Introduction
When it comes to cooling commercial or industrial spaces, reliability and efficiency are non-negotiable. Whether you’re managing a manufacturing facility, keeping critical equipment at the right temperature, or providing temporary climate control for an event, the right air conditioning system makes all the difference.
Direct expansion (DX) air conditioning is one of the most used cooling technologies in these settings. Compact, efficient and highly responsive, DX systems offer powerful temperature control with minimal infrastructure. But what is DX air conditioning, and how does it work?
In this guide, we’ll break down how DX systems operate, explore the different types available, and explain why they’re a popular choice for permanent and temporary cooling applications.
What Does DX Mean in Air Conditioning Terms?
In air conditioning, DX stands for direct expansion - a term used to describe how refrigerant is used to cool air directly within the system. In a DX air conditioning system, refrigerant absorbs heat from the indoor air at the evaporator coil and releases it outside via the condenser coil.
This is where DX systems differ from chilled water systems, which use water as an intermediary to transfer heat. Chilled water systems circulate cold water through air handling units or fan coil units to cool spaces, requiring more complex infrastructure such as pumps, pipes and a separate chiller plant.
DX systems are more self-contained and typically quicker to deploy. That makes them ideal for temporary installations, data centres, retail spaces, construction sites and any setting where fast, effective cooling is essential.
What is a DX Air Conditioning System? How Does a DX Unit Work?
A DX air conditioning system is a self-contained cooling solution that uses refrigerant to absorb heat from indoor air and release it outside. Unlike chilled water systems that rely on a central plant and water distribution, DX systems operate using a closed loop of refrigerant and a compact set of core components.
The system is made up of four key components:
- Evaporator coil: located inside the building or air handling unit, this is where warm indoor air passes over the coil, and heat is absorbed by the refrigerant.
- Compressor: the refrigerant, now in gas form, travels to the compressor where it is pressurised, raising its temperature.
- Condenser coil: typically located outside, the hot refrigerant gas is cooled and condensed back into a liquid as heat is released to the outdoor air.
- Expansion valve: this component reduces the pressure of the liquid refrigerant before it re-enters the evaporator, completing the cycle.
This continuous process delivers consistent, reliable cooling, making DX systems ideal for industrial and commercial environments where performance and simplicity are vital.
Types of DX Air Conditioning Systems
There isn’t a one-size-fits-all approach when it comes to direct expansion cooling. Several types of DX air conditioning systems are available to suit different environments, performance needs and levels of flexibility. Below are the most common types:
- Split systems
Split systems consist of two main parts: an indoor unit (evaporator coil and fan) and an outdoor unit (compressor and condenser). The two units are connected by refrigerant piping. They are common in smaller commercial premises or site offices where permanent infrastructure may not exist and are ideal for cooling individual rooms or zones with minimal disruption.
- Packaged DX units
Packaged systems house all key components within a single unit. These are often mounted outdoors and connected to ductwork that distributes cooled air throughout a building or enclosed space. They are frequently used for temporary cooling at events, construction sites or industrial facilities.
- Variable refrigerant flow (VRF) systems
VRF systems use DX technology but add advanced controls and the ability to serve multiple indoor units from one outdoor unit. These systems modulate the flow of refrigerant depending on demand in different zones. They are ideal for larger or more complex environments, such as data centres, multi-zone offices or healthcare settings, where precise temperature control and energy efficiency are essential.
Benefits of DX Air Conditioning
Whether you’re cooling a critical site, a temporary facility or a permanent structure, DX air conditioning systems offer several benefits. Their simplicity, flexibility and performance make them a go-to choice for industries where downtime isn’t an option.
Energy Efficiency
DX systems are designed to cool air directly using refrigerant, eliminating the need for a secondary chilled water loop. This direct approach reduces energy losses and delivers fast, targeted cooling, making them more energy efficient compared to larger central plant alternative, especially in smaller to mid-sized spaces.
Fast Installation and Modular Design
Time is often critical on site, and DX systems can be deployed quickly thanks to their self-contained design. Whether it’s a packaged unit or a split system, installation is typically faster and less disruption that chilled water systems. Their modular nature means you can scale cooling capacity up or down depending on your requirements, which is ideal for dynamic environments or phased projects.
Ideal for Temporary and Emergency Setups
DX air conditioning is ideal for temporary climate control for everything from events and construction to emergency response. These systems don’t require permanent infrastructure and can be rapidly deployed, connected and operational, minimising disruption and ensuring continuity.
Reliability and Scalability
DX systems are known for their dependable performance across a wide range of operating conditions. And because they can be configured in modular setups, you’re able to adapt quickly to changes in site demand, whether you need cooling in a single zone or across multiple buildings.
Where are DX Systems Used?
DX air conditioning is trusted across a wide range of sectors for their performance, flexibility and speed of deployment. Their ability to deliver targeted cooling without the need for complex infrastructure makes them a smart choice in the following environments:
- Industrial plants
In manufacturing and processing facilities, temperature control is essential for equipment efficiency and worker safety. DX systems provide reliable cooling for production areas, control rooms and storage zones, particularly where heat-generating machinery is in constant use.
- Commercial buildings
From offices to retail spaces, DX air conditioning systems offer a practical cooling solution with minimal disruption. Split systems or packaged units can be used to cool specific zones or entire floors, making them ideal for refurbishments, retrofits or buildings with limited access to central plant infrastructure. - Data centres
Maintaining a stable, cool environment is critical to prevent server failure and ensure uptime. DX systems, especially modular or VRF setups, are often used for their precise control and rapid deployment. They provide scalable cooling to match data centre expansion or emergency cooling during outages. - Events
Events, exhibitions and temporary structures often require short-term climate control. DX-based units are ideal for these setups, offering powerful cooling with fast setup and breakdown. Whether it’s a marquee, hospitality suite or backstage area, DX systems keep guests and equipment comfortable. - Construction and manufacturing
On-site conditions can vary, and DX units offer immediate cooling relief for site offices, welfare cabins or temperature-sensitive processes. Their portability and fast commissioning make them an essential tool on busy construction or production sites.
Direct expansion air conditioning systems offer a combination of efficiency, flexibility and speed, making them a reliable choice across commercial, industrial and temporary environments.
At Aggreko, we specialise in providing scalable, high-performance DX air conditioning solutions tailored to your exact needs. Backed by decades of experience and a nationwide support network, we’re ready to help you maintain the right environment - wherever and whenever you need it. Get in touch with our expert team to find out a how a DX air conditioning solution could work for your site.