Parametric Optimization And Thermodynamic Performance Comparison Of Single-Pressure And Dual-Pressure Evaporation Organic Rankine Cycles
Parametric Optimization And Thermodynamic Performance Comparison Of Single-Pressure And Dual-Pressure Evaporation Organic Rankine Cycles
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DOI：
10.31988/scitrends.14136
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发表时间：
2018-03
影响因子：
5.3
通讯作者：
Y. Duan
中科院分区：
文献类型：
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作者：
Y. Duan
双压蒸发有机朗肯循环（ORC）涉及两个不同压力的蒸发过程，与传统的单压蒸发有机朗肯循环相比，可显著降低吸热过程的（火用）损失。然而，双压蒸发式ORC的适用热源温度以及工质热物性对适用条件的影响仍不确定。还需要研究各种热源温度的最佳循环参数。这些问题的解决对双压蒸发有机硅的应用和推广具有重要意义。本研究的重点是一个典型的双压力蒸发ORC驱动的100-200 °C的热源没有限制的出口温度。选用了9种纯有机流体作为工质。对单压和双压蒸发式ORC的蒸发压力和蒸发器出口温度进行了优化，并对优化后的系统热力性能进行了比较。结果表明，随着工质临界温度的升高，双压蒸发ORC（Wnet，dual>Wnet，single）的适用热源温度范围普遍增大。适用热源温度（THS，in_TP）的上限与工质临界温度和夹点温差一般符合线性关系。对于低于THS，in_TP的热源温度，双压蒸发ORC的最大净功率输出大于单压蒸发ORC的净功率输出。随着热源温度的降低，温度增量逐渐增大，对于9种工质，温度增量最大可达21.4-26.7%.当热源温度高于THS，in_TP时，采用双压蒸发ORC是不合适的。
Dual-pressure evaporation organic Rankine cycle (ORC) involves two evaporation processes with different pressures, and can significantly reduce the exergy loss in the heat absorption process compared with conventional single-pressure evaporation ORCs. However, the applicable heat source temperatures of dual-pressure evaporation ORCs and the effects of the working fluid thermophysical properties on the applicable conditions remain indeterminate. Optimal cycle parameters for various heat source temperatures also need to be studied. Solving these questions is crucial for the application and promotion of dual-pressure evaporation ORCs. This study focuses on a typical dual-pressure evaporation ORC driven by the 100–200 °C heat sources without a limit on the outlet temperature. Nine pure organic fluids were selected as working fluids. Evaporation pressures and evaporator outlet temperatures of the single-pressure and dual-pressure evaporation ORCs were optimized, and their optimized system thermodynamic performance was compared. Results show that the applicable heat source temperature range of the dual-pressure evaporation ORC (Wnet,dual>Wnet,single) generally increases as the working fluid critical temperature increases. The upper limit of the applicable heat source temperatures (THS,in_TP), working fluid critical temperature and pinch point temperature difference generally conform to a linear relation. For the heat source temperature below THS,in_TP, the maximized net power output of the dual-pressure evaporation ORC is larger than that of the single-pressure evaporation ORC. Furthermore, the increment generally increases as the heat source temperature decreases, and the maximum increments are 21.4–26.7% for nine working fluids. For the heat source temperature above THS,in_TP, the dual-pressure evaporation ORC is unbefitting.