What Is Coolant Distribution Unit (CDU)?_
A CDU is the heat exchanger that sits between the facility water loop and the rack-level liquid cooling system. It transfers heat from the server-side coolant (typically propylene glycol solution) to the facility water, which then rejects heat through cooling towers or dry coolers. CDUs are typically deployed at row-level or rack-level depending on facility design.
Technical Details
CDUs serve as the thermal interface between the clean, controlled server-side coolant loop and the facility water loop. This separation is critical: the server-side loop uses treated propylene glycol/water mixture at precise concentrations, while the facility loop may use different water treatment and operates at different temperatures and pressures. CDUs include pumps for coolant circulation, heat exchangers (plate-and-frame or brazed plate), flow meters and temperature sensors, pressure regulation, and control systems for monitoring and alarming. CDU sizing depends on total heat load: a row of GB200/GB300 NVL72 racks at 120 kW each requires CDU capacity measured in megawatts. CDUs are typically located at end-of-row or in dedicated mechanical spaces.
How Leviathan Systems Works with Coolant Distribution Unit (CDU)
Leviathan Systems installs CDUs and connects them to rack-level manifolds as part of our liquid cooling integration scope, including pressure testing, flow verification, and leak detection system installation.