Air dehumidifiers are mainly divided into household dehumidifiers and industrial dehumidifiers according to the place of use. The air dehumidifier is composed of a compressor, heat exchanger, fan, housing, and controller. Its working principle is that the wet air is pumped into the machine by the fan, and it is suspected to form frost under the interaction of the refrigeration system (compressor, evaporator, refrigerator). The system automatically heats up and defrosts the water to discharge, and produces dry air to discharge, so as to reduce the indoor humidity. The air dehumidifier is easy to use and maintain, less affected by the external environment, and has a strong dehumidification ability. Air dehumidifiers are widely used in civil air defense engineering, tobacco factories, pharmaceutical factories, scientific research, industry, medical and health care, instruments and meters, commodity storage, underground engineering, computer rooms, archives, warehouses, and other places with high humidity to prevent the loss caused by dampness, rust, and mildew of instruments, meters, computers, telecommunications equipment, drugs, materials, etc.