Currently,people pay more and more attention to the transitional resettlement of victims after various natural disasters.There is an urgent need for a large number of temporary houses to resettle the victims after nat...Currently,people pay more and more attention to the transitional resettlement of victims after various natural disasters.There is an urgent need for a large number of temporary houses to resettle the victims after natural disasters.Disaster-relief temporary houses(DTHs)played an important role in the post-disaster resettlement in the past,which can not only be produced on a large scale,but also can be quickly and conveniently erected,which were the main means to solve the problem of transitional resettlement.However,due to their temporary nature,there was no extra energy consuming system installed in the DTHs generally.Hence the indoor thermal environment inside the DTHs was severe in summer.In this study,combined with the field experimental tests of the DTHs in Wenchuan Earthquake and Lushan Earthquake and the experimental study of the full-size DTH,it found that the thermal environment inside the DTH was intolerably high in summer.It had negative impact on victims.In order to improve the thermal environment inside DTHs during post-disaster period which lacked of extra energy resources,this study used the method of combining phase change materials(PCMs)with walls of the DTH to explore its feasibility and effectiveness.The results showed that PCMs could effectively improve the thermal environment inside the DTH in summer.Furthermore,the difference of the composite positions between PCMs and the wall affected the improvement effect.The energy release rate of the PCMs assembly system(PAS)varied according to the positions of the PCMs.展开更多
对 Si 含量为10%～13%的 Al-Si 合金进行了加速氧化、热循环和掺 Fe 实验,研究了其在不同热循环条件下的相变储热性能和可靠性．结果表明,在空气中经几百 h 的高温氧化后,氧化率小于0．01%,其影响可以忽略不计．经过0,4,23,60, 100,200,...对 Si 含量为10%～13%的 Al-Si 合金进行了加速氧化、热循环和掺 Fe 实验,研究了其在不同热循环条件下的相变储热性能和可靠性．结果表明,在空气中经几百 h 的高温氧化后,氧化率小于0．01%,其影响可以忽略不计．经过0,4,23,60, 100,200,300,400,500,600,700次熔化-凝固循环后,相变温度的变化为3．8～11．8℃,相变潜热从484．86 kJ/kg下降到432．62 kJ/kg．当 Al-Si 合金的掺铁量为0．5%时,相变潜热下降6．5%；对于缓冷的储能过程,偏析较小并在循环多次后趋于缓和和稳定．Al-Si 合金成份和结构的变化对材料的储热性能影响较小,在长期的热循环过程中有良好和稳定的储热性能．展开更多
The lauric-myristic-palmitic acid( LA-MA-PA) ternary eutectic mixtures/expanded graphite( EG) composite phase change materials( PCMs) were prepared by absorbing LA-MA-PA into the porous network of EG. The optimum rati...The lauric-myristic-palmitic acid( LA-MA-PA) ternary eutectic mixtures/expanded graphite( EG) composite phase change materials( PCMs) were prepared by absorbing LA-MA-PA into the porous network of EG. The optimum ratio of ternary eutectic mixtures to EG was determined to be 93∶7 without liquid LA-MA-PA leakage from the composite PCMs. In order to make the structure more stable, the composite PCMs were encapsulated by surface treatment agent to prepare LA-MA-PA/EG encapsulating form-stable PCMs which were characterized by scanning electron microscope( SEM),Fourier transformation infrared spectroscope( FT-IR),differential scanning calorimetry( DSC) and thermal treatment. The results showed there was no chemical reaction between surface treatment agent and LA-MA-PA,and the samples were compactly encapsulated which left almost no imprint on the filter paper after thermal treatment. The phase change temperature and latent heat of LA-MA-PA/EG encapsulating form-stable PCMs were tested to be29. 32 ℃ and 96. 20 J/g,respectively. Additionally,the heat transfer efficiency of heat storage was improved by the addition of EG.展开更多
This paper proposes a modified Kelvin model for high mechanical property open-cell metal foams and investigates its application in thermal simulations. The thermal conductivity is simulated based on the steady state m...This paper proposes a modified Kelvin model for high mechanical property open-cell metal foams and investigates its application in thermal simulations. The thermal conductivity is simulated based on the steady state method and the results are consistent with experimental values. The melting process of phase change materials (PCMs) in Kelvin model and its modified model is numerically investigated under a temperature constant heat resource. By detecting the temperature variations, it shows that the metal foam greatly improves the heat transfer in energy storage systems. Besides, the comparison of the melting process in two foam models indicates that the systems based on high mechanical property metal foams have a shorter melting time. The melting process of paraffin in modified Kelvin metal foam models with three different porosities (65%, 70% and 75%) are numerically analyzed and compared.展开更多
