45°C cooling design cuts data center water use to near zero

Cooling approach & what’s new

• NVIDIA proposes fully liquid-cooled servers with coolant around 45–55°C, rejecting heat via dry air-side heat exchangers instead of evaporative cooling towers or chillers in many climates.
• Key change vs older “hybrid” liquid cooling: not just CPUs/GPUs but also memory, PSUs, NICs, etc. get liquid cold plates; fans and large finned heatsinks are largely removed.
• Several commenters note similar warm‑water or liquid systems already exist in supercomputers, data centers, and HPC (NASA, Cray, Bull/Eviden, Supermicro), so they see this more as incremental engineering and packaging than a breakthrough.

Human comfort & indoor climate

• Concern: if coolant is 45–55°C, will buildings become uncomfortably hot?
• Replies: heat exchange is finite; racks can be hot while human areas are kept comfortable with relatively modest conventional A/C, since heat is carried away in the fluid and dumped outside.

Water, energy & environmental impact

• Traditional large data centers often use evaporative cooling, which consumes significant local water but saves electricity.
• New design reuses the same coolant in a closed loop, cutting steady-state direct water draw to “near zero” apart from initial fill and minor losses.
• Some argue the bigger unseen water use is in off‑site power generation; improved PUE helps but doesn’t eliminate that.
• Debate over whether DC water use is a serious problem or overhyped relative to agriculture, golf courses, etc., and whether siting in water‑scarce regions makes it locally serious.

Heat reuse & district heating

• Many see strong synergy with district heating and greenhouses; 45–55°C water is low‑grade but usable directly with large-area emitters or as an excellent source for heat pumps.
• Real-world examples cited in Nordic and European cities already using data center waste heat for homes, pools, and greenhouses; seasonal thermal storage is mentioned.
• Challenges: existing buildings often designed for hotter supply temperatures; district heating networks are capital‑intensive and not widespread; matching variable compute loads to heat demand is nontrivial.

Noise, siting & local externalities

• Some report urban data centers as unobtrusive; others describe loud installations, especially where on‑site gas turbines are used for power.
• Concerns raised about hum, vibration, infrasound (disputed with counter‑links), and visual intrusion; calls for stricter regulation and better design.
• Discussion on whether DCs should be pushed to remote locations vs kept near cities for workforce, grid, and network reasons.

Space-based datacenters

• One subthread debates orbital data centers: proponents see precedent in Starlink‑style constellations; skeptics note severe downsides (cooling only by radiation, radiation‑hardening, latency, cost, maintenance).
• Some suspect space DC talk is more hype or jurisdiction‑avoidance than practical engineering.

How big an innovation?

• Enthusiastic takes: meaningful reduction in direct water use, lower cooling energy in suitable climates, and enabling large-scale heat recovery; aligns with emerging “AI factory” scale.
• Skeptical takes: similar tech existed; article is partly PR/“AI‑written slop” and greenwashing; total DC heat still ends up in the environment, and core political disputes (power demand, siting, noise, water rights) remain.