Schreiber Chillers Modular Chillers - Manual (Page 9)

9
System Overview
This system is designed as a modular system where dual circuit chiller module can be utilized
as a part of a larger chilled water system, or on it’s own as standalone cooling solution. In
addition, the system is designed such that additional chiller or pump modules can be added
directly.
The system is a combination of chillers and pumping station to provide chilled water to the
process and chiller modules. The thermal mass of the reservoir helps to maintain stable
water temperatures and to prevent short cycling of the system. It also provides a convenient
place to fill the system with water and other water treatment chemicals. It is designed with
the same shape of the chiller modules to provide and integrated chiller system. When a
pump module is used, it serves as the master controller for all of the modules.
The integral pump draws water from the reservoir and pumps it through the chiller modules.
Depending on flow requirements, this pump can also be used to pump the chilled water
through the whole system.
CONTROL SYSTEM OVERVIEW
The control enclosure contains a fused disconnect, controller, and all of the pump starters.
The controller is a microprocessor based controller with a 4 x 20 built in LCD display. It
communicates with other chiller modules to control the entire system.
The Schreiber modular chillers use a control system that allows the individual controllers for
each module to be linked into one system. A single module is designated as the MASTER
controller. In a system with a pump/reservoir module, this module is usually the master.
The master module reads the supply temperature of the chilled water to the process. The
desired chilled water is also set at the master module. The master module then turns on the
individual compressors of each chiller module to match the load. The master also handles the
rotation of each module so that the same module does not always cycle first.
Each individual chiller module handles alarms, time delays, compressor rotation within the
module, and head pressure control for only that module.
A pump module acts as the master temperature control for all of the modules and handles
the on/off control of the pumps and the entire system.
Each module contains a display so that each module can be programmed. Each system will
have it own remote terminal. The connection is via 6-conduction phone type cable.