Nowadays,magnetic cooling(MC) technology by using the magnetocaloric effect(MCE) has attracted extensive research interest for its promising practical applications.A constant large/giant MCE covers wide refrigeration ...Nowadays,magnetic cooling(MC) technology by using the magnetocaloric effect(MCE) has attracted extensive research interest for its promising practical applications.A constant large/giant MCE covers wide refrigeration temperatures(denote as table-like shape) is beneficial for obtaining high efficiency performance for MC.In this paper,the HoNi/HoNi2 composite was successfully synthesized by arc-melting method and proved to be composed of HoNi and HoNi2 crystalline phases with weight ratios of 52.4 wt.% and 47.6 wt.%,respectively.The maximum magnetic entropy change(-ΔSMmax)is 18.23 J/(kg·K),and the refrigerant capacity values RC1,RC2,and RC3 are 867.9 J/kg,676.4 J/kg,and 467.8 J/kg with ΔH=0-70 kOe,respectively.The table-like shape MCE and large refrigerant capacity values make the composite attractive for cryogenic MC using the Ericsson cycle.展开更多
Composite adsorbents of CaC12 and sawdust prepared by carbonization for adsorption refrigeration with NH3 as refrigerant are tested, and the effects of carboniza tion temperature on the sorption capacity and rate are ...Composite adsorbents of CaC12 and sawdust prepared by carbonization for adsorption refrigeration with NH3 as refrigerant are tested, and the effects of carboniza tion temperature on the sorption capacity and rate are analyzed. The results show that the amount of pores in the sawdust of the composite adsorbents carbonized, apart from the content of CaCI2, is the most dominant factor influencing the NH3 sorption on composite adsorbents. The optimum carbonization temperature is 700℃, which gives the maximal NH3 sorption capacity as high as 0.774 kg of NH3 per kg of the composite, and the specific cooling power is approximately between 338 and 869 W/kg with the cycle duration varying from 5 to 20 minutes. The present study demonstrates that the composite absorbent of CaC12 and sawdust prepared by carbonization is more promising and competitive for adsorption refrigeration application.展开更多
Composite magnetic refrigerants were prepared by physical mixing LaFeSiHalloys with different Curie temperatures(Tc). The phase structures of these LaFeSiHalloys were analyzed by X-ray diffraction(XRD) and the magneto...Composite magnetic refrigerants were prepared by physical mixing LaFeSiHalloys with different Curie temperatures(Tc). The phase structures of these LaFeSiHalloys were analyzed by X-ray diffraction(XRD) and the magnetocaloric effect(MCE) and refrigerant capacity(RC) of these composite magnetic refrigerants were investigated by experiment and calculation in this paper. The magnetocaloric effect(MCE) and refrigerant capacity(RC) of these composite magnetic refrigerants were investigated by experiment and calculation in this paper. The results indicate the experimental magnetic entropy change(-△S)-Tcurve corresponds reasonably with the(-△S)-Tcurve calculated by the linear combination of(-△S)-T curves of the single material. An optimal mixing ratio can make the composite magnetic refrigerant possess a table-like(-△S)-Tcurve which is beneficial to magnetic Ericsson cycle. When three LaFeSiHalloys with different Tare mixed, the full width at half maximum(△T) of(-△S)-T curves is about 48.7 K and the RC is about 177.76 J/kg under a magnetic field change of 2 T. The composite magnetic refrigerants based on LaFeSiHalloys can be promising candidates for near room temperature magnetic refrigeration and the work will be helpful to develop novel composite magnetic refrigerants with table-like MCE and large RC.展开更多
本文以组合蓄冷板为研究对象,提出了一种箱内温度场均匀可控的组合蓄冷板式医药冷藏箱的设计方案,以此优化医药冷藏箱的热性能表现。首先搭建了实验平台,依据组合式蓄冷原理设计医药冷藏箱和组合蓄冷板,从等质量方案和等相变潜热方案的...本文以组合蓄冷板为研究对象,提出了一种箱内温度场均匀可控的组合蓄冷板式医药冷藏箱的设计方案,以此优化医药冷藏箱的热性能表现。首先搭建了实验平台,依据组合式蓄冷原理设计医药冷藏箱和组合蓄冷板,从等质量方案和等相变潜热方案的角度分别对比蓄冷板中相变材料(正十四烷、CaCl_(2)·6H_(2)O、水两两组合)内壁温度变化、蓄冷时长的表现,发现蓄冷板内层采用1.5 kg正十四烷、外层采用1.5 kg CaCl_(2)·6H_(2)O的等质量组合方案性能最优。在此基础上对比了性能最佳的蓄冷板在医药冷藏箱中不同摆放位置(两侧平放、两侧叠放、对角摆放、四周摆放)下,在2~8℃条件下的蓄冷时长、温度平均值、不均匀系数和释冷速率。结果表明:对角摆放的组合蓄冷板蓄冷时长最大;4种摆放方式的温度平均值均在2~8℃工况内;两侧叠放时的不均匀系数最小且箱内蓄冷板释冷速率最快。考虑到温度均匀优先原则,两侧叠放的等质量组合方案的蓄冷板蓄冷效果最好。展开更多
以分子筛为基材通过浸泡C aC l2和S rC l2溶液的方法制备复合吸附剂.在模拟制冷条件下,对以不同浓度溶液制备的复合吸附剂的吸附、解吸性能进行了测定,并将吸附解吸性能最好的复合吸附剂在自制的模拟制冷装置上进行了制冷实验.结果表明...以分子筛为基材通过浸泡C aC l2和S rC l2溶液的方法制备复合吸附剂.在模拟制冷条件下,对以不同浓度溶液制备的复合吸附剂的吸附、解吸性能进行了测定,并将吸附解吸性能最好的复合吸附剂在自制的模拟制冷装置上进行了制冷实验.结果表明,复合吸附剂具有良好的吸附、解吸性能,最大吸附量达51.6%,解吸率可达69.3%,在模拟制冷装置上系统的制冷系数达0.25,单位吸附剂的制冷功率为0.072 W/g,符合太阳能吸附制冷的要求.展开更多
