At present, the Ministry of Agriculture and the Ministry of Finance jointly issued the Notice on Doing a Good Job in the Initial Processing of Agricultural Products in 2014. This is to solve the problem of the initial processing conditions of China's agricultural production areas, reduce serious post-production losses, stabilize market prices, increase farmers' income, and improve the quality and safety of agricultural products. According to the “Notice”, the subsidy standard for drying facilities is 30%, which will greatly promote the application of drying equipment.

According to experts, the difference between heat pump dehumidification drying and traditional hot air drying lies in the way the air circulates and the air in the drying chamber dehumidifies. When the heat pump is dried, the air is closed in a closed cycle between the drying chamber and the heat pump dryer, and the cooling system of the heat pump dryer cools and dehumidifies the humid air from the drying chamber. When the moist air flows through the heat pump evaporator, the internal low-pressure refrigerant absorbs the heat of the air from the liquid state to the gaseous state, and the air discharges most of the condensed water due to the cooling. The low-pressure refrigerant vapor from the evaporator is boosted by the compressor and sent to the condenser. When the dehumidified dry cold air flows through the condenser, the internal high-pressure refrigerant releases heat due to condensation, and the external air is heated to hot air and returned to the drying room to continue drying the product to be dried. The high-pressure refrigerant discharged from the condenser is depressurized by the expansion valve and flows into the evaporator for the next cycle.

At present, air-energy heat pumps are widely used in tobacco drying, drying of fruits and vegetables, drying of medicinal materials, drying of seafood, drying of wax products, and drying of betel nuts. Air-energy heat pumps have higher quality, more energy-saving, and more environmentally friendly than traditionally dried products. The introduction of this document will enable the development of air-energy heat pumps to a new level.