Heat transfer improvement and pressure drop during condensation of refrigerant-based nanofluid; an experimental procedure

In this paper, experimental analysis is examined to estimate hydrothermal behavior of refrigerant-based nanofluid (nano-refrigerant) during condensation inside a horizontal tube. In order to produce nano-refrigerant, R600a and CuO are selected as base fluid and nanoparticle, respectively. Roles of mass flux, vapor quality, concentration of nanoparticles are investigated. Results indicate that the presence of nanoparticles generally increased the frictional pressure drop. The Brownian motion as well as the deposition of a molecular layer of nanoparticles on the inner tube surface intensifies the conduction and micro-convection in the fluid.