The air-cooled direct expansion air conditioning unit revolutionizes the traditional design concept of chilled water units and modular air handling units by replacing complex water systems with a refrigerant direct evaporation system. It simplifies the system composition, increases the evaporation temperature of the refrigerant, reduces the construction and operational costs of equipment, and is a classic example of a simple yet efficient design philosophy. This unit is professionally designed for matching purification projects and other air conditioning projects, meeting requirements for air conditioning, temperature and humidity control, dust-free, sterile, noise reduction, micro-processing programmable automatic control, ease of transportation, and simple installation. It solves the problems caused by different air volume and pressure head requirements for purification and air conditioning. It fully showcases the characteristics of direct expansion air conditioning and meets the various process requirements of the purification section, representing an innovation in purification air conditioning units.