Coolant Distribution Unit - Serie LEAN
Standardized Liquid Cooling in Data Centers
The CDU LEAN is a standardized product series designed for the reliable cooling of direct liquid cooling and direct-to-chip systems. A range of capacity options enables the right configuration for AI, GPU, and HPC infrastructures—with precise control of temperature, pressure, and flow rate. Made in Germany.
The LEAN Series at a Glance:
- for Direct Liquid Cooling and Direct-to-Chip
- Cooling capacities from 300 to 6,500 kW
- Compact, standardized design
- Integrated control, monitoring, and BMS connectivity
What is the CDU LEAN in the cooling system?
The CDU LEAN serves as the hydraulic interface between the on-site cooling water supply (primary circuit) and the IT cooling circuit (secondary circuit). It handles heat transfer and ensures that the connected direct-to-chip cooling systems receive the required flow rate, pressure, and temperature.
Technical Specifications
| Device Type | A-CDU27L | A-CDU54L | A-CDU108L | A-CDU216L | A-CDU324L |
|---|---|---|---|---|---|
| Pump Sizing / External Pressure Drop (Frequency-Controlled): | 27 m³/h at 2,5 bar | 54 m³/h at 2,5 bar | 108 m³/h at 2,5 bar | 216 m³/h at 2,5 bar | 324 m³/h at 2,5 bar |
| Cooling capacity: | 355 kW l 532 kW | 720 kW l 1.065 kW | 1.420 kW l 2.130 kW | 2.850 kW l 4.275 kW | 4.280 kW l 6.420 kW |
| ΔT Secondary Circuit Flow Temperature / Primary Circuit Inlet Temperature: | 3 K | 3 K | 3 K | 3 K | 3 K |
| ΔT Flow/Return Temperature, Secondary Circuit: | 12 K l 18 K | 12 K l 18 K | 12 K l 18 K | 12 K l 18 K | 12 K l 18 K |
| ΔT Primary Circuit Inlet/Outlet Temperature: | 12 K l 18 K | 12 K l 18 K | 12 K l 18 K | 12 K l 18 K | 12 K l 18 K |
| Coolant requirement (primary circuit): | 28 m³/h | 57 m³/h | 114 m³/h | 228 m³/h | 342 m³/h |
Media Connections
| Device Type | A-CDU27L | A-CDU54L | A-CDU108L | A-CDU216L | A-CDU324L |
|---|---|---|---|---|---|
| Secondary circuit: | DN 65 | DN 100 | DN 150 | DN 200 | DN 250 |
| Primary circuit: | DN 65 | DN 100 | DN 150 | DN 200 | DN 250 |
| Rated power: | 4,6 kW | 7,4 kW | 13,6 kW | 27,4 kW | 44,4 kW |
| Rated current under rated conditions: | 10 A | 10 A | 24 A | 49 A | 79 A |
| On-site safety measures: | 16 A | 16 A | 32 A | 63 A | 100 A |
Dimensions
| Device Type | A-CDU27L | A-CDU54L | A-CDU108L | A-CDU216L | A-CDU324L |
|---|---|---|---|---|---|
| Width (mm) | 980 | 980 | 1.380 | 2.780 | 3.380 |
| Depth (mm) | 1.200 | 1.200 | 1.600 | 1.600 | 1.600 |
| Height (mm) | 2.200 | 2.200 | 2.200 | 2.200 | 2.200 |
Control & Monitoring
The CDU LEAN is equipped with a Siemens S7 controller featuring a color touchscreen. Relevant operating parameters can be monitored directly at the system and transmitted via interfaces to higher-level monitoring and building management systems.
Monitoring
- Temperature
- Flow
- Supply Pressure
- Differential Pressure
- Operational and Fault Messages
Communication
- BACnet
- SNMP
- MQTT
- Modbus TCP/IP
- OPC UA
- Profinet
Performance Parameters *
depending on ΔT relative to the customer-supplied coolant temperature
other power ratings available upon request
Device Features *
- Flow pressure and differential pressure control in the secondary circuit
- Maximum pressure limit via the control system (secondary side)
- Redundancy design depending on the selected model or option
- Interfaces: BACnet, SNMP, MQTT, Modbus TCP/IP, OPC UA, and many more.
Options *
Based on ambient temperature
Multiple secondary circuit pumps
Redundant control (hot standby)
Dual control valve (parallel/bypass)
Additional heat exchanger
—also available with conductivity monitoring as an option
Energy meters
with simultaneous plausibility checks
Heat Recovery Module
Temperature Increase Using Heat Pump Technology
Frequently Asked Questions (FAQs)
A Coolant Distribution Unit (CDU) serves as the hydraulic and thermal interface between the building cooling system and the IT cooling circuit. It transfers heat from the IT equipment to the building cooling circuit while simultaneously maintaining the required operating conditions for temperature, pressure, and flow rate.
In addition to heat transfer, a CDU also performs key functions related to liquid cooling. These include, in particular, pump and flow rate control, pressure and differential pressure control, temperature control, as well as monitoring and protection functions.
The primary circuit, or FWS (Facility Water System), connects the CDU to the building's cooling water supply. The secondary circuit, or TCS (Technology Cooling System), supplies cooling fluid to IT-related consumers such as manifolds, servers, and cold plates. In a typical liquid-to-liquid CDU, both circuits are hydraulically isolated from each other.
The cooling capacity of a CDU does not depend solely on a fixed kW rating. Among other factors, the flow rate, temperature difference ΔT, refrigerant, and the temperature conditions at the heat exchanger are crucial. Therefore, performance specifications should always be considered in conjunction with the defined operating point.
Depending on the cooling concept, CDUs can be designed as in-rack, in-row, or central gray-space solutions. In-rack CDUs supply individual racks, in-row CDUs supply multiple racks within a row, and central gray-space CDUs supply larger IT areas or entire data halls.
Redundancy is a key component of availability planning in a data center. Depending on the overall design, measures such as redundant pumps, multiple CDUs, separate power paths, or the ability to perform maintenance during operation may be incorporated. Availability is not determined by a single CDU alone, but by the entire power distribution system.
Depending on the system design, different cooling media can be used. In addition to water, water-glycol mixtures such as PG25 are also used. However, the medium used affects heat capacity, viscosity, and pressure loss—and thus also the achievable cooling capacity and pump design.
Downloads
Do you need any additional documents?
Contact us—we'd be happy to help.
Are you planning to implement liquid cooling for a data center?
Determining which CDU is suitable for a project does not depend solely on the required cooling capacity. Temperatures, flow rates, pressure drops, redundancy, and the existing on-site cooling supply must all be considered together.
We assist you with the technical design of the CDU and its integration into the overall cooling circuit.
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