Stainless Steel Coil Tube (Coiltube) — Ice Storage Application Grade
Product Overview
The Stainless Steel Coil Tube (hereinafter referred to as "Coiltube") manufactured by Wenzhou Jixing Metal Materials Co., Ltd. is a precision-engineered tubular product designed for ice storage and ice-melting thermal energy systems. This product is specifically developed to meet the rigorous demands of thermal energy storage applications, where the coil tube serves as the primary heat exchange medium between the refrigerant (typically brine or direct-expansion coolant) and the phase-change ice matrix. The Coiltube is supplied in continuous coil form, enabling efficient fabrication of complex heat exchanger geometries with minimal welding joints, thereby reducing potential failure points and optimizing thermal performance.
The design philosophy of this product is grounded in extensive simulation and experimental research on the ice storage and melting processes (蓄冰盘管蓄冰融冰过程模拟与实验研究), ensuring that the tube geometry, wall thickness, and material selection are optimized for maximum heat transfer efficiency during both the freezing (ice storage) and thawing (ice melting) cycles.
Material & Properties
The Coiltube is fabricated from high-grade austenitic stainless steel, selected for its superior corrosion resistance, thermal conductivity, mechanical strength, and long-term durability in aqueous and brine environments.
Material Grades
- ASTM A213 TP304 / TP316 — Primary grades for general ice storage applications
- ASTM A213 TP316L — Low-carbon variant for enhanced resistance to chloride-induced pitting and crevice corrosion
- ASTM A213 TP321 / TP347 — Stabilized grades for elevated temperature cycling applications
Key Physical and Mechanical Properties
- Density (Density): 8.0 g/cm³
- Thermal Conductivity (Thermal Conductivity): 14–16 W/(m·K) at 25°C
- Specific Heat Capacity (Specific Heat Capacity): 500 J/(kg·K) at 25°C
- Tensile Strength (Tensile Strength): ≥ 515 MPa (minimum)
- Yield Strength (Yield Strength): ≥ 205 MPa (0.2% offset)
- Elongation (Elongation): ≥ 40% (at break)
- Operating Temperature Range (Operating Temperature Range): −196°C to +450°C
- Corrosion Resistance (Corrosion Resistance): Excellent resistance to brine, deionized water, and low-concentration chemical solutions
Specifications
| Parameter | Specification |
|---|---|
| Product Name | Stainless Steel Coil Tube (Coiltube) |
| Product Category | Heat Exchanger Tubing / Thermal Energy Storage Tubing |
| Material Grade | ASTM A213 TP304 / TP316 / TP316L / TP321 / TP347 |
| Outer Diameter (OD) | 3.0 mm – 25.0 mm (customizable) |
| Wall Thickness | 0.3 mm – 2.0 mm (customizable) |
| Coil Winding Diameter | ≥ 200 mm (minimum bend diameter to prevent deformation) |
| Coil Length (per coil) | 50 m – 500 m (adjustable per project requirement) |
| Surface Finish | Pickled & Passivated (2B finish) or Electropolished |
| End Condition | Plain end, beveled end, or welded with fittings |
| Maximum Working Pressure | Up to 1.6 MPa (standard); 2.5 MPa (enhanced wall thickness) |
| Tolerance — OD | ±0.05 mm (precision grade) |
| Tolerance — Wall Thickness | ±10% of nominal |
| Standards Compliance | ASTM A213, ASME B31.3, EN 10216-5, GB/T 17708 |
| Application Focus | Ice Storage (蓄冰) and Ice Melting (融冰) Thermal Energy Systems |
Manufacturing Process
The Coiltube is produced through a multi-stage precision manufacturing process that ensures dimensional accuracy, metallurgical integrity, and surface quality suitable for demanding thermal cycling applications.
- Raw Material Selection (Raw Material Selection): Virgin stainless steel wire rod or strip is sourced from certified mills, with full chemical composition analysis and mechanical property verification prior to processing.
- Hot-Rolling & Annealing (Hot-Rolling & Annealing): The base material is hot-rolled to the desired approximate dimensions, followed by solution annealing at 1050°C – 1150°C to achieve a fully austenitic microstructure and relieve internal stresses.
- Cold Drawing (Cold Drawing): The tube blank is cold-drawn through precision tungsten carbide dies to achieve the final outer diameter and wall thickness with tight tolerances. This step enhances surface finish and mechanical strength.
