92 ℃(P<0.01); the average rectal temperature was(38.74±0.04) ℃, decreased by 0.11 ℃(P>0.05); and the average daily weight gain was(0.65±0.52) kg/d, increased by 0.13 kg/d(P>0.05). The results indicated that fan-pad evaporative cooling system was able to improve the environmental conditions for beef cattle barns in Southern China, thus relieving heat stress of beef cattle. This provides a scientific basis for the extension and application of evaporative pad cooling systems in Southern China.
Although fan-pad evaporative cooling system is a kind of energy-saving and environment-friendly cooling method, its application in beef cattle barn is still very rare. A negative pressure ventilation system for wet curtain fan was tested in this study to improve the summer environmental conditions of beef cattle barn in Southern China and find out its suitability for hot and humid climates. The study was conducted in 2 cattle beef barns located at Gao'an, Jiangxi Province, where is hot and humid in summer. The system consists of a cellulosic cooling pad and 4 axial flow fans with an air volume of 38 048 m3/h and an electric power of 1.1 kW. According to the results of the preliminary experiment, the operation time of the cooling system was from 09:00 to 19:00. In this study, simmental beef cattle were randomly allotted in 2 confined barns where feed and water were freely available. The data of environmental factors and beef physiology were collected. Temperature-humidity-velocity index(THVI) and heat load index(HLI) value were calculated to estimate the effects of climatic variable and heat accumulation. The cooling effect of the system was affected by the ambient temperature and relative humidity. With the ambient temperature increased by 1 ℃, the cooling effect increased by 0.6 ℃; with the relative humidity increased by 10%, the cooling effect decreased by 1.6 ℃ There was a temperature gradient along the airflow direction, and the temperature increased 0.033 ℃ for every 1 meter increase in the distance from the cooling pad. The air velocity parallel to the direction of the airflow was also inconsistent. The air velocity near the cooling pad was higher than that at the fan outlet and the middle area(P<0.01), and the air velocity of the outlet of the fan was higher than that at the middle area(P<0.01). During the measurement period, the average temperature in the experiment barn was(29.7±0.5) ℃, compared with the control barn, decreased by 3.2 ℃(P<0.01); the average relative humidity was(89.9±1.9)%, increased by 21.3%(P<0.01); the average air velocity near the cow was(0.75±0.02) m/s, increased by 0.30 m/s(P<0.01); the average effective temperature was(29.1± 0.4) ℃, decreased by 1.8 ℃(P<0.01); the average concentration of CO2 was(498±14) ?10-6, deceased by 44 ?10-6(P<0.01); and the average concentration of NH3 was(3.63±0.33) ?10-6. However, because of the high relative humidity, HLI value of the experiment barn was slightly higher than that of the control barn(P>0.05). The average respiration rate in the experiment barn was(57±1)breaths/min, compared with the control barn, decreased by 13 breaths/min(P<0.01); the average skin temperature was(35.54±0.09) ℃, decreased by 0.92 ℃(P<0.01); the average rectal temperature was(38.74±0.04) ℃, decreased by 0.11 ℃(P>0.05); and the average daily weight gain was(0.65±0.52) kg/d, increased by 0.13 kg/d(P>0.05). The results indicated that fan-pad evaporative cooling system was able to improve the environmental conditions for beef cattle barns in Southern China, thus relieving heat stress of beef cattle. This provides a scientific basis for the extension and application of evaporative pad cooling systems in Southern China.
引文
[1]丁露雨,王美芝,郭霏,等.我国不同地区肉牛舍夏季环境状况测定[J].家畜生态学报,2011,32(1):68-72.Ding Luyu,Wang Meizhi,Guo Fei,et al.Determination of beef cattle housing condition in summer for different regions[J].Journal of Domestic Animal Ecology,2011,32(1):68-72.(in Chinese with English abstract)
[2]Brown-Brandl T M,Eigenberg R A,Nienaber J A.Water spray cooling during handling of feedlot cattle[J].International Journal of Biometeorology,2010,54(6):609-616.
[3]Schütz K E,Rogers A R,Cox N R,et al.Dairy cattle prefer shade over sprinklers:Effects on behavior and physiology[J].Journal of Dairy Science,2011,94(1):273-283.
[4]Smith T R,Chapa A,Willard S,et al.Evaporative tunnel cooling of dairy cows in the southeast.I:Effect on body temperature and respiration rate[J].Journal of Dairy Science,2006,89(10):3904-3914.
[5]Smith J F,Bradford B J,Harner J P,et al.Short communication:Effect of cross ventilation with or without evaporative pads on core body temperature and resting time of lactating cows[J].Journal of Dairy Science,2016,99(2):1495-1500.
