Stainless Steel Coil Tube (盘管) — Ice Storage & Thermal Energy Systems
Manufacturer: Wenzhou Jixing Metal Materials Co., Ltd (温州吉兴金属材料有限公司)
Product Category: Literature & Technical Study — Coil Tube for Ice Storage Cold Extraction Systems
Reference Document: "Experimental Study on the Effect of Ice Coil Density on the Cold Extraction Characteristics of Ice Storage Tanks" (《冰盘管密度对蓄冷槽取冷特性影响的实验研究》)
1. Product Overview
The Stainless Steel Coil Tube (盘管Coiltube) is a precision-engineered heat exchange component manufactured from austenitic stainless steel, specifically designed for integration into ice thermal storage tanks (Ice Storage Tanks) and latent heat energy storage systems. The coil tube serves as the primary heat transfer medium within ice storage cold extraction systems, facilitating the efficient transfer of thermal energy between the working fluid (typically water or a water-glycol mixture) and the surrounding ice matrix.
Based on the experimental research documented in the referenced study, the coil tube density — defined as the number of coil tube turns per unit volume of the storage tank — is a critical design parameter that directly governs the cold extraction rate, thermal efficiency, and operational longevity of the ice storage system. Wenzhou Jixing Metal Materials Co., Ltd. leverages this research foundation to provide coil tubes optimized for specific cold extraction performance targets.
Key Research Finding: The experimental study demonstrates that ice coil density significantly influences the cold extraction characteristics of ice storage tanks. An optimal coil density maximizes the heat transfer surface area while minimizing flow resistance and pressure drop, achieving a balance between thermal performance and hydraulic efficiency.
2. Material & Properties
2.1 Base Material
- Primary Grade: Austenitic Stainless Steel — SUS304 (UNS S30400) / SUS316 (UNS S31600)
- Alternative Grade: SUS321 (UNS S32100) for elevated-temperature applications
- Compliance: ASTM A269, ASTM A213, GB/T 12771, EN 10217-7
2.2 Mechanical Properties (Typical for SUS304)
| Property | Specification | Test Standard |
|---|---|---|
| Tensile Strength (抗拉强度) | ≥ 520 MPa | ASTM A269 / GB/T 228 |
| Yield Strength (屈服强度) | ≥ 205 MPa | ASTM A269 / GB/T 228 |
| Elongation (延伸率) | ≥ 40% | ASTM A269 |
| Hardness (硬度) | ≤ 92 HRB | ASTM E140 |
| Density (密度) | 7.93 g/cm³ | — |
2.3 Thermal Properties
| Property | Value | Temperature Range |
|---|---|---|
| Thermal Conductivity (导热系数) | 16.3 W/(m·K) | 25°C |
| Specific Heat Capacity (比热容) | 502 J/(kg·K) | 25°C |
| Thermal Expansion Coefficient (热膨胀系数) | 17.3 × 10⁻⁶ /K | 20–100°C |
| Critical Temperature (临界温度) | — | Non-magnetic above Curie point |
2.4 Corrosion Resistance
- Pitting Resistance (点蚀抗力): PREN ≥ 18 (SUS304) / PREN ≥ 24 (SUS316)
- Chloride Resistance (氯离子耐受性): Suitable for potable water and glycol-based fluids
- Oxidation Resistance (抗氧化性): Non-scaling up to 870°C (SUS304) / 925°C (SUS316)
- Welding Performance (焊接性能): Excellent; no pre-heat or post-heat treatment required for thin-wall coil tubes
3. Specifications
3.1 Geometric Specifications
| Parameter | Specification | Tolerance |
|---|---|---|
| Outer Diameter (外径, OD) | Φ6.0 mm – Φ32.0 mm (customizable) | ±0.1 mm |
| Wall Thickness (壁厚, WT) | 0.5 mm – 2.0 mm | ±0.05 mm |
| Coil Pitch (盘管螺距) | 15 mm – 80 mm (adjustable per design) | ±1.0 mm |
| Coil Diameter (盘管直径) | Φ50 mm – Φ200 mm | ±2.0 mm |
| Tube Length (管长) | Up to 12,000 mm (continuous coil) | ±10 mm |
| Surface Finish (表面粗糙度) | Ra ≤ 0.8 μm (interior); Ra ≤ 1.6 μm (exterior) | — |
| End Form (端部形式) | Beveled / Flat / Threaded (per customer specification) | — |
3.2 Coil Density Design Parameters (Based on Experimental Study)
| Coil Density Level | Turns per Unit Volume | Cold Extraction Rate | Pressure Drop | Recommended Application |
|---|---|---|---|---|
| Low Density (低密度) | 1–2 turns/dm³ | Moderate (baseline) | Low | Large-capacity storage; long-duration discharge |
| Medium Density (中密度) | 3–5 turns/dm³ | High (optimal balance) | Moderate | General HVAC peak-load shifting |
| High Density (高密度) | 6–10 turns/dm³ | Very High (rapid extraction) | High | Fast-response systems; compact installations |
Research Insight: The experimental study confirms that increasing coil density beyond an optimal threshold yields diminishing returns in cold extraction rate while significantly increasing hydraulic resistance. The recommended design window is 3–5 turns/dm³ for most commercial ice storage applications.
4. Manufacturing Process
4.1 Production Workflow
- Raw Material Selection & Inspection (原材料检验): Stainless steel seamless or welded tube stock verified against ASTM A269 / GB/T 12771 chemical and mechanical requirements. Incoming material undergoes spectroscopic analysis (光谱分析) for elemental composition verification.
