When to use: Nearly all electrical power delivered to IT/GPU equipment converts to heat that must be rejected. This tool converts IT load (kW) to total cooling tons, splits the load between liquid cooling (direct-to-chip/immersion) and residual air cooling, and estimates chilled-water flow rate — a first-pass check before detailed mechanical design.
This calculator converts IT/GPU electrical load into a total cooling load (tons and BTU/hr), splits it between liquid cooling and residual air cooling, and estimates chilled-water flow rate — a first-pass sizing check for chillers, CDUs (cooling distribution units), and CRAH/CRAC air handlers.
By conservation of energy, essentially all electrical power delivered to IT/GPU equipment is converted to heat during normal operation (a small fraction leaves as light/sound, negligible for sizing purposes). This is the standard data center design assumption: a facility with 4 MW of IT load must reject roughly 4 MW of heat (plus a safety margin), independent of what fraction is liquid- vs air-cooled — only how that heat is removed changes.
GPU accelerators generate far more heat per chip than CPUs, so most GPU servers now cool the GPUs and often CPUs via direct-to-chip cold plates connected to a facility chilled-water or dedicated liquid loop, while residual heat (memory, VRMs, storage, networking) is still removed by traditional rack-level air cooling. It is common in 2026-era GPU data centers to see 60-80% of total rack heat removed by liquid cooling and the remainder by air — full immersion cooling designs push that split much closer to 100% liquid.
Chilled water flow rate uses the standard HVAC relationship: GPM = BTU/hr ÷ (500 × ΔT°F), where 500 is a constant derived from water's specific heat and density, and ΔT is the chilled-water supply/return temperature difference (commonly 8-12°F in data center applications, wider deltas reduce pumping energy). This is a rule-of-thumb estimate for early design — final CHW plant sizing requires a full load profile and redundancy (N+1/2N) analysis.
Yes — a "ton" of refrigeration is a standard HVAC unit historically defined as the cooling effect of melting one short ton of ice in 24 hours, which works out to exactly 12,000 BTU/hr (3.517 kW). It remains the standard unit for specifying chiller and cooling equipment capacity in the US.
Water has roughly 3,500x the volumetric heat capacity of air, so moving the same amount of heat requires far less flow volume and far less pumping/fan energy compared to moving air — this is also why liquid-cooled systems can often operate at warmer supply temperatures and unlock more free-cooling hours, improving PUE.
Immersion cooling designs can approach it, submerging entire servers in dielectric fluid, but most direct-to-chip deployments still leave memory, storage, networking, and VRM components on air cooling, which is why 60-80% liquid / 20-40% air is a common practical split rather than 100/0.
This tool sizes the mechanical cooling plant itself (tons, chilled water flow); the PUE Calculator in this studio then uses the resulting cooling system electrical draw (chiller, CDU, pump, and CRAH/CRAC power) as one of the inputs to total facility power overhead.