scholarly journals Bi-Functional Paraffin@Polyaniline/TiO2/PCN-222(Fe) Microcapsules for Solar Thermal Energy Storage and CO2 Photoreduction

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 2
Author(s):  
Wenchang Sun ◽  
Yueming Hou ◽  
Xu Zhang
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Building Materials ◽  
Evolution Rate ◽  
Co2 Photoreduction ◽  
Tight Contact ◽  
Change Material

A novel type of bi-functional microencapsulated phase change material (MEPCM) microcapsules with thermal energy storage (TES) and carbon dioxide (CO2) photoreduction was designed and fabricated. The polyaniline (PANI)/titanium dioxide (TiO2)/PCN-222(Fe) hybrid shell encloses phase change material (PCM) paraffin by the facile and environment-friendly Pickering emulsion polymerization, in which TiO2 and PCN-222(Fe) nanoparticles (NPs) were used as Pickering stabilizer. Furthermore, a ternary heterojunction of PANI/(TiO2)/PCN-222(Fe) was constructed due to the tight contact of the three components on the hybrid shell. The results indicate that the maximum enthalpy of MEPCMs is 174.7 J·g−1 with encapsulation efficiency of 77.2%, and the thermal properties, chemical composition, and morphological structure were well maintained after 500 high–low temperature cycles test. Besides, the MEPCM was employed to reduce CO2 into carbon monoxide (CO) and methane (CH4) under natural light irradiation. The CO evolution rate reached up to 45.16 μmol g−1 h−1 because of the suitable band gap and efficient charge migration efficiency, which is 5.4, 11, and 62 times higher than pure PCN-222(Fe), PANI, and TiO2, respectively. Moreover, the CO evolution rate decayed inapparently after five CO2 photoreduction cycles. The as-prepared bi-functional MEPCM as the temperature regulating building materials and air purification medium will stimulate a potential application.

Preparation and Properties of Cement Bricks Based Paraffin for Thermal Energy Storage by Phase Change

2011 ◽  
Vol 279 ◽  
pp. 97-100
Author(s):  
Hai Feng Chen ◽  
Pei Song Tang ◽  
Feng Cao ◽  
Min Hong Xu
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Building Materials ◽  
National Standard ◽  
Vacuum Impregnation ◽  
Linear Change ◽  
Change Material

Using paraffin as phase change material, expanded perlite (EP) as porous materials, the EP/paraffin was prepared by vacuum impregnation treatment and tested by scanning electron microscopy (SEM). Adding other building materials, cement bricks based paraffin (CBBP) for thermal energy storage were molded and tested by means of water absorption, compressive strength and actual working of thermal energy storage. The testing results showed that paraffin was absorbed into the holes and cracks of EP, and CBBP had not linear change of various properties versus amount of cement or paraffin. Its mechanical strength was full compliance with national standard GB 21144-2007-T. At last, by phase change material exothermic or endothermic, CBBP effectively regulated outdoor surface temperature in summer: in temperature rising stage, CBBP was 4.63 °C lower than general cement bricks (GCB, no paraffin); in the cooling stage, CBBP was 2.30 °C higher than GCB.

Thermal Energy Storage Through Melting of a Commercial Phase Change Material in an Annulus with Radially Divergent Longitudinal Fins

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Tonny Tabassum Mainul Hasan ◽  
Latifa Begum
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Operating Conditions ◽  
Melting Time ◽  
Bottom Part ◽  
Change Material

This study reports on the unsteady two-dimensional numerical investigations of melting of a paraffin wax (phase change material, PCM) which melts over a temperature range of 8.7oC. The PCM is placed inside a circular concentric horizontal-finned annulus for the storage of thermal energy. The inner tube is fitted with three radially diverging longitudinal fins strategically placed near the bottom part of the annulus to accelerate the melting process there. The developed CFD code used in Tabassum et al., 2018 is extended to incorporate the presence of fins. The numerical results show that the average Nusselt number over the inner tube surface, the total melt fraction, the total stored energy all increased at every time instant in the finned annulus compared to the annulus without fins. This is due to the fact that in the finned annulus, the fins at the lower part of the annulus promotes buoyancy-driven convection as opposed to the slow conduction melting that prevails at the bottom part of the plain annulus. Fins with two different heights have been considered. It is found that by extending the height of the fin to 50% of the annular gap about 33.05% more energy could be stored compared to the bare annulus at the melting time of 82.37 min for the identical operating conditions. The effects of fins with different heights on the temperature and streamfunction distributions are found to be different. The present study can provide some useful guidelines for achieving a better thermal energy storage system.

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