A great deal has been made about the power and cooling needs of AI servers, and for good reason. The high TDPs of individual chips, combined with the densities vendors are pursuing, are resulting in racks that draw 200kW today and plans for 600kW+ racks in the future. As a result, data center operators have to contend not only with powering these systems but also with keeping them cool. Of the two, power is arguably the easier problem to solve, thanks to designs such as 800VDC busbars. That still leaves the burning topic of how to cool these systems.
At ASRock Rack’s Computex 2026 booth, the company showcased a complete NVIDIA Rubin Vera NVL72 setup. This included not only the NVL72 hardware rack itself, but also, in conjunction with partner Delta, a potential cooling option for the power-hungry rack. An even more massive liquid-to-air coolant distribution unit. Designed to discharge up to 150kW of heat, Delta’s GoCool-150 is positioned as a solution for data centers that want to house direct-liquid-cooled server racks but do not have a larger liquid-cooling loop integrated into the facility.
Delta GoCool-150
Historically, discharging 150kW of heat from a single computing rack would be kind of an absurd proposition to begin with. If you look at what folks consider “high-end,” like the new IBM Z17 mainframes, even those run at much lower power density. And yet, here we are. To that end, Delta has built an equally crazy heat exchanger to accomplish the task.
The GoCool-150 is essentially a massive radiator designed to cool a single liquid-cooled server rack. The company is aiming the CDU at data centers that want to accommodate liquid-cooled servers in facilities originally designed for classic air cooling, relying on air handlers and hot-air containment. As a result, those data centers cannot be easily retrofitted with building-scale liquid-cooling loops.
Absent the ability to use those larger heat exchanger setups, Delta has developed a rack-sized(ish) heat exchanger to be placed in air-cooled data centers. Build a big enough heat exchanger and run enough air through it, and you can indeed discharge upwards of 150kW of heat into such an environment.
The resulting system is an impressive sight of heatsinks, pumps, and fans. From the front of the opened cabinet, the GoCool-150’s two massive heatsinks are readily visible, running nearly the entire height of the CDU and showing off the 5 copper pipes that run through the heatsink.
As well, we can also see part of the plumbing that houses the coolant used on the liquid side of the cooler, and the valves used to add coolant to the system.
By the numbers, the CDU is designed to circulate 225 liters per minute of coolant, with the overall system designed to get that coolant down to 45C. This is in line with NVIDIA’s design goals for the Vera Rubin generation, where a major aspect of the systems is to allow them to run off of a 45C intake in order to make them easier to cool and to make that cooling less power-intensive as well.
At the top of the CDU are its management console, power supply, and control card.
Meanwhile, at the bottom of the CDU are the coolant pump units. Five in all, these pumps are hot-swappable so that faulty pumps can be replaced without requiring any downtime for the CDU or the hardware’s cooling.
Elsewhere, on the back side of the CDU, we find what actually cools the massive heatsinks: fans, lots of fans. The cooler’s 32 fan array is capable of moving 17,658 CFM of air, with the fans taking up most of the rear side of the CDU. Like the pumps, these fans are hot-swappable as well, as moving parts will eventually break down.
Delta is using its in-house developed PFD2048HT fans here, which are 200mm high-speed fans. Each fan is rated to draw up to 336 Watts of power (made easier by the use of 48VDC power) and, with a maximum rotational speed of 8250 RPM, can generate up to 81dBA of noise.
This rear view also shows off the massive coolant tubes leading in and out of the CDU along the top of the unit. With Vera Rubin NVL72 racks requiring liquid cooling, this is standardized infrastructure, but it is a good reference point for just how much coolant is flowing through even one of these racks at any given point.
Speaking of which, here is a great shot of the rear of the NVL72 rack as well, showing off how coolant is distributed throughout the rack from top to bottom.
Overall, the GoCool-150 is a massive box. The CDU alone weighs 1200kg (presumably without the coolant) and stands 2.3 meters tall. Meanwhile, the system is no lightweight in power consumption itself. The cooler needed to discharge 150kW of heat itself needs 18kW.
Final Words
Nothing about the next generation of AI servers is simple. Not the construction of the chips, the design of the server racks, powering the hardware, or extracting all of the heat that the system will generate. NVIDIA has made a very visible decision to go big with its data center hardware to deliver maximum performance, and as a result, we are seeing larger racks, clusters, and coolers.
Delta’s GoCool-150, in turn, is a great visual representation of just what it will take to keep a next-generation Vera Rubin rack cool. The use of liquid cooling somewhat obfuscates just how much heat even a single rack of that hardware can generate. Delta’s liquid-to-air exchanger is a very visible symbol of what it takes to move that heat with conventional air cooling. It is an impressive piece of kit in its own right, and one that will become increasingly necessary as server racks move to liquid cooling, both for the density it enables and the greater cooling efficiency it offers compared to pure air cooling alone.
