Abstract: System and process are disclosed for the hierarchial control of a plurality of discrete chiller units each having individual dedicated controls. The system and process imposes limits on the amount of compression that can be demanded by the individual dedicated controls. These limits are selectively changed in response to whether a level of chilling has been collectively achieved. The selective changing of these limits is premised on examinations of each individual chiller unit including the recent history of any changes in compression by the unit.

Abstract: System and process are disclosed for reacting to conditions that may arise in a plurality of discrete chiller units all individually controlled by dedicated control units. The system and process react to temperature conditions of the coolant when it enters and when it leaves the chiller units. The system normally supervises the manner in which the chillers are allowed to individually increase or decrease chilling capacity. The system furthermore overrides this supervisory control of the individual chiller units when the coolant entering the chiller units drops below a threshold value. The chilling capacity of all running chiller units is decreased when this latter condition occurs.

Abstract: System and process are disclosed for the monitoring of certain parameters for the purpose of exercising supervisory control over a number of discrete chiller units each having their individual dedicated controls. The supervisory control is accomplished by imposing limits on the amount of compression that can be demanded by the individual dedicated control units. These limits are selectively changed when certain parameters pertaining to the collective chilling capacity of all of the active chiller units exceed or fall below acceptable levels.