Performance of heat exchangers using nanofluids

Heat exchangers are equipments being used for transfer of heat between two or more fluids at different temperatures (Sundén 2012). They are widely used in various fields, including power plants, automotives, space heating, refrigeration and air-conditioning systems, chemical plants, petrochemical processes, electronic cooling, and environment engineering. Many heat transfer enhancement techniques have been developed for heat exchangers to improve their thermal efficiency by means of surface area enlargement and boundary layer modification. Conventional heat transfer fluids such as water, ethylene glycol, and engine oil have relatively low thermal conductivity values, which thus limit the heat transfer rates. Due to recent progress in nanotechnology, thermal conductivity values can be increased by adding nanometer-sized structures (e.g., particles, fibers, tubes) in conventional heat transfer fluids to form the so-called nanofluids