What is it?
Liquid cooling for data centers provides an alternative to the traditional air-cooled computer room air conditioning (CRAC) systems. Traditional air cooling systems function very similarly to any commercial or residential cooling system. Air is mechanically cooled, and then the cold air is blown over the server components. Liquid cooling systems put coolant directly in contact with the server components, eliminating the need for air cooling.
How does it work?
Liquids, such as water, are superior conductors of heat compared to gasses, like air. One gallon of water possesses 3,000 times more cooling capacity than a gallon of air. Using liquid coolant removes the need for mechanical cooling systems, saving cooling energy.
What are the most appropriate applications?
New data centers are the best fit for liquid cooling systems. Retrofits to existing air-cooled systems are available, but they can be cost prohibitive and require server downtime. High utilization datacenters (servers that are continually computing) are also great candidates for liquid systems because of the large cooling load.
What are the savings?
Utilizing liquid cooled servers can typically reduce cooling energy usage by 35% to 75%. In extreme computing situations, cooling energy is reduced by as much as 98%. A study in Minnesota showed a single liquid-cooled server saved 6,200 kWh per year, more than 10% of total usage. The liquid coolant can also be used for heat recovery, which would add additional energy (electricity or natural gas) savings.
What are the non-energy benefits?
The most considerable non-energy benefit is the ability to reduce the data center footprint, saving on installation costs. Liquid cooled servers are also significantly quieter, have better computing performance, and have lower maintenance costs.
What is the cost?
Costs are manufacturer-specific but can be as low as $100/kW of server max power draw.
What is the status/availability of the technology?
This technology is available through multiple vendors.
What kinds of incentives/programs are available?
Liquid cooling technology rebates come from Custom Rebate programs. Incentives vary depending on customer specifics, but in general, it would take a data center with at least four servers to be cost-effective.