Selection of suitable heat transfer fluid for heat dissipation is an important consideration in the design of heat exchanging systems. Nanofluid, a colloidal mixture made of a base fluid and a nanoparticle, is a new generation of heat transfer fluids becoming a high potential fluid in heat transfer applications due to enhanced thermal conductivity. Research studies about nanofluids are on the rise owing to the mounting interest and demand for nanofluids as heat transfer fluids in a wide variety of applications. Recently, nanofluid technology has a new dimension of impregnating two or more nanoparticles in base fluids, namely hybrid or composite nanofluids. This paper reviews the preparation of metal and metal oxides nanofluids and hybrid nanofluids and the various techniques used to study the physical and chemical characteristics of nanofluids. Thermo-physical and heat transfer properties of nanofluids including the improved thermal conductivity, viscosity and specific heat models for nanofluids are presented. Finally, various application areas of nanofluids, such as transportation, electronic cooling, energy storage, mechanical applications etc. are discussed.

A review on preparation, characterization, properties and applications of nanofluids

Review on thermal properties of nanofluids: Recent developments.

A review of recent advances in thermophysical properties at the nanoscale: From solid state to colloids

Towards hybrid nanofluids: Preparation, thermophysical properties, applications, and challenges

The effect of nano-additives in diesel-biodiesel fuel blends: A comprehensive review on stability, engine performance and emission characteristics

Thermal conductivity measurement of methanol-based nanofluids with Al2O3 and SiO2 nanoparticles

In the present study, suspensions of Al2O3 and SiO2 nanoparticles in methanol (nanofluid) are produced and analyzed for the application of CO2 absorption in a tray column absorber. The absorber is an acrylic tray column with twelve plates. The column is a sieve tray type which has flat perforated plates where the vapor velocity keeps the liquid from flowing down through the holes and the CO2 gas and methanol liquid are brought in contact in a counter-current flow. The test section is equipped with two mass flow meters to measure the absorption rate. The results show maximum enhanced absorption rates of 9.4% and 9.7% for Al2O3 and SiO2 particles (compared to pure methanol), respectively. It is also found that SiO2 nanoparticle is a better candidate than Al2O3 nanoparticle and 0.05 vol% of nanoparticles is an optimum condition for CO2 absorption enhancement for the present experimental conditions.

CO2 absorption enhancement by methanol-based Al2O3 and SiO2 nanofluids in a tray column absorber

In this study, the nanoparticles (i.e. SiO2 and Al2O3 nanoparticles) and methanol are combined into SiO2/methanol and Al2O3/methanol nanofluids to enhance the CO2 absorption rate of the base fluid (methanol). The absorption experiments are performed in the bubble type absorber system equipped with mass flow controller (MFC), mass flow meter (MFM) and silica gel (which can remove the methanol vapor existing in the outlet gases). The parametric analysis on the effects of the particle species and concentrations on CO2 bubble absorption rate is carried out. The particle concentration ranges from 0.005 to 0.5 vol%. It is found that the CO2 absorption rate is enhanced up to 4.5% at 0.01 vol% of Al2O3/methanol nanofluids at 20 °C, and 5.6% at 0.01 vol% of SiO2/methanol nanofluids at −20 °C, respectively.

CO2 bubble absorption enhancement in methanol-based nanofluids

Recently there have been growing concerns that anthropogenic carbon dioxide (CO2) emissions cause the global warming problem. Therefore, the cutting-edge technologies for the reduction, separation and collection of the CO2 are very important to alleviate this problem. The best methods for reducing the CO2 emission are to increase the energy efficiency and to remove it from the power plant. The CO2 absorption from the syngas in the integrated gasification combined cycle (IGCC) might increase the energy efficiency of the power generation systems, which also contribute to mitigate the global warming. In this study, the suspensions of nanoparticles in methanol (called the nanofluid) are developed and estimated to apply it to absorb CO2 gas in the IGCC systems. The nanofluids are prepared by the ultrasonic treatment and show the good stability. It is found that the CO2 absorption rate by the nanofluid is enhanced up to ∼8.3% compared to the pure methanol.

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CO 2 absorption characteristics of nanoparticle suspensions in methanol

The purpose of this study to enhance the absorption process of CO 2 in methanol by the addition of Al 2 O 3 and SiO 2 nanoparticles. The continuous removal system is an acrylic tray column with twelve plate where the CO 2 gas and methanol liquid are brought in contact in a counter-current flow. The test section is equipped with two mass flow meters to measure the absorption rate. It is found a maximum enhanced absorption rate (compared to pure methanol absorbent) of 9% for both particles.

Jae Won Lee

Papers

Thermal conductivity measurement of methanol-based nanofluids with Al2O3 and SiO2 nanoparticles

CO2 absorption enhancement by methanol-based Al2O3 and SiO2 nanofluids in a tray column absorber

CO2 bubble absorption enhancement in methanol-based nanofluids

CO 2 absorption characteristics of nanoparticle suspensions in methanol

CO₂ absorption in methanol-based Al₂O₃ and SiO₂ nanofluids in a continuous removal system