What is the primary characteristic of a Direct Expansion (DX) system?

A Direct Expansion (DX) system is primarily characterized by its self-contained individual units. This design allows for the cooling and heating to be achieved at the location where the conditioned air is used, which makes DX systems both efficient and versatile for various applications. Each unit typically contains its own compressor and evaporator, allowing it to operate independently without the need for extensive ductwork that would be required in centralized HVAC systems.

This characteristic is particularly advantageous in spaces where localized temperature control is desired, such as in residential buildings or small commercial spaces. The modular nature of DX systems also facilitates easier installation and maintenance compared to systems that require extensive infrastructure.

In contrast, options involving extensive ductwork are more typical of centralized systems, and multiple zones with a single duct suggests a different method of air distribution that does not align with the self-contained nature of DX systems. Moreover, while DX systems can be utilized in large-scale industrial buildings, they are not limited to such environments; they are commonly found in smaller settings as well.