A heat pump dryer is a new type of energy-saving dryer. Its working principle is based on the reverse Carnot cycle principle, using a small amount of electrical energy and a compressor to evaporate the working medium into a gaseous state in the evaporator after passing through an expansion valve, and absorb a large amount of heat energy from the air. The gaseous working medium is compressed by the compressor into a high-temperature and high-pressure gas, and then enters the condenser to release heat, heating the drying medium. By continuously cycling and heating, the drying medium can be heated to 40 ℃~75 ℃. Compared to electric dryers, it saves two-thirds of electricity.

Air drying equipment, an intelligent device that integrates heating, cooling, exhaust temperature, and ventilation, is a new type of energy-saving and emission reducing drying equipment.

2、 Technical characteristics of heat pump dryer:

A、 It can achieve low-temperature air enclosed circulation drying, with good material drying quality. By controlling the operating conditions of the device, the temperature of the hot dry air in the baking chamber can be maintained between 30-75 ℃, which can meet the high-quality drying requirements of most thermosensitive materials.

B、 **Energy saving. The heat used to heat the air in a heat pump dryer mainly comes from the sensible and latent heat contained in the warm and humid air discharged from the recovery baking chamber. The energy required for input is only the power consumption of the heat pump compressor, and the heat pump has the advantage of producing a large amount of heat by consuming a small amount of power. Therefore, the SMER (the amount of water removed from wet materials per unit of energy) of the heat pump drying device is usually 1.0-4.0kg/kWh, while the SMER value of the traditional convection dryer is about 0.2-0.6kg/kWh.

C、 Convenient temperature and humidity control. When the material has high requirements for the temperature and humidity of the air entering the baking room, the evaporation temperature and condensation temperature of the working medium in the evaporator and condenser can be adjusted to meet the material's requirements for quality, appearance, and other aspects.

D、 Environmentally friendly. In the heat pump drying device, the drying medium circulates in a closed loop, and there is no pollution caused by the discharge of material dust, volatile substances, and odors into the environment along with the drying exhaust gas. The waste heat in the baking chamber exhaust is directly recovered by the heat pump to heat the cold dry air, and there is no thermal pollution to the environment caused by the unit.