Google unveils CDU to unlock 1MW data centre racks
Fifth-generation CDU architecture will be contributed to OCP this year.
Google says its Project Deschutes CDU can unlock 1 MW data centre racks with liquid cooling, and it will share the full design with the OCP later this year.
At the 2025 OCP EMEA Summit yesterday, Google unveiled its fifth-generation liquid-cooling CDU for next-gen AI data centres.
It looks like what a mad scientist would come up with.
Liquid cooling for scale
First, why liquid cooling? To stay out of trouble from technical-minded readers, I quote directly from Google:
- Water can transport 4,000 times more heat per unit volume than air for a given temperature change.
- Thermal conductivity of water is roughly 30 times greater than air.
It's so good, that Google says it has been using liquid cooling for its TPUs, which are proprietary AI chips Google created for machine learning, since TPU v3 in 2018*.
*PS: To be clear, Google uses plenty of air-based cooling in its data centres - too much, some industry observers have told me. But that's a post for another day.
Project Deschutes CDU
After years of refinement, Google says it has achieved fleet-wide CDU availability of ~99.999% since 2020, which is impressive given how liquid cooling has its challenges.
Anyway, Google says it will share its CDU architecture with the rest of us soon.
- In-row CDU design.
- UPS for high availability.
- Redundant pump, heat exchanger.
The design takes multiple factors into account, including serviceability, operational excellence, deployment velocity, reliability, and performance.
I'm not sure why the AI rack looks the way it is. My guess is the design simply maximises the space savings that comes from swapping bulky heat sinks (air cooling) with cold plates (liquid cooling).
More room for GPUs
Google also introduced 400 VDC power delivery, bringing power delivery to data centre racks on par with the nominal voltage used by electric vehicles.
The idea is to disaggregate power components from the IT rack with a dedicated AC-to-DC power rack.
Benefits?
- Maximum densification of IT racks.
- Improved end-to-end efficiency of ~3%.
What's OCP?
The Open Compute Project (OCP) is an industry consortium that designs open, efficient, and scalable hardware for data centers.
The idea is to share designs openly to encourage industry-wide collaboration and accelerate the deployment of efficient computing solutions.
Did you know: PDG's SG1 data centre in Singapore is OCP Ready certified and hosts an OCP Experience Centre?