- Precision Coiling (Precision Coiling): The straight tube is wound onto a mandrel using a controlled coiling machine to produce the continuous coil form. The winding tension and speed are precisely controlled to prevent ovality, kinking, or work hardening.
- Pickling & Passivation (Pickling & Passivation): The coiled tube is subjected to acid pickling (typically nitric-hydrofluoric acid mixture) to remove scale and oxidation, followed by passivation treatment to restore and enhance the chromium oxide passive layer.
- Quality Inspection (Quality Inspection): Each coil undergoes hydrostatic testing, dimensional verification, visual inspection, and spectroscopic chemical analysis to confirm compliance with specified standards.
- Packaging & Dispatch (Packaging & Dispatch): The finished coil is wrapped in protective film, placed on a wooden or steel drum, and secured for safe transportation to the end user or downstream fabricator.
Applications
The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. is primarily engineered for the following application domains:
- Ice Storage Thermal Energy Systems (Ice Storage Thermal Energy Systems): The coil tube serves as the heat exchange element within ice storage tanks, where refrigerant flows through the coiled tubing to freeze surrounding water into ice. The coiled geometry maximizes surface area within a compact volume, facilitating rapid ice formation and subsequent melting.
- Ice Melting Heat Recovery Systems (Ice Melting Heat Recovery Systems): During peak-load shifting and demand-side energy management, the stored ice is melted by circulating warm water or air through the coil tubes, providing cooling capacity during peak electricity tariff periods.
- Commercial Building HVAC Systems (Commercial Building HVAC Systems): Large-scale commercial and industrial facilities utilize ice storage coils for peak-shaving, reducing daytime cooling load and optimizing energy costs.
- Food Processing & Cold Chain (Food Processing & Cold Chain): The corrosion-resistant and hygienic properties of stainless steel make this coil tube suitable for food-grade freezing and refrigeration applications.
- Process Cooling in Chemical & Pharmaceutical Industries (Process Cooling): The coil tube is employed in process cooling loops where thermal energy storage provides buffer capacity against load fluctuations.
- Geothermal & Heat Pump Systems (Geothermal & Heat Pump Systems): Coiled stainless steel tubing is used in ground-source heat exchangers and thermal wells for renewable energy integration.
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications and compliance credentials:
- ISO 9001:2015 — Quality Management System certification ensuring consistent product quality and process control
- ISO 14001:2015 — Environmental Management System certification demonstrating environmental responsibility
- ISO 45001:2018 — Occupational Health and Safety Management System certification
- CE Marking — Conformity with European health, safety, and environmental protection standards
- ASTM / ASME Compliance — Products manufactured in accordance with ASTM A213 and ASME B31.3 process piping standards
- GB/T Standards Compliance — Compliance with Chinese national standards including GB/T 17708 (stainless steel seamless tubes) and GB/T 12771
- Mill Test Reports (Mill Test Reports): Full chemical analysis, mechanical test results, and traceability documentation provided with each batch
- Hydrostatic Testing (Hydrostatic Testing): 100% hydrostatic pressure testing performed on all coils prior to shipment
Unique Selling Points
- Optimized for Thermal Cycling (Optimized for Thermal Cycling): The product design is informed by rigorous simulation and experimental research on ice storage and melting dynamics, ensuring reliable performance over thousands of freeze-thaw cycles without degradation.
- Superior Corrosion Resistance (Superior Corrosion Resistance): Austenitic stainless steel construction provides exceptional resistance to brine, deionized water, and corrosive fluids, ensuring long service life in aggressive thermal storage environments.
- High Heat Transfer Efficiency (High Heat Transfer Efficiency): Precision-wound coil geometry with minimal dead zones maximizes heat exchange surface area, reducing ice storage and melting cycle times.
- Customizable Dimensions (Customizable Dimensions): Flexible manufacturing capability allows customization of outer diameter, wall thickness, coil length, and winding diameter to meet specific project requirements.
- Low Maintenance & Long Lifespan (Low Maintenance & Long Lifespan): The seamless, corrosion-resistant construction eliminates the need for frequent maintenance, reducing total cost of ownership over the system lifecycle.
- Full Traceability (Full Traceability): Each coil is accompanied by complete documentation including mill test certificates, heat number traceability, and dimensional inspection records.
Note: The Stainless Steel Coil Tube from Wenzhou Jixing Metal Materials Co., Ltd. represents the integration of advanced metallurgical engineering, precision manufacturing, and thermal energy storage expertise. It is a critical component in next-generation thermal energy management systems, contributing to energy efficiency, peak-load mitigation, and sustainable building operations.