Enhancing the Thermal Performance of a Stearate Phase Change Material with Graphene Nanoplatelets and MgO Nanoparticles

Abstract

The effectiveness of dispersed nanomaterials to improve the thermal performance of phase change materials (PCMs) is well-proven in the literature. The proposal of new engineered nanoenhanced phase change materials (NePCMs) with customized characteristics may lead to more efficient thermal energy storage (TES) systems. This work is focused on the development of new NePCMs based on the dispersions of graphene nanoplatelets (GnPs) or MgO nanoparticles in a stearate PCM. The new proposed materials were synthesized using a two-step method, and acetic acid was selected as a surfactant to improve the stability of the dispersions. An extensive characterization of the constitutive materials and the developed dispersions using different spectroscopy techniques is reported. Also, the GnP nanopowder was explored by using the XPS technique with the aim to characterize the used carbon nanomaterial. The obtained spectra were investigated in terms of the chemical bonds related to the observed peaks. The thermophysical profile (density, thermal conductivity, isobaric heat capacity, and thermal diffusivity) was experimentally determined once the main components of the NePCMs were characterized and dispersions were designed and developed. This discussion focuses on the differentiated and distinguished effects of the dispersed GnPs and MgO on the properties of the NePCMs. A comprehensive analysis of the measurements to elucidate the mechanism that promoted higher improvements using GnPs instead of MgO was performed.

Continuous Dual-Scale Interpenetrating Network Carbon Foam–Stearic Acid Composite as a Shape-Stabilized Phase Change Material with a Desirable Synergistic Effect

“…The melting enthalpy decreases by 0.98, 2.80, and 3.11% after 200, 400, and 600 cycles, respectively, and the crystallization enthalpy also has a similar downward trend. However, the melting/crystallization enthalpy of the composite decreases completely within an acceptable range. , The fact demonstrates that the SA/DCF-900 composite has excellent cycle stability. In addition, its storage efficiency, which is defined by the division of the melting/crystallization enthalpy, is still as high as 99% after 600 thermal cycles.…”

“…However, the melting/crystallization enthalpy of the composite decreases completely within an acceptable range. 23,54 The fact demonstrates that the SA/DCF-900 composite has excellent cycle stability. In addition, its storage efficiency, which is defined by the division of the melting/crystallization enthalpy, is still as high as 99% after 600 thermal cycles.…”

“…Among various energy storage technologies, the latent heat energy storage technology using organic solid–liquid phase change materials (PCMs) as the working material has the advantages of high energy storage density, constant temperature during energy storage/release, and convenient operation. − Therefore, organic solid–liquid PCMs have aroused wide interest among researchers. Stearic acid (SA) is a typical organic solid–liquid PCM with unique characteristics such as a large energy storage capacity, noncorrosiveness, a negligible degree of supercooling, and excellent chemical stability and thermal stability; − consequently, it has been widely used in solar energy utilization, − building energy-saving, thermal management of electronic devices, and other fields. , However, SA has a poor ability to absorb sunlight similar to other organic PCMs, and therefore, it cannot directly convert solar radiant energy into heat energy for storage and utilization. In addition, the problems of low thermal conductivity (0.1–0.3 W/m·K) and liquid leakage of SA limit its practical application. − …”

“…Stearic acid (SA) is a typical organic solid−liquid PCM with unique characteristics such as a large energy storage capacity, noncorrosiveness, a negligible degree of supercooling, and excellent chemical stability and thermal stability; 15−18 consequently, it has been widely used in solar energy utilization, 19−21 building energy-saving, 22 thermal management of electronic devices, and other fields. 23,24 However, SA has a poor ability to absorb sunlight similar to other organic PCMs, 25 and therefore, it cannot directly convert solar radiant energy into heat energy for storage and utilization. In addition, the problems of low thermal conductivity (0.1−0.3 W/m•K) and liquid leakage of SA limit its practical application.…”

Biomimetic Membranes with Aqueous Nanochannels. Phase Transitions and Oscillations

“…Because of that, they have attracted much attention for thermal energy storage, improvement of building's energy efficiency, solar heating systems, etc. [1,2]. An attractive way to do this is to use porous composite materials with pores filled with fatty acids.…”