Stainless Steel Ice Storage Coil Tube (Model No. 1213)
Product Overview
The Stainless Steel Ice Storage Coil Tube (Model No. 1213) is a precision-engineered coiled tubular component manufactured by Wenzhou Jixing Metal Materials Co., Ltd., specifically designed for ice storage thermal energy systems and low-temperature air supply HVAC (Heating, Ventilation, and Air Conditioning) applications. This product represents a critical heat exchanger element within thermal energy storage systems, where the coil tube facilitates efficient heat transfer between the working fluid and the phase-change material (PCM) — typically water undergoing solidification into ice. The coil geometry maximizes the surface-area-to-volume ratio, enabling superior thermal exchange performance within compact installation footprints.
The design philosophy of this coil tube is grounded in the principles of convective heat transfer optimization and structural integrity under cryogenic cycling conditions. Academic research on ice storage coil tube heat transfer performance has demonstrated that the geometric configuration, material selection, and surface finish of the coil tube directly govern the system's coefficient of performance (COP), charging/discharging rates, and long-term operational reliability.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its exceptional combination of corrosion resistance, thermal conductivity, mechanical strength, and cryogenic toughness. The material composition adheres to international metallurgical standards, ensuring consistent microstructural properties and resistance to intergranular corrosion, stress corrosion cracking (SCC), and pitting in aggressive aqueous environments.
- Base Alloy: Austenitic stainless steel conforming to ASTM A269 / A270 or EN 10216-5 specifications
- Typical Grade: SUS 304 / 304L (1.4301 / 1.4307) or SUS 316L (1.4404) for enhanced chloride resistance
- Carbon Content: ≤ 0.08% (standard) or ≤ 0.03% (low-carbon variant for weldability)
- Chromium (Cr): 18.0–20.0% — provides primary corrosion resistance via passive oxide film
- Nickel (Ni): 8.0–10.5% — stabilizes austenitic crystal structure at all temperatures
- Molybdenum (Mo): 2.0–3.0% (in 316L grade) — enhances pitting and crevice corrosion resistance
- Thermal Conductivity: 14–16 W/(m·K) at ambient temperature
- Thermal Expansion Coefficient: 17.3 × 10⁻⁶ /°C (20–100°C)
- Mechanical Properties: Tensile strength ≥ 520 MPa; Yield strength ≥ 205 MPa; Elongation ≥ 40%
- Cryogenic Performance: Maintains ductility and toughness down to −196°C (liquid nitrogen temperature)
Specifications
| Parameter | Specification |
|---|---|
| Product Code | 1213 |
| Product Category | Coil Tube (盘管) |
| Outer Diameter (OD) | 6.0 mm – 25.4 mm (available range) |
| Wall Thickness | 0.5 mm – 2.0 mm |
| Coil Pitch | 10 mm – 50 mm (configurable) |
| Coil Diameter | 50 mm – 500 mm (customizable) |
| Tube Length (Uncoiled) | Up to 12,000 mm per continuous coil |
| Surface Finish | Mirror polish (Ra ≤ 0.2 μm) or matte finish (Ra ≤ 0.8 μm) |
| End Treatment | Deburred, chamfered; optional flanged or threaded connection |
| Operating Temperature Range | −40°C to +150°C |
| Design Pressure | Up to 2.5 MPa (gauge) |
| Fluid Compatibility | Water, brine (CaCl₂, MgCl₂), ethylene glycol solutions, refrigerants |
| Manufacturing Standard | ASTM A269, EN 10216-5, GB/T 14976 |
| Testing Standard | ISO 4494 (hydrostatic), ASTM A999 (eddy current) |
Manufacturing Process
The production of the stainless steel ice storage coil tube follows a rigorously controlled multi-stage manufacturing sequence to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Material Selection & Inspection: Cold-rolled stainless steel strip is sourced from certified mills and subjected to incoming material verification including chemical composition analysis (spectrometry), mechanical property testing, and visual surface inspection.
- Precision Forming: The strip is formed into a seamless tube via cold-forming techniques (roll-bending or extrusion) to achieve the specified outer diameter and wall thickness with tight tolerances (±0.05 mm).
- Coil Winding: Using CNC-controlled coiling machinery, the formed tube is wound into the specified helical geometry with precise pitch and diameter control. Computerized path planning ensures uniform coil spacing and structural consistency.
- Welding (if applicable): In cases where continuous length requires butt-joint welding, automated TIG (Tungsten Inert Gas) or orbital welding is employed with full-penetration welds, followed by internal and external grinding to restore surface finish and wall integrity.
- Heat Treatment: Solution annealing at 1050–1150°C followed by rapid quenching is performed to restore full austenitic structure, eliminate residual stresses, and ensure maximum corrosion resistance and ductility.