[6]程琼仪,刘继军,靳薇,等.冷风机-风管对南方开放式牛舍的降温效果[J].农业工程学报,2014,30(8):126-134.Cheng Qiongyi,Liu Jijun,Jin Wei,et al.Effects of cooling fan-duct on cooling performance in open-sided beef barn in Southern China[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2014,30(8):126-134.(in Chinese with English abstract)
[7]Malli A,Seyf H R,Layeghi M,et al.Investigating the performance of cellulosic evaporative cooling pads[J].Energy Conversion and Management,2011,52(7):2598-2603.
[8]Sethi V P,Sharma S K.Survey of cooling technologies for worldwide agricultural greenhouse applications[J].Solar Energy,2007,81(12):1447-1459.
[9]Hasan O,Atilgan A,Buyuktas K.The efficiency of fan-pad cooling system in greenhouse and building up of internal greenhouse temperature map[J].African Journal of Biotechnology,2009,20(820):5436-5444.
[10]王美芝,赵婉莹,刘继军,等.湿帘-风机系统对北京育肥猪舍的降温效果[J].农业工程学报,2017,33(7):197-205.Wang Meizhi,Zhao Wanying,Liu Jijun,et al.Cooling effect if water pad-fan system for fattening pig houses in Beijing[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2017,33(7):197-205.(in Chinese with English abstract)
[11]Fidaros D,Baxevanou C,Bartzanas T,et al.Numerical study of mechanically ventilated broiler house equipped with evaporative pads[J].Computers and Electronics in Agriculture,2018,149:101-109.
[12]刘卫东,程璞,王绍锋.高温期负压纵向通风加湿帘降温对育肥猪生产性能的影响[J].养猪,2006(5):25-26.
[13]贾汝敏,叶红,叶昌辉.炎热季节肉鸡生产使用湿帘降温系统效果评价[J].中国家禽,2007,29(13):19-22.Jia Rumin,Ye Hong,Ye Changhui.Effect evaluation of fan and pad cooling systems for broilers production in hot season[J].China Poultry,2007,29(13):19-22.(in Chinese with English abstract)
[14]Smith J F,Harner J P D.Comprehensive evaluation of a low-profile cross-ventilated freestall barn[C]//Proceedings of the 8th Western Dairy Management Conference,2007.Reno:Western Dairy Management Conference,2007:127-147.
[15]中国气象局气象中心气象资料室,清华大学建筑技术科学系.中国建筑热环境分析专用气象数据集[M].北京:中国建筑工业出版社,2005.
[16]Tao Xiuping,Xin Hongwei.Temperature-Humidity-Velocity Index for Market-size Broilers[J].American Society of Agricultural Engineers,2003:paper No.:034037.
[17]Gaughan J B,Mader T L,Holt S M,et al.A new heat load index for feedlot cattle[J].Journal of Animal Science,2008,86(1):226.
[18]Kittas C,Bartzanas T,Jaffrin A.Temperature gradients in a partially shaded large greenhouse equipped with evaporative cooling pads[J].Biosystems Engineering,2003,85(1):87-94.
[19]胥芳,蔡彦文,陈教料,等.湿帘-风机降温下的温室热/流场模拟及降温系统参数优化[J].农业工程学报,2015,31(9):201-208.Xu Fang,Cai Yanwen,Chen Jiaoliao,et al.Temperature/flow field simulation and parameter optimal design for greenhouses with fan-pad evaporative cooling system[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2015,31(9):201-208.(in Chinese with English abstract)
[20]龚建军,雷云峰,何志平,等.高温季节“湿帘-风机”系统降温效果研究[J].家畜生态学报,2016,37(1):46-52.Gong Jianjun,Lei Yunfeng,He Zhiping,et al.Investigation on cooling effect of cooling pad-fan system during hot season[J].Journal of Domestic Animal Ecology,2016,37(1):48-52.(in Chinese with English abstract)
[21]Wang C,Cao W,Li B,et al.A fuzzy mathematical method to evaluate the suitability of an evaporative pad cooling system for poultry houses in China[J].Biosystems Engineering,2008,101(3):370-375.
[22]刘引区,王斌,陈生会,等.夏秋季气温对肉牛肥育增重的影响[J].中国牛业科学,2010,36(6):48-50.Liu Yinqu,Wang Bin,Chen Shenghui,et al.Impact on fattening weight gain of beef cattle of summer and spring temperature[J].China Cattle Science,2010,36(6):48-50.(in Chinese with English abstract)
[23]丁露雨,王美芝,陈昭辉,等.南方开放式肉牛舍夏季喷雾降温效果[J].农业工程学报,2013,29(2):224-231.Ding Luyu,Wang Meizhi,Chen Zhaohui,et al.Effects of spraying cooling on open beef cattle barn in Southern China[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2013,29(2):224-231.(in Chinese with English abstract)
[24]Gaughan J B,Holt S M,Hahn G L,et al.Respiration rate-is it a good measure of heat stress in cattle[J].Asian Australasian Journal of Animal Sciences,2000,13(4):329-332.
