Performance analysis of organic Rankine cycle based on location of heat transfer pinch point in evaporator
Performance analysis of organic Rankine cycle based on location of heat transfer pinch point in evaporator
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DOI：
10.1016/j.applthermaleng.2013.09.036
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发表时间：
2014-01
影响因子：
6.4
通讯作者：
Cong Guo;Xiaoze Du;Lijun Yang;Yongping Yang
中科院分区：
文献类型：
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作者：
Cong Guo;Xiaoze Du;Lijun Yang;Yongping Yang
蒸发器传热夹点位置是确定有机朗肯循环（ORC）运行参数的基础。建立了寻找夹点位置的物理数学模型，通过该模型可以得到热源和工质的温度随UA的变化。以进口温度为160 °C的热源为例，在确定夹点温差的情况下，揭示了亚临界和超临界循环中热源与工质的匹配潜力。比较分析了不同传热夹点位置下的热效率、火用效率、单位面积做功量和最大做功量。结果表明，当热源出口温度较低时，超临界ORC具有较好的热效率、火用效率和功输出性能。否则，亚临界性能更好。传热系数小导致超临界ORC的单位面积功输出值低。IHX的引入降低了最佳蒸发压力，对热源出口温度和蒸发度有较大影响。分析结果可为ORC运行参数的选择和控制策略的制定提供参考。
The location of heat transfer pinch point in evaporator is the base of determining operating parameters of organic Rankine cycle (ORC). The physical mathematical model seeking the location of pinch point is established, by which, the temperature variations both of heat source and working fluid with UA can be obtained. Taking heat source with inlet temperature of 160 °C as example, the matching potentials between heat source and working fluid are revealed for subcritical and supercritical cycles with the determined temperature difference of pinch point. Thermal efficiency, exergy efficiency, work output per unit area and maximum work outputs are compared and analyzed based on the locations of heat transfer pinch point either. The results indicate that supercritical ORC has a better performance in thermal efficiency, exergy efficiency and work output while outlet temperature of heat source is low. Otherwise, subcritical performs better. Small heat transfer coefficient results in low value of work output per unit area for supercritical ORC. Introduction of IHX may reduce the optimal evaporating pressure, which has a great influence on heat source outlet temperature and superheat degree. The analysis may benefit the selection of operating parameters and control strategy of ORC.