What is the difference between DX & Chilled water ? Which one is preferable ?
Chillers vs. DX Units The primary distinction between these two types of units is that DX (direct expansion) units cool air while chiller units cool water. DX Units can be used as supplemental or emergency building air conditioning or as primary air conditioning at tented events or relief buildings. Chiller units chill water for use in various types of air conditioning systems, such as chilled water air handlers.
Package DX Units
The DX Air Conditioner system cools air that enters through a supply plenum and returns it to the area that requires cooling via the return. The unit circulates refrigerant effectively through a sequence of condensers and evaporators, where heated air is cooled and sent through the return. Another significant characteristic of DX Packaged units is the ability to house the entire cooling system in a single unit. This enables them to be installed on top of or alongside a building without taking up an excessive amount of space, and they are often less expensive to install.
The DX unit is self-contained. There is no risk associated with the DX unit.
Air Cooled Chiller Units
Chiller units, like DX units, use a vapor expansion/compression cycle to cool liquid refrigerant. The refrigerant is changed continually from a liquid to a vapor and back. This procedure chills the refrigerant as it travels through an evaporator. Warm water is passed over the evaporator via a supply pipe with a radius of 2-5 inches and cooled to the required temperature. The cooled water is typically used to cool existing air handler systems.
Chilled water units required chilled water to be supplied by the central cooling plant. As a result, its cooling performance fluctuates according to the temperature of the entering cooling water. The temperature of the cooling water from the central plant is constantly changing.
The chilled water unit’s operation is contingent upon the central cooling plant’s uptime.
There is a potential of water leakage in a datacenter when using a chilled water unit.
However, chilled water units have a lower operating cost (electricity cost) than DX units.
