CDU Components for Data Center Liquid Cooling Infrastructure
Coolant Distribution Units (CDUs) are the central heat rejection and fluid management systems in rack-level and row-level liquid cooling infrastructure. CDU components — including plate heat exchangers, reservoirs, bypass valves, pumps, and control interfaces — determine the thermal capacity, reliability, and controllability of the cooling loop.
How It Works
A CDU transfers heat from the server-side coolant loop to the facility water or cooling tower circuit through a plate heat exchanger. The server-side loop is a closed secondary circuit maintained at the required coolant temperature and pressure. A reservoir provides fluid volume buffer and allows for thermal expansion. Bypass valves regulate flow between the heat exchanger and the bypass circuit to maintain target coolant temperature. Pumps circulate coolant through the server-side loop. Control interfaces monitor temperatures, pressures, and flow rates and communicate with the building management system (BMS) or data center infrastructure management (DCIM) platform.
Applications
- Rack-level CDU for direct-to-chip GPU cooling
- Row-level CDU for multiple rack cooling loops
- Facility water interface for server-side cooling loops
- AI data center cooling infrastructure
- HPC cluster thermal management
- OEM liquid-cooled rack and server systems
- Modular data center cooling infrastructure
- Edge data center liquid cooling
Key Technical Specifications
| Heat Exchanger Types | Brazed plate, gasketed plate, shell-and-tube |
| Thermal Capacity | 5 kW to 100+ kW per unit — application dependent |
| Primary Circuit | Facility chilled water or cooling tower water |
| Secondary Circuit | Server-side coolant loop (water or glycol/water) |
| Reservoir Options | Inline, standalone, pressurized expansion vessel |
| Bypass Valve | Motorized 3-way valve, thermostatic valve |
| Control Interface | Analog (0–10V, 4–20mA), Modbus RTU/TCP, BACnet |
| Materials | Stainless steel 316L, copper-brazed, titanium options |
| Working Pressure | Up to 16 bar — confirm by component type |
| Certifications | Options available depending on configuration and manufacturing partner. Please specify project requirements. |
Specifications are indicative. Final parameters depend on manufacturing partner and project configuration. Contact us with your specific requirements.
Available Configurations
- Brazed plate heat exchanger — compact, high efficiency, fixed plate count
- Gasketed plate heat exchanger — serviceable, adjustable capacity by adding plates
- Shell-and-tube heat exchanger — high pressure, high temperature applications
- Pressurized expansion reservoir — maintains system pressure and fluid volume
- Motorized 3-way bypass valve — active temperature control
- Thermostatic bypass valve — passive temperature control without external power
- Modbus-enabled control interface — BMS and DCIM integration
- Redundant pump configuration — N+1 pump reliability
Materials
Operating Conditions
- Thermal capacity: specify rack heat load and number of racks per CDU
- Primary circuit: confirm facility water temperature, pressure, and flow rate
- Secondary circuit: specify target coolant supply temperature and flow rate
- Control integration: specify BMS protocol (Modbus, BACnet, or analog)
- Redundancy: specify N+1 or 2N pump and valve requirements
- Environment: specify ambient temperature range for CDU enclosure design
Selection Guide
CDU component selection requires: (1) Thermal capacity — size the heat exchanger to the total rack or row heat load with appropriate margin; (2) Primary circuit conditions — the facility water temperature, pressure, and flow rate determine heat exchanger sizing; (3) Secondary circuit temperature — the target coolant supply temperature determines the heat exchanger approach temperature and sizing; (4) Control requirements — specify BMS integration protocol and control strategy; (5) Redundancy — N+1 pump configurations are standard for critical cooling applications; (6) Serviceability — gasketed plate heat exchangers allow capacity adjustment and plate replacement; brazed plate exchangers are more compact but not field-serviceable.
OEM & Custom Manufacturing
Custom CDU assemblies and components are available for OEM equipment manufacturers and system integrators. Custom options include non-standard thermal capacities, proprietary control interfaces, specific material combinations for unusual coolant chemistries, and integrated monitoring packages. Provide your thermal load, facility water conditions, and control requirements for a design review.
Submit Custom RequirementQuality & Testing
CDU components for data center applications require pressure testing, leak testing, and thermal performance validation. Heat exchanger performance should be validated against the manufacturer's thermal rating at the specified operating conditions. Control interface functionality should be verified against the BMS integration specification before installation.
Frequently Asked Questions
What is the difference between a brazed plate and gasketed plate heat exchanger for CDU applications?
Brazed plate heat exchangers are compact and have no gaskets, making them suitable for high-pressure applications and environments where gasket maintenance is undesirable. Gasketed plate heat exchangers are larger but allow plates to be added or removed to adjust capacity, and gaskets can be replaced in the field. For data center CDU applications, gasketed plate exchangers are often preferred for their serviceability.
What coolant temperature does a CDU typically supply to the servers?
CDU supply temperature depends on the facility water temperature and heat exchanger approach temperature. With facility chilled water at 12–18°C, CDU supply temperatures of 20–30°C are typical. Higher supply temperatures (up to 45°C) are possible with warm water cooling designs, which can use free cooling or cooling tower water without mechanical refrigeration.
How is a CDU integrated with the building management system?
CDUs typically communicate with the BMS via Modbus RTU or TCP, BACnet, or analog signals (0–10V, 4–20mA). The CDU controller monitors coolant temperatures, pressures, flow rates, and pump status, and can receive setpoint commands from the BMS. Specify the required protocol and data points when requesting a CDU configuration.
What is the typical thermal capacity range for a rack-level CDU?
Rack-level CDUs for AI GPU racks typically range from 30 kW to 100+ kW per unit, depending on the rack power density. Row-level CDUs serving multiple racks may have capacities of 200 kW to 1 MW. Specify your rack heat load and number of racks for appropriate CDU sizing.
Need CDU Components for Your Project?
Send your connection size, coolant type, flow requirements and estimated quantity. Our team will review the application and identify suitable manufacturing options.