Fresh air purification device for classrooms

The utility model discloses a fresh air purification device for classrooms. The air conditioner indoor unit comprises a shell, an air inlet, an air outlet and an air channel, wherein the filtering device is arranged behind the air inlet and communicated with the air inlet, the first centrifugal fan is communicated with the filtering device, the heat exchanger is communicated with an outlet of thefirst centrifugal fan, the heat exchanger is further communicated with an inlet of the second centrifugal fan and the air channel, and an outlet of the second centrifugal fan is communicated with theair outlet. The filtering device comprises a primary filter screen, a high-efficiency filter screen, an activated carbon filter screen and a photocatalyst sterilization screen which are sequentially arranged. Due to the fact that a four-stage filtering mode is adopted for the outdoor air, it is guaranteed that the oxygen content of the air entering a room is saturated, the air is fresher and healthier, and the growth requi