Hitecsa EQPL-B 4360 Manual Del Operador página 71

II.8.5.2 Indications for unit when running
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
latter case, not considered here, depends on the size of the unit
system).
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 water
temperature 35°C; chilled water outlet temperature 7°C; temperature
differential at evaporator and condenser 5°C.
For different functioning conditions, the same coefficients can be used
as their variations are negligible.
IMPORTANT!
Mixing the water with glycol modifies the
performance of the unit
Table "H"
Design air temp.
2 0
in °C
% glycol in
10 15
weight
Freezing temp.
-5
-7
°C
fc G 1,025 1,039 1,054 1,072 1,093 1,116 1,140
fc Opw 1,085 1,128 1,191 1,255 1,319 1,383 1,468
fc QF 0,975 0,967 0,963 0,956 0,948 0,944 0,937
fc P 0,993 0,991 0,990 0,988 0,986 0,983 0,981
fc G = Correction factor of the glycol water flow to the evaporator
fc Opw = Correction factor of the pressure drops in the evaporator
fc QF = Cooling capacity correction factor
fc P = Correction factor for the total absorbed electrical current.
Use of anti-freeze solutions with the BT accessory
The table provides the percentage of ethylene/propylene glycol to be
used in units with the BT accessory, according to the temperature of the
chilled water produced. Use the UpToDate Software for unit
performance.
Outlet temperature
Minimum % glycol
glycoled water
evaporator
From -7,1°C a -8°C
From -6,1°C to -7°C
From -5,1°C to -6°C
From -4,1°C to -5°C
From -3,1°C to -4°C
From -2,1°C to -3°C
From -1,1°C to -2°C
From -0,1°C to -1°C
From 0,9°C a 0°C
From 1,9°C to 1°C
From 2,9°C a 2°C
From 3,9°C to 3°C
From 4,9°C to 4°C
-3 -6 -10 -15
20 25 30 35
-10 -13 -16 -20
Minimum % glycol
in weight in weight
33 34
32 33
30 32
28 30
26 28
24 26
22 24
20 22
20 20
18 18
15 15
12 12
10 10
-20
40
-25
72
SECTION II :: INSTALLATION AND MAINTENANCE