17
Par
t 2 - Engineering Da
ta
5 Performance adjustment factors
5.1 Ethylene and Propylene Glycol factors
The antifreeze must be required according to anyone condition as following:
The ambient temperature is below 0 ⁰C;
Don’t start up the unit for a long time.
The power supply was cut off and needn’t change the water in system.
A glycol solution is required when the unit with condition as mentioned. The use of glycol will reduce the performance of the
unit depending on concentration.
Concentration of
ethylene glycol (%)
Modification coefficient
Freezing point (°C)
Cooling capacity
Power input
Water resistance
Water flow
0
1.000
1.000
1.000
1.000
0
10
0.984
0.998
1.118
1.019
-4
20
0.973
0.995
1.268
1.051
-9
30
0.965
0.992
1.482
1.092
-16
40
0.960
0.989
1.791
1.145
-23
50
0.950
0.983
2.100
1.200
-37
Concentration of
propylene glycol
(%)
Modification coefficient
Freezing point (°C)
Cooling capacity
Power input
Water resistance
Water flow
0
1.000
1.000
1.000
1.000
0
10
0.976
0.996
1.071
1.00
-3
20
0.961
0.992
1.189
1.016
-7
30
0.948
0.988
1.380
1.034
-13
40
0.938
0.984
1.728
1.078
-22
50
0.925
0.975
2.150
1.125
-35
5.2 Evaporator temperature drop factors
Performance tables are based on a 5⁰C temperature drop through the evaporator. Adjustment factors for applications with
temperature ranges from 3⁰C to 6⁰C in follow table. Temperature drops outside this range can affect the control system’s
capability to maintain acceptable control and are not recommended.
5.3 Altitude correction factors
Performance tables are based at sea level. Elevations other than sea level affect the performance of the unit. The decreased air
density will reduce condenser capacity and reduce the unit’s performance. Maximum allowable altitude is 1800meters.
5.4 Fouling factor
Fouling refers to the accumulation of unwanted material on solid surfaces, most often in an aquatic environment. The fouling
material can consist of either living organisms (biofouling) or a non-living substance (inorganic or organic). Fouling is usually
distinguished from other surface-growth phenomena in that it occurs on a surface of a component, system or plant performing
a defined and useful function, and that the fouling process impedes or interferes with this function.