Asymptotic Effectiveness-NTU Formulas for Multipass Plate Heat Exchangers

The effectiveness of a plate heat exchanger with a finite number of plates is affected by the end channels, and the channels between two adjacent passes. These effects become less significant as the number of thermal plates becomes large, N > 40, as shown by Kandlikar and Shah (1989). In the present paper, closed-form equations are derived for plate heat exchangers with N = infinity in terms of temperature effectiveness P(1) as a function of the capacity rate ratio R(1) and the number of transfer units NTU(1) for the following pass arrangements: 1-1, 2-1, 2-2, 3-1, 3-2, 3-3, 4-1, 4-2, 4-3, and 4-4.