2. Training Overview
Purpose of a chilled water system
Parts of a chilled water system
Plate frame for cooling
Plate frame for reheat
System pumps
Multi pump / chiller systems
Chilled water system sequence of operation
Condenser sequence of operation
3. Purpose of a chilled water system
The purpose of a chilled water system is to provide cold
water to air-handler equipment for the purpose of cooling
supply air to control space temperature.
Water is cooled to a predetermined set-point that is set
within the chiller itself.
4. Parts of the chilled water system
Evaporator
Area of the chiller that cools the water
Condenser
Area of the system that pulls heat off the machine
Cooling Tower
Cools water from the condenser by dissipating it into the air.
Tower Bypass Valve
Controls condenser water flow either over the cooling tower
or recirculates it through the machine.
6. Plate frame for cooling
A system that has a plate frame heat exchanger configured
for cooling will provide chilled water to air-handlers by
using cooler outside air temperatures to cool the water.
Condenser water flows over cooling tower to be cooled
by outside air.
Cold condenser water flows through plate frame heat
exchanger to cool the chilled water.
8. Plate frame for reheat
A plate frame heat exchanger that is configured for
reheat uses the heat generated by the chiller to provide
heat for the hot water system.
Heat that isn’t pulled off the machine by the plate frame
is pulled off by the cooling tower.
10. System pumps
Single pump systems only have one chilled water pump
that moves water through the chiller and air handlers.
Multi pump systems have primary chilled water pumps
and secondary chilled water pumps.
Primary chilled water pump flows water through the
evaporator side of the chiller.
Secondary pumps flow water through AHU’s
Condenser pumps flow water over the cooling tower to
remove heat from the machine.
12. Multi pump / chiller systems
Some systems have a total of four chilled water pumps and
four condenser water pumps as well as two chillers.
Lead Lag Systems
Allow for either pump combination to run with any chiller
Fixed pump systems
Allow only for a specific pump to run with a specific chiller.
13. Chilled Water System Sequence
of Operation
Chilled water system lockout set-point
Common set-point for economizer disable and chilled water
system lockout.
System enable
Chilled water and condenser water pumps start BEFORE the
chiller startup
System disable
Chilled water and condenser pumps run for a period of time
AFTER chiller is disabled.
14. Condenser Sequence of operation
When condenser water reaches a specific temperature the
system reacts to keep temperature from getting too hot. A
high condenser temperature can damage the machine.
Most chillers will trip on high head pressure.
Cooling tower bypass valve (where equipped) allows
condenser water to flow over the tower or recirculate
through the machine.
Cooling tower fans help push air through the tower to
cool condenser water.
The Plate Frame heat exchanger (where equipped) will
also pull heat from the condenser loop.