给热系数，是一个热力学术语，主要应用于化学工程和物理学方面。给热系数是用来计算导热的，尤其是在固体液体之间对流，或是发生相变的情况下。通常用h代表，忽略给热面积的平均给热系数则用代表。

where

q = 流入或损失的热量， J/s = W

h = 给热系数， W/(mK)

A = 导热面积， m

= 固体表面与周围流体的温度差， K

The heat transfer coefficient or film coefficient, in thermodynamics and in mechanics is the proportionality constant between the heat flux and the thermodynamic driving force for the flow of heat (i.e., the temperature difference, ΔT):

where:

It is used in calculating the heat transfer, typically by convection or phase transition between a fluid and a solid. The heat transfer coefficient has SI units in watts per squared meter kelvin: W/(mK).