[25]黄昌澍.家畜气候学[M].南京:江苏科学技术出版社,1989.
[26]刘鹏,吴中红.兔舍湿帘降温和负压纵向通风设计使用要点及常见误区[J].中国养兔,2012(8):17-20.
[27]田海林,李曦,孙梦瑶,等.常用湿帘产品的技术性能测试[J].农机化研究,2013,35(4):148-151.Tian Hailin,Li Xi,Sun Mengyao,et al.Technical performance testing of commonly used specifications wet pad[J].Journal of Agricultural Mechanization Research,2013,35(4):148-151.(in Chinese with English abstract)
[28]蔡景义,冯堂超,廖阔遥,等.封闭型牛舍风机喷淋降温和饲粮添加铬改善肉牛生长性能[J].农业工程学报,2015,31(19):190-194.Cai Jingyi,Feng Tangchao,Liao Kuoyao,et al.Cooling with fans and spray in closed cowshed and chromium supplementation improving growth performance of beef cattle[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2015,31(19):190-194.(in Chinese with English abstract)
[29]陈昭辉,刘媛媛,吴中红,等.喷雾与纵向负压通风相结合的封闭牛舍降温效果[J].农业工程学报,2016,32(19):211-218.Chen Zhaohui,Liu Yuanyuan,Wu Zhonghong,et al.Cooling effects of spraying combined with tunnel negative pressure ventilation in enclosed feedlot barn[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2016,32(19):211-218.(in Chinese with English abstract)
[2]Brown-Brandl T M,Eigenberg R A,Nienaber J A.Water spray cooling during handling of feedlot cattle[J].International Journal of Biometeorology,2010,54(6):609-616.
[3]Schütz K E,Rogers A R,Cox N R,et al.Dairy cattle prefer shade over sprinklers:Effects on behavior and physiology[J].Journal of Dairy Science,2011,94(1):273-283.
[4]Smith T R,Chapa A,Willard S,et al.Evaporative tunnel cooling of dairy cows in the southeast.I:Effect on body temperature and respiration rate[J].Journal of Dairy Science,2006,89(10):3904-3914.
[5]Smith J F,Bradford B J,Harner J P,et al.Short communication:Effect of cross ventilation with or without evaporative pads on core body temperature and resting time of lactating cows[J].Journal of Dairy Science,2016,99(2):1495-1500.
[6]程琼仪,刘继军,靳薇,等.冷风机-风管对南方开放式牛舍的降温效果[J].农业工程学报,2014,30(8):126-134.Cheng Qiongyi,Liu Jijun,Jin Wei,et al.Effects of cooling fan-duct on cooling performance in open-sided beef barn in Southern China[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2014,30(8):126-134.(in Chinese with English abstract)
[7]Malli A,Seyf H R,Layeghi M,et al.Investigating the performance of cellulosic evaporative cooling pads[J].Energy Conversion and Management,2011,52(7):2598-2603.
[8]Sethi V P,Sharma S K.Survey of cooling technologies for worldwide agricultural greenhouse applications[J].Solar Energy,2007,81(12):1447-1459.
[9]Hasan O,Atilgan A,Buyuktas K.The efficiency of fan-pad cooling system in greenhouse and building up of internal greenhouse temperature map[J].African Journal of Biotechnology,2009,20(820):5436-5444.
[10]王美芝,赵婉莹,刘继军,等.湿帘-风机系统对北京育肥猪舍的降温效果[J].农业工程学报,2017,33(7):197-205.Wang Meizhi,Zhao Wanying,Liu Jijun,et al.Cooling effect if water pad-fan system for fattening pig houses in Beijing[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2017,33(7):197-205.(in Chinese with English abstract)
[11]Fidaros D,Baxevanou C,Bartzanas T,et al.Numerical study of mechanically ventilated broiler house equipped with evaporative pads[J].Computers and Electronics in Agriculture,2018,149:101-109.
[12]刘卫东,程璞,王绍锋.高温期负压纵向通风加湿帘降温对育肥猪生产性能的影响[J].养猪,2006(5):25-26.
