heat coefficients formula .

[maltamarco]

Hello

Please can some one translate me this heat coefficients formula .

Assume a heat exchanger is rated at 1000 Btu/hour ft oF how many latent heat is capable to move per hour ??

I can not understand why there is the F (Fahrenheit) in the formula ???

Thanks
Marco EU

[sterl]

From convective heat exchange:

Q = U A deltaT

Where: Q is heat transferred, BTU/hr.
A is heat transfer area; Sq Ft
DeltaT is the prevailing temperature difference:

May be the log mean Temp Diff or may be local Temp Difff; with Latent Heat Exchanger and low pressure differences the average calculates the same as log mean...

U is heat transmission coefficient: Nominally has units for entire exchanger of BTU/hour/ft^2/Def F. BUT

If you are evaluating something like a single heat exchanger tube; or a tube in tube heat exchanger; the object is to establish the Length of the heat exchanger required.....so you will end up with Heat; per unit length; per unit temperature difference and the HT area, per unit length, is developed within the 1000 number.

Insulation effectiveness also expressed without the area term as you are trying to arrive at an effective thickness...But your number well out of range for reasonable insulation performance.

Once you have the Q for the heat exchanger, the mass flow for the latent fluid, presuming constant pressure, is the Total Heat Exchanged divided by the Latent Heat of the refrigerant at that temperature.