Ethylene And Propolyne Glycol Correction Factors; Figure 19 - Glycol Solution Strengths; Table 5 - Ethylene And Propolyne Glycol Correction Factors; Table 6 - Recommended Glycol Solution Strengths - Quantech QWC3050T-200T Installation Operation & Maintenance

FORM QWC3-NM1
ISSUE DATE:11/20/2020
ETHYLENE AND PROPOLYNE GLYCOL
CORRECTION FACTORS
Evaporator Pressure Drop
When using evaporator pressure drop to determine
flow, error may result due to actual pressure drops that
are below the published data. In all cases, the published
values are worst case values. Errors of 10 to 25% be-
low published values are not uncommon due to manu-
facturing differences. When attempting to operate with
flow near the high end of the pressure drop curve, al-
ways use a flowmeter to avoid excessive flow through
the evaporator, which will cause damage and prema-
ture failure.
Table 5 on page 45 lists glycol correction factors
that should be used in conjunction with pressure drops.
Pressure drop will increase at a given flow rate as the
glycol concentration is increased.
TABLE 5 - ETHYLENE AND PROPOLYNE GLYCOL
CORRECTION FACTORS
ETHYLENE GLYCOL
% COMPR
TONS
WEIGHT KW
10 0.993 1.002
20 0.980 1.004
30 0.964 1.007
40 0.945 1.009
50 0.922 1.013
PROPYLENE GLYCOL
% COMPR
TONS
WEIGHT KW
10 0.985 1.002
20 0.968 1.005
30 0.937 1.008
40 0.898 1.012
50 0.862 1.019
TABLE 6 - RECOMMENDED GLYCOL SOLUTION
STRENGTHS
PROPYLENE
ETHYLENE
GLYCOL
GLYCOL
CONCENTRATION
LCHLT °C
% W/W
6 5
4 12
2 18
0 23
-2 28
-4 32
-6 35
QUANTECH
PRESS FREEZE
GPM
DROP PT
1.029 1.095 26
1.040 1.191 18
1.055 1.302 7
1.071 1.435 -8
1.091 1.599 -29
PRESS FREEZE
GPM
DROP PT
1.003 1.078 26
1.000 1.157 19
0.992 1.266 9
0.982 1.414 -6
0.985 1.605 -28
CONCENTRATION
% W/W
5
13
20
25
30
34
38
Pressure drop across the evaporator should only be
used as a guide for setting up flow. When very accu-
rate flows need to be measured, use a flowmeter. When
gauges are used to measure pressure drop and calculate
flow, always use a single gauge to measure the pressure
drop at both inlet and outlet of the evaporator to avoid
introducing more error into the measurement resulting
from the use of two gauges.
The cooler and condenser design allows
for an increase in pressure drop of up to
15% above the design value given. Debris
in the water may also cause additional
pressure drop.
When using glycol solutions, pressure
drops are higher than with water. Spe-
cial care must be taken not to exceed the
maximum allowed.
ETHYLENE GLYCOL
A
PROPYLENE GLYCOL
A
A = Correction Factor
C = Concentration % Through Cooler

FIGURE 19 - GLYCOL SOLUTION STRENGTHS

SECTION 5 – TECHNICAL DATA
C
B
C
B
LD06934
B = Temperature
45
5