Alternative refrigerants have been used in refrigerating and air-conditioning systemsdue to the phase out of CFC-12, HCFC-22 and R502 etc. Most of them are mixtures.The composition fractionation and thermal performanc...Alternative refrigerants have been used in refrigerating and air-conditioning systemsdue to the phase out of CFC-12, HCFC-22 and R502 etc. Most of them are mixtures.The composition fractionation and thermal performance change during refrigerant leakedout from system must be paid attention. The compositions of mixture THR02 were mea-sured by gas chromatographic analysis. Then we developed a general model to calculate thecomposition fractionation of zeotropic, near-azeotropic and azeotropic mixtures. The max-imum deviations between the calculated compositions and experimental results are within5% for the mixture THR02, R4O7C, R404A and R507. THR02 is a near-azeotropic mixture,it is remain unflammable under the worst case, and the change of system performance onlyresulted from composition fractionation during refrigerant leakage can be neglected.展开更多
Adsorption performance of adsorbents for the adsorption cooling cycle was discussed. Adsorption isotherms and adsorption rate of water or ethanol on composite adsorbents prepared by the authors (named M4-0132, M1- 000...Adsorption performance of adsorbents for the adsorption cooling cycle was discussed. Adsorption isotherms and adsorption rate of water or ethanol on composite adsorbents prepared by the authors (named M4-0132, M1- 0001, M1-9906 and M2-0003 respectively), were tested. The results of fitting to the micro-pore filling theory equation and calculation of characteristic ads orption work based on these pairs were presented. The results showed that the a mount of water adsorbed by composite adsorbents was as high as 2 times that by s ilica gel and 2.5 times that by 13X molecular sieve, respectively, and characte ristic adsorption work calculated was 2.55～4.78 kJ·mol-1, only 12%～29 % of that on 13X molecular sieve. The values of adsorption rate of water on com posite adsorbents were higher than that on silica gel. Analysis for ethanol ads orption on composite adsorbent, M1-0001, showed occurrence of capillary condens ation, which resulted in a considerably higher ethanol uptake than on activated carbon at higher relative vapor pressure. The characteristic adsorption work of ethanol on composite sorbents was 2.55～4.78 kJ·mol-1, merely 10%～20% of that on activated carbon. Based on comprehensive estimate of adsorption pro perties, including adsorption loading, characteristic adsorption work and adsorp tion rate etc., M4-0132 and M1-0001 composite adsorbents were more prefer red for the adsorption cooling process, and the preferable type of isotherm for adsorption cooling cycle appeared to be the Ⅴ type of Brunauer classification.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51690162)Science and Technology Committee of Shanghai,China(Grant No.19ZR1418300)+1 种基金Independent Research and Development Project of State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(Grant No.SKLASS 2019-Z003)the Science and Technology Commission of Shanghai Municipality,China(Grant No.19DZ2270200).
文摘Nowadays,magnetic cooling(MC) technology by using the magnetocaloric effect(MCE) has attracted extensive research interest for its promising practical applications.A constant large/giant MCE covers wide refrigeration temperatures(denote as table-like shape) is beneficial for obtaining high efficiency performance for MC.In this paper,the HoNi/HoNi2 composite was successfully synthesized by arc-melting method and proved to be composed of HoNi and HoNi2 crystalline phases with weight ratios of 52.4 wt.% and 47.6 wt.%,respectively.The maximum magnetic entropy change(-ΔSMmax)is 18.23 J/(kg·K),and the refrigerant capacity values RC1,RC2,and RC3 are 867.9 J/kg,676.4 J/kg,and 467.8 J/kg with ΔH=0-70 kOe,respectively.The table-like shape MCE and large refrigerant capacity values make the composite attractive for cryogenic MC using the Ericsson cycle.
文摘Composite adsorbents of CaC12 and sawdust prepared by carbonization for adsorption refrigeration with NH3 as refrigerant are tested, and the effects of carboniza tion temperature on the sorption capacity and rate are analyzed. The results show that the amount of pores in the sawdust of the composite adsorbents carbonized, apart from the content of CaCI2, is the most dominant factor influencing the NH3 sorption on composite adsorbents. The optimum carbonization temperature is 700℃, which gives the maximal NH3 sorption capacity as high as 0.774 kg of NH3 per kg of the composite, and the specific cooling power is approximately between 338 and 869 W/kg with the cycle duration varying from 5 to 20 minutes. The present study demonstrates that the composite absorbent of CaC12 and sawdust prepared by carbonization is more promising and competitive for adsorption refrigeration application.
