Use Of Antifreeze Solutions - Hitecsa EQS 2335 Manual Del Usuario

I.4.2

Use of antifreeze solutions

The use of ethylene glycol is recommended if
you do not wish to drain the water from the
hydraulic system during the winter stoppage,
or if the unit has to supply chilled water at
temperatures lower than 5°C The addition of
glycol changes the physical properties of the
water and consequently the performance of
the unit. The proper percentage of glycol to
be added to the system can be obtained from
the most demanding functioning conditions
from those shown below.
Table "H"
Design air temperature in °C
% glycol in weight
Freezing temperature °C
fc G
fc Δpw
fc QF
fc P
Correction factor of the glycol water flow to the evaporator
fc G
Correction factor of the pressure drops in the evaporator
fc Δpw
Cooling capacity correction factor
fc QF
Correction factor for the total absorbed electrical current
fc P
Table "H" shows the multipliers which allow
the changes in performance of the units to be
determined in proportion to the required
percentage of ethylene glycol.
The multipliers refer to the following
conditions: condenser inlet air temperature
35°C; chilled water temperature 7°C;
temperature differential at evaporator 5°C.
For different functioning conditions, the same
coefficients can be used as their variations
are negligible.
2 0
10 15
-5 -7 -10
1.025 1.039 1.054
1.085 1.128 1.191
0.975 0.967 0.963
0.993 0.991 0.990
49
Evaporator antifreeze heater (RA accessory),
the DS desuperheater RC100 recovery unit
antifreeze heater (RDR accessory), the P1-
P2 electric pump antifreeze heater (RAE1
accessory), the antifreeze heater for DP1-
DP2 double electric pumps (RAE2
accessory) avoid the unwanted effects of
frost during stops with winter operation
(provided that the unit is kept running).
Attention:
Besides the 20% glycol, check the pump
absorption limits (in versions P1/P2,
DP1/DP2).
-3 -6 -10
20 25 30
-13 -16
1.072 1.093
1.255 1.319
0.956 0.948
0.988 0.986
EQS
-15 -20
35 40
-20 -25
1.116 1.140
1.383 1.468
0.944 0.937
0.983 0.981