The invention provides an internal descaling and external
defrosting novel air conditioner applying ultrasonic oscillators. The internal descaling and external
defrosting novel air conditioner comprises an outdoor unit and an indoor unit. The outdoor unit and the indoor unit are connected through a pipeline. The indoor unit comprises the indoor ultrasonic oscillators and an indoor
heat exchanger, wherein the indoor ultrasonic oscillators are located around the indoor
heat exchanger. The indoor
heat exchanger is a
shell and tube heat exchanger and comprises fins, U-shaped pipes, an air inlet
pipe, process reinforcement tubes, a liquid outlet
pipe and bridging elbows. Each U-shaped
pipe comprises two free ends extending in the same direction in parallel, and a bent part located between the two free ends, wherein the free ends are inserted in the corresponding fins. Ports of the free ends of every two adjacent U-shaped pipes are connected through the corresponding bridging
elbow. The outdoor unit comprises a capillary tube, a compressor, an outdoor heat exchanger, the outdoor ultrasonic oscillators, a four-way valve, air-liquid separators, a filter and a
check valve, wherein the outdoor ultrasonic oscillators are located around the outdoor heat exchanger. By means of the internal descaling and external
defrosting novel air conditioner, ultrasonic non-stop on-line internal descaling and external defrosting can be achieved, the stable running environment of the air conditioner is ensured, and the service life is prolonged.