Ice storage technology is a key energy-saving solution for modern buildings. By making ice during off-peak night hours (using lower electricity rates) and melting it for cooling during peak daytime, it significantly reduces air-conditioning operating costs. A critical component in this system? The U-shaped stainless steel heat exchanger tubes inside the storage tank—their design directly impacts efficiency, stability, and lifespan. Let’s break down this essential technology.
How Ice Storage Units Work & the Tank’s Role
An ice storage system consists of a refrigeration unit, ice storage tank, heat exchanger, and control system. Its core processes:• Nighttime ice-making:
During low electricity demand, the refrigeration unit cools water or glycol in the tank below freezing, forming ice on the outer surface of heat exchanger tubes to store cold energy.
• Daytime ice-melting for cooling:
When demand peaks, hot return water is pumped into the tank. It exchanges heat with the ice, producing cold water for air conditioning.
The U-shaped stainless steel tubes play dual roles:
• In ice-making: They circulate refrigerants (like glycol) to transfer cold to the surrounding water.• In ice-melting: They act as channels for cold water circulation, absorbing energy from melting ice.
Advantages of U-Shaped Stainless Steel Tubes
Compared to straight or coiled tubes, U-shaped stainless steel designs offer key benefits:Efficient Heat Transfer & Uniform Ice Formation
• Larger contact area: The U-bend allows even tube distribution in limited space, boosting ice-making/melting efficiency.
• Reduced dead zones: Proper spacing avoids uneven ice buildup (common with straight tubes), ensuring uniform growth.
Freeze Expansion Resistance & Stress Relief
• Flexible structure: The U-bend absorbs stress from ice expansion via minor deformation, preventing cracks in low temperatures.
• Fewer welds: One-piece molding (one-piece construction) reduces leak risks from straight tube joints.
Corrosion Resistance & Longevity
• Stainless steel (304 or 316L) outperforms carbon steel in resisting chloride corrosion—ideal for long-term contact with water, glycol, and cold.• Smooth surfaces minimize scale buildup, cutting maintenance needs.
Key Specifications & Selection Tips
• Material: 316L stainless steel suits high-chloride water (e.g., coastal areas) for better pitting resistance.• Wall thickness: 0.8–1.5mm, based on pressure (atmospheric/pressurized systems) and freeze resistance.
• Design: DN15–DN25 diameters with spacing balancing efficiency and ice expansion room; U-bend radius ≥3x pipe diameter (to reduce flow resistance).
• Installation: Factory-assembled modular tube sets for on-site lifting; nylon/stainless steel brackets prevent vibration wear.
Real-World Case & Benefits
A commercial complex with an 800m³ tank (316L U-tubes, DN20, 1.2mm wall) achieved:
• 15% higher storage efficiency, 8-hour daytime cooling.
• Zero corrosion leaks over 10 years.
• Annual electricity savings of ~¥450,000, with a <4-year payback.
Future Trends
• Coatings: Anti-corrosion/nanoscale anti-scale coatings for longer life.• Smart monitoring: Sensors tracking ice thickness and tube status to optimize storage.
• Lightweight design: Thin-walled high-strength stainless steel (e.g., duplex steel) reduces tank load.