AI Server Liquid Cooling Fan Solutions
Fengheng Technology supplies high-performance cooling fans purpose-built for AI data center liquid cooling architectures — including Rear-Door Heat Exchangers (RDHx), CDU pump stations, and GPU module auxiliary cooling. Established in 2011, ISO 9001 certified, with CE, RoHS, FCC, VDE and UKCA approvals.
Why AI Servers Still Need Fans in Liquid Cooling Systems
Modern AI data centers operate on a 70% liquid / 30% air hybrid cooling architecture. Even in fully liquid-cooled rack deployments, high-static-pressure PWM fans remain essential for:
- Rear-Door Heat Exchangers (RDHx) — fans pull warm exhaust air through chilled water coils, removing 30–120 kW per rack
- CDU Pump Station Heat Dissipation — fans cool the CDU chassis electronics and ensure safe ambient temperatures around the pump loop
- GPU Module Auxiliary Cooling — DIMMs, power supplies, NICs and storage controllers are not covered by cold plates and require dedicated airflow
- Telecom & Edge AI Nodes — sealed enclosures with liquid cold plates still need airflow to handle residual heat from non-liquid-cooled components
Recommended Fengheng Products for Liquid Cooling Applications
| Model | Size | Voltage | Max RPM | Application |
|---|---|---|---|---|
| FH9225-PWM | 92×25mm | 12V DC PWM | 4,500 RPM | RDHx radiator fan, CDU station |
| FH12025-PWM | 120×25mm | 12V/48V DC PWM | 3,800 RPM | High-density rack liquid cooling assist |
| FH12038-PWM | 120×38mm | 12V DC PWM | 4,500 RPM | CDU booster, high-airflow liquid cooling |
| FH17251-EC | 172×51mm | 220V EC | 2,800 RPM | Large RDHx, row-level liquid cooling |
| FH240-AL | 240mm Aluminum | 12V DC | 2,000 RPM | Water-cooled aluminum radiator fan |
Key Technical Specifications for AI Liquid Cooling Fans
- Voltage range: 12V / 24V / 48V DC; 110V / 220V / 380V AC/EC
- Speed control: 4-pin PWM (10–100% speed range), 0–10V analog, RS485
- Bearing type: Dual ball bearing — MTBF ≥ 50,000 hours @ 40°C
- Operating temperature: −40°C to +105°C (wide-temp industrial grade)
- Airflow: Up to 185 CFM (120×38mm high-speed series)
- Static pressure: Up to 0.85 inH₂O — suitable for dense heatsink/radiator fin stacks
- Certifications: CE, RoHS, FCC, VDE, UKCA, SGS, ISO 9001
- IP rating: IP55 available for wet/mist liquid cooling environments
Three Core Application Scenarios
Scenario 1: Rear-Door Heat Exchanger (RDHx) Fans
RDHx units mount on the rear of server racks, removing heat from hot exhaust air before it enters the data center aisle. Active RDHx configurations require high-static-pressure fans to force airflow through dense copper/aluminum fin coils. Fengheng 92×25mm and 120×38mm PWM fans are drop-in replacements for standard RDHx fan arrays, delivering up to 4,500 RPM with <45dBA noise. Each unit removes 50–120 kW per rack at typical data-center chilled-water supply temperatures of 18–20°C.
Scenario 2: CDU (Coolant Distribution Unit) Station Cooling
CDU pump stations circulate chilled water or dielectric fluid between the facility chiller and server cold plates. The CDU chassis itself — housing pumps, manifolds, heat exchangers, and control electronics — requires reliable ambient cooling. Fengheng 48V DC fans with dual-ball bearings and MTBF ≥ 50,000 hours are ideal for 24/7 CDU operation. The 48V architecture reduces current draw by 4× versus 12V, minimizing heat from the PDU and improving overall rack PUE.
Scenario 3: GPU Module & Memory Auxiliary Cooling
Even in direct liquid-cooled AI compute nodes (e.g., NVIDIA HGX H100/H200, AMD MI300X), DIMMs, VRMs, PCIe switches, and NVMe drives generate residual heat that cold plates do not cover. Server OEMs retain 2–4 system fans per 1U/2U node to handle this airflow path. Fengheng slim-profile DC fans (25–60mm thickness) with PWM control are engineered for the tight mechanical envelopes of modern AI server trays.
