period four
Chiller-Plant Control
notes
Operator Interface
Figure 109
There is an amazing amount of information available within a chilled-water system. Often the problem is not a lack of information, but how to interpret that information. Therefore, a clear and concise interface between the control system and the system operator is extremely important.
Information that should be communicated to the operator includes:
nChiller-water system temperatures
nChiller status (on or off)
nInformation specified by ASHRAE Guideline 3
nAny pending control actions (chiller about to turn on or off)
nStatus of system time delays
nStatus of ancillary equipment (pumps, cooling towers, and so forth)
In addition, the chiller-plant control system should notify the operator of problems that are occurring, or are about to occur, in the system. These warning or diagnostic messages may point to a single piece of equipment malfunctioning, or be indicative of system changes that may cause problems. Diagnostics that occur at the chiller control panel should be communicated to the chiller-plant control system.
