Ice Bank Tank

CAPACITY : 300 LPH TO 3000 LPH

An “Ice Bank Tank” is a thermal energy storage system that uses the phase change of water to store and later provide cooling energy. In essence, these tanks freeze water (often with glycol additives) during off‐peak hours—when electricity is less expensive—and then release the stored “cold” during peak hours to cool a facility or process. This basic concept takes advantage of water’s latent heat of fusion, which is very high (about 333 kJ/kg), enabling a high energy storage density compared to systems that only store sensible heat.

1. Operational Principles

Off-Peak Charging Cycle

Freezing Process:

During periods of low electricity demand (typically at night), a chiller circulates a cooled water–glycol mixture through a network of heat exchanger tubes located inside the tank. The fluid—often at temperatures around 25°F (–4°C)—freezes the water around the tubes. Because freezing involves extracting a significant amount of energy (the latent heat of fusion), the ice builds up uniformly if the design ensures proper circulation and heat extraction.
(For example, CALMAC’s design employs closely spaced counter-flow heat exchanger tubes to create a uniform ice deposit that minimizes stresses on the tank structure.)

On-Peak Discharge Cycle

Melting Process and Cooling:

When the cooling demand is high during daytime, the stored ice is used to cool a working fluid. As the warmer coolant enters the tank, the ice melts, absorbing heat in the process. This chilled water is then distributed through the building’s HVAC system to provide cooling. The process allows the chiller to run at a lower capacity or for shorter periods during peak hours, thereby reducing energy costs.
(Many installations use a bypass loop with a temperature-modulating valve to ensure that a mix of chilled and bypassed fluid results in a target temperature for the cooling coils.)

Key Benefits

Peak Load Reduction and Energy Savings:

By shifting the cooling load to off-peak hours, the system reduces peak electrical demand. This not only cuts energy costs (since off-peak power is often much cheaper) but also allows for the use of smaller, more efficient chillers.

Enhanced Reliability and Efficiency:

The use of ice as a storage medium leverages its high latent heat capacity. With proper design, the system provides a stable and consistent cooling capacity during peak demand, even when chiller operation is reduced.

Modular and Scalable Design:

Systems like the CALMAC Model C tanks allow for a modular approach, making them suitable for both retrofits and new construction. Smaller systems (like Model A tanks) remain popular in smaller installations.

Environmental Benefits:

Fewer compressors operating during peak hours lower greenhouse gas emissions and reduce overall energy consumption.

Applications

Commercial HVAC:

Used in office buildings, hotels, and hospitals where load-shifting can result in significant utility savings.

Industrial Cooling:

Applied in food processing, dairy cooling, and other industrial sectors requiring rapid and reliable cooling.

Integration with Renewable Energy:

Ice banks can be combined with photovoltaic systems or other renewable sources to store surplus energy, further enhancing sustainability.