A model for air-to-refrigerant microchannel condensers with variable tube and fin geometries

A generalized finite volume-based model to simulate Microchannel Heat Exchangers (MCHXs) with variable tube and fin geometries using a three-stream UA-AMTD method is presented in this paper. MCHXs with variable geometry can have different port dimensions, tube sizes and fin surfaces within the heat exchanger core and can have single or multiple tube banks. These novel MCHX design can further enhance the heat exchanger performance and improve its material utilization. A comprehensive literature review reveals that there is no experimental or numerical investigation of such innovative designs nor is there a modeling approach that can handle such flexible geometries. The model is validated against 227 experimental data points for eight different fluids, and eighteen MCHX geometries, including four different variable geometry microchannel condensers. This validation effort is the most comprehensive MCHX model validation presented in open literature. The average absolute capacity deviation between predicted and measured values was 2.7%.