During the freezing process of food, the heat release is actually an uneven exothermic process, so the cooling amount required for the cooling equipment during the freezing process is also uneven.

The freezing process of food consists of three stages:

The first stage is the cooling stage. The temperature of the food drops to about 0°C due to the higher than 0°C.

The second stage is the ice crystal formation stage, and the food temperature drops from 0°C to -5°C.

The third stage is the freezing and cooling stage, and the food temperature drops from -5°C to about -15°C.

In the three stages of food freezing, the second stage requires the maximum amount of cold, and the equipment equipped with the freezing room should be fully put into operation at this time. In the first and third stages, due to the small heat load per unit time, the wind speed can be appropriately reduced to reduce the air volume, so as to achieve the purpose of energy connection.In the past, the cooling fan used for freezing was only one kind of rotating speed, which could not be adjusted. If the cooling fan was equipped with a double-speed or variable-speed motor, the frozen circulating air volume could be adjusted to achieve the purpose of energy saving.