Condensation Performance of Symmetrical and Parallel Capsule Plate Heat Exchangers

Condensation characteristics of symmetrical and parallel capsule plate heat exchangers were experimentally investigated in this article. Plate heat exchangers with parallel capsule corrugation, symmetrical capsule corrugation, and chevron-type corrugation are manufactured as the test sections, each containing 41 plates. Pure steam and water are the hot and cold fluids, respectively. The experiments covered a range of equivalent Reynolds number from 9,000 to 25,000, mass flux of condensing fluid from to 18 to 49 kg/(m²·s), liquid Prandtl number from 1.37 to 1.71, average vapor quality from 0.5 to 0.7, and condensation pressure from 110 to 240 kPa. The correlations of condensation heat transfer coefficient and friction factor of the symmetrical and parallel capsule plate heat exchangers are developed. Compared with chevron-type plate heat exchangers, capsule plate heat exchangers show low friction pressure drop, and 33% higher energy efficiency index for condensation flow and heat transfer. Specifically, the energy efficiency index of the symmetrical capsule plate heat exchanger is 8.6% higher than that of the parallel capsule plate heat exchanger, indicating the superiority of counter-rotating longitudinal vortices over co-rotating longitudinal vortices in condensation, similar to what is observed in single-phase flow and heat transfer.