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The immediate and most noteworthy difference between these two units is that the DX (direct expansion) unit cools air, and chiller units cool water. They also differ in that DX units use refrigerant as a cooling fluid, while chiller units use either water or a glycol mixture, due to glycol’s low freezing point when blended with water. However, not all chillers use water as a coolant. Air cooled chillers use air as a cooling medium in place of water.
Beyond cooling mediums and the logistics of cooling, there are some more specific differences between DX units and chillers, which we’ll delve into further.
DX units vary in use between supplemental or emergency building AC, or primary AC at tented events or relief structures. Chiller units cool water for use in other AC systems like chilled water air handlers. Chiller units are typically used in commercial spaces, including spas, pools, and recreational facilities. They are also used in large industrial environments, such as providing cooling for manufacturing, pharmaceuticals, food storage, and data storage facilities.
The DX air conditioner system (sometimes referred to as a DX packaged unit or DX HVAC unit) uses a refrigerant vapor expansion and compression cycle to cool air coming in through a supply plenum. It then returns it to the area that needs cooling through the return.
The unit effectively circulates refrigerant through a series of condensers and evaporators. During this process, warm air moves through the system and is cooled down before being pushed through the return.
One key advantage of DX packaged units is that the entire cooling system is self-contained in one unit. This allows for the installation on top of or alongside a building without too large of a footprint, and are generally less expensive to install.
In addition to lower installation costs and energy usage, DX air conditioning systems also offer lower maintenance costs. Similarly, because all parts are contained in a single unit, it’s easier for technicians to make adjustments when periodically testing and rebalancing the system.
A DX split system places the compressor and condenser outside the building. The system’s evaporator and fans are inside the building. This differs from a DX packaged unit in that its components are “split” between the interior and exterior of the building the system is meant to cool, instead of packaging them in a single unit installed outside.
Chiller units also use a vapor expansion/compression cycle for liquid refrigerant, much like the DX units. The refrigerant is continuously transformed from a liquid, to a vapor, and back again. This process cools down the refrigerant which is passed through an evaporator. Warm water coming through a 2-5 inch radius supply hose is passed over the evaporator and cooled off to the desired temperature. Typically, the cooled water is used for existing air handler systems.
Depending on their size, chiller units provide intense cooling in an energy-efficient package. In highly-sensitive operations that require strict temperature controls – such as chemical manufacturing, hydraulics, food storage, medical and pharmaceutical production, as well as data maintenance and storage – chiller units offer efficient cooling solutions and minimize damage to equipment and products. Additionally, chiller systems can be adjusted to work in both indoor and outdoor environments.
Whether you need to rent a DX unit or chiller for long-term or short-term purposes, Sunbelt Rentals is there to help. If you need to replace an existing unit, our technicians will provide units that are as close a match as possible to one that has malfunctioned. No matter the scenario, our team of knowledgeable professionals can help you decide on the best system for your unique needs.