According to the fin arrangement, there are two types of finned tubes: longitudinal finned tubes and horizontal finned tubes. According to the shape of the base tube, the finned tube includes round finned tube, elliptical finned tube and flat tube finned tube. On the market, round finned tube heat exchangers play a leading role, but a large number of experiments have shown that, compared with round finned tubes, the backflow area and windward area of the elliptical tube are much smaller, which effectively reduces the air side. When the number of tube bundles is the same, the elliptical tube and the flat tube are more compact than the round tube structure, and the volume of the heat exchanger is smaller, which reduces the cost.