Coolant Distribution Unit (CDU) High Capacity Server Cooling

Why Use A Coolant Distribution Unit?

Boyd’s Coolant Distribution Units (CDUs) help lower data center total cost of ownership. CDUs right-sized and custom configured for specific applications mean hyperscale compute systems get the exact, optimal cooling performance the system needs, when it needs it.

In Row Coolant Distribution Unit (CDU)

Freestanding In-Row CDUs are designed to manage high heat loads in hyperscale compute and data center environments.

In Rack Coolant Distribution Unit

In Rack CDUs are designed to integrate into a server chassis and distribute coolant to a series of servers or heat sources.

Coolant Distribution Unit Components

CDU components typically include a rack manifold, rear door heat exchanger and/or a reservoir pumping unit (RPU) for full liquid cooling system functionality.
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Greener Cooling

Data center carbon emissions reduce 30% on average when switching to liquid cooling.

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Lower Data Center Operating Cost

More efficient cooling systems reduce data center energy demand and cost.

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Maximize Compute Density

Compact, high thermal density cooling systems open up more design space in rack design.

What is inside a Coolant Distribution Unit (CDU)?

How to Cool a Data Center? Liquid Cooling System Solutions

Standard Boyd Cooling Distribution Units

System Type Nominal Cooling Capacity Standard Process Temp. Temperature Stability Ambient Temperature Range Dimensions (L x W x H) Typical Industry Datasheet 
2U CDU Liquid to Liquid 15 kw 5°C to 45°C 
(41° to 113°F) 
+/- 1 °C 5°C to 50°C 
(41° to 122°F) 
918 x 480 x 85.5mm
(36.14 x 18.89 x 3.37in) 
Enterprise 2U L2L CDU Datasheet
4U CDU Liquid to Liquid 80 kW 25° to 60°C
(77° to 140°F) 
+/- 1.5 °C 5°C to 45°C 
(41° to 113°F) 
982 x 450 x 175 mm
(38.66 x 17.72 x 6.89in) 
Enterprise 4U L2L CDU Datasheet
10U CDU Liquid to Air 32 kW 25° to 50°C
(77° to 122°F) 
+/- 1 °C 10° to 45°C
(50° to 113°F) 
982 x 538 x 440mm
(38.66 x 21.18 x 17.32in) 
Enterprise 10U L2A CDU Datasheet 
In-Row CDU Liquid to Liquid 305 kW 20° to 49°C 
(68° to 120°F) 
+/- 2 °C 5°C to 40°C 
(41° to 104°F) 
600 x 1885 x 1000mm
(38.66 x 21.18 x 17.32in)
MCS20 – Stand Alone Liquid to Air 1.3 kW  55°C
  15.5°C to 27°C
(60°F to 80°F) 
439 x 384 x 338mm
(17.3 x 15.1 x 13.3in) 
Industrial  MCS20 Datasheet
MCS30 – Stand Alone Liquid to Air 2.1 kW   55°C
  15.5°C to 27°C
(60°F to 80°F) 
 439 x 384 x 338mm 
(17.3 x 15.1 x 13.3in) 
Industrial MCS30 Datasheet
MCS40 – Stand Alone Liquid to Air 2.4 kW  55°C
  5°C to 40°C
(41° to 104°F) 
381 x 381 x 610mm 
(15 x 15 x 24in) 
Industrial MCS40 Datasheet
MCS50 – Stand Alone Liquid to Air 3.5 kW  55°C
5°C to 40°C
(41° to 104°F) 
381 x 381 x 610mm
(15 x 15 x 24in) 
Industrial MCS50 Datasheet
LCS20 Liquid to Liquid 20 kW 10°C to 60°C +/- 0.5 °C 5°C to 40°C
(41°F to 104°F) 
543 x 705 x 810mm 
(21.4 x 27.8 x 31.9in) 

Reliable Field Performance of a Boyd Server Cooling System

Coolant Distribution Units are essential components that ensure liquid cooled servers meet or exceed lifetime expectations. Operation logic integrated into intelligent controllers, automatic diagnostics, warnings, and troubleshooting, in addition to smart flow, pressure, and temperature controls manage server cooling system performance. Advanced system controls respond to peak demands while remaining economical and efficient during non-peak operation and prevent problems before they occur. Blind mate quick disconnects with 360 swivel fittings make servicing data server cooling systems fast for minimized maintenance downtime.

