Development of paraffinic phase change material nanoemulsions for thermal energy storage and transport in low-temperature applications

Cabaleiro, David; Agresti, F.; Barison, S.; Marcos, Marco A.; Prado, Jose I.; Rossi, Stefano; Bobbo, Sergio; Fedele, Laura

doi:10.1016/j.applthermaleng.2019.113868

Cited by 53 publications

(45 citation statements)

References 75 publications

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“…where r is the radius of the PCM droplet, µ water is the viscosity of the surrounding media and Γ is the interfacial tension between droplets and base fluid. In our case, even in the nano-emulsion containing 10 wt.% of RT21HC, individual paraffin droplets exhibited average hydrodynamic sizes lower thañ 160 nm (value measured 1 month after preparation) [32], while interfacial tension between RT21HC and water was~0.042 N/m (Γ reduced to~0.008 N/m when SDS was added to water, see Section 3.2.1). Thus, droplet relaxation times are expected to be very short, λ d < 2×10 −9 s, and drop deformation very small, even for relatively high shear rates [23].…”

Section: Surface Propertiesmentioning

confidence: 62%

“…The hydrodynamic sizes and ζ-potential values of paraffin droplets were determined at 298 K using a Zetasizer Nano-ZS90 (Malvern Instruments Ltd., Worcestershire, UK) based on Dynamic Light Scattering (DLS) method [33]. Figure 1a shows the size distributions obtained for the three emulsions designed without nucleating agent [32] just after PCME formulation. At 2 and 4 wt.% paraffin contents, PCM droplets exhibited average hydrodynamic sizes around ~90-100 nm and polydispersity indexes (pdl) ~0.17-0.23.…”

Section: Nano-emulsion Formulationmentioning

confidence: 99%

“…ζ-potential measurements showed negative values larger than −80 mV, indicating that electrostatically repulsive charges among droplets are strong enough to prevent agglomeration and coalescence. A thoughtful study of stability throughout storage, after freeze-thaw cycles and under mechanical shear was performed for these PCM nano-emulsions in our previous work [32]. At 2 and 4 wt.% paraffin contents, PCM droplets exhibited average hydrodynamic sizes around 90-100 nm and polydispersity indexes (pdl)~0.17-0.23.…”

Section: Nano-emulsion Formulationmentioning

confidence: 99%

“…Experimental measurements were carried out at temperatures ranging from 275 to 303 K to evaluate whether the solid/liquid state of paraffin droplets had any effect on studied physical properties. With this work we intend to complete the characterization of this nano-emulsion system started in our recent publication [32], in which phase change transitions, thermal conductivities and volumetric behavior were analyzed.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Viscosity, Surface Tension and Wetting Behavior Studies of Paraffin–in–Water Nano–Emulsions

et al. 2019

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This work analyzes the dynamic viscosity, surface tension and wetting behavior of phase change material nano–emulsions (PCMEs) formulated at dispersed phase concentrations of 2, 4 and 10 wt.%. Paraffin–in–water samples were produced using a solvent–assisted route, starting from RT21HC technical grade paraffin with a nominal melting point at ~293–294 K. In order to evaluate the possible effect of paraffinic nucleating agents on those three properties, a nano–emulsion with 3.6% of RT21HC and 0.4% of RT55 (a paraffin wax with melting temperature at ~328 K) was also investigated. Dynamic viscosity strongly rose with increasing dispersed phase concentration, showing a maximum increase of 151% for the sample containing 10 wt.% of paraffin at 278 K. For that same nano–emulsion, a melting temperature of ~292.4 K and a recrystallization temperature of ~283.7 K (which agree with previous calorimetric results of that emulsion) were determined from rheological temperature sweeps. Nano–emulsions exhibited surface tensions considerably lower than those of water. Nevertheless, at some concentrations and temperatures, PCME values are slightly higher than surface tensions obtained for the corresponding water+SDS mixtures used to produce the nano–emulsions. This may be attributed to the fact that a portion of the surfactant is taking part of the interface between dispersed and continuous phase. Finally, although RT21HC–emulsions exhibited contact angles considerably inferior than those of distilled water, PCME sessile droplets did not rapidly spread as it happened for water+SDS with similar surfactant contents or for bulk–RT21HC.

