Central air conditioners fall into two categories: direct expansion (DX) or chilled water. Today, with the help of this article from BrightHub.com, we will attempt to better describe one of these systems, direct expansion, which unlike chilled water systems that first chill water through a refrigeration plant then use that to chill the air, DX systems pass air directly over the cooling coil to be chilled.
This means that the cooling efficiency of the DX system is much higher than water chilled units, but because it is not always feasible to carry the refrigerant piping over large distances, DX systems are usually only used for cooling small buildings or rooms on a single floor.
DX systems comprise of three main components:
1. The Plant Room: This area of the DX system is comprised of the refrigeration system, compressor and condenser.
2. The Air Handling Unit Room: The refrigerant leaving the condenser in the plant room enters the thermostatic expansion valve and then the air handling unit. This area is comprised of the evaporator or the cooling coil, air filter and the large blower.
3. Air Conditioned Room: This is the room that is to be air conditioned. The ductwork running from the air handling unit filters the cooled air into these rooms.
While the efficiency of DX systems is higher than water chilled systems, the refrigerant piping cannot be kept at very long distance since there will be lots of drop in pressure of the refrigerant along the way and there will also be cooling losses. So DX systems do not always make sense.
To see if you could benefit from a direct exchange air conditioning system, contact Fresh Air Concepts by calling 1-800-708-4FAC or click here today!