Manual

43
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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 rst 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
specied (LCWT) of 44°F, and at the TSD calculated above at
125°F CAPACITY = 283 TONS, KW = 306
3 To nd 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 ow 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 nd 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, rst derive the chiller performance data
(CAPACITY, KW, GPM & PRESSURE DROP) assuming pure
water ow 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 uid 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