With the rapid development of dehumidifier technology research, the degree of intelligence is getting higher and higher, so that it can be widely used in various fields. Such as industrial production, agricultural planting, national defense construction, medical treatment, commercial activities and daily life and so on.

The design of 20kg/h dehumidifier is described in this paper. The design of evaporator and condenser, compressor selection are included in this paper. Cooling dehumidification technology is adopted in this dehumidifier. The principle is that the first wet air is cooled to the dew point temperature through the evaporator, and then the water vapor is condensed into water droplets, thus reducing the air humidity, and finally the dry air is heated, so as to achieve the goal of dehumidification. The theoretical calculation method is adopted in this paper. According to the given conditions, the process of wet air treatment is determined by the environmental conditions. The best rated air volume is determined by the determined refrigerating capacity under the condition that the dehumidifier obtains the maximum dehumidifying capacity. Then the design of the refrigeration cycle and each state point is determined; The structure design and check calculation of evaporator and condenser and the resistance calculation of system components are obtained.

Key words: dehumidifier evaporator condenser cooling dehumidifier