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Use a refractometer or equivalent to test the solution's
glycol concentration after the system has been filled and
circulated for 24 hours. If the solution's glycol
concentration is less than 25% or above 12°F (-11.1°C),
draw off a sufficient amount of mixture and add pure
glycol to achieve a 25% concentration.
iii. Finish Adding More Water to Tank. At this
time, after heat transfer fluid has been added to the heat
exchanger, finish filling the tank with water to a height just
covering the top heat exchanger (HX) tube, except for
Model 1220, which is filled to the bottom of the top HX
tube. For water level instructions in MIXAIR tanks, see
Installation Manual for MIXAIR Ice Bank® tanks #IB- 158.)
iv. Add Water Treatment. Pour in the initial
treatment of biocide into the tank water upon
filling, into the inspection port. This will help to control
biological growth. CALMAC® recommends a 20% Tetrakis
hydroxymethyl phosphonium sulfate solution such as
Aquacar PS20. All tank models require 16 oz. of biocide
solution per tank.
The CAS number is 555-66-30-8
Note: The cover must always be in place whenever the
tank is in operation in order to prevent floating of
the heat exchanger. You are now ready to freeze the
tank(s)!
e. Insulation. All piping must be insulated to prevent
condensate dripping as well as exposure to sunlight (to
prevent ultra-violet degradation). Since these liquid lines
run cooler than most chilled water systems the thickness
of the insulation may need to be slightly greater than
normal to avoid condensation.
5. RECOMMENDED OPERATING TEMPERATURES
The storage system will operate most efficiently if the
chiller controls are set to terminate charging at the highest
return temperature that will charge the tanks in the
available hours. In most cases, with a 6ºF (-14.4°C)
temperature difference across the chiller, the average
leaving chilled coolant temperature will be approximately
25ºF (-3.9°C) with a 31ºF (-0.6°C) return. Most commonly,
if the chiller unit is set to turn off when the coolant
temperature leaving the tank reaches 28ºF (-2.2°C)
(See project engineers specification for exact
temperature.) the tanks will be completely charged.
If the chiller is allowed to run at lower conditions than
required the free water above the heat exchanger may
freeze causing an "ice cap". This ice cap will in turn cause
a shortage of water during discharge, thereby impairing
the discharge performance and wasting energy.
6. REPAIRS AND MAINTENANCE
Note: The cover must always be in place whenever the
tank contains ice in order to prevent floating of the
heat exchanger.
a. Routine Maintenance.
i. Annually. The water/ice level in the tanks
should be checked at least once a year. (Check Ice Bank®
IB-SVX186B-EN
Ice Storage Operation and Maintenance Manual #IB-
SVX147*-EN for complete details). When the tanks are
100% frozen, usually first thing in the morning, there
should be approximately 4 to 7 inches (10 to 15 cm) of
water above the submerged insulation depending on the
tank model. The water level should be within ½ inch (1.27
cm) of the bottom of the tank covers. Add water if this is not
the case. (If the tanks are not fully frozen, adding water
may cause the tanks to overflow when fully charged, which
will not hurt the tanks however, it may cause flooding of
the area).
At the end of the cooling season, you should fully charge
the tanks and leave them frozen until the start of your next
air-conditioning season.
If the tank is equipped with an inventory meter sensor,
altering the water level may require re-calibration of the
meter. Refer to "Ice Inventory Meter Installation and
Operation Manual", #IB-153.
The coolant should be checked annually for proper
corrosion and freeze protection. This service should be
available from the glycol manufacturer.
ii. Tank Water Treatment. Generally, if tanks are
kept at least partially frozen year round, provide
retreatment with biocide as needed. However, if tanks are
not kept frozen year round, retreatment may be required
more often and the tanks should be checked for slime or
odor seasonally.
b. Warranty Repairs. Authorization for in-warranty
field repairs must be obtained in writing from CALMAC®
before any repairs are attempted.
Note: To find out more about Ice Bank
visit calmac.com or trane.com/energystorage
Introduction
®
energy storage
9
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