The hot air pump dryer is a new type of high-efficiency and energy-saving dryer. Its working principle is based on the principle of reverse Carnot cycle, using a small amount of electric energy, using a compressor to evaporate the working fluid into a gaseous state in the evaporator after passing through an expansion valve, and a large amount of Absorbing the heat energy in the air, the gaseous working fluid is compressed by the compressor into high temperature and high pressure gas, and then enters the condenser to release heat, heating the drying medium, and heating continuously in this way, the drying medium can be heated to 40-80 degrees Celsius. Save 2/3 of the electric energy than the electric dryer.