MWCNT in PEG-400 nanofluids for thermal applications: A chemical, physical and thermal approach

Marcos, Marco A.; Podolsky, Nikita E.; Cabaleiro, David; Lugo, Luis; Zakharov, Alexey O.; Постнов, В. Н.; Чарыков, Н. А.; Ageev, Sergei V.; Semenov, Konstantin N.

doi:10.1016/j.molliq.2019.111616

Cited by 39 publications

(33 citation statements)

References 81 publications

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“…This trend is in agreement with that predicted from C p data measured in our laboratory for the base fluid and dry PVP-capped Ag nanoparticles by using Equation (1). Other studies on nanofluids using PEG400 as base fluid found diminutions of 3% for the concentration of 1wt% of multiwalled carbon nanotubes (MWCNT) [32], or 0.34% for a dispersion of 0.5 wt% using functionalized graphene nanoplatelets [30]. Hence, it can be concluded that the addition of the PVP-capped Ag nanoparticles does not lead to a significant reduction in the sensible heat capacity of the phase change material.…”

Section: Isobaric Heat Capacitysupporting

confidence: 90%

“…Experimental isobaric heat capacities, Cp, for PEG400, the dry powder of Ag nanoparticle, and the Ag(0.5 wt%)/PEG400 nanofluid in the temperature range from 283.15 to 333.15 K are shown in Figure 7. Obtained values for base fluid exhibit a good agreement with data reported by Francesconi et al [70] and Marcos et al [30,32] for other poly(ethylene glycol) with similar average molecular weights, around 400 g•mol −1 . Results measured for dry silver nanoparticles were also compared with the values recommended by Touloukian and Buyco [71] for bulk silver.…”

Section: Isobaric Heat Capacitysupporting

confidence: 89%

“…Other studies conducted with PEG400 as base fluid reported that Hamilton-Crosser, Murshed, Xue, or Nan models also underestimated thermal conductivity results. So, differences of 5.6% (H-C), 5.5% (Murshed) and 2.6% (Xue), were obtained when dispersed MWCNT [32] while the Nan correlation allowed obtaining 1% for GnP suspensions [30]. The cause of those larger experimental enhancements in thermal conductivity may be due to the size dependence of thermal conductivity.…”

Section: Thermal Conductivitymentioning

confidence: 93%

“…Those enhancements rose with increasing nanoparticle loading, a maximum improvement of 3.9% being reached in the case of the 1.1 wt% concentration. Other studies conducted with PEG400 as base fluid reported higher increases in thermal conductivity, 12.7% for 1 wt% MWCNT/PEG400 nanofluid [32] and 23% for a PEG400 dispersion containing 0.5 wt% of functionalized graphene nanoplatelets (fGnP) [30]. The PVP-capped procedure carried out with silver nanoparticles to favor the stability of the conceived dispersions entailed a penalty in the expected improvement of the intrinsic heat transfer of the sample.…”

Section: Thermal Conductivitymentioning

confidence: 99%

“…Therefore, average number molar mass is equal to Mn = 520.50 g•mol −1 , average mass molar mass being Mw = 532.94 g•mol −1 and polydispersity index Mw/Mn = 1.02 (quasi-monodisperse polymer). Molecular mass values obtained by ESI-MS were larger than expected for a poly(ethylene glycol) commercialized as PEG400 [30,32,58,59]. Particle size distribution was obtained by measuring the diameter of a representative number of nanoparticles using ImageJ software (http://rsb.info.nih.gov/ij/).…”

Section: Nanoparticle and Base Fluid Characterizationmentioning

confidence: 99%

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NePCM Based on Silver Dispersions in Poly(Ethylene Glycol) as a Stable Solution for Thermal Storage