- Coil Forming (盘管成型): Precision cold coiling using CNC-controlled forming machines to achieve the specified coil diameter, pitch, and geometry. The forming process is controlled to prevent work hardening and maintain dimensional accuracy.
- Heat Treatment (热处理): Solution annealing at 1040–1120°C followed by rapid water quenching to restore full austenitic structure and eliminate residual stresses introduced during cold forming.
- Surface Treatment (表面处理): Optional pickling and passivation (酸洗钝化) to remove surface contaminants and enhance corrosion resistance. Electropolishing (电解抛光) available for ultra-smooth interior surfaces.
- End Preparation (端部加工): Beveling, threading, or flattening of tube ends per customer specification for welding or flange connection.
- Quality Inspection (质量检测): 100% dimensional inspection, hydrostatic pressure testing (水压试验) at 1.5× working pressure, and optional radiographic testing (射线检测) for weld integrity.
- Packaging & Shipping (包装运输): Protective wrapping, moisture barriers, and secure crating for domestic and international shipment.
4.2 Process Control
- Full traceability from raw material heat number to finished coil tube serial number (全程可追溯)
- Statistical Process Control (SPC) applied to critical dimensions during coiling
- In-process inspection at each manufacturing stage with documented records
5. Applications
5.1 Primary Applications
- Ice Thermal Storage Systems (冰蓄冷系统): Coil tubes embedded within ice storage tanks for latent heat cold storage and discharge in commercial and industrial HVAC systems.
- Chilled Water Storage Tanks (冷冻水蓄冷槽): Heat exchange coils for sensible heat storage in chilled water systems.
- Food & Beverage Industry (食品饮料行业): Sanitary-grade coil tubes for cooling systems in breweries, dairies, and food processing facilities.
- Pharmaceutical & Medical (医药医疗): High-purity coil tubes for temperature-controlled storage and processing equipment.
- Marine & Offshore (海洋工程): SUS316 coil tubes for cryogenic and refrigeration systems in marine environments.
- Chemical Processing (化工): Corrosion-resistant coil tubes for heat exchange in chemical reactors and storage vessels.
5.2 System Integration
The coil tubes are designed for seamless integration into ice storage tank systems, where they serve as the heat transfer interface between the circulating working fluid and the ice matrix. Proper coil density design — informed by the experimental research — ensures optimal cold extraction performance, minimizing the time required to discharge stored thermal energy while maintaining acceptable pressure drops across the system.
6. Quality Certifications & Standards
6.1 Product Certifications
- ISO 9001:2015 — Quality Management System (质量管理体系)
- ISO 14001:2015 — Environmental Management System (环境管理体系)
- CE Marking — European Conformity for pressure equipment components
- GB/T 19001-2016 — Chinese national quality management standard
6.2 Applicable Standards
| Standard | Scope |
|---|---|
| ASTM A269 / A269M | Seamless and welded austenitic stainless steel tubes for general applications |
| ASTM A213 | Welded austenitic stainless steel tubes for heat transfer equipment |
| GB/T 12771 | Stainless steel seamless tubes for general applications (Chinese standard) |
| EN 10217-7 | Non-alloy and alloy steel tubes for pressure purposes — austenitic stainless steels |
| JIS G3446 | Stainless steel seamless tubes for general use (Japanese standard) |
| ASME B31.3 | Process piping design code (applicable to system integration) |
6.3 Testing & Verification
- Chemical Analysis (化学成分分析): Spectroscopic verification of Cr, Ni, Mo, C, Mn, Si, and other alloying elements per applicable standard.
- Mechanical Testing (力学性能测试): Tensile, hardness, and impact testing per ASTM E8 / E140.
- Hydrostatic Testing (水压试验): 100% of coil tubes tested at 1.5× maximum working pressure with minimum dwell time of 30 seconds.
- Dimensional Inspection (尺寸检测): 100% inspection of OD, wall thickness, coil diameter, and pitch using calibrated instruments.
- Corrosion Testing (耐蚀性测试): Salt spray testing (盐雾试验) per ASTM B117 for SUS316 grades; intergranular corrosion testing (晶间腐蚀试验) per ASTM A262.
- Third-Party Certification (第三方认证): Available upon request from SGS, Bureau Veritas, or TÜV.
7. Unique Selling Points
- Research-Driven Design: Coil tube specifications are informed by peer-reviewed experimental research on ice coil density effects on cold extraction performance, ensuring scientifically validated thermal design parameters.
- Customizable Coil Density: Tailored coil pitch and turn density to match specific cold extraction rate requirements, pressure drop constraints, and tank geometry.
- Full Traceability: Complete material traceability from mill heat number to finished product, supporting quality assurance and regulatory compliance.
- Multi-Grade Availability: SUS304, SUS316, and SUS321 options to address diverse corrosion environments and temperature ranges.
- Sanitary & Food-Grade Option: Electropolished interior surfaces with Ra ≤ 0.4 μm for pharmaceutical and food-grade applications.
- Engineering Support: Technical consultation on coil density optimization, system integration, and performance modeling based on the documented experimental study.
8. Technical Reference
Source Study: 《冰盘管密度对蓄冷槽取冷特性影响的实验研究》 (Experimental Study on the Effect of Ice Coil Density on the Cold Extraction Characteristics of Ice Storage Tanks). This research provides the empirical foundation for coil density optimization in ice storage systems, demonstrating quantifiable relationships between coil density, heat transfer coefficients, and cold extraction efficiency.
Company: Wenzhou Jixing Metal Materials Co., Ltd (温州吉兴金属材料有限公司)