1. Due to the significant temperature difference between grain and air, ventilation should be carried out during daylight hours to reduce the distance between grain and air temperatures and minimize the occurrence of condensation. In the future, ventilation should be carried out at night as much as possible. As this ventilation is mainly focused on cooling, the atmospheric humidity is relatively high and the temperature is low at night. This not only reduces water loss but also fully utilizes the low temperature at night, improving the cooling effect.

2. During the initial stage of ventilation with a centrifugal fan, condensation may occur on doors, windows, walls, and even on the surface of the grain. Simply stop the fan, open the window, turn on the axial flow fan, and if necessary, flip the grain surface to sweep away the humid and hot air inside the warehouse. Using an axial flow fan for slow ventilation will not result in condensation, only a slow increase in grain temperature in the middle and upper layers, followed by a steady decrease in grain temperature as ventilation continues.

When using an axial flow fan for slow ventilation, due to the small air volume of the axial flow fan and the fact that grains are poor conductors of heat, the ventilation initially appears to be slow in a single area. As the ventilation continues, the temperature of the entire silo will gradually balance.

4. It is necessary to sort the grain that undergoes slow ventilation through a vibrating screen, and the grain that enters the warehouse must be promptly cleaned of the impurity area formed by active grading, otherwise it is easy to form uneven ventilation.

5. Energy consumption calculation: The axial flow fan used in Warehouse 14 has been ventilated for 50 days, with an average of 15 hours per day, for a total of 750 hours. The moisture content has decreased uniformly by 0.4%, and the cooling temperature has decreased uniformly by 23.1 degrees. The unit energy consumption is 0.027kw. h/t. ℃. Warehouse 28 has been ventilated for 6 days, totaling 126 hours. The moisture content has decreased uniformly by 1.0%, and the temperature has decreased uniformly by 20.3 degrees. The unit energy consumption is 0.038kw. h/t. ℃.

6. Advantages of using axial flow fans for slow ventilation: good cooling effect; Low unit energy consumption is particularly important in today's advocacy for energy conservation; Easy to grasp ventilation opportunities and less prone to condensation; No need to equip a fan alone, convenient and sensitive. Defect: Due to low air volume and long ventilation time; The precipitation effect is not significant, and high moisture grains should not be ventilated with axial flow fans.

7. Advantages of centrifugal fans: significant cooling and precipitation effects, short ventilation time; Defect: High unit energy consumption; Poor grasp of ventilation opportunities can lead to condensation.

Conclusion: In ventilation with the intention of cooling, axial flow fans are used for safe and energy-saving slow ventilation; Use centrifugal fans in ventilation with the intention of precipitation.