CALMAC® Energy Storage Tanks - Model A

CALMAC® Energy Storage Tanks - Model A

CALMAC® Energy Storage Tanks - Model A

Key Features:

  • Two-inch flanged connections
  • Fork lift base
  • Non-corroding materials of construction which is 99% reusable or recyclable
  • Indoor or outdoor locations
  • Translucent heat exchanger tubes for easy visual inspections
  • Seamless one-piece tank provides structure and containment with no containment liners or moving parts to maintain
  • Factory-assembled quality with cataloged charge and discharge performance curves
  • Modular design —so you can add more tanks over time and relocate them easily
  • Available in different sizes to accommodate differing space constraints
  • Counter-flow heat exchanger allows some of the warmest ice making temperatures in the industry for efficient charging and discharging
  • Can freeze solid without sustaining damage
  • Average lifetime —35+ years
  • Backed by a 10-year limited warranty

How Energy Storage Tanks Work

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

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.

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.

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.

Glycol recommendations

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.


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.


Looking for BIM?

Select your Model C tank below and download CAD file for your project. 


Learn more about the benefits of thermal energy storage

Check out the links below to learn more about the benefits that thermal storage energy can provide for you.

Case Studies

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