With the rapid growth of AI, GPU computing, and hyperscale infrastructure, data centres are experiencing a sharp rise in thermal loads. Rack densities are now reaching 50 kW, 80 kW, and in some HPC environments, more than 200 kW.
In this context, traditional room-based air cooling is increasingly reaching its physical and operational limits.
The challenge of high-density infrastructure
Rising rack power densities introduce several critical challenges:
- Emergence of hotspots caused by uneven airflow
- High energy consumption from cooling systems
- Difficulty managing densities above 50 kW per rack
- Space constraints in existing data centres
Air, due to its relatively low thermal capacity, becomes inefficient at these load levels. Larger and larger air volumes must be moved, increasing both system complexity and energy costs.
A more targeted approach: rack-level cooling
USystems’ Rear Door Heat Exchangers (RDHx) offer an effective alternative by capturing heat directly at the rack exhaust.
The principle is straightforward:
- Hot air is expelled by the servers
- It passes through a heat exchanger integrated into the rear door
- Heat is transferred to a liquid cooling circuit
- Cooled air is returned to the room
This enables direct, source-level cooling without relying solely on room-based air conditioning.
A hybrid and scalable solution
RDHx systems integrate into air-assisted liquid cooling architectures and are compatible with existing infrastructure. This allows operators to transition towards higher-density environments without requiring a complete data centre redesign.
Key benefits
- High density capability: supports up to 200 kW per rack
- Improved energy efficiency: reduced load on traditional cooling systems
- Better PUE: values as low as 1.035 in optimised conditions
- Space optimisation: increased IT capacity per m²
- Simplified retrofit: deployable on existing rack infrastructure
Towards the next generation of data centres
As AI and HPC workloads continue to grow, cooling strategies must evolve. Rack-level cooling, and in particular Rear Door Heat Exchangers, provide a response to the increasing demands for density, efficiency, and scalability.
A more targeted approach to heat removal is becoming a key enabler for the next generation of data centre design.
For more information, visit the Legrand website:
👉 for the Dutch version: https://www.legrand.be/nl/campagne-rdhx-usystems?gad_campaignid=23725716930&gad_source=1
👉 for the French version: https://www.legrand.be/fr/campagne-rdhx-usystems?gad_campaignid=23725716930&gad_source=1