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Section: Surface Propertiesmentioning

confidence: 62%

Section: Nano-emulsion Formulationmentioning

confidence: 99%

Section: Nano-emulsion Formulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic Viscosity, Surface Tension and Wetting Behavior Studies of Paraffin–in–Water Nano–Emulsions

et al. 2019

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“…Thus, in addition to developing and utilizing new renewable sources, improving the use efficiency of existing energy (such as fossil energy and renewable energy) is also an important issue. [6][7][8][9] As one of the most important energy forms in modern society, electric energy, generated by hydroelectric power, thermal power, and wind power, etc., is widely used in all aspects of national life, and it also provides great convenience for human life. For a variety of reasons, the generation of electric energy is usually huge and continuous.…”

Section: Introductionmentioning

confidence: 99%

Polyethylene Glycol/Carbon Black Shape-Stable Phase Change Composites for Peak Load Regulating of Electric Power System and Corresponding Thermal Energy Storage

Lu¹,

Liu²,

Murugadoss³

et al. 2020

Eng. Sci.

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In this work, a unique electrically conductive polyethylene glycol (PEG)/carbon black (CB) shape-stable phase change composite (SSPCC) for peak load regulating of electric power system was prepared via a vacuum impregnation approach. Scanning electron microscope (SEM), differential scanning calorimeter (DSC) and X-ray diffraction (XRD) were used to study the micro morphology, crystallization behavior, crystallization structure and thermal properties. Leakage test and DSC results showed that when the PEG content in PEG/CB SSPCC was as high as 86 wt%, the phase change enthalpy and relative enthalpy efficiency were up to 147.7 J/g and 95.1%, respectively. Fourier transform infrared (FTIR) and XRD showed no chemical reaction between CB and PEG. Thermal cycling test showed that the PEG/CB SSPCC had excellent thermal stability and thermal reliability. Moreover, the good electro-tothermal conversion ability of PEG/CB SSPCC (0.2 S/m) provided rich possibilities for peak load regulating of electric power system and corresponding thermal energy storage.

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Salt hydrates as phase change materials for photovoltaics thermal management

Choo

Wei

2021

Energy Science & Engineering

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Conventional source of energy, for example fossil fuels, are depleting with time. The combustion of fossil fuels also lead to increased carbon emission in environment, causing global warming. To meet the world's increasing energy demand, the utilization of alternative resources like solar energy must be improved. Solar energy can be harvested directly into electricity by using photovoltaic (PV) module. However, when the solar radiation reaches a PV module, it is not only converted into electricity but also into thermal energy, which increases the PV system temperature. 1 There are many factors affecting the solar power output of the PV system. Temperature is one of them. The productivity of a PV-module is the inverse of the temperature. According to the Standard Test Conditions, if a PV module is operated at temperature higher than the ambient temperature, 25°C, at each increase of degree Celsius, the conversion rate of the PV module decreases, up to 0.5%. 2 As expected, summer is the season with the highest solar radiation, when a PV system such as solar panel can absorb most solar energy and produce heat or electricity

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Development of paraffinic phase change material nanoemulsions for thermal energy storage and transport in low-temperature applications

Cited by 53 publications

References 75 publications

Dynamic Viscosity, Surface Tension and Wetting Behavior Studies of Paraffin–in–Water Nano–Emulsions

Dynamic Viscosity, Surface Tension and Wetting Behavior Studies of Paraffin–in–Water Nano–Emulsions

Polyethylene Glycol/Carbon Black Shape-Stable Phase Change Composites for Peak Load Regulating of Electric Power System and Corresponding Thermal Energy Storage

Salt hydrates as phase change materials for photovoltaics thermal management

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