Experimental investigation on thermal performance of nano coated surfaces for air-conditioning applications

Abstract

Extended surfaces are frequently used in heat exchanging devices for increasing the heat transfer between a primary surface and the surrounding fluid. Heat transfer augmentation by providing an extended surface to air side, increases weight of the system, obstruct air-flow, increases pressure drop and pumping power to keep the fluid stream flowing. These major problems will be minimized with the help of recent developments in the field of nanotechnology that provides an avenue to augment heat transfer by providing a coating of nanometer thickness on the heat ex-changer surface. The present work aims to investigate the effect of the nanocoating on the heat exchanger surface with the experiments. The experimental results show that the presence of nanocoating does not have any effect on drag change, where the actual pressure drop of the coil for air velocity of 0.6 m/s, 1.6 m/s is 20 Pa and 60 Pa, respectively. For nanocoated surface, 24.2% improvement in heat transfer rate was observed and transient temperature response of the nanocoated heat exchanger tube is higher than uncoated one for a given experimental conditions.