Phase change materials(PCMs)have great potential in thermal energy management,but their low ther-mal conductivity,easy leakage,and poor thermal stability limit their wide application.After constructing the biomimetic ...Phase change materials(PCMs)have great potential in thermal energy management,but their low ther-mal conductivity,easy leakage,and poor thermal stability limit their wide application.After constructing the biomimetic leaf-vein-like three-dimensional(3D)structure of boron nitride(BN)and impregnated with polyethylene glycol(PEG),the comprehensive properties of phase change composites were effec-tively enhanced under low filler content.The PEG is stored in the 3D structure of BN,which can prevent leakage at high temperatures and enhance the composites’thermal stability and storage modulus.As a fast channel of transmission of phonons,the BN skeleton can effectively reduce thermal resistance.When the amount of filler is 10 vol%,the highest thermal conductivity of the composite PCMs is 2.62 W m-1 K-1,which is 10.1 times than that of pure PEG.Under the infrared camera,the composite PCMs yielded excellent battery thermal management performance,indicating that the material has great potential in thermal management.展开更多
Phase change materials(PCMs)play a leading role in overcoming the growing need of advanced thermal management for the storage and release of thermal energy which is to be used for different solar applications.However,...Phase change materials(PCMs)play a leading role in overcoming the growing need of advanced thermal management for the storage and release of thermal energy which is to be used for different solar applications.However,the effectiveness of PCMs is greatly affected by their poor thermal conductivity.Therefore,in the present review the progress made in deploying the graphene(Gr)in PCMs in the last decade for providing the solution to the aforementioned inadequacy is presented and discussed in detail.Gr and its derivatives((Gr oxide(GO),Gr aerogel(GA)and Gr nanoplatelets(GNPs))based PCMs can improve the thermal conductivity and shape stability,which may be attributed to the extra ordinary thermo-physical properties of Gr.Moreover,it is expected from this review that the advantages and disadvantages of using Gr nanoparticles provide a deep insight and help the researchers in finding out the exact basic properties and finally the applications of Gr can be enhanced.In this work,Gr and its derivatives based PCMs was characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction spectroscopy(XRD),and scanning electron microscopy(SEM)by which crystal structure was known,phase was identified along with the knowledge of surface structure respectively.The increase in the mass fraction(%)of the filler(Gr and its derivatives)led to even better thermo-physical properties and thermal stability.The thermal characterization was also done by differential scanning calorimetry(DSC),thermo gravimetric analysis(TGA)and thermal conductivity tests.The enthalpy of freezing and melting showed that Gr and its derivatives based PCMs had a very high energy storage capability as reflected in its various applications.展开更多
文摘Currently,people pay more and more attention to the transitional resettlement of victims after various natural disasters.There is an urgent need for a large number of temporary houses to resettle the victims after natural disasters.Disaster-relief temporary houses(DTHs)played an important role in the post-disaster resettlement in the past,which can not only be produced on a large scale,but also can be quickly and conveniently erected,which were the main means to solve the problem of transitional resettlement.However,due to their temporary nature,there was no extra energy consuming system installed in the DTHs generally.Hence the indoor thermal environment inside the DTHs was severe in summer.In this study,combined with the field experimental tests of the DTHs in Wenchuan Earthquake and Lushan Earthquake and the experimental study of the full-size DTH,it found that the thermal environment inside the DTH was intolerably high in summer.It had negative impact on victims.In order to improve the thermal environment inside DTHs during post-disaster period which lacked of extra energy resources,this study used the method of combining phase change materials(PCMs)with walls of the DTH to explore its feasibility and effectiveness.The results showed that PCMs could effectively improve the thermal environment inside the DTH in summer.Furthermore,the difference of the composite positions between PCMs and the wall affected the improvement effect.The energy release rate of the PCMs assembly system(PAS)varied according to the positions of the PCMs.
