Experimental Study on Condensation Heat Transfer Characteristics of Eco-friendly HFO Refrigerants for Marine Refrigeration Systems

This study applied the next-generation refrigerant R-1234yf to facilitate the eco-friendly transition of marine and fisheries refrigeration and air conditioning systems. By experimentally analyzing the condensation heat transfer characteristics within horizontal smooth tube, the following conclusions were drawn. As mass flux and vapor quality increased, annular flow developed, leading to an increase in the condensation heat transfer coefficient. Conversely, as the saturation temperature rose, the heat transfer coefficient decreased due to increased thermal resistance of the liquid film. Although R-1234yf exhibits a somewhat lower heat transfer coefficient compared to R-134a due to material limitations (high density, low thermal conductivity), it was demonstrated that this can be sufficiently overcome through tube diameter optimization and tube design. Furthermore, the study verified that the Dobson & Chato and Bashar correlations can be effectively utilized in practical design applications. The condensation heat transfer characteristics of R-1234yf and the correlation verification results presented in this study can serve as fundamental data for the thermal design and performance prediction of refrigeration and air conditioning condensers utilizing small-diameter horizontal smooth tubes. However, since this study was conducted within a single tube diameter and a limited range of mass flow rates and saturation temperatures, follow-up research considering various tube diameters, operating conditions, vibration and inclination, and actual marine operating environments is necessary to expand its application as design data for marine and fisheries refrigeration systems.