Preparation and Melting/Freezing Characteristics of Cu/Paraffin Nanofluid as Phase-Change Material (PCM)

Abstract

A new sort of nanofluid phase-change material (PCM) is developed by suspending a small amount of nanoparticles in melting paraffin. Cu, Al, and C/Cu nanoparticles were selected to add to the melting paraffin to enhance the heat-transfer rate of paraffin. Cu nanoparticles have the best performance for heat transfer. Five dispersants were chosen to make Cu nanoparticles stably suspended in melting paraffin. The nanofluids with Cu nanoparticles show good stability in melting paraffin under the action of Hitenol BC-10, even suspending for 12 h in a constant temperature trough. The Fourier transform infrared (FTIR) spentrum shows that it is a physical interaction among Cu, paraffin, and Hitenol BC-10. The differential scanning calorimetric (DSC) results reveal that the latent heats of Cu/paraffin shift to lower values compared to those of pure paraffin; however, the melting and freezing temperatures are kept almost the same as pure paraffin. The latent heats and phase-change temperatures change very little after 100 thermal cycles. Furthermore, the heating and cooling rates of PCMs were significantly improved upon the addition of Cu nanoparticles. For composites with 1 wt % Cu nanoparticle, the heating and cooling times can be reduced by 30.3 and 28.2%, respectively.

Nano-enhanced phase change materials for improved building performance

“…The two-step method is the most economic method to produce the materials in large scale and has been extensively used to prepare nano-enhanced PCMs [31,[33][34][35][36]. In this method, the ultrasonic vibration technique is usually used to ensure that nanometer-sized materials are well dispersed into the base fluid [33][34][35][36] and appropriate surfactants are used to enhance the stability of nanometer-sized materials in the PCM base fluid to maintain good suspension performance [33,36].…”

“…A number of studies have used various nanometer-sized materials to improve the thermal conductivity of paraffin. The dispersion of copper nanoparticles in paraffin was reported by Wu et al [19,34]. Hitenol BC-10 was used as the surfactant.…”

Synergistically-Enhanced Thermal Conductivity of Shape-Stabilized Phase Change Materials by Expanded Graphite and Carbon Nanotube

“…The general way to improve thermal conductivity of paraffin PCMs is to add highly thermally-conductive fillers. Metal fillers have good thermal conductivity and, thus, were used often [5][6][7][8][9]. For example, Wu et al [6] reported that by adding 1 wt % Cu nanoparticles into paraffin (Tm = 58-60 • C), the heating and cooling times were reduced by 30.3% and 28.2%, respectively.…”

“…Metal fillers have good thermal conductivity and, thus, were used often [5][6][7][8][9]. For example, Wu et al [6] reported that by adding 1 wt % Cu nanoparticles into paraffin (Tm = 58-60 • C), the heating and cooling times were reduced by 30.3% and 28.2%, respectively. Xiao et al [8] prepared paraffin (Tm = 60-62 • C)/nickel foam and paraffin/copper foam composites by using a vacuum impregnation method.…”

Supercooling and cold energy storage characteristics of nano-media in ball-packed porous structures

“…17 Experiments on the thermophysical properties of nanofluids as phase-change material have been conducted. [18][19][20] Li et al 21 investigated heat transfer characteristics of phase change nano-composite materials for thermal energy storage application. Jia et al 22 investigated solid-liquid phase transition of nanofluids and found that the effect on phase transition time and enthalpy was more significant at low cooling rates than at high cooling rates.…”