What do coolant distribution units do in a data center?
Keeps the server coolant separate, clean, moving, and monitored. A coolant distribution unit (CDU) is the boundary between facility water and the technology loop serving cold plates or other rack equipment. A heat exchanger keeps the fluids apart; pumps, valves, filters, sensors, expansion capacity, and controls deliver the required temperature, flow, pressure, and chemistry. Units range from in-rack appliances to shared row and plant systems. Key interfaces are primary water, secondary headers or manifolds, electrical feeds, drains or fill points, leak detection, and building and data-center controls. Capacity is not one fixed number. It changes with approach temperature, flow, fluid mix, external pressure loss, fouling, and the required failure state. A pump, drive, controller, sensor, filter, heat exchanger, or power feed can limit the whole served group, so redundancy must be traced through the ordered configuration. Operators need isolation, safe fill and venting, filter changes, water tests, alarm response, and a way to commission added racks without upsetting live ones. Procurement should request rated and partial-load curves at site conditions, electrical and heat loss, materials, chemistry limits, connection details, turndown, controls, sound, floor load, service access, factory tests, and an explicit sequence for every credible fault.