Magnetically-accelerated photo-thermal conversion and energy storage based on bionic porous nanoparticles

Recently, the technology of mixing phase change materials with high thermal conductivity fillers was developed, which has allowed thermal energy storage to be implemented in a wide range of industrial technologies and processes. In the present study, a hierarchical bionic porous nano-composite was prepared, which efficiently merged the nanomaterial characteristics of magnetism and high thermal conductivity in order to form a magnetically-accelerated solar-thermal energy storage method. The morphology and thermo-physical properties of materials were analysed. The experimental outcomes of phase change heat transfer demonstrated that the maximum storage efficiency increases by 102.7% when the hierarchical bionic porous structure is used, and a further 27.1% improvement can be achieved with the magnetic field. At the same time, the heat transfer process of energy storage in hierarchical porous composites under external physical fields is explained by simulation. Therefore, this magnetically-accelerated method demonstrated the superior solar-thermal energy storage characteristics within a hierarchical bionic porous structure which is particularly beneficial for the utilisation of solar direct absorption collectors and energy storage technology

Using mesoporous carbon to pack polyethylene glycol as a shape-stabilized phase change material with excellent energy storage capacity and thermal conductivity

A novel shape-stabilized phase change material was successfully prepared using polyethylene glycol (PEG) as PCM and mesoporous carbon FDU-15 as support via the melting impregnation method. The structural and thermal properties of materials were measured by TEM, SEM, XRD, FT-IR, nitrogen adsorption-desorption isotherms and DSC, respectively. The maximum loading of PEG/FDU-15 reaches up to 75 wt%, and the corresponding crystallization ratio is 71%, which is superior to other mesoporous-based composite phase change materials. Molecular dynamic (MD) analysis showed that some PEG adhered to the pore wall with an amorphous structure which failed to crystallize, ultimately resulting in a gap between the measured latent heat and the theoretical value. It was interesting that the filling of PEG could stimulate the frequency shift of atomic vibration in FDU-15, which then just fell in the dominant vibrational zone of PEG, despite the suppressed atomic vibration of PEG after compounding. Accordingly, the thermal conductivity of the composite is more than 60% higher compared to pure PEG, which relates to the reinforced matching of the atomic vibration between the skeleton and PCM material. FDU-15 was applied to pack PCM for the first time and delivered a better thermal performance compared with other mesopore-based composite PCMs

Thermal properties of PEG/MOF-5 regularized nanoporous composite phase change materials: A molecular dynamics simulation

In this paper, a metal-organic framework MOF-5 loaded polyethylene glycol (PEG) nanowire was used to form composite phase change material PEG/MOF-5. The molecular dynamics method was used to simulate the thermal conductivity, melting point and latent heat by G-K function and pseudo-supercritical path method, respectively. The results show that the pores of MOF-5 promote the increase of the angle of the PEG main chain and the extension of the helical segment. Therefore, the thermal conductivity of the composite (0.60 W/m·K) is 17.6% and 100% higher than that of the PEG nanowire (0.51 W/m∙K) and the skeleton (about 0.3 W/m∙K), respectively. At the same time, MOF-5 can improve the crystallinity of the PEG to a certain extent. The predicted latent heat of PEG/MOF-5 composite material is as high as 78.4 kJ/kg with a mass filling rate of 50%. This paper explores the mechanism from a microscopic perspective in order to provide models and data for the thermal design of such materials

A review of phase change heat transfer in shape-stabilized phase change materials (ss-PCMs) based on porous supports for thermal energy storage

