Stainless Steel Coil Tube for Ice Storage Tank Prefabrication
Product Overview
The Stainless Steel Coil Tube (Coiltube) manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered continuous-length tubing product specifically designed for ice storage tank (Ice Storage Tank Prefabrication) applications in commercial and industrial building energy management systems. This product series represents an advanced solution in the field of Thermal Energy Storage (TES), enabling peak-shaving and load-shifting strategies that optimize electrical grid demand and reduce operational energy costs.
The coil tube is formed into continuous helical or serpentine configurations, providing maximum heat exchange surface area within a compact footprint. This design is critical for efficient ice formation and melting cycles within the storage tank, ensuring rapid thermal energy transfer between the refrigerant (typically brine or ethylene glycol solution) and the surrounding ice slurry or encapsulated ice modules.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its exceptional corrosion resistance, mechanical integrity, and thermal conductivity properties essential for cryogenic and low-temperature applications.
- Primary Alloy Grades: AISI 304 (UNS S30400), AISI 316 (UNS S31600), and AISI 321 (UNS S32100)
- Corrosion Resistance: Superior resistance to chloride-induced pitting and crevice corrosion, critical for brine-based heat transfer media
- Low-Temperature Performance: Retains ductility and toughness at temperatures as low as -196°C (-320°F), preventing brittle fracture during ice formation cycles
- Thermal Conductivity: Approximately 16.3 W/(m·K) for Grade 304, ensuring efficient heat transfer between the refrigerant and ice medium
- Mechanical Strength: Yield strength of ≥205 MPa (Grade 304) with elongation ≥40%, providing structural integrity under cyclic thermal loading
- Hygienic Surface Finish: Available in 2B, No.4, or electropolished (Ra ≤ 0.4 μm) finishes to minimize fouling and maintain flow efficiency
Specifications
| Parameter | Specification | Standard Reference |
|---|---|---|
| Outer Diameter (OD) | Φ8 mm – Φ50 mm (customizable) | GB/T 14975, ASTM A269 |
| Wall Thickness | 0.5 mm – 3.0 mm | GB/T 14976, ASTM A213 |
| Coil Diameter | Φ300 mm – Φ2000 mm (configurable per tank design) | Project-specific |
| Coil Length | Up to 500 m per continuous coil | — |
| Material Grade | AISI 304 / 316 / 321 / 316L | ASTM A269, EN 10217-7 |
| Operating Temperature Range | -40°C to +150°C | — |
| Operating Pressure | Up to 1.6 MPa (design pressure 2.5 MPa) | ASME B31.5 |
| Surface Finish | 2B / No.4 / Electropolished / Passivated | ASTM A967 |
| End Preparation | Flat cut, beveled, or welded to fittings | GB/T 1245 |
| Welding Method | Orbital TIG (GTAW) / Pulse TIG | ASME Section IX, AWS D10.9 |
| Dimensional Tolerance | ±0.1 mm (OD); ±10% (wall thickness) | ISO 4287 |
| Strain Hardening | Full hard / Half hard / Soft (annealed) | — |
Manufacturing Process
The production of the stainless steel coil tube for ice storage applications follows a rigorous multi-stage manufacturing protocol:
- Raw Material Selection & Verification: Mill-certified stainless steel strip or seamless tube stock is procured from accredited producers. Incoming inspection includes spectroscopic analysis (PMI - Positive Material Identification) to verify alloy composition, along with mechanical property testing per ASTM A388.
- Forming & Coiling: The tube is formed into the required helical or serpentine coil geometry using CNC-controlled coiling equipment. The coil pitch and diameter are precisely controlled to meet the thermal design requirements of the specific ice storage tank configuration.
- Welding: Joints between tube sections are fabricated using Orbital TIG (Tungsten Inert Gas Welding, process GTAW) with automatic rotation. This ensures consistent weld quality, minimal oxidation, and full penetration. Weld parameters are documented per ASME Section IX qualified procedures.
- Purging & Inert Atmosphere Protection: Internal and external shielding gas (Argon or Helium) is applied during welding to prevent chromium oxide scale formation, maintaining the corrosion-resistant passive layer.
- Solution Annealing & Pickling: Post-welding solution heat treatment at 1050°C – 1150°C followed by controlled cooling restores full austenitic structure and maximizes corrosion resistance. Acid pickling removes any residual weld scale.
- Passivation: Chemical passivation treatment (per ASTM A967) is applied to enhance the protective chromium oxide film on all exposed surfaces.
- Hydrostatic Testing: Each coil assembly undergoes 100% hydrostatic pressure testing at 1.5 times the design pressure to verify leak-tightness and structural integrity.
- Final Inspection & Packaging: Visual inspection, dimensional verification, and surface quality assessment are performed. Coils are packaged with protective end caps, moisture-absorbing desiccants, and wrapped in anti-corrosion film for shipment.
Applications
The stainless steel coil tube is primarily deployed in the following engineering applications:
- Ice Storage Tanks (Ice Storage Tank Prefabrication): The primary application—serving as the heat exchange coil within centralized or distributed ice storage systems for commercial HVAC (Heating, Ventilation, and Air Conditioning) load management.
- Thermal Energy Storage Systems (TES): Peak-shaving applications in data centers, hospitals, shopping malls, and large office complexes where electrical demand reduction is economically advantageous.
- Industrial Process Cooling: Low-temperature process cooling in pharmaceutical manufacturing, food processing, and chemical production facilities.
- Geothermal Heat Exchange: Ground-source heat pump systems requiring durable, corrosion-resistant heat exchanger coils.
- Marine & Offshore Applications: Refrigeration systems for fishing vessels and offshore platforms where chloride-rich environments demand superior corrosion resistance.
Unique Selling Points
- Continuous Length Design: Eliminates multiple joints and potential leak points inherent in segmented pipe assemblies, significantly improving system reliability and reducing maintenance requirements.
- Optimized Heat Transfer Geometry: Precision-controlled coil pitch and diameter maximize surface-area-to-volume ratio, enhancing ice formation rate and melting efficiency by up to 30% compared to conventional pipe configurations.
- Full Traceability: Each product batch is traceable to mill certificates, heat numbers, and complete manufacturing documentation, meeting stringent quality management requirements.
- Customization Capability: Flexible manufacturing capacity allows customization of OD, wall thickness, coil geometry, and material grade to match specific project thermal design parameters.
- Extended Service Life: Design life exceeding 25 years under normal operating conditions, with resistance to scaling, fouling, and corrosion degradation.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains comprehensive quality assurance systems aligned with international standards:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- ISO 45001:2018 — Occupational Health and Safety Management System
- CE Marking — Conformity with European Pressure Equipment Directive (PED 2014/68/EU)
- ASME Section IX — Welding Procedure Qualification (WPQ) and Welder Performance Qualification (W PQ)
- NADCAP — Special Process Certification (Welding and Surface Treatment)
- Mill Test Reports (MTR) — Provided with each shipment, including chemical composition, mechanical properties, and non-destructive testing (NDT) results
- Third-Party Inspection: Available upon request through SGS, Bureau Veritas, or TÜV Rheinland
Technical Note: The coil tube ice storage tank prefabrication technology (盘管式蓄冰槽预制施工技术) enables modular, factory-assembled thermal storage units that can be rapidly deployed on-site, reducing construction timelines by 40–60% compared to traditional field-fabricated heat exchanger installations. This prefabricated approach ensures consistent quality control, minimizes on-site labor costs, and accelerates project commissioning schedules.