Thermal energy storage is like an "HVAC battery" for a building’s air-conditioning system. Trane Thermal Energy Storage uses standard cooling equipment, plus an energy storage tank to shift all or a portion of a building’s cooling needs to off-peak hours. Model A tanks store energy in the form of ice during off-peak periods when utilities generate electricity more efficiently with lower energy and demand charges. The stored ice is then used to cool the building occupants the next day, during the peak periods when utility rates are at their highest.
CALMAC® Ice Bank® Model A Tanks
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The "Gold Standard" in Thermal Energy Storage
The classic CALMAC Energy Storage Model A tank became the industry's
informal benchmark soon after its 1979 introduction – and remains so
today. The Model A was among the first thermal storage tank to be
incorporated into a full chiller plant, which quickly made it the
industry "gold standard." This proven solution has stood the
test of time and remains a popular approach for engineers and
buildings owners.
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Ideal for smaller installations
The model A tank features two-inch flanges. Unlike the CALMAC Model C
tanks, each A model tank needs to be connected individually to
distribution piping, so this solution works best for smaller installations.
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Control strategies
There are any number of control strategies that can be utilized to
take advantage of the benefits of thermal energy storage. However,
there are two basic approaches that define the common limits of system
design. Electric rates and building usage will determine which control
strategies are best for the project.
Full Storage A chiller sized large enough to
charge enough energy storage can shift the entire load to
off-peak periods.
Partial Storage The chiller
works in conjunction with the CALMAC energy storage tanks during
on-peak periods to manage the building’s cooling load. During
off-peak hours, the chiller charges the tanks for use during the
next day’s on peak cooling period.
A secondary fluid is needed that can operate and flow at temperatures
low enough to freeze water. An ethylene-based or propylene-based
glycol solutions is recommended. A premixed solution of an industrial
heat transfer solution that is specially formulated for low viscosity
and superior heat-transfer properties should be used. Industrial based
HTF’s contain a multi-component corrosion-inhibitor system that can be
maintained and provide a long useful life.
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Maintenance
You can maintain your CALMAC tanks and the energy storage system by
using a maintenance process similar to that used for conventional
cooling.
Perform chiller maintenance as required.
Ensure the controls are operating properly and in sync with the
utility rates.
Check the health of the glycol fluid
annually.
Check the water level in the tanks. Add
biocide as needed to eliminate algae growth.