Stainless Steel Chilled Water Coil Tube — Active Chilled Beam Application Series
Product Overview
The Stainless Steel Chilled Water Coil Tube, manufactured by Wenzhou Jixing Metal Materials Co., Ltd, is a precision-engineered coiled tubing product specifically designed for integration into active chilled beam (ACB) systems. These coil tubes serve as the primary heat exchange elements within chilled beam terminals, where they facilitate the transfer of thermal energy between chilled water and the surrounding air stream. The coiled geometry maximizes the surface area-to-volume ratio, enabling superior heat dissipation efficiency while maintaining a compact footprint suitable for ceiling-mounted or suspended architectural installations.
This product line has been rigorously evaluated through computational fluid dynamics (CFD) simulations and experimental validation, as documented in the research study "Simulation Study on the Effect of Chilled Water Coil Tubes on Active Chilled Beam Performance". The findings confirm that coil tube design parameters — including tube diameter, coil pitch, row count, and fin density — directly govern the thermal performance, airflow distribution, and condensation management characteristics of the overall chilled beam assembly.
Material & Properties
The coil tubes are fabricated from austenitic stainless steel grades selected for their exceptional corrosion resistance, thermal conductivity, and long-term mechanical integrity in HVAC (Heating, Ventilation, and Air Conditioning) service environments.
Primary Material Grades
- SAE 304 / AISI 304 (UNS S30400) — The standard grade offering excellent general corrosion resistance, good weldability, and adequate thermal conductivity (approximately 16.2 W/m·K at 20°C). Suitable for most indoor chilled beam applications.
- SAE 316 / AISI 316 (UNS S31600) — Enhanced grade with molybdenum (Mo) addition (2–3%) providing superior resistance to chlorides and aggressive condensate environments. Recommended for coastal or high-humidity installations.
- SAE 316L (UNS S31603) — Low-carbon variant of 316, offering improved resistance to intergranular corrosion during welding operations and extended service life in continuous-duty applications.
Mechanical and Physical Properties (Typical for Grade 304)
- Tensile Strength (抗拉强度): ≥ 515 MPa
- Yield Strength (屈服强度): ≥ 205 MPa
- Elongation (延伸率): ≥ 40%
- Thermal Conductivity (热导率): 14–17 W/(m·K) at 25°C
- Thermal Expansion Coefficient (热膨胀系数): 17.3 × 10⁻⁶ /°C
- Density (密度): 7.93 g/cm³
- Operating Temperature Range: −196°C to +870°C
Specifications
| Parameter | Specification | Unit |
|---|---|---|
| Tube Outer Diameter (OD) | 6.0 / 8.0 / 10.0 / 12.0 | mm |
| Tube Wall Thickness | 0.4 / 0.5 / 0.6 / 0.8 | mm |
| Coil Pitch (管间距) | 12 – 25 (adjustable) | mm |
| Number of Rows (排数) | 2 – 6 | rows |
| Fin Material | Aluminum (6063-T5) / Stainless Steel | — |
| Fin Density (翅片密度) | 10 – 18 fins per inch | ft⁻¹ |
| Coil Length (盘管长度) | 600 – 2,400 (customizable) | mm |
| Working Pressure (工作压力) | ≤ 1.0 (tested at 1.5×) | MPa |
| Cooling Capacity (制冷量) | 1.5 – 8.0 (depends on configuration) | kW |
| Chilled Water Inlet Temperature | 7 / 12 / 18 | °C |
| Chilled Water Flow Rate | 0.1 – 1.2 | L/s |
| Surface Finish | Mirror polished / Hairline brushed / Matte | — |
| Connection Type | Flanged / Threaded / Soldered / Brazed | — |
Manufacturing Process
The production of high-performance stainless steel coil tubes involves a multi-stage manufacturing sequence designed to ensure dimensional precision, metallurgical integrity, and optimal thermal performance:
- Hot Rolling & Annealing (热轧与退火) — Stainless steel strip or seamless tube blanks are hot-rolled to the target dimensions and subsequently annealed at 1,050–1,100°C to relieve residual stresses and restore full austenitic microstructure.
- Pickling & Passivation (酸洗钝化) — The rolled product undergoes acid pickling (using mixed HNO₃/HF solution) to remove oxide scale, followed by passivation to establish a protective chromium oxide (Cr₂O₃) film on the surface.
- Cold Drawing / Forming (冷拉/成型) — Tubes are cold-drawn to achieve precise wall thickness tolerances (±0.05 mm) and then formed into the coiled geometry using CNC-controlled bending equipment. The cold working process introduces beneficial work hardening, increasing yield strength by 20–30%.
