High resolution infrared measurements of single-phase flow of R245fa and R236fa within a compact plate heat exchanger, Part 1: Experimental setup and pressure drop results

Abstract

This two-part paper presents experimental work to characterize thermal and hydraulic performances of a compact plate heat exchanger. Upward single-phase heat transfer and pressure drop of low pressure, liquid refrigerants R245fa and R236fa was investigated within a plate prototype fabricated with a 1 mm pressing depth and a chevron angle of 65°. Specifically in Part 1, experiments were carried out for Reynolds numbers ranging from 34 to 1615, corresponding to a range of mass flux from 8 to 384 kg m−2 s−1 and Prandtl numbers ranging from 4.9 to 6.5. The Fanning friction factor was found to be strongly dependent on the Reynolds number and the experimental pressure drop database was validated against several prediction methods available in the open literature. Fine resolution infrared measurements were performed to obtain local (pixel-by-pixel) heat transfer coefficient, fully described in Part 2, while the technique developed to reduce the experimental data is detailed in Part 1. Finally, a frictional pressure drop prediction method, which captured the entire experimental databank within a bandwidth of ± 20% and mean absolute error of 8.2%, was also provided.