Expert Guide to Integrating Liquid Cooling in Your Facility
High-density racks are becoming more common, even in small to mid-sized facilities. As a supplier of mission critical equipment, we’ve seen firsthand how air cooling alone can’t serve small to mid-sized facilities anymore; liquid cooling is also required. This doesn’t mean you have to redesign your entire facility to replace air cooling equipment with liquid cooling systems though. Instead, your facility can adopt a hybrid approach to data center cooling to save money and maintain ideal temperatures. Here’s how:
- Decide what you’re really cooling
- Pick the right liquid cooling approach
- Understand the two loops and where the CDU fits
- Plan the heat path
- Start with a pilot, then scale
In this guide, we’ll break down the five steps small to mid-sized facilties need to take to find and integrate the right cooling system. Let’s get started:
Step 1: Decide What You’re Really Cooling
Liquid cooling is often described as the most efficient way to reduce heat in facilities, but this doesn’t mean every piece of equipment needs it. Every device produces a different amount of heat and smaller amounts of heat don’t need liquid cooling to dissipate them. Generally speaking, the following data center cooling solutions are most cost-effective when paired with the corresponding amounts of heat produced:
- Air cooling solutions: 3kW – 15kW
- Hybrid cooling system: 15kW – 40kW
- Liquid cooling solutions: 40kW+
Don’t just consider your current rack densities, but future rack densities as well. This way you can plan to integrate liquid cooling systems before overheating becomes an immediate concern. Once you know how much cooling your facility needs, you can pick the right solution.
Step 2: Pick the Right Liquid Cooling Approach
There is no one-size-fits-all liquid cooling solution. Which one works best for your facility depends on what type of equipment you need cooled by liquid systems instead of air. Here are the most common liquid cooling solutions and when each one is the best option:
Direct-to-Chip
This liquid cooling system goes straight to the source and uses liquid coolants to dissipate heat directly from computer chips. Typically installed as plates on top of the heat-generating components, this solution takes up minimal space while still effectively removing heat. This makes direct-to-chip cooling ideal for high-density servers in environments with limited space.
Rear-Door Heat Exchangers
This liquid cooling solution replaces the rear door on server racks with a liquid heat exchanger that dispels the warm air from the equipment. Instead of replacing air cooling, rear-door heat exchangers usually work with traditional data center cooling systems to maintain ideal temperatures around critical equipment. As a result, rear-door heat exchangers are ideal for mixed-density server rooms.
Immersion Cooling
Immersion cooling systems are a unique data center cooling solution as they completely submerge servers and rack components in a cooling liquid that absorbs heat as soon as it is produced. This liquid cooling system completely eliminates the need for air cooling, making it ideal for extremely high-density facilities.
After you determine which cooling solution will best fit your facility’s needs, you can start integrating this new system.
Step 3: Understand the Two Loops and Where the CDU Fits
One of the most confusing parts of integrating liquid cooling into your facility is understanding how everything connects. There are usually two loops you need to consider:
- The facility loop, which moves heat through the building
- The technology loop, which serves the racks
Between these two loops sits the CDU, or coolant distribution unit. This piece of equipment plays an integral role in your liquid cooling system by pumping liquid to the racks, controlling temperature and flow, and transferring heat safely between loops. Some CDUs transfer heat to building water, while others reject heat to air inside the room. The right choice depends on how your facility handles heat overall.
Step 4: Plan the Heat Path
No matter how you cool your servers, heat has to leave your facility somehow. In many facilities, heat is rejected using chillers. An air-cooled chiller is a common choice, especially where water use is limited or cooling towers are not practical. Not only does an air-cooled chiller reject heat outdoors using fans and coils, but it also offers a simpler installation than water-cooled systems. When liquid cooling is added, the air-cooled chiller may:
- Support the CDU through chilled water
- Handle added heat loads from high-density areas
- Remain part of a hybrid data center cooling design
Remember to review chiller capacity, redundancy, and controls when planning liquid cooling growth to ensure every piece of your data center cooling system works together. Once you have a plan for how to integrate your new cooling system, you need to test it out before fully committing to this solution.
Step 5: Start with a Pilot, then Scale
Whether you’re converting to a hybrid facility or a total liquid cooling system, implement these changes in phases. Start by integrating your chosen liquid cooling solution into one row or a single rack and monitor its performance closely. Measure success metrics like:
- Uptime
- Energy use
- Thermal performance
- Operational friction
Keep a record of how the installation went as well as the system’s performance afterwards. For example, answer the following questions:
- What took longer than expected?
- Were there any preventable issues that arose?
- Was staff adequately trained on the new data center cooling system or were there education gaps?
This data will give you a clear indicator of how well the new liquid cooling system works in your facility. As a result, you’ll be able to expand liquid cooling to the rest of your facility with a clear plan and less stress.
Looking for More Guidance on Data Center Cooling?
Liquid cooling isn’t an all-or-nothing decision. For many facilities, it’s a smart addition to an existing data center cooling strategy. Sometimes, though, it can feel like this strategy is always changing. Contact us today and speak to one of our experts about your facility’s cooling needs and find the ideal setup that keeps your equipment cool.
Liquid Cooling FAQs
What is liquid cooling in a data center?
Liquid cooling uses fluid to remove heat from servers more efficiently than air.
Is liquid cooling better than air cooling?
It is better for high heat loads. Air cooling still works well for lower-density areas.
Can liquid cooling and air-cooling work together in the same data center cooling system?
Yes. Many data center cooling designs use liquid cooling for high-density racks and air systems connected to an air-cooled chiller for the rest of the room.
Does adding liquid cooling affect facility redundancy?
It can, depending on the design. A well-planned liquid cooling system should maintain or improve redundancy rather than compromise it, especially when the CDU and cooling loops are sized with N+1 in mind.
Do I need specialized staff to maintain a liquid cooling system?
Liquid cooling does require some additional training beyond traditional air cooling, but most facilities teams can be brought up to speed with proper onboarding and service support from their local Vertiv office.
What is a CDU and why is it important for liquid cooling and data center cooling with an air-cooled chiller?
A CDU controls flow and temperature for liquid cooling. It connects rack cooling to facility data center cooling systems and may link to an air-cooled chiller.
How does liquid cooling improve data center cooling efficiency compared to air cooling alone?
Liquid cooling moves heat faster than air, which reduces strain on fans and chillers. This helps data center cooling systems run more efficiently, even when using an air-cooled chiller.
Does liquid cooling reduce floor space needs compared to traditional air cooling?
Often, yes. Because liquid cooling removes heat more efficiently at the source, it can reduce the footprint needed for air handling equipment, freeing up space for additional racks or other uses.
Does liquid cooling reduce the risk of hot spots in data center cooling systems that use an air-cooled chiller?
Yes. Liquid cooling removes heat close to the source, which helps prevent hot spots and supports stable data center cooling, even when heat is rejected by an air-cooled chiller.
How do I know when to move from air cooling to liquid cooling in my data center cooling strategy?
If rack power keeps rising and air struggles to keep up, it may be time to add liquid cooling. Many data center cooling plans still keep an air-cooled chiller in place.