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Dell Tech World stood out not only for Dell’s strong lineup of product launches but also for the innovative solutions showcased by their partners in the expo hall. This year, no category drew more attention than the diverse array of liquid-cooling technologies on display. Interest in liquid cooling is so high that our social media videos featuring these systems have racked up millions of views in just the past few weeks. Unless your workloads are completely routine, liquid cooling is destined to make its way into your data center. Below is a breakdown highlighting which technologies might suit your needs, depending on where you are in your liquid-cooling journey.
Direct-to-Chip Internal Loop
By far the simplest way to adopt liquid cooling in a data center is through a closed internal loop. Similar to a CPU cooler in a gaming PC, these systems use a cold plate paired with a large radiator to draw heat away from key components. JetCool offers such solutions; at the event, they demonstrated both Intel and AMD-powered Dell systems equipped with an internal closed loop.
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The biggest advantage of these systems is that they deliver substantial power savings—10-15% according to JetCool—without the complexity of connecting to facility water lines. In some data centers, a full liquid cooling loop may not even be feasible, making this method the best alternative to air-cooled servers.
JetCool Internal Loop
While the power savings from a closed internal loop aren’t as high as those from other options, even a 10% reduction is significant for data centers limited by the amount of power they can supply per rack. A small power saving from a closed internal loop could enable support for an extra one or two servers per rack.
It’s also worth noting that Dell uses an internal loop on the PowerEdge XE8640 GPU server. You can learn more about this model, along with the XE9640, in a recent YouTube video we produced.
Direct-to-Chip Full Liquid Loop
The next step from an internal loop is connecting to facility water, which helps remove heat not just from the servers but from the entire data center. There are halfway measures, though. In a recent review, we featured CoolIT Systems, where we retrofitted an R760 server for liquid cooling by adding cold plates. We also installed a small manifold and a coolant distribution unit (CDU), though our CDU was liquid-to-air. This means we were removing heat from the R760 but still releasing it into the data center, requiring additional cooling to eliminate it.
Dell R760 with CoolIT Coldplates
Our small-scale setup can support a few servers, but if you’re preparing for new liquid-cooled Dell PowerEdge XE9680L GPU servers, for example, you’ll need a more robust solution. CoolIT has been a key partner in Dell’s liquid-cooling roadmap, and at the event, they showcased their new Omni cold plates, advanced CDUs, and a range of other cooling technologies.
But direct-to-chip cooling isn’t a one-size-fits-all solution; there are multiple implementation methods. This is most evident with ZutaCore’s offering, which uses a unique two-phase approach to cool chips. ZutaCore had several displays, the highlight being a retrofitted XE9680 GPU server equipped with 14 cold plates—8 for the GPUs, 4 for the switches, and 2 for the CPUs. This is an extremely compelling technology, and we have an in-depth podcast about it if you want to learn more.
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To highlight another variation of direct-to-chip cooling, we’ll mention Chilldyne. While they weren’t technically at the Dell Tech World expo, we met with members of their team at a hotel bar—close enough in our book. To be clear, Chilldyne is a Dell partner, and we’ve seen their equipment in Dell’s labs.
Chilldyne’s key innovation is a negative-pressure liquid loop, which means if a line is cut, no fluid is lost. Leaks are the top concern holding back liquid cooling adoption in data centers, so Chilldyne is onto something significant here. We’ve created a short video highlighting their technology, which has become one of our most popular social media videos this year.
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Rear Door Heat Exchangers (RDHx)
Rear Door Heat Exchangers are passive or active heat exchangers that replace a server rack’s back door. They essentially absorb heat from the server exhaust air and transfer it to a liquid loop for cooling. Passive doors are completely silent, with no fans, while active RDHx can add fans to boost efficiency.
Liebert DCD50 RDHx
While RDHx weren’t a major focus at Dell Tech World, they’re worth mentioning for two key reasons, spanning opposite ends of the adoption spectrum. First, they’re a relatively simple first step to adding liquid cooling to your data center and can be deployed in various standalone configurations. Second, RDHx can be paired with other liquid cooling technologies to achieve 100% heat recapture via liquid cooling—a topic of discussion at last week’s event in Las Vegas.
Liebert DCD50 RDHx
Nearly all companies working at the rack scale offer some form of RDHx, including Dell Tech World exhibitors like CoolIT and Vertiv. It’s also worth noting that Dell is promoting RDHx as part of its XE9680L initiative: “A 70KW design that uses air cooling with Rear Door Heat Exchangers (RDHx), supporting 64 GPUs – ideal for NVIDIA H100/H200/B100. We also have a 100KW design that uses liquid cooling with RDHx, supporting 72 B200 GPUs – this is the most compact rack scale architecture in the industry.”
Full Immersion Liquid Cooling
Up to this point, all the data center liquid cooling options we’ve discussed are relatively mainstream. Full immersion, however, is where things get a bit more complex, according to the feedback we’ve received. As the name suggests, this technology takes off-the-shelf servers (with minor modifications) and submerges them in an engineered fluid (proprietary dielectric coolants). BP and Shell, among others, produce fluids for this purpose. We’ve seen full immersion racks at trade shows like Dell Tech World for 3-4 years, and this year both Submer and GRC offered live immersion demos.
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Single-phase immersion cooling (two-phase had a brief moment of popularity but has largely fallen out of favor) makes sense in many scenarios and is a favorite among crypto miners. However, the rules change slightly when considering enterprise servers like PowerEdge systems. For servers, the first step is to remove the fans, which provides immediate power savings. Convection—either natural or assisted by pumps—circulates the fluid over the server’s components. From there, heat is captured via a heat exchanger and removed from the data center.
This system eliminates the need for air cooling, and both GRC and Submer cite data indicating that servers in immersion cooling have longer lifespans and fewer service incidents than air-cooled servers. But one of the biggest challenges is that servers must be removed from the fluid for maintenance. While this isn’t difficult, it’s more cumbersome than servicing traditionally racked equipment. A server in immersion must be taken out of the fluid, dried off slightly, and then placed on a table for service. It’s not an impossible task, but it does require a bit more effort.
Other concerns include the weight of the tanks and fluid, as well as floor space efficiency compared to standard vertical racks. The immersion industry argues that tanks can be stacked and that systems in immersion tanks are actually more efficient. We have a informative podcast on immersion cooling if you want to dive deeper.
Conclusion
If your organization is involved with AI or other applications that use dense GPU setups, liquid cooling is inevitable for your data center. It’s highly likely that if you purchase an 8-way GPU server today, by the time it arrives at your facility in a year, it will come with a closed internal loop—unless you’ve already invested in a full liquid loop by then. The good news is that the industry is identifying the barriers to adoption, such as the lack of universal manifold connectors, and working to solve these issues, making liquid cooling more accessible for enterprises.
Beijing Qianxing Jietong Technology Co., Ltd.
Sandy Yang/Global Strategy Director
WhatsApp / WeChat: +86 13426366826
Email: yangyd@qianxingdata.com
Website: www.qianxingdata.com/www.storagesserver.com
Sandy Yang/Global Strategy Director
WhatsApp / WeChat: +86 13426366826
Email: yangyd@qianxingdata.com
Website: www.qianxingdata.com/www.storagesserver.com
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