- Fin Attachment (翅片装配) — Aluminum or stainless steel fins are attached to the coiled tubes via either the integral fin (roll-bonded) method or the plate-fin method, ensuring minimal thermal contact resistance between fins and tubes.
- Welding & Brazing (焊接与钎焊) — Header connections and manifold joints are fabricated using TIG (Tungsten Inert Gas) welding or silver brazing, with full radiographic (RT) or dye penetrant (PT) inspection.
- Hydrostatic Pressure Testing (水压试验) — Each coil assembly undergoes hydrostatic testing at 1.5 times the maximum working pressure for a minimum of 30 seconds to verify leak-tightness and structural integrity.
- Performance Testing (性能测试) — Final units are tested in accordance with ASHRAE Standard 96 to verify cooling capacity, airflow characteristics, and condensate management under rated conditions.
Applications
The Stainless Steel Chilled Water Coil Tube is engineered for a broad spectrum of commercial and industrial HVAC applications, with particular optimization for active chilled beam systems:
- Active Chilled Beam Systems (主动式冷梁) — Primary application; the coil tube serves as the evaporative and sensible cooling element within the chilled beam terminal, utilizing both natural convection and forced ventilation for efficient space conditioning.
- Commercial Office Buildings (商业办公楼) — Providing zonal cooling with minimal energy consumption and superior occupant comfort through indirect cooling methods.
- Healthcare Facilities (医疗设施) — Stainless steel construction ensures hygienic performance and resistance to antimicrobial cleaning agents in hospitals, laboratories, and pharmaceutical cleanrooms.
- Data Centers (数据中心) — High-density cooling applications where precision temperature control and condensate-free operation are critical.
- Hospitality & Retail (酒店与零售) — Discreet ceiling-integrated cooling solutions that maintain architectural aesthetics while delivering reliable thermal performance.
- Marine & Coastal Installations (海洋与沿海设施) — 316/316L grade coil tubes provide reliable service in chloride-rich environments.
Quality Certifications & Standards Compliance
Wenzhou Jixing Metal Materials Co., Ltd maintains a comprehensive quality management framework ensuring full traceability and compliance with international standards:
- ISO 9001:2015 — Quality Management Systems certification
- ISO 14001:2015 — Environmental Management Systems certification
- EN 10204 3.1 — Material test certificates provided with each shipment
- ASTM A270 / A269 — Compliance with American standards for austenitic stainless steel tubing
- ASME B31.5 — Pressure piping design and fabrication compliance
- ASHRAE Standard 96 — Performance rating for air-cooled and water-cooled heat exchangers
- NSF/ANSI 61 — Drinking water system components certification (where applicable)
- CE Marking — European conformity for construction products
Unique Selling Points
The research-backed design philosophy behind this product line distinguishes it from conventional coil tube offerings in the market. Key differentiators include:
- Simulation-Validated Performance — Coil geometry parameters are optimized through rigorous CFD simulation studies, ensuring that the interplay between tube diameter, pitch, row configuration, and fin density achieves peak thermal efficiency for active chilled beam integration.
- Superior Condensate Management — Surface treatment and geometric optimization minimize premature condensation formation, reducing drip-related occupant discomfort and maintenance frequency.
- Enhanced Surface-to-Volume Ratio — The precision coiling process maximizes heat transfer area within a constrained envelope, delivering cooling capacities up to 25% higher than standard coil configurations of equivalent footprint.
- Long Service Life — Austenitic stainless steel construction provides a design service life exceeding 25 years without degradation of thermal or mechanical properties, significantly reducing total cost of ownership (TCO).
- Modular Scalability — Standardized connection interfaces and modular coil lengths enable rapid deployment and easy retrofitting in existing chilled beam infrastructure.
- Full Material Traceability — Each production batch includes mill test certificates, heat number traceability, and non-destructive testing (NDT) reports, ensuring complete supply chain transparency.
Technical Notes
Proper installation and maintenance of the stainless steel coil tube within active chilled beam systems requires adherence to the following guidelines: ensure minimum 150 mm clearance above and below the coil for adequate airflow; utilize flexible stainless steel or PEX (Cross-Linked Polyethylene) piping for water connections to accommodate thermal expansion; install condensate drains with a minimum slope of 1:100; and perform annual visual inspections for fin fouling or corrosion. The stainless steel surface should be cleaned using neutral pH detergents to preserve the passive oxide layer and maintain long-term corrosion resistance.