Multi-floor buildings for raising pigs have recently attracted widespread attention as an emerging form of intensive livestock production especially in eastern China,due to the fact that they can feed a much larger nu...Multi-floor buildings for raising pigs have recently attracted widespread attention as an emerging form of intensive livestock production especially in eastern China,due to the fact that they can feed a much larger number of animals per unit area of land and thus alleviate the shortage of land available for standard single-floor pig production facilities.However,this more intensive kind of pig building will pose new challenges to the local environment in terms of pollutant dispersion.To compare the dispersion air pollutants(ammonia as a representative)emitted from multi-versus single-floor pig buildings,ammonia dispersion distance and concentration gradients were investigated through three-dimensional simulations based on computational fluid dynamics.The validation of an isolated cubic model was made to ensure the simulation method was effective.The effects of wind direction,wind speed and emission source concentration at 1.5 m(approximate human inhalation height)during summer were investigated.The results showed that the ammonia dispersion distance of the multi-floor pig building was far greater than that of the single-floor building on a plane of Z=1.5 m.When the wind direction was 67.5°,the wind speed was 2 m·s^(−1) and the emission source concentration was 20 ppmv,the dispersion distance of the multi-floor pig building could reach 1380 m.Meanwhile,the ammonia could accumulate in the yard to 7.68 ppmv.Therefore,future site selection,wind speed and source concentration need to be given serious consideration.Based on the simulation used in this study with source concentration is 20 ppmv,the multi-floor pig buildings should be located 1.4 km away from residential areas to avoid affecting residents.The results of this study should guidance for any future development of multi-floor pig buildings.展开更多
楼房猪场可节约占地面积,楼房猪舍常增设新风过滤装置和排风除臭墙用以改善舍内环境和减少废气排放。为了解此类楼房猪舍夏季环境控制情况,选择北京郊区某楼房猪舍的三个楼层作为监测对象,底层(1层)、中间层(3层)和顶层(5层)新风过滤装...楼房猪场可节约占地面积,楼房猪舍常增设新风过滤装置和排风除臭墙用以改善舍内环境和减少废气排放。为了解此类楼房猪舍夏季环境控制情况,选择北京郊区某楼房猪舍的三个楼层作为监测对象,底层(1层)、中间层(3层)和顶层(5层)新风过滤装置洁净度分别为优、差和良,中间层和顶层风机开启6台,底层风机开启5台,通过监测猪舍的温度、湿度和二氧化碳浓度(质量分数)、风机处静压差等环境参数,分析楼房猪舍不同楼层通风量、温度、温度分布均匀度及环境舒适度。结果显示,底层、中间层和顶层风机处静压差分别为69.7、110.1和98.7 Pa;高静压差导致猪舍实际通风量和风机能效比降低,猪舍实际通风量中间层(205313 m^(3)/h)和顶层(233611 m^(3)/h)显著低于底层(247903 m^(3)/h)(P<0.05),风机能效比中间层(15.3 m^(3)/(h·W))和顶层(17.4 m^(3)/(h·W))显著低于底层(22.5 m^(3)/(h·W))(P<0.05);底层舍内温度(24.2℃)显著低于中间层(24.6℃)和顶层(24.7℃)(P<0.05),舍内不同位置同期最大温差(0.4℃)显著低于中间层(1.1℃)和顶层(0.6℃)(P<0.05),综合温湿度和风速计算母猪等效温度指数(Equivalent Temperature Index for Sows,ETIS),底层最小,中间层最大。该研究可为楼房猪舍提高通风效率、优化楼房猪舍夏季环境控制方案提供理论依据。展开更多
基金supported by the National Key R&D Program of China(2022YFE0115600)the Key Research and Development Program of Zhejiang Province(2022C02045).
文摘Multi-floor buildings for raising pigs have recently attracted widespread attention as an emerging form of intensive livestock production especially in eastern China,due to the fact that they can feed a much larger number of animals per unit area of land and thus alleviate the shortage of land available for standard single-floor pig production facilities.However,this more intensive kind of pig building will pose new challenges to the local environment in terms of pollutant dispersion.To compare the dispersion air pollutants(ammonia as a representative)emitted from multi-versus single-floor pig buildings,ammonia dispersion distance and concentration gradients were investigated through three-dimensional simulations based on computational fluid dynamics.The validation of an isolated cubic model was made to ensure the simulation method was effective.The effects of wind direction,wind speed and emission source concentration at 1.5 m(approximate human inhalation height)during summer were investigated.The results showed that the ammonia dispersion distance of the multi-floor pig building was far greater than that of the single-floor building on a plane of Z=1.5 m.When the wind direction was 67.5°,the wind speed was 2 m·s^(−1) and the emission source concentration was 20 ppmv,the dispersion distance of the multi-floor pig building could reach 1380 m.Meanwhile,the ammonia could accumulate in the yard to 7.68 ppmv.Therefore,future site selection,wind speed and source concentration need to be given serious consideration.Based on the simulation used in this study with source concentration is 20 ppmv,the multi-floor pig buildings should be located 1.4 km away from residential areas to avoid affecting residents.The results of this study should guidance for any future development of multi-floor pig buildings.
文摘楼房猪场可节约占地面积,楼房猪舍常增设新风过滤装置和排风除臭墙用以改善舍内环境和减少废气排放。为了解此类楼房猪舍夏季环境控制情况,选择北京郊区某楼房猪舍的三个楼层作为监测对象,底层(1层)、中间层(3层)和顶层(5层)新风过滤装置洁净度分别为优、差和良,中间层和顶层风机开启6台,底层风机开启5台,通过监测猪舍的温度、湿度和二氧化碳浓度(质量分数)、风机处静压差等环境参数,分析楼房猪舍不同楼层通风量、温度、温度分布均匀度及环境舒适度。结果显示,底层、中间层和顶层风机处静压差分别为69.7、110.1和98.7 Pa;高静压差导致猪舍实际通风量和风机能效比降低,猪舍实际通风量中间层(205313 m^(3)/h)和顶层(233611 m^(3)/h)显著低于底层(247903 m^(3)/h)(P<0.05),风机能效比中间层(15.3 m^(3)/(h·W))和顶层(17.4 m^(3)/(h·W))显著低于底层(22.5 m^(3)/(h·W))(P<0.05);底层舍内温度(24.2℃)显著低于中间层(24.6℃)和顶层(24.7℃)(P<0.05),舍内不同位置同期最大温差(0.4℃)显著低于中间层(1.1℃)和顶层(0.6℃)(P<0.05),综合温湿度和风速计算母猪等效温度指数(Equivalent Temperature Index for Sows,ETIS),底层最小,中间层最大。该研究可为楼房猪舍提高通风效率、优化楼房猪舍夏季环境控制方案提供理论依据。
