In winter, the temperature in winter in North China is cold. In the process of ventilation management, the contradiction between ventilation and heat insulation is outstanding. When coordinating the contradiction between the two, the minimum ventilation should be clearly ensured, regardless of the low ambient temperature of the house. , must ensure that the house has the minimum effective ventilation. 1 Winter ventilation management focuses mainly on ventilation in winter, with a colorless, odorless, and no boring feeling. The somatosensory wind speed is within 0.1m/s, the shepherding temperature is above 13°C, and the temperature difference between day and night is 3 -5°C, and maintain a relatively stable condition. In the peak period of egg production, while satisfying the minimum respiration volume, attention should be paid to the somatosensory wind speed of the chicken, and the stable production period and the late stage of production should focus on the air quality. 2 Basic parameters and principles of winter ventilation management in intensive houses The applicable closed house types: The house has good airtightness and adopts the “longitudinal fan + horizontal ventilation small window†ventilation management model. 2.1 Basic parameters of ventilation management 2.1.1 Fan wind speed In order to maintain the consistency of the front and rear air intake volume in winter, higher internal static pressure is required, which in turn leads to lower fan power. The wind speed of general wind turbines is between 5.5-6.0 m/s. 2.1.2 Exhaust area The effective exhaust area of ​​each fan (1.4m*1.4m) is 0.76m2. 2.1.3 Small window minimum opening distance Small window minimum opening distance 2.5-3.0cm. 2.1.4 Small window minimum wind speed The minimum wind speed of small windows (house with a span of 12 meters) should be maintained at 3.8m/s or more to ensure that the incoming fresh air is evenly distributed within the house. 2.2 Basic Principles of Ventilation Management Ventilation in winter sheds is based on the principle of maintaining minimum ventilation. 1 Determine the number of fans to be turned on based on the minimum amount of ventilation. 2 Determine the number of small windows to open based on the number of fans and the number of fans. When the above fan is used for normal rotation, all the small windows are used. When it is lower than the two fans, consider closing half the small windows. 3 The small window is opened to ensure the uniformity of ventilation in the house. The small windows on both sides must be symmetrical, uniform, and consistent. ; 4 Small windows adjust the time to maintain the relative stability of day and night temperatures. Generally, the temperature starts to increase at 8:30 in the daytime. At this time, the small window is gradually increased according to Sherwin's temperature. The temperature gradually decreases from 7:00 to 8:00 at night, and the small window is gradually reduced according to Shervin. 3 the establishment of ventilation control mode 3.1 to control the temperature of the fan ventilation based on the minimum ventilation to ensure that the minimum temperature at night to open the door to ensure that the temperature of the chicken house is not lower than 13 °C. If the temperature is set too high, the air circulation in the house is poor; if the temperature is too low, the ventilation time is too long and the temperature of the house is too low, which may cause stress to the flock. In addition, in cold season, when the temperature of the house is lower than the temperature set by the thermostat, the fan cannot start and the house needs to maintain a minimum ventilation. It is necessary to use a regular fan to intermittently operate the ventilation so that the temperature inside the house can be controlled. No flickering phenomenon can occur. 3.2 Adjusting the air inlet properly In the cold season, the ventilation of the chicken house adopts different air inlet methods, which will greatly affect the comfort of the flock and the production performance. There are two commonly used - ordinary windows and adjustable ventilation window. The small ventilation window has the best use effect, and the air inlet can be adjusted according to the outside temperature, so that the cold air entering the chicken house can be sent upward at a relatively high speed to the top of the chicken house, to the center of the chicken house, and the warm air above the chicken house. Mix to avoid cold stress on the flock. If the air inlet opening is too small, the static pressure of the chicken house is too high, and the amount of air entering the house will be insufficient. If the air inlet is opened too much, static pressure will drop, resulting in lower wind speed and uneven air intake. Specific practices should be based on the actual situation to explore the law. 4Problems during the winter ventilation control process 4.1 The structure of the house 1 The window is installed too high or the ceiling is too low, causing the wind to hit the roof directly, refracting, causing uneven ventilation, cold wind blowing chicken; 2 small window openings There are obstacles that lead to unequal ventilation in the house. 3 The tightness of the house is not strict, resulting in cold air entering through the air leakage outlet, causing local temperature to be too low. 4.2 The temperature setting aspect 1 The target temperature is set too high, resulting in a small number of fans to open, can not meet the minimum respiration requirements; 2 target temperature is set to low, the fan turns on more, causing cold stress; 3 delay temperature set low Causes the fan to turn off frequently. The general winter delay temperature is set to 0.2°C. 4.3 Small window adjustment aspect 1 The opening size of both sides of the small window is inconsistent, resulting in uneven temperature within the house; 2 The window size is adjusted too early or too late, resulting in an increase in the temperature difference between day and night; 3 The small window is opened too large or too small, too large Cause uneven wind speed, too small resulting in excessive wind speed; 4 small window at night according to personal feelings adjust, causing each person to adjust the size of the small window is inconsistent, the wind speed inside the house constantly changes, affecting the performance of egg production; 5 that the small window to open more The smaller the wind speed is, the larger the window opening is when the static pressure in the house is large enough, the greater the wind speed in the house. 4.4 Fan Use The main problem with the use of fans is the loss of speed. Tightening the fan belt or installing the tensioner at regular intervals. To sum up, the key to successful ventilation in winter sheds is summarized as follows: Do not flicker in controlling indoor temperature; provide correct air flow patterns to prevent cold stress in chickens; provide appropriate fresh air to control Humidity, ammonia, dust, microbes, etc.
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