Stainless Steel Coil Tube (盘管) for HVAC Fan Coil Units
Product Overview
The Stainless Steel Coil Tube (盘管, Coiltube) is a precision-engineered thermal exchange component manufactured by Wenzhou Jixing Metal Materials Co., Ltd. This product is designed for integration into series-parallel dry fan coil unit systems with independent fresh air air conditioning configurations. The coil tube serves as the core heat transfer element within HVAC (Heating, Ventilation, and Air Conditioning) applications, delivering superior thermal efficiency, corrosion resistance, and long-term structural integrity under demanding operational conditions.
Based on extensive research into series-parallel dry fan coil unit performance, this coil tube is engineered to optimize heat exchange rates while maintaining low pressure drop characteristics, making it an ideal solution for commercial and industrial air conditioning systems that require reliable, maintenance-free operation.
Material & Properties
The coil tube is fabricated from high-grade austenitic stainless steel, selected for its exceptional combination of mechanical strength, thermal conductivity, and resistance to environmental degradation.
- Primary Material: AISI 304 (UNS S30400) / AISI 316L (UNS S31603) austenitic stainless steel
- Carbon Content: ≤ 0.08% (304) / ≤ 0.02% (316L)
- Chromium Content: 18.0%–20.0%
- Nickel Content: 8.0%–10.5%
- Molybdenum Content (316L): 2.0%–3.0%
- Thermal Conductivity: 14.5–16.3 W/(m·K) at 20°C
- Operating Temperature Range: −196°C to +870°C
- Surface Finish: 2B, BA (Bright Annealed), or No. 4 brushed finish
Specifications
| Parameter | Specification | Unit |
|---|---|---|
| Outer Diameter (OD) | 6.0 / 8.0 / 9.5 / 12.0 (customizable) | mm |
| Wall Thickness | 0.3 – 1.0 | mm |
| Coil Pitch (Row Spacing) | 15 – 50 | mm |
| Tube Length per Pass | 300 – 1200 | mm |
| Number of Rows | 1 – 6 | — |
| Coil Length (Overall) | 300 – 1500 | mm |
| Coil Width | 300 – 1200 | mm |
| Fin Material | Aluminum (Al-MgSi) or Stainless Steel | — |
| Fin Thickness | 0.10 – 0.20 | mm |
| Fin Pitch (FPI) | 8 – 14 | Fin Per Inch |
| Working Pressure | ≤ 1.6 | MPa |
| Hydrostatic Test Pressure | 2.4 | MPa |
| Refrigerant Compatibility | R22, R407C, R410A, R134a, R32, Water/Glycol | — |
| Tolerance on OD | ±0.05 | mm |
| Tolerance on Wall Thickness | ±10% | — |
| Applicable Standard | ASTM A269 / ASTM A270 / GB/T 12771 | — |
Manufacturing Process
- Material Selection & Inspection: Incoming stainless steel strip or seamless tube stock is verified for chemical composition (via XRF spectroscopy) and mechanical properties in accordance with ASTM A269/A270 standards.
- Forming & Bending: Precision CNC-controlled bending machines shape the tube into serpentine coil configurations with controlled bend radii (typically ≥ 3× OD) to prevent wall thinning and micro-cracking.
- Fin Insertion & Brazing: Aluminum or stainless steel fins are inserted between tube rows and secured via high-temperature brazing or mechanical crimping to ensure intimate thermal contact between tube and fin surfaces.
- Hydrostatic Pressure Testing: Each coil assembly undergoes 100% hydrostatic testing at 2.4 MPa for a minimum dwell time of 30 seconds to verify weld integrity and structural soundness.
- Surface Treatment & Cleaning: Interior surfaces are acid-pickled and passivated to remove oxide scale and restore the protective chromium oxide layer, ensuring long-term corrosion resistance.
- Final Dimensional Inspection: Coordinate Measuring Machine (CMM) and optical measurement verify coil geometry, tube OD tolerance, fin pitch uniformity, and overall dimensional compliance.
Applications
The stainless steel coil tube is purpose-built for the following HVAC and thermal management applications:
- Dry Fan Coil Units (FCU): Series-parallel configurations with independent fresh air systems for precision temperature and humidity control in commercial buildings.
- Chiller & Heat Pump Systems: Evaporator and condenser coils in water-source and air-source heat pump installations.
- Commercial Air Conditioning: Office buildings, hotels, hospitals, and data centers requiring low-maintenance, high-efficiency cooling solutions.
- Industrial Process Cooling: Chemical processing, pharmaceutical manufacturing, and food and beverage industries where corrosion resistance is critical.
- Refrigeration Systems: Cold storage facilities and refrigeration equipment operating with various refrigerants including R410A and R32.
- Marine & Coastal Environments: Applications exposed to salt spray and high humidity where AISI 316L grade provides superior chloride resistance.
Quality Certifications & Compliance
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- CE Marking — Conformity with European Health, Safety, and Environmental Protection Standards
- EN 1273 — European Standard for Tubular Heat Exchangers
- GB/T 12771 — Chinese National Standard for Welded Stainless Steel Tubes
- ASTM A269 / A270 — American Standards for Stainless Steel Tubing
- Material Test Reports (MTR) — Full chemical and mechanical analysis certificates provided per batch
- NDT (Non-Destructive Testing) — Helium leak testing or dye penetrant inspection for weld integrity verification
Unique Selling Points
- Superior Corrosion Resistance: The austenitic stainless steel construction eliminates internal corrosion, significantly extending service life compared to copper or carbon steel alternatives — particularly in glycol-water mixtures and humid environments.
- Optimized Thermal Performance: Coil geometry is engineered based on series-parallel fan coil unit performance research to maximize heat transfer coefficient while minimizing pressure drop across the coil.
- Hygienic Design: Smooth, passivated internal surfaces prevent biofilm formation and scale accumulation, making the coil suitable for pharmaceutical and food-grade applications.
- Customization Capability: Flexible manufacturing parameters allow tailored coil configurations (OD, wall thickness, fin density, row count) to match specific system design requirements.
- Low Maintenance Lifecycle: Elimination of internal corrosion and scaling translates to reduced cleaning frequency and lower total cost of ownership (TCO) over the system lifespan.
- Refrigerant Versatility: Compatible with all major refrigerants currently in use, including eco-friendly alternatives (R32, R134a), ensuring forward compatibility with evolving environmental regulations.
Note: All specifications listed are standard reference values. Custom configurations are available upon request. Wenzhou Jixing Metal Materials Co., Ltd provides full technical support, engineering consultation, and sample testing services for project-specific requirements.