Stainless Steel Coil Tube (Coiltube) — External Melting Ice Storage Cooling Application
Product Overview
The Stainless Steel Coil Tube (Coiltube) is a precision-engineered tubular product manufactured by Wenzhou Jixing Metal Materials Co., Ltd. Specifically designed for external melting ice storage cooling systems (External Melting Ice Storage Cooling System), this coil tube serves as the critical heat exchange element in latent heat thermal energy storage (LHTES) applications. The product is wound into a compact spiral configuration, maximizing the heat transfer surface area within a confined volume, thereby enabling efficient freezing and melting of water or brine media to store and release thermal energy on demand.
Based on extensive experimental research into the cooling characteristics of external melting ice coil tubes, this product has been optimized for superior thermal performance, structural integrity, and long-term corrosion resistance in refrigeration and HVAC (Heating, Ventilation, and Air Conditioning) environments.
Material & Properties
Primary Material Grades
- 304 (AISI 304 / SUS 304 / 0Cr18Ni9) — Austenitic stainless steel with excellent general corrosion resistance and formability, suitable for ambient and moderate-temperature applications.
- 316 (AISI 316 / SUS 316 / 0Cr17Ni12Mo2) — Enhanced austenitic grade with molybdenum addition, offering superior resistance to chlorides, brines, and aggressive chemical environments.
- 321 (AISI 321 / SUS 321) — Titanium-stabilized austenitic grade for elevated temperature service and resistance to sensitization.
Key Mechanical and Physical Properties
| Property | 304 Grade | 316 Grade |
|---|---|---|
| Tensile Strength (MPa) | ≥ 520 | ≥ 515 |
| Yield Strength (MPa) | ≥ 205 | ≥ 170 |
| Elongation (%) | ≥ 40 | ≥ 40 |
| Density (g/cm³) | 7.93 | 8.00 |
| Thermal Conductivity (W/m·K, 20°C) | 16.3 | 16.3 |
| Operating Temperature Range (°C) | −196 to +870 | −196 to +870 |
| Corrosion Resistance | Good (general environments) | Excellent (chloride/brine environments) |
Specifications
| Parameter | Specification |
|---|---|
| Outer Diameter (OD) | Φ6 mm – Φ50 mm (customizable) |
| Wall Thickness (WT) | 0.3 mm – 2.0 mm |
| Coil Outer Diameter (COLD) | Φ200 mm – Φ1500 mm |
| Coil Length / Turns | As per customer requirement (typically 5 m – 100 m per coil) |
| Surface Finish | Bright Annealed (BA), Pickled & Passivated, or Custom Polish |
| Winding Pattern | Spiral / Helical with controlled pitch to ensure uniform spacing and flow distribution |
| Tolerance on OD | ±0.1 mm (standard); ±0.05 mm (precision grade available) |
| Tolerance on Wall Thickness | ±10% of nominal (standard); ±5% (precision grade available) |
| End Condition | Open ends, flared, or threaded (upon request) |
| Standards Compliance | ASTM A213, ASTM A269, GB/T 14976, GB/T 12771, EN 10217 |
Manufacturing Process
- Raw Material Selection: Certified stainless steel seamless tubes are sourced from reputable mills with full mill test certificates (MTC) per EN 10204 3.1.
- Cold Drawing / Rolling: Tubes are precision-drawn to achieve exact OD and wall thickness tolerances while maintaining microstructural integrity.
- Pipe Bending (Coil Forming): Using CNC-controlled bending machines with tooling designed to minimize ovality and avoid wall thinning at bend radii. Minimum bend radius is typically 5× the tube OD to ensure structural soundness.
- Spiral Winding: Tubes are wound into the designated coil geometry with controlled inter-pass pitch to optimize heat transfer efficiency and fluid distribution.
- Welding & Finishing: Inlet and outlet ports are formed and welded (TIG/GTAW welding with argon gas shielding) to ensure leak-free integrity. Weld seams are ground and polished.
- Pickling & Passivation: Chemical treatment to remove surface oxides, contaminants, and carbon residue, followed by passivation to restore and enhance the chromium oxide protective layer.
- Hydrostatic / Pneumatic Testing: Every coil tube undergoes pressure testing (typically at 1.5× the maximum operating pressure) to verify leak tightness and structural integrity.
- Final Inspection & Packaging: Visual and dimensional inspection, followed by protective packaging suitable for shipping and storage.
Applications
- Ice Storage Cooling Systems: Primary application in external melting ice storage systems where the coil tube facilitates efficient heat exchange between the refrigerant/brine and water to form and melt ice, providing thermal energy storage for peak load shifting.
- Commercial and Industrial Refrigeration: Used in walk-in coolers, freezers, cold chain logistics, and process cooling applications requiring reliable thermal performance.
- HVAC Systems: Integrated into air handling units, chiller plants, and district cooling networks for energy-efficient temperature regulation.
- Food & Beverage Processing: Employed in pasteurization, fermentation, and cold storage systems where hygiene and corrosion resistance are paramount.
- Chemical & Pharmaceutical Industry: Suitable for process cooling loops where resistance to corrosive media and compliance with sanitary standards are essential.
- Heat Exchangers & Condensers: The compact spiral geometry makes these coil tubes ideal for compact heat exchanger designs requiring high surface-area-to-volume ratios.
Quality Certifications & Standards
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control.
- ISO 14001:2015 — Environmental Management System certification reflecting sustainable manufacturing practices.
- ASTM A213 / A269 — Compliance with American standards for stainless steel tubing.
- GB/T 14976 / GB/T 12771 — Compliance with Chinese national standards for stainless steel seamless tubes.
- EN 10217 — Compliance with European standards for seamless stainless steel tubes.
- Mill Test Certificates (MTC) per EN 10204 3.1 — Provided with every shipment for material traceability and verification.
- NACE MR0175 / ISO 15156 — Available for sour service applications requiring resistance to sulfide stress cracking.
Unique Selling Points
- Optimized for Latent Heat Storage: Coil geometry specifically engineered based on experimental research into external melting ice storage cooling characteristics, ensuring maximum heat transfer efficiency during both charging (freezing) and discharging (melting) cycles.
- Superior Corrosion Resistance: Stainless steel construction provides exceptional longevity in brine, glycol, and aqueous environments where carbon steel alternatives would rapidly corrode.
- Compact Design: High surface-area-to-volume ratio enables smaller system footprints while delivering equivalent or superior cooling capacity.
- Customizability: Full range of OD, wall thickness, coil diameter, and length configurations to match specific system designs and performance requirements.
- Leak-Free Integrity: Precision TIG welding with inert gas shielding ensures hermetic joints critical for refrigerant and brine systems.
- Full Traceability: Every batch is accompanied by comprehensive material documentation and test reports for regulatory compliance and quality assurance.
Note: All specifications listed above are representative and may be customized to meet specific project requirements. Customers are encouraged to consult with Wenzhou Jixing Metal Materials Co., Ltd. engineering team for application-specific design recommendations and material selection guidance.