ClimaCool IOM AR2 SERIES - Manual (Page 45)

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SELECTION INPUT DATA
To select a ClimaCOOL Remote Air-Cooled Chiller system, the
following information is required:
1 . System Load in TONS .
2 . Chilled water temperature drop (CWTD) .
3 . Leaving chilled water temperature (LCWT) .
4 . Ambient Air Temp . Entering Condenser (TA)
5 . Condenser TD (or CTD) . Saturated condensing temp . minus
ambient air temp .
Using Performance Tables
When reading data from the performance tables on page 45, it is
necessary to first calculate the ‘Saturated Refrigerant Discharge
Temperature’ or TSD as follows:
TSD = TA + CTD
where TA = Ambient Air Temp . Entering Condenser and
CTD = Condenser TD (Temp . difference between ambient air
temp . & sat . condensing temp .)
Given the leaving chilled water temp . (LCWT), and the
calculated TSD, the CAPACITY in TONS are read from the
appropriate performance table . The performance tables are based
on a 10°F temp . drop in chilled water . For temp . drops other than
10°F, and/or for altitudes other than sea level, multiply the TONS
by the factor found in Chart AM-6 .
Chilled Water Selection Example
(Select AR2-30*H2 Modules)
Input Data:
1 . LOAD = 84 TONS .
2 . CWTD = 8°F .
3 . LCWT = 44°F .
4 . TA = 95°F .
5 . CTD = 30°F .
1 . Determine saturated discharge temperature
(TSD) TSD = TA + CTD
TSD = 95°F+30°F = 125°F
2 . Select the appropriate performance table based on the selected
module type (AR2-30*H2) . Record the CAPACITY and KW
of a single module at the leaving chilled water temperature
specified (LCWT) of 44°F, and at the TSD calculated above at
125°F . CAPACITY = 28 .3 TONS, KW = 30 .6
3 . To find the equivalent tons capacity at 8°F chiller drop by a
single module tabulated at 10°F drop values, divide the tons
capacity by the factor in Chart AM-6as:
CAPACITY REQUIRED = 84/0 .995= 84 .4 TONS
MODULES REQ’D = 84 .4/28 .3 = ~ 3 MODULES
POWER INPUT = (30 .6)(3) = 91 .8 KW
At 8°F temperature drop, applying Chart AM-6 performance
adjustment factor results in:
TONS = (84 .9)( .995) = 84 .5 vs sys . load of 84 TON
4 . CHILLED WATER FLOW RATE Chilled water flow rate is
determined as follows:
GPM=(24)(TONS)/(CHILLED WATER TEMP DROP)
or GPM = (24)(TONS)/(CWTD) GPM = (24)(83 .7)/8 =
251 .1
To find GPM per Module:
GPM/(# of Modules) = 251 .1/3 = 83 .7 .
5 . CHILLED WATER PRESSURE DROP Chilled water
pressure drops are provided in Figure 1 . Using the ‘GPM/
Module’ results from step 4 above, refer to Figure 1 on page
41, and read pressure drop from the middle curve for model #
AR2-30*H2 as:
Pressure Drop = 14 ft . of water
Chiller Performance With Glycols
When analyzing performance data of chillers employing glycol
and water solutions, first derive the chiller performance data
(CAPACITY, KW, GPM & PRESSURE DROP) assuming pure
water flow through the chiller . Then you can apply adjustment
factors to the performance data from the pure water case . These
factors are found in Figures AM-1 through Fig . AM-4 on page 42,
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 fluid temperature through the chillers, at sea level, and
at 95F entering condenser air temp . Fig . AM-5 is provided for
solution freeze temps . of glycol concentrations . Chart AM-6
provides adjustment factors for sea level changes and chiller
temp . drops other than 10F, all assuming a fouling factor of
0 .0001 in the chiller .
Propylene Glycol Selection Example
(Select AR2-30*H2 Module)
Determine CAPACITY, KW, GPM and Pressure Drop for an
AR2- 30*H2 module, given the following Inputs:
CWTD = 10°F
LCWT = 42°F
TA = 95°F CTD = 30°F .
30% Propylene Glycol/ 70% Water in Chiller
1 . Determine saturated discharge temperature
TSD = TA + CTD
TSD = 95°F+30°F = 125°F
ClimaCool Selection Procedure