ClimaCool FLEX SERIES 30, 50, 65 - Manual (Page 14)

12
ClimaCool Selection Procedures
The following information must be known in order to properly select
a ClimaCool ® modular chiller:
• System capacity
• Entering chilled water temperature
• Chilled water fl ow rate
• Leaving condenser temperature
If any three of the fi rst four parameters are supplied, the missing
parameter may be found by the following formula.
Sample Selection
GIVEN: Select a water cooled chiller to cool 691 GPM of water
entering at 54°F and leaving at 44°F when supplied with 832 GPM
of condenser water entering at 85°F and leaving at 95°F leaving.
Solution:
1. Chilled water range (CWTD) = 54°F to 44°F = 10°F
2. Condenser water range = 85°F to 95°F = 10°F
3. Capacity (tons) = (GPM x Chilled Water Range/24 =
691 x 10/24 = 288 tons.
4. Select the closest” project tons” value from the
ClimaCool ® Quik Select tables on page 16 and 17 which meets
or exceeds the load of 288 tons. In this case, the closest match
is a Project Tons of “290”, delivering an actual capacity of 293
tons. This selection comprises a total of (4) 65-ton modules
PLUS (1) 30-ton module. S
5. Evaporator water pressure drop and condenser water pressure
drop can be found on separate charts on page 13 of this manual.
If not provided, fl ow rates can be determined from the follow-
ing formulas:
Chilled Water GPM = (Tons) x24 ( )
Chilled Water delta T(°F)
Condenser = (Tons+ (0.285 ( ( x Compressor kW))x24 p ))
Water GPM Condenser Water delta T (°F)
Once the GPM is determined, it can be divided by the number of mod-
ules (weighted according to tonnage) to establish GPM per module.
NOTE : Quik Select Tables (page 16 and 17) are based on a maxi- t
mum allowable water fl ow rate of 1000 GPM through each of the 6”
main, water headers serving chiller and condenser sections. This re-
sults in a maximum of fi ve FLEX 65 modules at the customary 10°F
Chilled Water Range, and 10°F Condenser Water Range. Additional
banks of modules can be selected for larger tonnage requirements.
Also, the maximum number of modules which can be controlled by
a single ClimaCom controller is seven. Additional controllers can
be selected for projects requiring more than seven modules.
CHILLER PERFORMANCE WITH GLYCOLS
When analyzing performance data of chillers employing glycol
and water solutions, fi rst derive the chiller performance data
(CAPACITY, KW, GPM & PRESSURE DROP) assuming pure
water fl ow through the chiller. Then you can apply adjustment
factors to the performance data from the pure water case. These
factors are found in Fig. AM-1 through Fig. AM-4 on page 14,
and depend upon the type and percent of glycol used in the chiller
circuit. Fig. AM-1 and Fig. AM-2 provide factors for propylene
glycol. Fig. AM-3 and Fig. AM-4 are for ethylene glycol. The
factors in all Fig’s AM-1 through Fig. AM-4 are based on 10°F
drop in fl uid temperature through the chillers and 85°F entering
condenser water (ECDW), and at 10°F rise through the condenser
(CDTD). Fig. AM-5 is provided for solution freeze temps. of
glycol concentrations. Fig. AM-6 provides adjustment factors for
chiller temp. drops other than 10°F, all assuming a fouling factor
of 0.0001 in the chiller.
Propylene Glycol Selection Example
(Select a FLEX 65 Module)
Determine CAPACITY, KW, GPM and Pressure Drop for a single
FLEX 65 module, given the following Inputs:
CWTD = 10°F
LCWT = 42°F
ECDW = 85°F
CDTD = 10°F.
30% Propylene Glycol/ 70% Water in Chiller
1. Assume a 10°F rise in the condenser, thus 95°F leaving con-
denser water.
2. From the Performance Data Table on page 18:
CAPACITY: 63 TONS; KW: 46.6
3. First fi nd the chiller water fl ow and pressure drop for pure water
as in the previous example.
GPM = (24)(63)/10 = 151.2 GPM
From page 13, bottom graph - right most curve, read pressure
drop from mid. Curve as:
Pressure drop = 7.0 ft. of water
4. To convert performance data for pure water to data using 30%
Propylene Glycol, record the adjustment multipliers from Fig.
AM-1 & Fig. AM-2 on page 14:
CAPACITY factor: 0.97
KW factor: 0.988
GPM factor: 1.022
Pressure Drop factor: 1.20
5. Calculate chiller performance using 30% Propylene Glycol by
multiplying the chiller performance data for pure water by the
adjustment factors as follows:
CAPACITY: 63 x 0.97 = 61.1 TONS
KW: 46.6 x 0.988 = 46.04 KW
GPM: 151.2 x 1.022 = 154.5 GPM
Pressure Drop: 7.0 x 1.20 = 8.4 ft. of water
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