Liquid-to-liquid coolant distribution unit for liquid-cooled high-performance servers. The CDU In-Rack separates the building’s water circuit from the refrigerant circuit of the IT equipment. This ensures that the requisite volumetric flow, pressure and quality of the cooling medium in the secondary circuit are maintained at all times.; Liquid-to-liquid coolant distribution unit for liquid-cooled high-performance servers. The CDU In-Rack separates the building’s water circuit from the refrigerant circuit of the IT equipment. This ensures that the requisite volumetric flow, pressure and quality of the cooling medium in the secondary circuit are maintained at all times.