- Surface Finishing: Electropolishing or mechanical polishing is applied to achieve the required surface roughness, which is critical for minimizing flow resistance and enhancing convective heat transfer coefficients within the coil tube.
- Quality Testing: Each coil tube undergoes hydrostatic pressure testing (at 1.5× design pressure), dimensional verification via coordinate measuring machine (CMM), and non-destructive testing (NDT) including eddy current or ultrasonic inspection for internal defects.
Applications
The stainless steel ice storage coil tube (Model No. 1213) finds extensive application in the following engineering domains:
- Ice Storage Thermal Energy Systems: As the primary heat exchange element within ice storage tanks, the coil tube enables off-peak electricity utilization by storing thermal energy in the form of ice during low-demand periods and releasing it during peak cooling demand, thereby reducing grid load and operational costs.
- Low-Temperature Air Supply HVAC Systems: Integrated with chilled water or brine loops, the coil tube facilitates the generation of low-temperature supply air (as low as 5–10°C), improving cooling capacity and reducing air volume requirements.
- Commercial & Industrial Cooling: Shopping malls, data centers, hospitals, and manufacturing facilities benefit from the system's peak-shaving capability and enhanced thermal efficiency.
- Cold Chain Logistics: Refrigerated warehouses and cold storage facilities utilize coil tube assemblies for efficient heat removal from ambient spaces.
- Process Cooling: Industrial applications requiring precise temperature control in pharmaceutical manufacturing, food processing, and chemical production.
- Research & Development: Academic and laboratory applications studying phase-change heat transfer dynamics, as documented in studies on ice storage coil tube thermal performance.
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system with the following certifications and compliance standards:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and continuous improvement
- ISO 14001:2015 — Environmental Management System certification
- ISO 45001:2018 — Occupational Health and Safety Management System
- CE Marking — Conformity with European health, safety, and environmental protection standards
- PED 2014/68/EU — Pressure Equipment Directive compliance for pressure-containing components
- Mill Test Certificates (MTC) — EN 10204 Type 3.1 certified material traceability documentation for every batch
- Third-Party Inspection — Available upon request from SGS, Bureau Veritas, or TÜV Rheinland
Unique Selling Points
The Model No. 1213 Stainless Steel Ice Storage Coil Tube distinguishes itself through several technically significant advantages:
- Superior Heat Transfer Efficiency: The optimized helical geometry and precision surface finish (Ra ≤ 0.2 μm) maximize the convective heat transfer coefficient, reducing ice formation time by 15–25% compared to standard coil configurations, as validated by experimental studies on ice storage coil tube thermal performance.
- Exceptional Cryogenic Durability: The austenitic stainless steel matrix retains full ductility and fracture toughness at sub-zero temperatures, eliminating the risk of brittle fracture during repeated freeze-thaw cycling — a critical advantage over carbon steel alternatives.
- Corrosion Resistance in Brine Environments: The alloy composition provides outstanding resistance to chloride-induced pitting and stress corrosion cracking, ensuring service life exceeding 20 years even in aggressive calcium chloride or magnesium chloride brine solutions used in ice storage systems.
- Customizable Geometry: CNC-controlled coiling allows precise customization of coil diameter, pitch, and tube length to match specific system design parameters, enabling optimal integration into varied tank configurations and space-constrained installations.
- Seamless Continuous Construction: The cold-formed seamless tube eliminates weld seams along the coil length, removing potential failure points and ensuring uniform hydraulic performance and long-term structural integrity under cyclic thermal loading.
- Full Traceability: Each product batch is accompanied by complete material certification, dimensional inspection reports, and pressure test documentation, providing full supply chain traceability for compliance with international engineering standards.
Academic Reference Context
The design and performance characteristics of this coil tube are informed by and validated against published research on ice storage coil tube heat transfer performance and low-temperature air supply HVAC systems (蓄冰盘管传热性能及低温送风空调系统研究). Key findings from this body of research confirm that:
- The heat transfer rate in ice storage coil tubes is governed primarily by the natural convection coefficient on the ice side and forced convection on the fluid side, with the Nusselt number (Nu) scaling with the Rayleigh number (Ra) to the power of approximately 0.25–0.33 depending on the flow regime.
- Optimal coil pitch-to-diameter ratios (typically 2.0–3.0) balance heat transfer surface area against flow resistance and pressure drop, maximizing the system COP.
- Low-temperature air supply systems utilizing ice storage achieve cooling capacity improvements of 20–40% over conventional chilled water systems due to the increased temperature differential driving force.
- Material thermal conductivity and surface roughness significantly influence the onset and progression of ice formation, with smoother surfaces promoting more uniform ice layer growth and reduced thermal resistance.
Wenzhou Jixing Metal Materials Co., Ltd. leverages these established principles to deliver coil tube products that represent the state-of-the-art in thermal energy storage component engineering.