We theoretically investigate the electricity storage/generation in a reversible solid oxide cell stack. The system heat is for the first time tentatively stored in a phase-change metal when the stack is operated to ge...We theoretically investigate the electricity storage/generation in a reversible solid oxide cell stack. The system heat is for the first time tentatively stored in a phase-change metal when the stack is operated to generate electricity in a fuel cell mode and then reused to store electricity in an electrolysis mode. The state of charge （H2 frication in cathode） effectively enhances the open circuit voltages （OCVs） while the system gas pressure in electrodes also increases the OCVs. On the other hand, a higher system pressure facilitates the species diffusion in electrodes that therefore accordingly improve electrode polarizations. With the aid of recycled system heat, the roundtrip efficiency reaches as high as 92% for the repeated electricity storage and generation.展开更多
Steel industry is high energy-consuming industry, and its waste?heat recovery is critically?important for energy utilization. In this study, pipeline bundle is used to enhance heat transfer in?waste?heat recovery devi...Steel industry is high energy-consuming industry, and its waste?heat recovery is critically?important for energy utilization. In this study, pipeline bundle is used to enhance heat transfer in?waste?heat recovery device,?and?associated gas-solid heat transfer and energy utilization performance with different pipeline arrangement, pipe diameter and shape of internal component are further analyzed. The temperatures of gas and particle in device with pipeline bundle periodically fluctuate in horizontal direction, and those in staggered system distribute more uniformly than those in paralleled system. Compared with paralleled device, exergy and waste heat utilization efficiency of staggered device have been improved, and they are both higher than?those without pipeline. As pipe diameter increases, exergy and waste heat utilization efficiency first increases and then decreases, and they reach the maxima with optimal pipe diameter.?As the width of internal component keeps constant, influence of its shape on heat transfer is very little.展开更多
目前降低原油黏度的加热方法主要是电加热,而全天电加热的方式存在高能耗和高成本的问题。为满足环保和工业生产的需要,将原油降黏加热法与谷电、相变材料相结合,设计了一种新型的相变蓄热电加热装置,并对装置的相变蓄热放热性能进行数...目前降低原油黏度的加热方法主要是电加热,而全天电加热的方式存在高能耗和高成本的问题。为满足环保和工业生产的需要,将原油降黏加热法与谷电、相变材料相结合,设计了一种新型的相变蓄热电加热装置,并对装置的相变蓄热放热性能进行数值模拟研究,分析不同进口流量和泡沫金属孔隙率对放热过程的影响。结果表明:随着工质进口流量的增加,出口温度不断降低。并且,当出口温升为10℃时,装置进口流量可满足1.413~2.120 m 3/h的流量范围。同时,泡沫镍的加入使相变材料内部温度更加均匀,而且相变材料内部温度随泡沫金属的孔隙率的降低而降低。采用增加电加热棒的数量和降低单个电加热棒的功率的方法,对装置进行结构优化,使得局部高温现象明显改善。利用该装置既能保持较高的换热效率,又能降低生产成本。展开更多
文摘We theoretically investigate the electricity storage/generation in a reversible solid oxide cell stack. The system heat is for the first time tentatively stored in a phase-change metal when the stack is operated to generate electricity in a fuel cell mode and then reused to store electricity in an electrolysis mode. The state of charge （H2 frication in cathode） effectively enhances the open circuit voltages （OCVs） while the system gas pressure in electrodes also increases the OCVs. On the other hand, a higher system pressure facilitates the species diffusion in electrodes that therefore accordingly improve electrode polarizations. With the aid of recycled system heat, the roundtrip efficiency reaches as high as 92% for the repeated electricity storage and generation.
文摘Steel industry is high energy-consuming industry, and its waste?heat recovery is critically?important for energy utilization. In this study, pipeline bundle is used to enhance heat transfer in?waste?heat recovery device,?and?associated gas-solid heat transfer and energy utilization performance with different pipeline arrangement, pipe diameter and shape of internal component are further analyzed. The temperatures of gas and particle in device with pipeline bundle periodically fluctuate in horizontal direction, and those in staggered system distribute more uniformly than those in paralleled system. Compared with paralleled device, exergy and waste heat utilization efficiency of staggered device have been improved, and they are both higher than?those without pipeline. As pipe diameter increases, exergy and waste heat utilization efficiency first increases and then decreases, and they reach the maxima with optimal pipe diameter.?As the width of internal component keeps constant, influence of its shape on heat transfer is very little.
文摘目前降低原油黏度的加热方法主要是电加热,而全天电加热的方式存在高能耗和高成本的问题。为满足环保和工业生产的需要,将原油降黏加热法与谷电、相变材料相结合,设计了一种新型的相变蓄热电加热装置,并对装置的相变蓄热放热性能进行数值模拟研究,分析不同进口流量和泡沫金属孔隙率对放热过程的影响。结果表明:随着工质进口流量的增加,出口温度不断降低。并且,当出口温升为10℃时,装置进口流量可满足1.413~2.120 m 3/h的流量范围。同时,泡沫镍的加入使相变材料内部温度更加均匀,而且相变材料内部温度随泡沫金属的孔隙率的降低而降低。采用增加电加热棒的数量和降低单个电加热棒的功率的方法,对装置进行结构优化,使得局部高温现象明显改善。利用该装置既能保持较高的换热效率,又能降低生产成本。
文摘设计了基于圆柱形相变蓄热单元的相变蓄热装置,通过循环实验对蓄热装置的运行特性进行分析,研究了装置的蓄热影响因素。研究结果表明;在等质量相变材料(Phase Change Material,PCM)时,相变单元数量对装置蓄热速率的影响较大;蓄热单元布置间距对装置蓄热速率的影响较小;当增大换热流体(Heat Transfer Fluid,HTF)的流量时,装置总蓄热时间分别缩短了14.5%和29%;提高换热流体入口温度时,不仅增加了蓄热装置的总蓄热量,并且总体蓄热时间分别缩短了10.6%和16.5%。
