The convective heat transfer coefficient (h), defines, in part, the heat transfer due to convection. The convective heat transfer coefficient is sometimes referred to as a film coefficient and represents the thermal resistance of a relatively stagnant layer of fluid between a heat transfer surface and the fluid medium. Common units used to measure the convective heat transfer coefficient are Btu/hr - ft2 - oF.
h = q / ΔT
q : amount of heat transferred ( heat flux ), W/m2 i.e., thermal power per unit area , q = d Q / dA
h : heat transfer coefficient, W / (m2 · K)
ΔT: difference in temperature between the solid surface and surrounding fluid area, K
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/(m2 K).
The heat transfer coefficient is the reciprocal of thermal insulance . This is used for building materials ( R-value ) and for clothing insulation .
See: Convective Heat Transfer Coefficients Table