An experimental investigation of natural convection heat transfer over outer surface of vertical helical coil condenser

摘要

Free convection heat transfer over the outer surface of helical coil condenser (HCC) and existing wire-on-tube condenser (WOTC) in air was experimentally studied under steady state condition. Two types of condenser are tested: helical coil condenser of different coil diameter to tube diameter ratio and an existing wire-on-tube condenser. The experiments were conducted for turbulent flow outside, the helical coil surface as well as, conventional wire-on-tube condenser surface and comparative analysis was done. The experimental results show that decrease in diameter ratio as well as pitch leads to increase in outside heat transfer coefficient. 12.42% higher outside heat transfer coefficient was obtained for helical coil condenser in comparison with the conventional wire-on-tube condenser. It was also observed that the COP of the domestic refrigerator with designed HCC is 12.77 % higher than existing WOTC.