Liquid Cooling in High-Density Data Centers

Exploring the Benefits and Challenges of Implementation

Three Primary Liquid Cooling Technologies

It is currently common for large data centers already to utilize water to cool their facilities. Chillers use chilled water to reduce air temperature by transferring heat. Cooling towers use evaporation to cool hot air. Adiabatic economizers spray water to cool the air that enters the data center. In hyperscale facilities, this adds up to an enormous amount of water loss. In some areas where water supplies are strained, governments are imposing moratoriums on new data center facilities.

Clearly, this approach is not sustainable. But by bringing water into the data center white space, operators can remove heat at its source without wasting any water and may find power savings as most liquid cooling technologies today are able to utilize higher water temperatures.

There are three primary liquid cooling designs:

• Rear door heat exchangers sit on the back of a cabinet and remove heat at its discharge point before it enters the white space. Hot air discharged from the IT equipment moves across a coil, and the heat is transferred to water. Room-neutral air comes out of the back of the cabinet. Rear door heat exchangers remove 100 percent of heat and can support 100kW+ per rack.
• Direct-to-chip cooling puts water on a heat sink or cooling plate inside the IT equipment to remove heat before it is discharged. It removes 60 percent to 80 percent of heat and can support 120kW+ per rack.
• Immersion cooling fully submerges high-performance IT systems in a non-conductive liquid coolant which absorbs the created heat and transfers away via a heat exchanger. Heat generated by compute loads never enter the room, creating a room neutral high density cabinet in existing data centers.

Benefits and Challenges

These techniques conserve water because they are closed systems. Data center operators create a secondary loop that supports the liquid cooling in the white space. The secondary loop uses water or other liquid to remove the IT heat load without interfering with the primary loop that cools the facility as a whole. This enables strict containment and precise control of the liquid cooling system.

A cooling distribution unit (CDU) sits between the two loops, in its own in-row cabinet or as a rackmount unit. It circulates the water through the secondary loop and has a heat exchanger that transfers heat from the secondary to the primary. The water inside the two loops never mix.

Nevertheless, bringing water into the data center white space creates operational challenges. Suddenly, mechanical systems need to enter the IT cabinet, creating a potential conflict when trade contractors and data center operators need access to a customer’s IT equipment. There’s also the question of workforce readiness. Data centers will need to update their methods of procedure (MOPs), standard operational procedures (SOPs) and emergency operating procedures (EOPs) to address this new model.

How Wesco Can Help

Wesco delivers a comprehensive suite of solutions and services for liquid cooling in high-density environments, from discovery through design, deployment and support. By acting as prime contractor, we help reduce the risk of high-density cooling deployment. We can also enter and exit projects at any point.

For customers new to liquid cooling in the data center white space, we can evaluate their existing chilled water capacity and technical configuration and recommend the right technology for greenfield, brownfield, and supplementary projects. We are vendor-neutral, with a wide range of partnerships to support each customer’s needs and preferences.

Once the high-density cooling technology is selected, we can develop an implementation plan and construction-related materials. We can also oversee the deployment of the chosen high-density cooling technology. From Day two forward, we help customers support and maintain their high-density cooling systems, with playbooks, MOPs/SOPs, and recommendation maintenance.

Liquid cooling is an essential component of high-density environments. Wesco can help you select and implement the right cooling solution to take your data center into the future.