Introduction
Cooling systems account for approximately 35% to 40% of overall electricity consumption in enterprise data centres. With the Council on Energy, Environment and Water (CEEW) projecting India's data centre capacity to cross 5 GW by 2030, driven by AI and high-performance computing, adopting sustainable thermal management technologies has become critical for national energy and water security.
Major Cooling Technologies: Advantages and Limitations
Data centres rely on two primary cooling mediums to dissipate thermal loads generated by densely packed server racks.
- Air-Based Cooling Systems: Encompasses Computer Room Air Conditioning (CRAC) and Computer Room Air Handler (CRAH) units, hot/cold aisle containment, and air-side economisers.
- Advantages: Lower upfront capital expenditure (CapEx), mature global supply chains, simplified maintenance protocols, and complete elimination of fluid-leak hazards to sensitive server motherboards.
- Limitations: Air has a low volumetric heat capacity, restricting thermal handling to rack densities below 15–20 kW. High fan power inflates Power Usage Effectiveness (PUE) to 1.5–1.8, rendering air cooling inadequate for modern AI/GPU workloads exceeding 40 kW per rack.
- Water and Liquid-Based Cooling Systems: Encompasses evaporative cooling towers, direct-to-chip (cold plate) liquid loops, and single- or two-phase immersion cooling.
- Advantages: Liquids possess roughly 3,000 times the volumetric heat capacity of air. This enables extreme rack densities exceeding 100 kW, drastically curtails auxiliary fan power, and drives PUE down to 1.1–1.2.
- Limitations: Evaporative cooling towers exert enormous pressure on local freshwater, consuming up to 2 million litres daily for a 100 MW facility. Immersion systems involve steep CapEx, specialized dielectric fluid handling, retrofit engineering barriers, and chemical management challenges.
Balancing Data-Centre Growth with Sustainability in India
To support digital growth without compounding environmental stressors, India requires institutional, technological, and spatial interventions:
- Energy Efficiency Benchmarks: Enforce mandatory Bureau of Energy Efficiency (BEE) star-rating standards and cap operational PUE under 1.35, aligned with the criteria established under MeitY’s IndiaAI cloud infrastructure tenders.
- Safeguarding Water Security: Mandate closed-loop dry chillers to eliminate evaporation losses; enforce Water Usage Effectiveness (WUE) caps alongside Zero Liquid Discharge (ZLD); and mandate the substitution of potable groundwater with treated municipal sewage treatment plant (STP) water.
- Geographic Siting and Clean Power: Decongest hyper-concentrated, water-stressed metro hubs like Mumbai and Chennai by nudging developments toward tier-2 corridors endowed with abundant clean energy. Leverage the Green Energy Open Access Rules, 2022, to procure 24/7 round-the-clock solar, wind, and storage power.
- Circularity and Waste Heat Utilisation: Introduce fiscal incentives for data centres that export waste heat to neighbouring industrial drying, district heating, or desalination facilities, coupled with stringent end-of-life recovery norms for PFAS and dielectric fluids.
Conclusion
Standardising closed-loop liquid architectures and enforcing water-neutral operating mandates will allow India to safeguard its digital sovereignty while upholding its commitments to Net Zero by 2070. Harmonising compute infrastructure expansion with resource conservation ensures sustainable digital public infrastructure for the AI era.