Solve the ventilation problem of broiler breeding in one step, 10 golden rules for cage ventilationin autumn
With the arrival of autumn, environmental control and ventilation issues in chicken houses need to be adjusted. For caged broiler houses, what are the aspects of ventilation management settings in autumn?
1. General construction data of current standard chicken houses
We often talk about the ventilation of standard chicken houses, so what kind of chicken houses are standard chicken houses?
Three-layer cage: 85-95 meters long, 15.5-17.5 meters wide, eaves height 3.2-3.4 meters, top height 2.4-2.6 meters. Four-layer cage: 75-85 meters long, 16-18 meters wide, eaves height 4.2-4.5 meters, top height 2.5-2.6 meters. No distinction is made between spires and vaults. The number of small windows is 200-250 pieces/piece, and the number of fans is 1500-2000 pieces/piece.
2. Setting of time-controlled cycle period
Based on the standard chicken house, it is recommended to use a 3-4 minute cycle for common cycle times. The first fan start time should be at least 20 seconds. A large cycle of 5-8 minutes can be used. Gradually increase the fan start time to more than 30 seconds before starting to reduce the stop time. Or directly reduce the stop time and shorten the cycle period to 3-4 minutes.
3. Ventilation level setting and time-controlled cycle setting
The opening time is mainly the basic ventilation volume. The main influencing factor is the selection of the respiration rate. The respiration rate is selected according to the lowest temperature at night. For example, the lowest temperature at night is about 15-20°C. You can choose the basic respiration rate 1 to float. The number of chickens × kilogram weight × respiration rate / basic fan exhaust volume is the fan opening ratio, and then multiplied by the cycle period, the fan opening time can be obtained. The cycle period minus the start time is the stop time.
4. The fan time control setting is very important during autumn ventilation, especially at night. A problem often encountered is the increase or decrease of basic fans. So when should the basic fans be added? What is shared below is personal experience and is for reference only: the lowest outside temperature at night is above 20-25℃, and the fan activation ratio is greater than 80%, increase the starting fan. 15-20℃ at night, 70%. 10-15℃, 60%. Below 10℃, 50%. Of course, this is for reference only and needs to be modified according to the actual situation.
5. Autumn ventilation When the temperature is high during the day, low humidity often occurs, and when the temperature is low at night, high humidity often occurs. At this time, ventilation control should be based on body temperature. It is necessary to know the wind cooling effect of wind speed caused by turning on the fan, and the damp and heat compensation caused by humidity changes. Somatosensory temperature = room temperature - air cooling effect + damp heat effect. Determine whether ventilation is excessive based on the value. So how to calculate the air cooling effect and moist heat effect?
6. About air cooling and damp heat
Several parameters of body temperature are for your reference, 1-6 weeks, air cooling: 7 6 5 4.2 3.5 3. Damp heat: 0.16 0.12 0.1 0.085 0.08 0.11. The standard humidity is 65 60 55-60 55 50 50. Air cooling is calculated based on the longitudinal wind speed generated by turning on the fan. How to calculate the fan exhaust volume/chicken house cross-sectional area. For example, the cross-sectional area we calculated is about 70㎡, the fan exhaust volume is 40000m³/h, and the wind speed is approximately is 0.16m/S. Damp heat calculation range is 30-80%.
7. In the ventilation level setting, what is the appropriate temperature control temperature setting for the fan?
This also involves somatosensory temperature, so the calculation of somatosensory temperature is very important. The setting of the temperature control temperature is mainly based on the air cooling effect, supplemented by humidity changes. For example, in our current chicken house, the approximate wind speed generated by a fanis 0.16m/s, the air cooling coefficient in the third week is 5, and the air cooling effect is 0.8. Therefore, the temperature control temperature is 0.8℃/unit, 1.5 units is 1.2, and two units is 1.6.
8. Adjustment of fan temperature control temperature
In autumn, as the daytime temperature rises, the increase in ventilation in the house will lead to a decrease in the humidity in the house. It can be calculated according to the normal temperature control temperature, for example, the current temperature is 0.8℃/station. However, there are sometimes more foggy days in autumn and the air humidity is high. If you increase the fan, the humidity in the house will not drop significantly, so the temperature control temperature will be lowered and set to 0.6 or 0.7. Why is this? The higher the temperature, the smaller the wind chill. The higher the humidity, the smaller the wind chill. The older the weather, the smaller the wind chill. vice versa.
9. The number of high-temperature fans turned on during the day is controlled 1
There are many hot days during the day in autumn, most of which are 30-32℃. If the temperature is high or not, it will not heat the chickens; if it is low, the chickens will open their mouths and pant a lot. If the chickens have respiratory problems, they will often heat up. The medicine is also difficult to take. So how to turn on the fan to cool down? The first is to turn on the fan according to the normal temperature control temperature, and control the number of fans to be turned on through the maximum ventilation volume. The maximum ventilation volume is 10 times the basic ventilation volume; the minimum at night is about 20, the minimum is 1.2, and the maximum is 12 to calculate the number of fans to turn on. . If the chickens are older, the water curtain can be opened to cool down after reaching the maximum ventilation volume.
10. Control the number of high-temperature fans turned on during the day 2
The number of high-temperature fans during the day in autumn can also be controlled based on the upper limit temperature of the chickens combined with the outside temperature. Under normal circumstances, fan ventilation can control the temperature inside the house to a maximum of +1℃ outside temperature. For example, 31 outside can control 32 inside the house. In other words, if the temperature is higher than 32 degrees Celsius, ventilation can be used to reduce the temperature. The upper limit temperature of chickens in this season is 32°C 30 days ago, 30°C 30-35 days ago, and 28°C after 35 days. If it is too high, you can use a water curtain to suppress the temperature.
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