CDU (Coolant Distribution Unit)

Overview

A Coolant Distribution Unit (CDU) is the facility-level component that manages the interface between the data center's technology cooling system (TCS) loop and the facility water or heat rejection system. CDUs regulate coolant temperature, pressure, flow rate, and quality for the IT-side liquid cooling loop, isolating it from the building-side water network. As liquid cooling scales from rack-level to facility-level, CDUs become a critical standardization target: they must interoperate with cold plates from multiple vendors, handle flow rates from tens to hundreds of liters per minute, and maintain the coolant quality (filtration, chemistry) required by increasingly sensitive cold plate geometries.

Google's Project Deschutes 1.0 is the first OCP CDU specification, establishing a baseline for CDU performance, interfaces, and monitoring. The OCP CE TCO Tool v1.3 includes CDU as one of the cooling architecture options for total cost of ownership comparison alongside Direct-to-Chip Cooling, RDHX, and CRAH configurations. CDU standardization is positioned as essential infrastructure for the liquid cooling market projected at approximately $55-60B by 2035.