Film condensation dynamics of fourth-generation refrigerants under multiphase mixed convection on an inclined plate

To promote environmentally friendly HVAC systems, there has been a recent rise in the use of fourth-generation refrigerants with low ozone depletion potential (ODP) and low global warming potential (GWP). Numerous studies have examined the film condensation of these refrigerants in horizontal tubes under saturated vapour conditions, focusing on factors such as tube diameter , vapour quality, and more. This study investigates the underexplored influence of plate inclination on the heat transfer coefficient (HTC) associated with the film condensation of fourth-generation refrigerants-including R1234ze(E), R1234yf, R1233zd(E), R1234ze(Z), R1224yd(Z), R1243zf, R1336mzz(Z), and RE347mcc-highlighting its importance in optimizing pumping power and reducing fouling. Using an analytical model based on a boundary layer integral approach, the study examines how HTC varies with plate and free stream inclination for pure and mixed refrigerants across different levels of superheating, subcooling, and vapour quality. Additionally, the research examines blends of fourth-generation refrigerants within their class and third-generation refrigerants under the same conditions. The analytical model is validated against an existing numerical model supported by experimental data and is then utilized to investigate the influence of various input parameters of pure refrigerants or refrigerant mixtures on heat transfer performance. • Developed a boundary layer integral method for mixed convection film condensation. • Introduced dimensionless parameters and analyzed plate inclination effects. • Studied less-explored refrigerants: R1234ze(Z), R1224yd(Z), R1243zf, R1336mzz(Z), RE347mcc. • Nusselt number drops with vapour quality, superheating; rises with subcooling. • Observed heat transfer and suction/compression trends in refrigerant mixtures.