Average temperature drop

Temperature drop averaged over the heat-transfer surface.

Comment. We distinguish between:
a) mean arithmetic temperature drop

b) mean logarithmic temperature drop

c) mean integral temperature drop

where Δt is the local temperature drop; Δt₁, Δt₂ are the values of the local temperature drop at the beginning and the end (in the direction of flow of the heat-transfer agent) of the heat-exchange system, F is the area of the heat transfer surface.