Hitachi SAMURAI CLG2, Manual, Page: 110 / 118

Application Data
Technical Catalogue
TCGB0051 rev 0 - 09/2009
110
16.3. Ethylene Glycol Application
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Low ambient application
Under the condition where the ambient temperature is low in winter, there is a case where the unit and
piping will become damaged by freezing during the shutdown periods.
To prevent freezing, it is effective to operate the pump. This Chiller has the pump ON/OFF operation
control to avoid freezing. This control become available by connecting Pump Operation circuit. (See Wiring
Diagram).
Additionally, in a case where measures such as water raining are difficult, utilise antifreeze mixture of
ethylene glycol.
Below table shows the ethylene glycol percentage suggested for the different temperature values.
The table also shows the correction factors, since unit with antifreeze mixture have a slight different
performance compared with no glycol.
Example:
−
Cooling Capacity with ethylene glycol = Kc × Cooling Capacity without ethylene glycol
−
Input Power, Flow Rate and Pressure Drop is calculated in the same way as Cooling Capacity
(Water Outlet Temperature: 5 ~ 15°C)
Minimum Ambient Temperature °C -3 -7 -13 -22
Required Ethylene Glycol
Percentage
wt% 10 20 30 40
Cooling Capacity Correction
Factor
Kc 0.99 0.98 0.97 0.96
Input Power Correction Factor
Ki 1.00 0.99 0.99 0.98
Flow Rate Correction Factor
Kf 1.00 1.01 1.04 1.08
Pressure Drop Correction Factor
Kp 1.04 1.11 1.18 1.29
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Low water temperature application (option)
When utilizing water less than 5 °C, antifreezing mixture of ethylene glycol shall be input to the water
system.
Low water temperature Option is categorised 3 level depending on water outlet temperature.
Therefore, please specify the level when ordering .
Freeze Protection Thermostat has been set in the factory.
Table shows Required Ethylene Glycol percentage for each category.
1. Category
Category
Outlet Water
Temp. (°C)
Required
Ethylene
Glycol (wt%)
Ethylene
Glycol
Freezing Temp.
(°C)
Low 1 4 ~ 0 20 -7
Low 2 -1 ~ -5 30 -13
Low 3 -6 ~ -10 40 -22
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NOTE:
Freeze Protection Thermostat is the electronic control, but non-adjustable.
For the performance, each value can be given by using following table. (See example in the next page)