Decades of reliable field performance have enabled Boyd to fine tune system design in liquid cooled servers with validated thermal reliability and leak-free performance for optimal data center cooling. These full liquid cooling systems distribute coolant in and out of a series of server chassis capable of tying into existing facility cooling systems or designed to be fully self-contained. When server or chassis heat loads outpace what traditional air-cooled systems can achieve, CDUs offer higher thermal performance for in-row and server rack cooling. In-rack coolant distribution unit configurations are available for 2U and 4U space and feature redundancy pump design, dynamic condensation-free control, automatic coolant replenishing, a bypass loop for stand-by operation and automatic leak detection. A liquid cooled server negates the need for bulky heat sinks, fan trays, and components in data center cooling systems that create significant environmental noise pollution and consume more energy. 

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Coolant Distribution Unit Flexibility and Space-Saving Benefits

In a server cooling system, integrated CDUs enable greater processing power density with quieter operation and more efficient natural resource utilization. Integrate in-rack CDUs directly into facility water or facility-level cooling systems for direct rack server cooling or design self-contained in-row cooling that offer the next level of flexibility for liquid cooled servers. Leverage CDU cooling capacity to cool the rack, chassis, or blade down even to the processor or silicon. CDUs can be designed to integrate into existing data center or chassis configurations.


The flexibility and space-saving benefits of in-row cooling and rack server cooling may enable data center and chassis designers to completely rethink footprint configuration opportunities to maximize power density. Boyd in-rack and in-row CDUs are designed to meet IEC62368-1 and tested to withstand 3X maximum working pressure. All new subcomponent designs undergo harsh maximum pressure testing to destruction to ensure reliable data and server cooling systems. Reliability testing incudes thermal cycling, min /max storage and packaging testing.

Liquid to Liquid Cooling Distribution Units (L2L CDU)

Liquid to Liquid CDUs require facility water to remove heat from rack and row equipment but come with a battery of benefits to offset added system complexity. Liquid cooled data centers offer higher energy efficiency from the higher heat capacity of liquid, which requires less energy to remove and dissipate more heat. Liquid cooling can replace excessive noise and vibration from fans and blowers improving data integrity and workplace safety. These liquid cooling systems enable smaller footprints and lower total cost of ownership, ideal for artificial intelligence and advanced analytics, blockchain and cryptocurrency, mainframe and gaming servers and supercomputer applications.

While a liquid cooled data center that leverages L2L CDUs to provide responsive, high-capacity cooling, there are additional design and project challenges. From leak-proofing, additional capital expense, installation and training costs, colocations and data center architects must weight the benefits against these project requirements above air cooling. Boyd’s liquid to liquid coolant distribution units are designed and manufactured to mitigate potential risk to enable the fullest benefit of liquid cooling.

Black In Rack 4U Liquid to Liquid Coolant Distribution Unit
Black In Rack 10U Liquid to Air Coolant Distribution Unit

Liquid to Air Cooling Distribution Units (L2A CDU)

Many facilities are not designed for system-wide liquid cooling, so Liquid to Air Coolant Distribution Units can provide the benefits of liquid cooling without the full-scale implementation of facility water. L2A CDUs enable localized liquid cooling for high output IT equipment but leverages the data center’s air conditioning to dissipate heat from the server rack or row. Liquid to Air CDUs maximize the cooling possible with established air-cooled data centers and mature leak-free liquid cold plate and liquid system technologies. By leveraging existing data center cooling systems, liquid to air coolant distribution units minimize thermal management equipment and installation costs but still provide higher capacity cooling that air alone would offer.

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