This article investigates the in-tube, superheated, saturated, and subcooled condensation of zeotropic refrigerant mixture R454C. R454C is proposed to replace R404A for commercial refrigeration applications. Quasi-local heat transfer coefficients were measured in a 4.7 mm horizontal tube at mass fluxes ranging from 100 to 500 kg m−2 s−1 at three different saturation...
The objective of this paper was to measure and compare the heat transfer coefficient and pressure drop of R404A and two potential replacement candidate refrigerants with a lower global warming potential, R448A and R452A. Experiments were conducted inside a 4.7 mm horizontal tube at mass fluxes ranging from 100 to...
Heat transfer coefficients and frictional pressure drop values are experimentally measured during condensation of R134a and its proposed low global warming potential (GWP) replacement, R450A. R450A is a non-flammable zeotropic mixture of R134a and R1234ze (42/58% by mass). Experiments were conducted in a horizontal tube (ID = 4.7 mm) for...
Qualitative two-phase flow regime data are obtained from high-speed visualization of condensing flows of R-134a at mass fluxes from 75 to 150 kg m−2 s−1 and quality from 0.1 to 0.8 in square microchannels (DH = 0.84 mm) cooled from a single side. Superheated R-134a is distributed into multiple parallel microchannels and then partially condensed, using...