Research On The Application Effect Of The Insulation Screen In The Dairy Barn In The Cold Area

There is a contradiction between the ventilation and insulation of the closed cow house in the cold area in winter,which leads to the low temperature and high humidity in the house environment for a long time.In order to grasp the distribution and variation of the main environmental parameters in the closed house of the cowshed,the on-site temperature,relative humidity and wind speed of the closed natural ventilation barn in Baicheng City,Jilin Province were continuously tested and utilized.The CFD software numerically simulates the temperature and humidity environment in the house before the renovation.On this basis,the on-site renovation of the cowshed building was carried out.First,the insulation curtain commonly used in the greenhouse was installed at a distance of 4.0 m above the barn to increase the insulation of the cow activity area below the house;The roof was evenly installed with 16 chimney fans specially designed for the ventilation of the cowshed,and seven different operating conditions were designed.The continuous test results of the modified barn and the control barn showed that:(1)During the test period,the average outside temperature was-14.58 ?,the average relative humidity was 51.51%,the average temperature in the house was-3.92 ?,and the average relative humidity was 85.7%.The house was in a low temperature and high humidity state for a long time.The 1.2 m average temperature is 1.49 ? lower than the average temperature of 4.3 m.The average temperature near the cross section of the gate is 4.56 ? lower than the average temperature of the middle cross section.The temperature distribution of the whole house is distributed.At the same time,the CFD numerical simulation shows that the air flow field inside the house is affected by the rolling door.Larger,the main heat source is cows,and the heat is collected in the bed under the action of heat and pressure,resulting in a higher temperature in the bed.(2)In winter,the temperature in the house is maintained at 0 ? as the transformation target.The corresponding insulation curtain material is selected to be installed on the inner side of the house.After installation,the temperature and humidity in the house are continuously tested.The average temperature on the side of the installation screen is lower than that of the insulation.The average temperature on the side of the curtain is increased to 3.55 ?,and the relative humidity is increased by 1.04%.The insulation effect of the insulation screen is the same in different cross-sections,and the lower the temperature outside the house,the better the insulation effect of the insulation inside the house.The ventilation has been improved,and the insulation screen has a significant effect on the insulation inside the house,but it has not solved the problem of high humidity in the house.(3)When installing 16 roof chimney fans in the house,the overall relative humidity is improved when 16 and 12 units are opened all day,but the temperature inside the house is obviously reduced.The insulation effect on the side of the installation screen is not obvious,and 8 units are opened.At the same time,the thermal insulation effect of the thermal insulation screen has been improved,but the effect of improving the relative humidity in the house is not obvious.The opening of 12 wind turbines does not improve the temperature distribution inside the house,and the sectional opening scheme of the fan is determined by comparison.