文摘对 Si 含量为10%～13%的 Al-Si 合金进行了加速氧化、热循环和掺 Fe 实验,研究了其在不同热循环条件下的相变储热性能和可靠性．结果表明,在空气中经几百 h 的高温氧化后,氧化率小于0．01%,其影响可以忽略不计．经过0,4,23,60, 100,200,300,400,500,600,700次熔化-凝固循环后,相变温度的变化为3．8～11．8℃,相变潜热从484．86 kJ/kg下降到432．62 kJ/kg．当 Al-Si 合金的掺铁量为0．5%时,相变潜热下降6．5%；对于缓冷的储能过程,偏析较小并在循环多次后趋于缓和和稳定．Al-Si 合金成份和结构的变化对材料的储热性能影响较小,在长期的热循环过程中有良好和稳定的储热性能．
基金National Science&Technology Pillar Program during the Twelfth Five-Year Plan Period,China(No.2014BAL03B04)
文摘The lauric-myristic-palmitic acid( LA-MA-PA) ternary eutectic mixtures/expanded graphite( EG) composite phase change materials( PCMs) were prepared by absorbing LA-MA-PA into the porous network of EG. The optimum ratio of ternary eutectic mixtures to EG was determined to be 93∶7 without liquid LA-MA-PA leakage from the composite PCMs. In order to make the structure more stable, the composite PCMs were encapsulated by surface treatment agent to prepare LA-MA-PA/EG encapsulating form-stable PCMs which were characterized by scanning electron microscope( SEM),Fourier transformation infrared spectroscope( FT-IR),differential scanning calorimetry( DSC) and thermal treatment. The results showed there was no chemical reaction between surface treatment agent and LA-MA-PA,and the samples were compactly encapsulated which left almost no imprint on the filter paper after thermal treatment. The phase change temperature and latent heat of LA-MA-PA/EG encapsulating form-stable PCMs were tested to be29. 32 ℃ and 96. 20 J/g,respectively. Additionally,the heat transfer efficiency of heat storage was improved by the addition of EG.
文摘This paper proposes a modified Kelvin model for high mechanical property open-cell metal foams and investigates its application in thermal simulations. The thermal conductivity is simulated based on the steady state method and the results are consistent with experimental values. The melting process of phase change materials (PCMs) in Kelvin model and its modified model is numerically investigated under a temperature constant heat resource. By detecting the temperature variations, it shows that the metal foam greatly improves the heat transfer in energy storage systems. Besides, the comparison of the melting process in two foam models indicates that the systems based on high mechanical property metal foams have a shorter melting time. The melting process of paraffin in modified Kelvin metal foam models with three different porosities (65%, 70% and 75%) are numerically analyzed and compared.
基金Lanzhou Science and Technology Plan Project Funding(Project No.:2021-1-44)and Project Funding of Fangda Carbon New Material Co.,Ltd.
文摘Phase change materials(PCMs)have great potential in thermal energy management,but their low ther-mal conductivity,easy leakage,and poor thermal stability limit their wide application.After constructing the biomimetic leaf-vein-like three-dimensional(3D)structure of boron nitride(BN)and impregnated with polyethylene glycol(PEG),the comprehensive properties of phase change composites were effec-tively enhanced under low filler content.The PEG is stored in the 3D structure of BN,which can prevent leakage at high temperatures and enhance the composites’thermal stability and storage modulus.As a fast channel of transmission of phonons,the BN skeleton can effectively reduce thermal resistance.When the amount of filler is 10 vol%,the highest thermal conductivity of the composite PCMs is 2.62 W m-1 K-1,which is 10.1 times than that of pure PEG.Under the infrared camera,the composite PCMs yielded excellent battery thermal management performance,indicating that the material has great potential in thermal management.
文摘Phase change materials(PCMs)play a leading role in overcoming the growing need of advanced thermal management for the storage and release of thermal energy which is to be used for different solar applications.However,the effectiveness of PCMs is greatly affected by their poor thermal conductivity.Therefore,in the present review the progress made in deploying the graphene(Gr)in PCMs in the last decade for providing the solution to the aforementioned inadequacy is presented and discussed in detail.Gr and its derivatives((Gr oxide(GO),Gr aerogel(GA)and Gr nanoplatelets(GNPs))based PCMs can improve the thermal conductivity and shape stability,which may be attributed to the extra ordinary thermo-physical properties of Gr.Moreover,it is expected from this review that the advantages and disadvantages of using Gr nanoparticles provide a deep insight and help the researchers in finding out the exact basic properties and finally the applications of Gr can be enhanced.In this work,Gr and its derivatives based PCMs was characterized by Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction spectroscopy(XRD),and scanning electron microscopy(SEM)by which crystal structure was known,phase was identified along with the knowledge of surface structure respectively.The increase in the mass fraction(%)of the filler(Gr and its derivatives)led to even better thermo-physical properties and thermal stability.The thermal characterization was also done by differential scanning calorimetry(DSC),thermo gravimetric analysis(TGA)and thermal conductivity tests.The enthalpy of freezing and melting showed that Gr and its derivatives based PCMs had a very high energy storage capability as reflected in its various applications.
