As heat loads rise with AI and hyperscale computing, cooling has become one of the most critical—and expensive—aspects of data center operations. Fortunately, new technologies and architectural strategies are making it possible to significantly reduce cooling energy consumption while enhancing thermal performance and operational reliability.
Below is a breakdown of the most effective cooling innovations and design approaches available today.
1. Liquid Cooling Technologies
a. Immersion Cooling
Servers are submerged in a thermally conductive dielectric fluid that absorbs and transfers heat directly from the components.
- Single-phase immersion: Fluid remains in liquid state and is pumped to a heat exchanger.
- Two-phase immersion: Fluid boils at low temperatures and changes to gas, removing heat through phase change.
Advantages:
- Up to 95% more efficient than traditional air cooling
- No need for chillers, CRACs, or fans
- Lower hardware failure rates
- Ideal for high-density or GPU-intensive workloads (e.g., AI, blockchain)
Challenges:
- Requires specially sealed and compatible equipment
- Higher upfront CapEx
- Custom design and integration needed
b. Direct-to-Chip Liquid Cooling
Coolant is pumped through cold plates attached directly to the CPU, GPU, and memory modules, extracting heat at its source.
Benefits:
- Reduces reliance on ambient room cooling
- Precise, high-efficiency thermal control
- Scalable and increasingly standard in HPC environments
2. Enhanced Air Cooling Systems
a. Rear Door Heat Exchangers (RDHx)
Chilled water coils are mounted at the rear of server racks to extract hot exhaust air before it re-enters the room.
Advantages:
- Localized, rack-level cooling
- Retrofittable to existing racks
- Supports higher rack power density without overcooling the room
b. Cold Aisle / Hot Aisle Containment
This architectural strategy separates hot and cold airflows to prevent mixing and maximize cooling efficiency.
- Cold aisle containment: Encloses cold aisles to keep cold supply air directed at servers.
- Hot aisle containment: Encloses hot aisles and extracts heated air directly to CRAC or exhaust systems.
Benefits:
- Can reduce cooling energy consumption by up to 30%
- Improves equipment performance and lifespan
- Suitable for both new and retrofitted data centers
3. Free Cooling and Economization
In suitable climates, free cooling uses outside air to reduce the need for mechanical chillers.
a. Air-Side Economization
Draws in cool outside air and filters it to maintain acceptable indoor conditions. Requires climate control and filtration to handle humidity and particulates.
b. Water-Side Economization
Uses cooling towers or dry coolers to chill water for CRACs without compressors when ambient temperatures are low.
Ideal Locations: Temperate regions with cool winters and low humidity (e.g., Scandinavia, parts of Australia’s Southern Highlands)
4. AI and Machine Learning-Driven Cooling Optimization
Companies like Google and Meta are using machine learning to analyze real-time data from thousands of sensors to:
- Adjust airflow and temperature dynamically
- Predict hotspots before they occur
- Optimize chiller operation based on IT load forecasts
- Reduce Power Usage Effectiveness (PUE)
Outcome: Google achieved a 40% reduction in data center cooling energy after deploying DeepMind’s AI platform.
5. Thermal Energy Storage (TES)
TES systems store excess cooling capacity during off-peak hours (usually nighttime) and deploy it during high-demand periods.
Types:
- Ice-based: Chillers freeze water at night and melt it during the day to cool the data center.
- Phase-change materials (PCMs): Absorb or release heat during phase transitions, providing stable thermal output.
Benefits:
- Load shifting to reduce peak demand charges
- Improved energy resilience
- Complements renewable integration by balancing intermittency
6. Raised Floor vs Overhead Cooling Design
Raised floor systems historically allowed cool air to be pushed under racks. While still in use, many modern data centers are moving to overhead cooling for flexibility and better maintenance access.
Key tips:
- Use computational fluid dynamics (CFD) simulations to optimize airflow path
- Ensure no leakage or short-circuiting of airflow
- Use blanking panels and grommets to prevent bypass air
7. Monitoring and Controls
No cooling system is complete without smart monitoring.
- Temperature sensors at multiple rack levels (top/middle/bottom)
- Airflow monitoring to detect obstruction or failure
- Humidity control to prevent electrostatic discharge (ESD) or condensation
- Remote BMS integration for real-time oversight and alarming
Final Thought: Holistic Energy Design
To truly optimize cooling, it’s essential to integrate mechanical, electrical, and IT infrastructure from the outset. The best results come when facilities design, engineering, and operations teams collaborate to:
- Align cooling strategies with IT load profiles
- Reuse waste heat where viable
- Select server and storage hardware designed for high-efficiency operation
- Design redundancy (N+1, 2N) intelligently to avoid overprovisioning
If you’re building or upgrading data center infrastructure, Nettlefold Projects can provide full electrical and controls engineering support—from cooling system specification and design to energy performance audits, control system integration, and commissioning.
