Air Cooled Condensers are one method  to cool  the compressors of a Test chamber.  The other method utilizes Water Cooled Condensers.  Here is a relatively simplistic explanation of both systems:

Air Cooled Condensers
Test Chambers with larger compressors (normally larger than 3HP) often use Remote Air Cooled Condensers.  For those not familiar, Remote Air Cooled Condensers are similar to the condensers one finds installed outside buildings which include central air conditioning.  The size of the Air Cooled Condenser will vary depending on the size of the compressors to which it is connected.  Typically Air Cooled Condensers are installed on the roof of a building or outside the building on the ground.  Installation involves refrigerant and electric lines which need to be  connected between the Remote Air Cooled Condenser and  Test Chamber (which contains the compressors) - Installing these requires the expertise of a Refrigeration Technician - Therefore significant installation costs may be associated with a test chamber which requires a Remote Air Cooled Condenser.   

The main advantages of Remote Cooled Condensers are:
(a) Heat removed by the Air Cooled Condenser is removed and dissipated outside the building where the chamber is located.
(b) Noise from the chamber is reduced due to the Air Cooled Condenser Fan which is also located outside the building (used to cool the Air Cooled Condenser).
(c) Since refrigerant lines are connected between the test chamber and the Remote Air Cooled Condenser, the chamber cannot easily be moved to another location.

Most smaller Test Chambers however utilize a Self Contained Air Cooled Condenser which is included in the Compressor Compartment of the Chamber.  The advantage of this type of system is that it  allows the Test Chamber to be portable and easily moved around if necessary (since the only utility is Electric Power).  

However, there are disadvantages to the Self Contained Air Cooled Condenser which may  need consideration.
(a) Heat is dissipated from the condenser within the test chamber  inside the building where the chamber is located.
(b) The condenser fan generates additional noise from the chamber.

Water Cooled Condensers
Water Cooled Condensers are another way to cool the compressors of a test chamber.  The Water Cooled Condenser is located in the compressor compartment of  the test chamber.  Water needs to be supplied to the Water Cooled Condenser to remove the heat generated from the compressors.   Since a fairly continuous flow of water is required,  a Water Tower is normally required to cool the heated water.  Water towers are normally located outside the building on  the roof or on the ground.  Water lines connecting the  test chamber to the Water Tower  need to be installed as well as electricity to power the Water Tower pump.  The water tower is sized according to the size of the compressors of the test chamber  to which it is connected.  

The main advantage of a Water Cooled Test Chamber is that the water tower does  not require a refrigeration technician to install.

The main disadvantage is  that they do require  regular maintenance such as treatment of the water to prevent freezing (in cold weather) and various  types of contamination.