From the different cold (heat) sources, modular air conditioning units can be divided into two types: chilled water type and direct evaporation type: (1) modular air conditioning units that use chilled water (or hot water, etc.) as the cold (heat) source are generally referred to as modular air handling units (Modular Air Handling Units or Central station Air Handling Units). The modular air handling unit is the most important terminal equipment of the central air conditioning system, which, together with chillers such as modular units, screw units, centrifuges, etc., forms a large central air conditioning system. (2) The modular rooftop air conditioning unit (Modular Rooftop Air Conditioning Unit), which uses direct evaporation (i.e. compressor direct refrigeration), is generally designed and manufactured in the form of a rooftop unit. The modular roof air conditioner delivers processed air to the space in need of air conditioning through an external air duct

Combination air conditioners generally consist of three or more functional segments. For example, the initial air return section, surface cooling water blocking section, heating section, humidification section, secondary air return section, fan section, noise reduction section, medium efficiency filtration section, sterilization section, and heat recovery section can be combined with different functional sections to achieve different air treatment requirements. Combination air conditioning units have high requirements for air leakage rate, cold bridge factor, and mechanical strength of the box.

Classified by structural type, it can be divided into horizontal, vertical, and suspended ceiling types; According to their usage characteristics, they can be classified into general units, fresh air units, purification units, and dedicated units (such as rooftop units, subway units, and computer room dedicated units, etc.); It can also be classified by specifications, and the basic specifications of the unit can be represented by the rated air volume.