Heat flux

Heat flux or thermal flux is a change in energy over a given area and time. Heat is represented by the symbol Q.

Additional recommended knowledge

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Essential Laboratory Skills Guide

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The heat transfer rate, or heat flow per unit time, is denoted by:

.

It is measured in watts in SI units (a watt is one joule per second).

Heat flux is defined as rate of heat transfer per unit cross-sectional area, and is denoted q, resulting in units of watts per square meter, though slightly different notation conventions can be used.

See also

• Heat#Notation
• Heat conduction
• Heat transfer
• Critical heat flux
• Latent heat flux
• Rate of heat flow
• Insolation