Product specifications

17
APPLICATION DATA
Cooler Design Data
1. Maximum - Leaving chilled fluid temperature
(LCFT) is 60°F (18°C). The unit can start and pull
down with up to 80°F (27°C) entering-water
temperature. For sustained operation, it is
recommended that the entering water temperature
not exceed 70°F (21°C).
2. Minimum - LCFT is 42°F (5.5°C) for all models
except ACDSB 025D, 030D, 035D and 040D for
water applications with standard coolers . Oversized
coolers
CH2 for 42°F (5.5°C) water on models ACDSB
025D, 030D, 035D and 040D and CH3 for 40°F (4.4°C)
water for most models are available from the
factory for chilled w ater applications. Medium
temperature glycol application selections from 20°F
(6.6°C) to 39°F (3.9°C) are available from the factory.
3. Minimum/Maximum Flow Rates and Vessel Fluid
Volume - refer to Physical Specifications, pages 28-
31.
4. Pressure Drop Data - refer to Figure 13 and glycol
correction factors, Tables 4a and 4b.
5. Wide Range !T - Low Flow Applications
a. Multiple smaller chillers may be applied in
series, each providing a portion of the design
temperature range of roughly 10°F (5.5°C)
each.
b. Special cooler baffling may be provided from
the factory for applications from 12.5°F to 20°F
(7°C to 11°C) chiller fluid ranges.
c. Chilled fluid may be recirculated through the
cooler as shown below to allow the chiller to
operate with acceptable flow rates and
temperature ranges (Figure 10a).
Figure 10a
The mixed fluid temperature range
through the cooler for units with standard
coolers, should not be less than 7.5°F
(4.2°C).
6. Narrow Range !T - High Flow Applications
a. Special cooler baffling is available from the
factory for 5°F to 7.5°F (2.7°C to 4.2°C) !T
applications.
b. For Extra-Narrow Range !T applications a
partial cooler bypass piping and valve
configuration can be used as shown below.
This permits a higher !T and lower !P
(pressure drop) through the cooler (Figure
10b).
Figure 10b
The fluid mixes after the cooler.
SUPPLY
FLUID
COOLER BYPASS
PORTION OF FLOW
C
H
I
L
L
E
R
C
O
O
L
E
R
THERMOSTAT SENSOR
T
RETURN
FLUID
Chilled Fluid Loop Volume (CFLV)
Careful consideration needs to be given to the “Chilled
Fluid Loop Volume” (CFLV) or System / Inertia to
maintain an acceptable leaving fluid temperature.
In close-coupled systems as the compressor starts and
stops, the leaving fluid temperature will shift up and
down 2°F to 4°F (1.1°C to 2.2°C) per step of capacity
control. The 5-minute anti-recycle timer will prevent
the compressor from starting for up to 5 minutes and
will further complicate the leaving fluid temperature
shift.
Air Conditioning Applications
The chilled fluid loop volume must equal or exceed 3
gallons per nominal ton of cooling (3.25 L per kW).
Process & Special Air Conditioning Applications
Where leaving fluid temperature is often more critical,
the chilled fluid loop volume should be increased to 6
to 10 gallons per ton minimum (6.5 to 10.8 L per kW).
RETURN
FLUID
SUPPLY
FLUID
RECIRCULATED
PORTION OF FLOW
C
H
I
L
L
E
R
C
O
O
L
E
R
THERMOSTAT SENSOR
T