et al. 2019

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The main objective of this study is to design and characterize silver suspensions based on poly(ethylene glycol) PEG400, Ag/PEG400, as energy storage media for low-temperature applications. A polyvinylpyrrolidone (PVP) treatment was applied to ~22 nm silver nanoparticles to ensure good stability in poly(ethylene glycol). An array of different experimental techniques was utilized to analyze the molecular mass and purity of base poly(ethylene glycol), morphology of dry PVP-capped Ag nanoparticles, hydrodynamic average size of dispersed Ag particles, as well as thermal stability of PEG400 and Ag/PEG400 dispersions. Samples exhibited good temporal stabilities with average hydrodynamic diameter around 50 nm according to dynamic light scattering analyses. Melting and solidification transitions were investigated in terms of temperature and enthalpy from differential scanning calorimeter (DSC) thermograms. The thermophysical characterization was completed with thermal conductivity (k), dynamic viscosity (η), isobaric heat capacity (Cp), density (ρ), and surface tension (σ) measurements of designed materials using a Hot Disk thermal conductivimeter, a rotational rheometer, a DSC calorimeter working with a quasi-isothermal modulated method, a U-tube densimeter and a drop shape analyzer, respectively. For a nanoparticle loading of only 1.1% in mass, sub-cooling reduced by 7.1% and thermal conductive improved by 3.9%, with almost no penalization in dynamic viscosity (less than 5.4% of increase). Maximum modifications in Cp, ρ, and σ were 0.9%, 2.2%, and 2.2%, respectively. Experimental results were compared with the values provided by using different theoretical or semi-empirical equations. In particular, good descriptions of dynamic viscosity as functions of temperature and nanoparticle volume concentration were obtained by using the Vogel–Fulcher–Tammann equation and a first-order polynomial η( ϕ v , n p ) correlation, with absolute average deviations of 2.2% and 0.55%, respectively.

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Section: Isobaric Heat Capacitysupporting

confidence: 90%

Section: Isobaric Heat Capacitysupporting

confidence: 89%

Section: Thermal Conductivitymentioning

confidence: 93%

Section: Thermal Conductivitymentioning

confidence: 99%

Section: Nanoparticle and Base Fluid Characterizationmentioning

confidence: 99%

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NePCM Based on Silver Dispersions in Poly(Ethylene Glycol) as a Stable Solution for Thermal Storage

et al. 2019

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Nanofluids as heat transfer fluids: Hurdles to industrial application and economic considerations

2022

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Nanofluids have gained substantial interest over the past years due to their enhanced thermal properties. However, these nanoparticle dispersions remain scarcely used in industrial applications. In this work, we demonstrate how the stability of nanofluids and economic factors are the major hurdles preventing their industrial large-scale use through an economic analysis. The costeffectiveness of multiwalled carbon nanotubes (MWCNT)-water and copper oxide-water nanofluids used in a concentric tube heat exchanger as substitutes for freshwater was assessed in four different scenarios. It was determined that three of the four cases were not economically viable, as a deficit was generated due to a recurring annual investment for the renewal of the nanofluids because they destabilized with time. The fourth case, however, was sustainable because of the nanofluid's high stability (5 years) and showed a payback period on investment of less than a year. Finally, a tool illustrating the operating window for nanofluid economics in our selected heat exchanger geometry was developed.

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An updated review of nanofluids in various heat transfer devices

Okonkwo

Wole‐Osho

Almanassra

et al. 2020

J Therm Anal Calorim

239

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The field of nanofluids has received interesting attention since the concept of dispersing nanoscaled particles into a fluid was first introduced in the later part of the twentieth century. This is evident from the increased number of studies related to nanofluids published annually. The increasing attention on nanofluids is primarily due to their enhanced thermophysical properties and their ability to be incorporated into a wide range of thermal applications ranging from enhancing the effectiveness of heat exchangers used in industries to solar energy harvesting for renewable energy production. Owing to the increasing number of studies relating to nanofluids, there is a need for a holistic review of the progress and steps taken in 2019 concerning their application in heat transfer devices. This review takes a retrospective look at the year 2019 by reviewing the progress made in the area of nanofluids preparation and the applications of nanofluids in various heat transfer devices such as solar collectors, heat exchangers, refrigeration systems, radiators, thermal storage systems and electronic cooling. This review aims to update readers on recent progress while also highlighting the challenges and future of nanofluids as the next-generation heat transfer fluids. Finally, a conclusion on the merits and demerits of nanofluids is presented along with recommendations for future studies that would mobilise the rapid commercialisation of nanofluids.

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MWCNT in PEG-400 nanofluids for thermal applications: A chemical, physical and thermal approach

Cited by 39 publications

References 81 publications

NePCM Based on Silver Dispersions in Poly(Ethylene Glycol) as a Stable Solution for Thermal Storage

NePCM Based on Silver Dispersions in Poly(Ethylene Glycol) as a Stable Solution for Thermal Storage

Nanofluids as heat transfer fluids: Hurdles to industrial application and economic considerations

An updated review of nanofluids in various heat transfer devices

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