The Rack
A steel cabinet: servers stacked like drawers, with power, water and network threaded through.
How big?About 2 m tall, a little taller than a grown-up.
Real: What it looks like.
Keys: arrows rotate · + / − zoom · 0 reset · 1–4 views · S signal · T tour · L labels · Space spin. Models are stylised and built from code: proportions are honest, details are simplified.
What it is
Racks are measured in 'U' (1.75 inches). A standard rack is 42U. AI servers are tall, so only a few fit before the rack runs out of power or cooling.
Top-of-rack switches link the servers to the cluster network. Power distribution units (PDUs) run down the back. In liquid-cooled racks, two big manifolds carry cool water down and warm water up.
Why AI needs it
A normal office rack draws 5–10 kW. An AI rack can draw 40 to well over 100 kW, enough to need its own plumbing and very thick cables.
Every labeled part
- 1
AI servers
Explode to slide them out like drawers.
- 2
Top-of-rack switches
Every server's network cables run up to these.
- 3
Power shelf
Converts and distributes power for the rack.
- 4
PDUs
Power strips the height of the rack. Yellow flow in Signal mode.
- 5
Coolant manifolds
Blue down, red up. Every server taps into them with quick-disconnect hoses.
- 6
Fiber bundle
Light carrying data up to the switches and out to the hall.
- 7
Door + side panels
X-ray or explode to see inside.
Try it · concept lab
Fill a rack
Add servers until something gives.
Rack type
dashed line = what the rack can power and cool
Rack draw
43 kW
≈ US homes (avg)
36
Verdict
fits
Assumes ~10 kW per 8-GPU server plus ~2.5 kW for switches and fans; an average US home uses about 1.2 kW around the clock. Rough figures.
Big idea: AI racks are limited by power and cooling, not space. That's why liquid cooling and new power designs matter.
Swap it: other ways to do the same job
Air-cooled rack
Simpler and fits old data centers, but limited to lower power per rack.
Rack-scale 'one computer'
Copper spines inside the rack wire dozens of GPUs into one domain. Huge speed, heavy and power-dense.
Rear-door heat exchanger
A water-cooled radiator on the back door lets air-cooled racks run hotter.
Talk about it
- Q1
An AI rack can need its own water pipes. What other things in a building need their own plumbing?
- Q2
Older buildings weren't made for racks this hot. Is it better to fix up old buildings or build new ones? Why?
For grown-ups: there are no right answers here. Ask a question, then ask "why do you think that?" The reasons matter more than the answer.
Printable question sheet (PDF)