Model Selection; Selection Example - Hitachi RCUE40AG1 Installation, Operation And Maintenance Instructions

MODEL SELECTION

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15. MODEL SELECTION

15.1. SELECTION EXAMPLE

1. Determine the system requirements
Condenser Air Inlet Temperature:
Chilled Water Outlet Temperature:
Chilled Water Inlet Temperature:
Cooling Load:
Refrigerant:
3. Select Model and Read the Performance
From the cooling capacity table, model RCUE100AG1 can
be selected with the following performance.
Cooling Capacity:
Chilled Water Flow Rate:
Water Cooler Pressure Drop:
Compressor Input Power:
3. Correct the Data
Flow Rate
-
When the water Inlet/Outlet temperature difference is not
5°C, correct the flow rate by the following formula:
5(°C) × Tabulated Flow Rate (CFR)
Corrected
=
Flow Rate
Given Temp. Difference(°C)
The corrected Flow Rate must be confirmed to be within
the working range.
Cooling Capacity and Compressor Input.
-
When the fouling factor is taken into consideration, the
cooling capacity and the compressor input will be
different from the value indicated in the cooling capacity
table.
Corrected Capacity = Kfc × CAP
Corrected Input = Kfi × IPT
CAP: Tabulated Cooling Capacity
IPT: Tabulated Compressor Input
Kfc: Capacity Correction Factor
Kfi: Compressor Input Correction Factor
Fouling Factor
2
m h°C/kcal
2
(m °C/kW)
0
0.00005(0.044)
0.0001(0.088)
30 °C
7 °C
12 °C
250 kW
R407C
260.8 kW
44.9 m³/h
39.4 kPa
71.6 kW
Kfc Kfi
1.00 1.00
1.00 1.00
0.99 1.01
4. Water Pressure Drop
Water pressure drop is given by the following formula
-
PD = α x Q
PD: Pressure Drop (kPa)
Q:
Water Flow (m
α,β β Parameters (table below)
Model:
RCUE-AG1
40 0.1730
50 0.1220
60,70 0.0878
80 0.0459
100 0.0308
120,140 0.0280
150 0.0150
180, 200 0.0127
240, 270 0.0079
300, 330 0.0054
360,400 0.0038
β
³ /h)
α α α α β β β β
1.846
1.840
1.840
1.875
1.881
1.826
1.867
1.831
1.826
1.828
1.826