Editing Countercurrent exchange (section)

==== Conditions for higher transfer results ====
Nearly complete transfer in systems implementing countercurrent exchange, is only possible if the two flows are, in some sense, "equal".

For a maximum transfer of substance concentration, an equal flowrate of [[solvent]]s and [[Solution (chemistry)|solution]]s is required. For maximum heat transfer, the average [[specific heat capacity]] and the mass flow rate must be the same for each stream. If the two flows are not equal, for example if heat is being transferred from water to air or vice versa, then, similar to cocurrent exchange systems, a variation in the gradient is expected because of a buildup of the property not being transferred properly.<ref>The specific heat capacity should be calculated on a mass basis, averaged over the temperature range involved. This is in keeping with the second law of thermodynamics</ref>