“…It was observed that the difference between the melting and crystallisation temperatures was only 2.3 °C for the bulk Sn, but 118.9 °C and 90.3 °C for the 60–80 nm and <300 nm Sn nanoparticles, respectively. Hence supercooling temperature was lower for the smallest particles, but was noticeable for both studied types 28 . Figure 4 Differential Scanning Calorimetry (DSC) analysis of nanoencapsulation suitability and integrity.…”
Nanofluids using nanoencapsulated Phase Change Materials (nePCM) allow increments in both the thermal conductivity and heat capacity of the base fluid. Incremented heat capacity is produced by the melting enthalpy of the nanoparticles core. In this work two important advances in this nanofluid type are proposed and experimentally tested. It is firstly shown that metal and metal alloy nanoparticles can be used as self-encapsulated nePCM using the metal oxide layer that forms naturally in most commercial synthesis processes as encapsulation. In line with this, Sn/SnOx nanoparticles morphology, size and thermal properties were studied by testing the suitability and performance of encapsulation at high temperatures and thermal cycling using a commercial thermal oil (Therminol 66) as the base fluid. Secondly, a mechanism to control the supercooling effect of this nePCM type based on non-eutectic alloys was developed.
“…It was observed that the difference between the melting and crystallisation temperatures was only 2.3 °C for the bulk Sn, but 118.9 °C and 90.3 °C for the 60–80 nm and <300 nm Sn nanoparticles, respectively. Hence supercooling temperature was lower for the smallest particles, but was noticeable for both studied types 28 . Figure 4 Differential Scanning Calorimetry (DSC) analysis of nanoencapsulation suitability and integrity.…”
Nanofluids using nanoencapsulated Phase Change Materials (nePCM) allow increments in both the thermal conductivity and heat capacity of the base fluid. Incremented heat capacity is produced by the melting enthalpy of the nanoparticles core. In this work two important advances in this nanofluid type are proposed and experimentally tested. It is firstly shown that metal and metal alloy nanoparticles can be used as self-encapsulated nePCM using the metal oxide layer that forms naturally in most commercial synthesis processes as encapsulation. In line with this, Sn/SnOx nanoparticles morphology, size and thermal properties were studied by testing the suitability and performance of encapsulation at high temperatures and thermal cycling using a commercial thermal oil (Therminol 66) as the base fluid. Secondly, a mechanism to control the supercooling effect of this nePCM type based on non-eutectic alloys was developed.
“…Δ G V is the free energy change per unit volume and can be expressed as Δ G V = Δ g m ( T )/ V m , where V m is the molar volume of the element, and Δ g m ( T ) can be expressed as: 34 where Δ H m means the melting enthalpy. Based on the Helmholtz free energy 23 Δ H m ( T ) = Δ g m ( T ) − Td Δ g m ( T )/d T and eqn (2), Δ H m ( T ) can be written as:Δ H m ( T ) = Δ H m ( T / T m ) 2 …”
Section: Theoretical Modelmentioning
confidence: 99%
“…Petrov et al 21 developed a freezing temperature model under the nanoscale, while some of the parameters were obtained experimentally. Zhang 22 and Li 23 studied the T f ( r ) of metallic or semi-metallic nanoparticles by considering the degree of super-cooling and classical nucleation theory. The size effect on T f ( r ) of water nanodroplets was not involved, and not considered in the case of the heterogeneous system.…”
Freezing of water and melting of ice at the nanoscale play critical roles in science and technology fields, including aviation systems, infrastructures, and other broad spectrum of technologies.
“…It was observed that the difference between the melting and crystallisation temperatures was only 2.3 °C for the bulk Sn, but 118.9 °C and 90.3 °C for the 60-80 nm and <300 nm Sn nanoparticles, respectively. Hence supercooling temperature was lower for the smallest particles, but was noticeable for both studied types 59 .…”
Section: Nanoencapsulation Stability After Thermal Cycling and Maximumentioning
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