Preparation of a Sustainable Shape-Stabilized Phase Change Material for Thermal Energy Storage Based on Mg2+-Doped CaCO3/PEG Composites

Abstract

The properties of polyethylene glycol-6000 (PEG)/MgCaCO3, a low-cost shape-selective phase change material (ss-PCM), make it highly suitable for solar thermal applications. Nanosized porous MgO-doped CaCO3 with Mg molar concentrations of 5%, 10%, and 15% were synthesized using a hydrothermal technique. The prepared MgO-CaCO3 matrices were then impregnated with PEG to obtain PEG/MgCaCO3 as an ss-PCM. Samples identified as PEG-5MgCaCO3 (P-5-MCC), PEG-10MgCaCO3 (P-10-MCC), and PEG-15MgCaCO3 (P-15-MCC) were prepared and studied. Interestingly, P-10-MCC has the smallest particle size together with a good porous structure compared to the other two materials. The results of thermogravimetric analyses and differential scanning calorimetry indicate that the small particle size and porous structure facilitate the impregnation of approximately 69% of the PEG into the 10-MCC matrix. The latent heat and energy storage efficiency of PEG in the P-10-MCC sample are 152.5 J/g and 96.48%, respectively, which are significantly higher than those of comparable materials. Furthermore, in addition to the improvement of the thermal conductivity of the P-10-MCC, its supercooling is also reduced to some extent. The combined mesoporous and macro-porous structure of P-10-MCC is critical to retaining a large amount of PEG within the matrix, resulting in a high latent heat in the operating temperature range of 35–57 °C. The P-10MCC sample also demonstrates a high energy storage capacity (98.59%), high thermal energy storage/release rates, and exceptional shape-stabilized PCM properties.

Energy Conversion Efficiency Enhancement of Polyethylene Glycol and a SiO2 Composite Doped with Ni, Co, Zn, and Sc Oxides

“…Solar energy conversion into thermal energy and the energy storage capacity of PCMs may be computed simultaneously using the present technique, which takes into account the high latent heat and good optical characteristics of PCMs. 4 Also, PEG/Sc-SiO 2 absorbs higher light higher compared with pure PEG across the whole visible region. Several temperature recorders were placed under the solar simulators to evaluate the conversion of solar energy into thermal energy by PEG and PEG/Sc-SiO 2 .…”

“…Recently, we demonstrated that solar energy conversion efficiency (η) can be increased by incorporating organic PCMs in an inorganic support. 4 Although many materials selectively absorb visible light, collecting and converting full-band solar radiation are challenging.…”

“…Owing to its high storage density and phase change temperature, polyethylene glycol (PEG) is one of the most promising PCMs for hot climates. , However, the low thermal conductivity of PEG and leakage issues associated with systems based on it are primary shortcomings in practical applications. Leakage problems associated with PEG can be overcome by encapsulating it in a matrix to create a form-stable composite phase change material (fs-CPCM) with the PEG polymer functioning exclusively within the matrix. − …”

“…Given that UV–vis light accounts for approximately 45% of the total solar energy, harvesting it is critical for efficient solar energy conversion. Recently, we demonstrated that solar energy conversion efficiency (η) can be increased by incorporating organic PCMs in an inorganic support . Although many materials selectively absorb visible light, collecting and converting full-band solar radiation are challenging.…”

Nanoparticles to Enhance Melting Performance of Phase Change Materials for Thermal Energy Storage

“…These options are more attractive when compared with other options because of the relatively high storage density and the fact that it is almost possible to achieve isothermal storage conditions. Proposed TES systems that use phase change materials (PCMs) [ 4 ] can store several times more energy than systems using sensitive storage materials, even when the same material types and volumes are used [ 5 ]. However, most phase change materials have the disadvantageous property of relatively low thermal conductivity [ 6 ], which strongly inhibits the energy charge and discharge rates.…”