Hitachi SAMURAI CLG2, Manual, Page: 100 / 118

Model Selection
Technical Catalogue
TCGB0051 rev 0 - 09/2009
100
15.1. Selection Example
1. Determine the system requirements
Condensing Temperature: 40 °C
Chilled Water Inlet Temperature: 12 °C
Chilled Water Outlet Temperature: 7 °C
Cooling Load: 300 kW
Refrigerant: R407C
2. Select Model and Read the Performance.
From the cooling capacity table, model RCUE100CLG2 can be selected with the following performance.
Cooling Capacity: 302.1 kW
Heat Rejection 377.7 kW
Chilled Water Flow Rate: 52.0 m³/h
Water Cooler Pressure Drop: 54.7 kPa
Compressor Input Power: 75.5 kW
3. Determine a Matching Remote Condenser.
From the above heat rejection requirements, select a matching remote condenser according to the
manufacturer’s data.
4. Check the Balancing Condensing Temperature.
Determine the final balancing point at the designed conditions, and confirm that the condensing temperature
balanced at the maximum temperature conditions does not exceed the permissible condensing temperature
range specified in “working range”.

NOTE:
The condensing temperature can generally be predetermined by adding approximately 16°C to the designed outdoor
temperature for air-cooled remote condensers, and approximately 5°C to the condenser water outlet temperature for
water-cooled condensers.
5. Correct the Data
−
Flow Rate
When the water Inlet/Outlet temperature difference is not 5°C, correct the flow rate by the following formula:
Corrected
Flow Rate
=
5(°C)
×
Tabulated Flow Rate (CFR)
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
6. Water Pressure Drop
−
Water pressure drop is given by the following formula
PD = α x Q
β
PD: Pressure Drop (kPa)
Q:
Water Flow (m
³
/h)
α , β Parameters (table below)
Fouling Factor
m
2
h °C/kcal
(m
2
°C/kW)
Kfc Kfi
Water
Cooler
0 1.00 1.00
0.00005 (0.043) 1.00 1.00
0.0001(0.086) 0.99 1.01
Model:
RCUE-CLG2
α β
Cooler
40 0.0764 1.9123
50 0.0648 1.9123
60 0.0437 1.9123
80 0.0188 1.8971
100 0.0188 1.8971
120 0.0188 1.8971