Air as a heat-transport medium

Definition

Air is a poor medium for moving heat because of its low specific heat and very low density compared with water.

Air has a specific heat near 0.24 BTU per pound per degree Fahrenheit and is roughly 800 times less dense than water, so moving the same heat requires far larger ducts and fans. A six-inch chilled water pipe can carry as much cooling as a four-foot air duct, with a fraction of the pumping energy. This contrast is why large systems move cool water instead of cool air.

Related concepts

Specific heat of water · Chilled water loop · Cooling load scale

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Part of The Blueprint of Water · 🔥 thermodynamics