Latent heat thermal energy storage (LHTES) uses phase change materials (PCMs) to store and release heat, and can effectively address the mismatch between energy supply and demand. However, it suffers from low thermal conductivity and the leakage problem. One of the solutions is integrating porous supports and PCMs to fabricate shape-stabilized phase change materials (ss-PCMs). The phase change heat transfer in porous ss-PCMs is of fundamental importance for determining thermal-fluidic behaviours and evaluating LHTES system performance. This paper reviews the recent experimental and numerical investigations on phase change heat transfer in porous ss-PCMs. Materials, methods, apparatuses and significant outcomes are included in the section of experimental studies and it is found that paraffin and metal foam are the most used PCM and porous support respectively in the current researches. Numerical advances are reviewed from the aspect of different simulation methods. Compared to representative elementary volume (REV)-scale simulation, the pore-scale simulation can provide extra flow and heat transfer characteristics in pores, exhibiting great potential for the simulation of mesoporous, microporous and hierarchical porous materials. Moreover, there exists a research gap between phase change heat transfer and material preparation. Finally, this review outlooks the future research topics of phase change heat transfer in porous ss-PCMs

Numerical investigation on improving the heat storage and transfer performance of ceramic /D-mannitol composite phase change materials by bionic graded pores and nanoparticle additives

To speed up the thermal response rate of the latent heat storage system, this research draws on the ideas of bionics and proposes two methods to enhance the performance of heat storage and heat transfer during phase change process. First, a biomimetic, double-gradient porous ceramic was applied to assemble phase change material (PCM) D-mannitol. The optimized gradient pore structure ensures that the composite possesses higher effective thermal conductivity, and better uniformity of phase interface evolution, with reasonable heat storage density. Numerical simulation predicts a 226 % increase in effective thermal conductivity comparing with the pure D-mannitol. Then, two kinds of carbon-based nanoparticles were added to further reinforce the heat transfer performance. Results found that graphite nanoparticles provide the most significant enhancement in the effective thermal conductivity of the composite material under the premise of ensuring a higher heat storage density. In conclusion, the effective thermal conductivity of the final composite achieves 3.33-fold increase due to the collaboration of the double gradient pore framework and the additive graphite nanoparticles. Accordingly, the overall heat transfer rate could be raised by 4.2 times, comparing with the pure PCM sample. This work demonstrates that the bidirectional gradient pore skeleton has significant advantages in heat storage and transfer over the single pore and unidirectional gradient pore

Plantamajoside alleviates acute sepsis-induced organ dysfunction through inhibiting the TRAF6/NF-κB axis

AbstractContext Plantamajoside (PMS) possesses rich pharmacological characteristics that have been applied to remedy dozens of diseases. However, the understanding of PMS in sepsis remains insufficient.Objective Role of PMS in sepsis-regulated organ dysfunction and potential mechanisms were investigated.Materials and methods Thirty C57BL/6 male mice were adaptive fed for three days and used to establish acute sepsis model by caecal ligation and perforation (CLP). These experimental mice were divided into Sham, CLP, CLP + 25 mg PMS/kg body weight (PMS/kg), CLP + 50 mg PMS/kg and CLP + 100 mg PMS/kg (n = 6). The pathological and apoptotic changes of lung, liver and heart tissues were observed via HE and TUNEL staining. The injury-related factors of lung, liver and heart were detected by corresponding kits. ELISA and qRT-PCR were applied to assess IL-6/TNF-α/IL-1β levels. Apoptosis-related and TRAF6/NF-κB-related proteins were determined using Western blotting.Results All doses of PMS enhanced the survival rates in the sepsis-induced mouse model. PMS remitted sepsis-mediated lung, liver and heart injury through prohibiting MPO/BALF (70.4%/85.6%), AST/ALT (74.7%/62.7%) and CK-MB/CK (62.3%/68.9%) levels. Moreover, the apoptosis index (lung 61.9%, liver 50.2%, heart 55.7% reduction) and IL-6/TNF-α/IL-1β levels were suppressed by PMS. Furthermore, PMS lowered TRAF6 and p-NF-κB p65 levels, whereas TRAF6 overexpression reversed the protective influences of PMS in organ injury, apoptosis and inflammation triggered by sepsis.Discussion and conclusions PMS suppressed sepsis-induced organ dysfunction by regulating the TRAF6/NF-κB axis, and PMS treatment may be considered as a novel strategy for sepsis-caused damage in future