Cooling Water Control; Temperature Control; Water Quality Control For Cooling Water - Hyundai HDFN-80-1400 Operation Instructions Manual

9.4 Cooling Water Control

9.4.1 Temperature control

Cooling water condition effects on the operation cycle of the chiller-heater greatly. Generally, too
low or too high temperature of cooling water may cause the following troubles :
Too low temperature of cooling water ------- Solution crystallization
Too high temperature of cooling water ---- High pressure trip and capacity drop
In general, absorption chiller-heaters are designed to be operated at 32 ℃ of cooling water inlet
temperature. However, it is better for the absorption chiller-heater to be operated at lower cooling
water temperature in the range of no trouble. Because the lower the temperature, the more the
fuel consumption rate is improved. (Note that the allowable lowest cooling water inlet temperature
is about 22 ℃).
On the contrary, as the cooling water temperature goes down, the solution concentration becomes
weak. Therefore, the range of capacity control becomes narrow to some extent because of
charged quantity of refrigerant.
9.4.2

Water quality control for cooling water

Since the contamination of cooling water may cause to lower the heat exchange efficiency due to
deposit of scales on the heat exchangers and may also cause a serious accident such as
submersion of the chiller-heater by the corrosion damage of heat transfer tubes, perform water
quality control as per the following procedure.
(1) Make-up water quality
The cooling water is required to satisfy the standard shown in the table below. If the cooling
water fails to satisfy the standard, it is required to be treated properly or passed without
recirculation.
(2) Standard of cooling water quality
Table 9.3 Cooling Water Quality Standard Recommended by Japan Refrigeration and Air-
conditioning Industry (JRA-GL-02-1994)
PH(PH(at 25℃)
Conductivity
Chlorine ion
Standard
Sulfuric ion
Item
M Alkalinity (PH4.8)(mgCaCO
Total hardness
Calcium hardness (mgCaCO
Ionized silica
Total iron
Copper
Sulfur ion
Reference
Ammonium ion
Item
Residuary chlorine
Isolated carbonic acid (mgCO
Index of stability
(3) Blow-down of cooling water
Cooling Water System
Circulation
Circulation
Water
6.5~8.2
≤80
(ms/m) (25℃)
{≤800}
(S/cm) (25℃)
-
/ℓ) ≤200
(mgCl
-
2
/ℓ) ≤200
(mgSO
4
/ℓ) ≤100
3
/ℓ) ≤200
(mgCaCO
3
/ℓ) ≤150
3
/ℓ) ≤50
(mgSiO
2
(mgFe/ℓ) ≤1.0
(mgCu/ℓ) ≤0.3
-
2
/ℓ)
(mgS Not detected
/ℓ) ≤1.0
(mgNH
4
(mgCl/ℓ) ≤0.3
2
/ℓ) ≤4.0
6.0~7.0
50
Pass Way
Make-up Pass Way
Water Water
6.0~8.0 6.8~8.0
≤30 ≤40
{≤300} {≤400}
≤50 ≤50
≤50 ≤50
≤50 ≤50
≤70 ≤70
≤50 ≤50
≤30 ≤30
≤0.3 ≤1.0
≤0.1 ≤1.0
≤0.1 ≤1.0
≤0.3 ≤0.3
≤4.0 ≤4.0
- -
Tendency
Corro-
Scale
sion
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