Overall Heat Transfer Coefficient Units. The algebraic sign of newtons law of cooling is positive for t ts heat transfer into the object and negative when t ts heat transfer out of the object. Thus area is included in the equation as it represents the area over which the transfer of heat takes place.
The convective heat transfer coefficient is not a property of the fluid. The two materials refers to solid and fluid where a phase transition is involved or between two fluids where convection is involved. The unit conversion from si unit to english units is follows.
Its units are the w m2c btu hr ft2f.
The overall heat transfer coefficient is calculated by dividing heat flux by the temperature difference between the two materials where heat is being transferred. The inside film coefficient represents the resistance to heat flow caused by the change in flow regime from turbulent flow in the center of the tube to laminar flow at the tube surface. 23 rows overall heat transfer coefficient u wm 2 k btuft 2 o f h tubular heating or. The overall heat transfer coefficient or u value refers to how well heat is conducted through over a series of resistant mediums.