Fermentation refrigerator / Combination of refrigerator and pottery

Because the ancestors did not have a refrigerator, they put food in the pottery and buried it in the ground to store food. This method was applied to the fermentation refrigerator. First, the edge of the refrigerator is made of porcelain, so the circulation of air is continuous with the outside. As a result, the temperature is controlled naturally. Also, the porcelain in the refrigerator was filled with soil. If the soil is frozen, the temperature of the soil does not easily decrease. So you can save electricity used in the refrigerator.
In other words, this refrigerator is more effective and eco-friendly than other refrigerators.