← All parts of this equation

Equation 1 · Part 7 · How AI Datacenter Power and Cooling Actually Work

subscript

Q˙=m˙ cp ΔT\dot{Q} = \dot{m}\, c_p\, \Delta T
subscript

What this part means

The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.

Its job in the formula

A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.

The passage around this formula

The physical reason liquid cooling becomes necessary at all is straightforward: air has a volumetric heat capacity roughly one four-thousandth that of water, so once a rack’s heat density crosses roughly 20–30 kW, moving enough air through the rack to hold a safe temperature rise requires impractical airflow velocities and fan power. The heat-removal budget for a cold plate loop follows directly from the sensible-heat relation: Q˙=m˙ cp ΔT\dot{Q} = \dot{m}\, c_p\, \Delta T. where Q˙\dot{Q} is the heat to be removed (watts), m˙\dot{m} is the coolant mass flow rate, cpc_p is its specific heat, and Δ\Delta T is the temperature rise the coolant is allowed across the cold plate. This is the one relationship every cooling-loop…

Read this part in the article →

Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

Open the illustrated subscripts: which member of a family? guide →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.