基金supported by the Key Project of National Natural Science Foundation of China(51176065)
文摘Composite magnetic refrigerants were prepared by physical mixing LaFeSiHalloys with different Curie temperatures(Tc). The phase structures of these LaFeSiHalloys were analyzed by X-ray diffraction(XRD) and the magnetocaloric effect(MCE) and refrigerant capacity(RC) of these composite magnetic refrigerants were investigated by experiment and calculation in this paper. The magnetocaloric effect(MCE) and refrigerant capacity(RC) of these composite magnetic refrigerants were investigated by experiment and calculation in this paper. The results indicate the experimental magnetic entropy change(-△S)-Tcurve corresponds reasonably with the(-△S)-Tcurve calculated by the linear combination of(-△S)-T curves of the single material. An optimal mixing ratio can make the composite magnetic refrigerant possess a table-like(-△S)-Tcurve which is beneficial to magnetic Ericsson cycle. When three LaFeSiHalloys with different Tare mixed, the full width at half maximum(△T) of(-△S)-T curves is about 48.7 K and the RC is about 177.76 J/kg under a magnetic field change of 2 T. The composite magnetic refrigerants based on LaFeSiHalloys can be promising candidates for near room temperature magnetic refrigeration and the work will be helpful to develop novel composite magnetic refrigerants with table-like MCE and large RC.
文摘本文以组合蓄冷板为研究对象,提出了一种箱内温度场均匀可控的组合蓄冷板式医药冷藏箱的设计方案,以此优化医药冷藏箱的热性能表现。首先搭建了实验平台,依据组合式蓄冷原理设计医药冷藏箱和组合蓄冷板,从等质量方案和等相变潜热方案的角度分别对比蓄冷板中相变材料(正十四烷、CaCl_(2)·6H_(2)O、水两两组合)内壁温度变化、蓄冷时长的表现,发现蓄冷板内层采用1.5 kg正十四烷、外层采用1.5 kg CaCl_(2)·6H_(2)O的等质量组合方案性能最优。在此基础上对比了性能最佳的蓄冷板在医药冷藏箱中不同摆放位置(两侧平放、两侧叠放、对角摆放、四周摆放)下,在2~8℃条件下的蓄冷时长、温度平均值、不均匀系数和释冷速率。结果表明:对角摆放的组合蓄冷板蓄冷时长最大;4种摆放方式的温度平均值均在2~8℃工况内;两侧叠放时的不均匀系数最小且箱内蓄冷板释冷速率最快。考虑到温度均匀优先原则,两侧叠放的等质量组合方案的蓄冷板蓄冷效果最好。
文摘Alternative refrigerants have been used in refrigerating and air-conditioning systemsdue to the phase out of CFC-12, HCFC-22 and R502 etc. Most of them are mixtures.The composition fractionation and thermal performance change during refrigerant leakedout from system must be paid attention. The compositions of mixture THR02 were mea-sured by gas chromatographic analysis. Then we developed a general model to calculate thecomposition fractionation of zeotropic, near-azeotropic and azeotropic mixtures. The max-imum deviations between the calculated compositions and experimental results are within5% for the mixture THR02, R4O7C, R404A and R507. THR02 is a near-azeotropic mixture,it is remain unflammable under the worst case, and the change of system performance onlyresulted from composition fractionation during refrigerant leakage can be neglected.
文摘Adsorption performance of adsorbents for the adsorption cooling cycle was discussed. Adsorption isotherms and adsorption rate of water or ethanol on composite adsorbents prepared by the authors (named M4-0132, M1- 0001, M1-9906 and M2-0003 respectively), were tested. The results of fitting to the micro-pore filling theory equation and calculation of characteristic ads orption work based on these pairs were presented. The results showed that the a mount of water adsorbed by composite adsorbents was as high as 2 times that by s ilica gel and 2.5 times that by 13X molecular sieve, respectively, and characte ristic adsorption work calculated was 2.55～4.78 kJ·mol-1, only 12%～29 % of that on 13X molecular sieve. The values of adsorption rate of water on com posite adsorbents were higher than that on silica gel. Analysis for ethanol ads orption on composite adsorbent, M1-0001, showed occurrence of capillary condens ation, which resulted in a considerably higher ethanol uptake than on activated carbon at higher relative vapor pressure. The characteristic adsorption work of ethanol on composite sorbents was 2.55～4.78 kJ·mol-1, merely 10%～20% of that on activated carbon. Based on comprehensive estimate of adsorption pro perties, including adsorption loading, characteristic adsorption work and adsorp tion rate etc., M4-0132 and M1-0001 composite adsorbents were more prefer red for the adsorption cooling process, and the preferable type of isotherm for adsorption cooling cycle appeared to be the Ⅴ type of Brunauer classification.
