Experimental Approach for Enhancing the Natural Convection Heat Transfer by Nanofluid in a Porous Heat Exchanger Unit

Abstract

Natural convection heat transfer is a significant component in the energy transfer mechanism and plays an essential role in a wide range of scientific and industrial technologies. This research seeks to enhance the energy transfer by nanofluid, which is compatible with some applications, such as heat exchanger thermal energy storage (HXTES). For this purpose, a triplex tube heat exchanger (TTHX) is designed to receive the hot and cold flow by two pumps from two thermal baths, respectively. Samples of the Copper (Cu) nanoparticles were then carefully selected in a volume concentration range of 0.05 ≤ ∅ ≤ 0.5 to promote the thermal conductivity of the base fluid, which consists of 55% water and 35% ethylene glycol (EG), and to form nanofluid. On the other side, the effect of the porous medium of glass spheres inside a TTHX is considered. Experimentally, and after preparing the nanofluid, temperature readings of six various thermocouples locations have been investigated. The effects of Cu volume concentrations under different temperatures of 20 °C, 30 °C and 50 °C on nanofluid heat transfer are evaluated, respectively. One more result: the yields in the heat transfer coefficient of the hot tube were higher compared to those of the cold tube under Reynolds number (Re) between 200 and 7000. The efficiency of transition and turbulent flow through TTHX is clearly appointed. Overall, these findings support the supposition that the heat transfer enhancement is optimized by 0.05% nanoparticle volume concentration due to increasing thermal conductivity and fluid movement effectiveness. Ultimately, a natural progression of this work is to analyze more convective form using controlled trial applications, such as solar collectors.