The air change rate(ACR)of naturally ventilated dairy buildings(NVDBs)plays an important part in the design and control of the ventilation system,as well as in the estimation of the gaseous emission rate.The objective...The air change rate(ACR)of naturally ventilated dairy buildings(NVDBs)plays an important part in the design and control of the ventilation system,as well as in the estimation of the gaseous emission rate.The objectives of this research were to model the ACR based on a quantitative investigation of the relationship between the ACR and its potential influencing factors,including the opening ratio(r),the building length to width ratio(a),the wind speed(U),and the wind direction(0).The investigations were performed using the response surface methodology integrated with the Box-Behnken design and Computational Fluid Dynamics(CFD)simulations.Three response surface models of the ACR of NVDBs were established for three opening ratio ranges of 5%-42.5%,42.5%-80%,and 5%-80%,respectively.It was found that the selection of the opening ratio range had almost no effect on the developed response surface models.The results showed that the ACR of NVDBs was not influenced by a,but was significantly affected by r,U,6,and interaction effects between every two of the three factors.The highest ACR was 6.7 s^(-1),6.0 s^(-1),and 4.0 s^(-1)when 0,U,and r was at their respective medium value while the rest parameters were at the highest values,indicating that the r played an important role in the value of ACR.It was concluded that in the prediction of the ACR of a building,the influences of both individual and interactional effects of 0,U,and r should be considered.展开更多
基金supported by the research project“Optimized animal-specific barn climatization facing temperature rise and increased climate variability”(OptiBarn)in the FACCE ERANET+initiative,granted by the German Federal Ministry of Food and Agriculture(BMEL)through the Federal Office for Agriculture and Food(BLE),DE-Grant No.2814ERA02Cby the Innovation Foundation Denmark,DK-Grant No.4215-00004Bby the research project“Green precision ventilation for future livestock housing”(GreenLiv)from Ministry of Environment and Food of Denmark,Grant No.34009-16-1144.
文摘The air change rate(ACR)of naturally ventilated dairy buildings(NVDBs)plays an important part in the design and control of the ventilation system,as well as in the estimation of the gaseous emission rate.The objectives of this research were to model the ACR based on a quantitative investigation of the relationship between the ACR and its potential influencing factors,including the opening ratio(r),the building length to width ratio(a),the wind speed(U),and the wind direction(0).The investigations were performed using the response surface methodology integrated with the Box-Behnken design and Computational Fluid Dynamics(CFD)simulations.Three response surface models of the ACR of NVDBs were established for three opening ratio ranges of 5%-42.5%,42.5%-80%,and 5%-80%,respectively.It was found that the selection of the opening ratio range had almost no effect on the developed response surface models.The results showed that the ACR of NVDBs was not influenced by a,but was significantly affected by r,U,6,and interaction effects between every two of the three factors.The highest ACR was 6.7 s^(-1),6.0 s^(-1),and 4.0 s^(-1)when 0,U,and r was at their respective medium value while the rest parameters were at the highest values,indicating that the r played an important role in the value of ACR.It was concluded that in the prediction of the ACR of a building,the influences of both individual and interactional effects of 0,U,and r should be considered.
