You’re responsible for keeping thousands of servers running reliably, and the biggest threat to uptime isn’t cyberattacks or power failures – it’s heat. Modern data centers generate massive amounts of thermal energy, with server racks producing heat densities that can exceed 20 kilowatts per rack. Without effective cooling strategies, equipment fails, performance can easily break down, and you find yourself facing costly downtime that impacts your entire organization.
The challenge is clear: How can you keep temperatures stable while managing energy costs that potentially account for 40 percent or more of your total operational expenses?
The answer to this question isn’t always as straightforward as you might like, but here are a few options:
1. Hot Aisle/Cold Aisle Containment Systems
The foundation of efficient data center cooling starts with how you arrange your equipment. Hot aisle/cold aisle containment creates physical separation between the cold air being supplied to your servers and the hot air being exhausted from them. You arrange server racks in alternating rows, with cold aisles facing the fronts of the servers and hot aisles at the backs.
Taking this concept further, you can implement full containment systems that use doors, curtains, or panels to completely seal either the hot or cold aisles. Cold aisle containment keeps the cooling supply isolated from the rest of the data center, ensuring cold air reaches equipment intakes efficiently. Hot aisle containment captures heated exhaust air before it mixes with the rest of the facility, making it easier to remove that heat from your building.
The efficiency gains from proper containment are pretty substantial. You reduce the mixing of hot and cold air that forces your cooling systems to work harder. Your CRAC (Computer Room Air Conditioning) units operate more efficiently when they’re not fighting against hot spots and cold spots throughout the facility. You can also raise your cooling setpoints. (Many contained data centers operate successfully at 75 to 80 degrees Fahrenheit instead of the traditional 68 to 72 degrees Fahrenheit, cutting cooling energy consumption by 20-30 percent.)
2. Liquid Cooling Solutions
As server densities continue climbing, air cooling approaches practical limits. You’re dealing with chips that generate more heat in smaller spaces than air can effectively remove. Liquid cooling transfers heat far more efficiently than air – water, for instance, has about 3,500 times the heat capacity of air by volume.
- Direct-to-chip liquid cooling uses cold plates mounted directly on processors and other high-heat components. Liquid flows through these plates, absorbing heat at the source before carrying it away to be cooled and recirculated. You dramatically reduce the heat load on room-level air cooling systems, and you can handle rack densities of 50 kilowatts or higher that would be impossible with air cooling alone.
- Rear door heat exchangers offer a less invasive liquid cooling option. You replace standard rack doors with heat exchanger units that cool the hot exhaust air from servers as it exits the rack. This approach works with your existing server configurations and doesn’t require modifications to individual servers, making it easier to implement in established facilities.
- Immersion cooling is one of the most aggressive liquid cooling strategies. You submerge entire servers in dielectric fluid that doesn’t conduct electricity. The fluid absorbs heat directly from all components, providing the most efficient heat transfer possible. While immersion cooling requires specialized infrastructure and purpose-built servers, it allows for the highest possible densities and can nearly eliminate the need for traditional air cooling systems.
The challenge with liquid cooling is higher complexity and upfront costs. You’re adding plumbing infrastructure, pumps, and new maintenance requirements to your facility. However, as long as you work with a custom data center cooling provider that is capable of developing a modular system for your specific environment, you should be good.
3. Free Cooling with Economizers
Why pay to mechanically cool air when outside conditions can do the work for you? Economizers allow you to use outside air to cool your data center when ambient temperatures are low enough, dramatically reducing or eliminating the energy required for mechanical cooling during cooler months or in temperate climates.
- Air-side economizers bring filtered outside air directly into your data center when outdoor temperatures drop below your setpoint. You’re using nature’s cooling instead of running chillers and compressors. In a lot of climates, you can operate in economizer mode for up to 30-70 percent of the year, slashing cooling costs during those periods.
- Water-side economizers use cooling towers or dry coolers to produce chilled water without running chillers when conditions allow. Even when outdoor temperatures aren’t quite cold enough for full free cooling, water-side economizers reduce the load on your chillers, lowering energy consumption compared to fully mechanical cooling.
The effectiveness of economizers depends heavily on your location. Facilities in cool climates like the Pacific Northwest or Nordic regions can leverage economizers year-round, while hot, humid locations see more limited benefits.
Finding the Right Strategy
It’s rare that a company will find a single cooling solution for a large data center. In most cases, it requires a custom blend of approaches that work for the nuances of your specific environment.
Hopefully, this article has given you ideas for some strategies that work so you can begin engineering the right approach.