Why Fengheng for AI Liquid Cooling
- ✅ Proven in premium automotive — Bentley Motors supplier since 2022; same engineering standards applied to data center fans
- ✅ 48V transition-ready — full 48V DC fan range matching next-gen Open Rack v3 / OCP power architecture
- ✅ Dual counter-rotating fans — bidirectional airflow option for RDHx where both push and pull are required in a single module
- ✅ AI-proportional thermal control — field-oriented vector control (FOC) PWM driver enables precise RPM management by BMC/IPMI
- ✅ Custom OEM/ODM — Dongguan OEM facility (est. 2021) supports full customization: blade count, frame size, connector type, firmware
Frequently Asked Questions — AI Liquid Cooling Fans
Q: Do liquid-cooled AI servers still need cooling fans?
A: Yes. In the dominant 70% liquid / 30% air hybrid architecture, fans are required for Rear-Door Heat Exchangers (RDHx), CDU station electronics, DIMMs, power supplies, NICs, and storage — components not covered by liquid cold plates. Eliminating fans entirely is only possible in full-immersion cooling, which currently represents less than 2% of AI server deployments.
Q: What fan size is recommended for a 120 kW RDHx unit?
A: A 120 kW RDHx typically uses a 6×4 array of 80mm or 92mm fans, or a 2×3 array of 120mm fans. Fengheng FH9225-PWM (4,500 RPM, 68 CFM each) and FH12038-PWM (4,500 RPM, 185 CFM each) are both field-validated in commercial RDHx deployments. Contact our engineering team for CFD-backed selection based on your specific fin pitch and water temperature.
Q: What voltage should I choose — 12V or 48V DC?
A: For new AI rack builds, 48V DC is strongly recommended. It reduces current by 4×, allowing thinner power cables, lower resistive losses, and better compatibility with OCP Open Rack v3 and NVIDIA MGX power delivery. Fengheng offers a complete 48V fan portfolio from 40mm to 220mm. Legacy 12V racks can use our 12V/48V dual-voltage models for a drop-in upgrade path.
Q: What MTBF do your liquid cooling fans achieve?
A: Fengheng dual-ball bearing fans achieve MTBF ≥ 50,000 hours (approximately 5.7 years of continuous operation) at 40°C ambient. This is validated per IEC 60068-2-6 vibration testing and ISO 16750-3 automotive-grade shock standards — the same testing applied to our Bentley Motors automotive fan supply program.
Q: Can fans operate in humid or mist-prone liquid cooling environments?
A: Yes. Fengheng IP55-rated fans are tested to withstand water jet ingress and sustained high-humidity environments, making them suitable for immersion-adjacent deployments, outdoor edge AI nodes, and environments where coolant micro-misting is a risk. FDA/FDB fluid dynamic bearing models are also available for near-zero vibration in precision liquid cooling installations.
Q: Do you support PWM speed control for BMC/IPMI integration?
A: Yes. All Fengheng 4-pin PWM fans are compatible with standard BMC (Baseboard Management Controller) and IPMI fan speed control. We also support 0–10V analog control, RS485 bus, and tachometer signal output for closed-loop thermal management integration. Custom firmware for specific PWM curves is available under NDA for OEM partners.
Q: What certifications do your fans carry for data center use?
A: CE, RoHS, FCC (USA), VDE (Germany), UKCA (UK), SGS, and ISO 9001:2015 quality management system. For data center applications requiring EMC compliance, we can provide pre-tested configurations. UL certification is available upon request for North American deployments.
Q: Can you supply OEM/ODM custom fans for our liquid cooling product?
A: Yes. Our Dongguan OEM facility (established 2021) specializes in custom fan design and manufacturing for OEM and system integrators. Minimum order quantities, tooling timelines, and NDA terms available upon request. We have supplied custom fans to clients in the UK luxury automotive, Japanese electronics retail, and Singapore air purifier markets.
Request a Liquid Cooling Fan Sample or Quote
Contact Fengheng Technology to request engineering samples, custom specifications, or volume pricing for AI data center liquid cooling fan applications.
- 📧 Email: [email protected]
- 📱 WhatsApp: +86-181 0301 7365
- 🌐 Product catalog: View All Cooling Fans