[13]贾汝敏,叶红,叶昌辉.炎热季节肉鸡生产使用湿帘降温系统效果评价[J].中国家禽,2007,29(13):19-22.Jia Rumin,Ye Hong,Ye Changhui.Effect evaluation of fan and pad cooling systems for broilers production in hot season[J].China Poultry,2007,29(13):19-22.(in Chinese with English abstract)
[14]Smith J F,Harner J P D.Comprehensive evaluation of a low-profile cross-ventilated freestall barn[C]//Proceedings of the 8th Western Dairy Management Conference,2007.Reno:Western Dairy Management Conference,2007:127-147.
[15]中国气象局气象中心气象资料室,清华大学建筑技术科学系.中国建筑热环境分析专用气象数据集[M].北京:中国建筑工业出版社,2005.
[16]Tao Xiuping,Xin Hongwei.Temperature-Humidity-Velocity Index for Market-size Broilers[J].American Society of Agricultural Engineers,2003:paper No.:034037.
[17]Gaughan J B,Mader T L,Holt S M,et al.A new heat load index for feedlot cattle[J].Journal of Animal Science,2008,86(1):226.
[18]Kittas C,Bartzanas T,Jaffrin A.Temperature gradients in a partially shaded large greenhouse equipped with evaporative cooling pads[J].Biosystems Engineering,2003,85(1):87-94.
[19]胥芳,蔡彦文,陈教料,等.湿帘-风机降温下的温室热/流场模拟及降温系统参数优化[J].农业工程学报,2015,31(9):201-208.Xu Fang,Cai Yanwen,Chen Jiaoliao,et al.Temperature/flow field simulation and parameter optimal design for greenhouses with fan-pad evaporative cooling system[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2015,31(9):201-208.(in Chinese with English abstract)
[20]龚建军,雷云峰,何志平,等.高温季节“湿帘-风机”系统降温效果研究[J].家畜生态学报,2016,37(1):46-52.Gong Jianjun,Lei Yunfeng,He Zhiping,et al.Investigation on cooling effect of cooling pad-fan system during hot season[J].Journal of Domestic Animal Ecology,2016,37(1):48-52.(in Chinese with English abstract)
[21]Wang C,Cao W,Li B,et al.A fuzzy mathematical method to evaluate the suitability of an evaporative pad cooling system for poultry houses in China[J].Biosystems Engineering,2008,101(3):370-375.
[22]刘引区,王斌,陈生会,等.夏秋季气温对肉牛肥育增重的影响[J].中国牛业科学,2010,36(6):48-50.Liu Yinqu,Wang Bin,Chen Shenghui,et al.Impact on fattening weight gain of beef cattle of summer and spring temperature[J].China Cattle Science,2010,36(6):48-50.(in Chinese with English abstract)
[23]丁露雨,王美芝,陈昭辉,等.南方开放式肉牛舍夏季喷雾降温效果[J].农业工程学报,2013,29(2):224-231.Ding Luyu,Wang Meizhi,Chen Zhaohui,et al.Effects of spraying cooling on open beef cattle barn in Southern China[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2013,29(2):224-231.(in Chinese with English abstract)
[24]Gaughan J B,Holt S M,Hahn G L,et al.Respiration rate-is it a good measure of heat stress in cattle[J].Asian Australasian Journal of Animal Sciences,2000,13(4):329-332.
[25]黄昌澍.家畜气候学[M].南京:江苏科学技术出版社,1989.
[26]刘鹏,吴中红.兔舍湿帘降温和负压纵向通风设计使用要点及常见误区[J].中国养兔,2012(8):17-20.
[27]田海林,李曦,孙梦瑶,等.常用湿帘产品的技术性能测试[J].农机化研究,2013,35(4):148-151.Tian Hailin,Li Xi,Sun Mengyao,et al.Technical performance testing of commonly used specifications wet pad[J].Journal of Agricultural Mechanization Research,2013,35(4):148-151.(in Chinese with English abstract)
[28]蔡景义,冯堂超,廖阔遥,等.封闭型牛舍风机喷淋降温和饲粮添加铬改善肉牛生长性能[J].农业工程学报,2015,31(19):190-194.Cai Jingyi,Feng Tangchao,Liao Kuoyao,et al.Cooling with fans and spray in closed cowshed and chromium supplementation improving growth performance of beef cattle[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2015,31(19):190-194.(in Chinese with English abstract)
[29]陈昭辉,刘媛媛,吴中红,等.喷雾与纵向负压通风相结合的封闭牛舍降温效果[J].农业工程学报,2016,32(19):211-218.Chen Zhaohui,Liu Yuanyuan,Wu Zhonghong,et al.Cooling effects of spraying combined with tunnel negative pressure ventilation in enclosed feedlot barn[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2016,32(19):211-218.(in Chinese with English abstract)