Experimental and computational study on helical coil and flat type sub-cooled condenser for air conditioner in automobile vehicle 2020-01-1246
Due to the compact structure, large heat transfer area, and high heat transfer capability, this paper provides the importance of helical coil sub-cooled condenser as comparing to flat type sub-cooled condenser in the automobile vehicle. By improving the coefficient of performance of the air-conditioning (A/C) system, the reduction in vehicular emission can be possible. Because A/C unit is the most power consumption unit after the engine. Previous studies explain that there is a generation of secondary flow inside the fluid in circular cross-section of the helical coil. By using the effect of secondary flow generation, the author’s tried to enhance the heat transfer rate as it leads to heterogeneous temperature distribution across the periphery of the tube and causes a higher heat transfer. During the studies, a prototype with square cross-sectional 2.7mm X 2.7mm channel with flat fins towards outer side has been constructed. Experimentally, heat transfer characteristics for the square channel helical coil cub-cooled condenser has been evaluated and then compared with CFD analysis. During the bench test, the Calorimeter was used to obtain the desired ambient temperature along with the humidity level inside a control volume. It has been displayed from the results that the helical coil sub-cooled condenser provides enhanced heat transfer as well as higher turbulent kinetic energy characteristics on the refrigerant side. Additionally, the results from the CFD analysis revealed that the heat transfer coefficient for the helical coil sub-cooled condenser on the refrigerant side was 1.35 times greater than the conventional type of sub-cooled condenser. This is because the turbulent kinetic energy, which is the essential factor for enhancing heat transfer coefficient shows a higher value for helical as compared to flat type sub-cooled condenser.