The cold storage door, also known as the refrigerated door for cold room, is one of the important facilities of the cold storage, is also the passage for the cold storage to get in and out of the goods, and is one of the important parts for the cold storage to run cold. Because of the temperature difference between the inside and outside of the cold storage, when the door of the cold storage is opened, the hot air will have strong convection through the door opening, resulting in the exchange of hot and humid air into the warehouse, increasing the heat load of the cold storage. This part of the heat load is usually called the cooling capacity or cooling loss of the opening door. When opening the cold storage door, the hot air volume entering the cold storage is related to the height and width of the door, the temperature difference inside and outside the cold storage, and of course, the time and times of opening the door. For energy saving, the number of cold storage doors should be controlled as much as possible and the size of the door opening should be reduced as much as possible.