Anti-Freeze; Cooling Tower/Boiler Systems; Ground Coupled, Closed Loop And Plateframe Heat Exchanger Well Systems - Carrier Aquazone 50RHE 006 Installation, Operation And Maintenance Instructions

6.7 - Anti-freeze

In areas where entering loop temperatures drop below 4.4°C or
where piping will be routed through areas subject to freezing,
anti-freeze is needed.
Alcohols and glycols are commonly used as anti-freeze agents.
Freeze protection should be maintained to 8.3 K below the lowest
expected entering loop temperature. For example, if the lowest
expected entering loop temperature is -1.1°C, the leaving loop
temperature would be -5.6 to -3.9°C. Therefore, the freeze
protection should be at -9.4°C (-1.1°C -8.3°C = -9.4°C).
IMPORTANT: All alcohols should be pre-mixed and pumped
from a reservoir outside of the building or introduced under
water level to prevent fuming.
Calculate the total volume of fluid in the piping system (see
Table 11). Use the percentage by volume in Table 12 to determine
the amount of anti-freeze to use. Anti-freeze concentration should
be checked from a well mixed sample using a hydrometer to
measure specific gravity.
6.7.1 - Freeze protection selection
The -1.1°C FP1 factory setting (water) should be used to avoid
freeze damage to the unit.
Once anti-freeze is selected, the JW3 jumper (FP1) should be
clipped on the control to select the low temperature (anti-freeze
13 F) set point to avoid nuisance faults.
Table 11 - Approximate fluid volume (l) per 30 m of
Pipe Diameter, in
Copper 1
1.25
1.5
Rubber hose 1
Polyethylene 3/4 IPS SDR11
1 IPS SDR11
1-1/4 IPS SDR11
1/2 IPS SDR11
2 IPS SDR11
1-1/4 IPS SCH40
1-1/2 IPS SCH40
2 IPS SCH40
Legend
IPS - Internal pipe size
SCH - Schedule
SDR - Standard dimensional ratio
Note: Volume of heat exchanger is approximately 3.78 litres.
Table 12 - Anti-freeze percentages by volume
Anti-freeze Minimum temperature for freeze protection,
-12
Methanol (%) 25
100% USP food grade
Propylene glycol (%) 38
pipe
Volume, l
15.5
24.2
34.8
14.7
10.6
17.0
30.0
41.2
68.1
31.4
41.2
64.3
-9 -7 -4
21 16 10
30 22 15

6.8 - Cooling tower/boiler systems

These systems typically use a common loop temperature
maintained at 15.6 to 32.2°C. Carrier recommends using a
closed circuit evaporative cooling tower with a secondary heat
exchanger between the tower and the water loop. If an open
type cooling tower is used continuously, chemical treatment
and filtering will be necessary. The optional cupronickel heat
exchanger must also be used in this case.
6.9 - Ground coupled, closed loop and plateframe
heat exchanger well systems
These systems allow water temperatures from -1.1 to 43.3°C.
The external loop field is divided up into 51 mm polyethylene
supply and return lines. Each line has valves connected in such
a way that upon system start-up, each line can be isolated for
flushing using only the system pumps. Locate air separation in
the piping system prior to the fluid re-entering the loop field.
°
C
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