Blue Box SIGMA 2002 - Operation with Low Temperature Chilled Water at Evaporator

Blue Box - 41
TABLE 4 - FREEZING POINT FOR WATER-ANTIFREEZE MIXTURES
If ambient temperatures lower than the freezing point of water can be
expected, antifreeze mixtures in the percentages indicated in table 4
must be utilised.
LIQUID OUTLET TEMPERATURE
OR MINIMUM AMBIENT TEMPERATURE (°C)
FREEZING POINT (°C) -5° -10° -15° -20° -25° -30° -35° -40° -45°
ANTIFREEZE
ETHYLENE GLYCOL 6 22 30 36 41 46 50 53 56
PROPYLENE GLYCOL 15 25 33 39 44 48 51 54 57
METHANOL 8 14 20 26 30 34 38 41 45
CALCIUM CHLORIDE 9 14 18 21 24 26 27 28 30
TEMPER -20
TEMPER -40 ---
TEMPER -60
TIFOXITE 50 60 63 69 73 ---
FREEZIUM 10 20 25 30 34 37 40 43 45
PEKASOL 50 59 68 75 81 86 90 ---
-40°
% BY WEIGHT
40
50
T -20°C
T -40°C
T -60°C
---
-20° -25° -30° -35°+0° -5° -10° -15°
If the glycol percentage is higher than 30%, units with special pump
seals must be used.
4.12 LOW TEMPERATURE WATER AT CONDENSER
The units are not designed to operate with a condenser cooling water temperature below 20 °C. Below this limit,
the unit could require substantial changes. Contact Blue Box for further information.
If chilled water at the evaporator outlet is required below 5 °C, it is necessary to operate with a mixture of water
and ethylene glycol. In this case, control and antifreeze set points must be changed. If low temperature is
specified the set-points will be factory set.
The ethylene glycol percentage must be selected in relation to the required chilled water temperature (see Table
4).
Standard units are not designed to operate with a water temperature
below 5°C at the evaporator outlet. To operate below this limit, the unit
will need to be modified. Contact Blue Box for further information.
4.13 OPERATION WITH LOW TEMPERATURE CHILLED WATER AT EVAPORATOR