The total efficiency for a finned surface may be defined as the ratio of the total heat transfer of the combined area of the surface and fins to the heat that would be transferred if this total area were maintained at the base temperature T0. Show that this efficiency can be calculated from

where
ηt = total efficiency
Af = surface area of all fins
A = total heat-transfer area, including fins and exposed tube or other surface
ηf = fin efficiency

Transcribed Image Text:

=1-4(1-n)