A combined air-conditioning unit is an air handling equipment assembled from various air processing functional sections. It is suitable for air conditioning systems with resistance greater than 100Pa. The air processing functional sections of the unit include air mixing, flow uniformization, filtration, cooling, primary and secondary heating, dehumidification, humidification, supply fans, return fans, water spray, noise elimination, heat recovery, and other units.

Combined clean air-conditioning units come in 30 specifications with air volumes ranging from 3500m³/h to 200000m³/h and offer 12 functional sections for users to freely select and combine. They are primarily applicable to air purification systems in various clean workshops, such as industrial electronics factories, precision machinery manufacturing plants, textile workshops, automobile spray painting workshops, GMP pharmaceutical factories, cosmetics factories, food factories, pure water workshops, hospital operating rooms, ICUs, and other occasions.

Classification-wise, they can be divided into horizontal, vertical, and ceiling-mounted types based on structural forms; into general units, fresh air units, purification units, and special units (such as rooftop units, subway units, and computer room-specific units, etc.) based on usage characteristics; and can also be classified based on specifications, where the basic specification of the unit is represented by the rated air volume.

The setting of functional sections in purification units should be determined according to production processes or cleanroom requirements, which is a fundamental principle. The combination and omission of functional sections in purification units should be closely integrated with the design of the air-conditioned room.