摘要
在对变温热源驱动非共沸混合工质ORC(有机朗肯循环)换热器中冷热流体温度匹配性能分析的基础上,提出了用于评价非共沸混合工质ORC换热器中冷热流体间温度匹配性能的指标DMPC(温度匹配指标的标准偏差).采用该指标对换热过程进行所得的结果与采用热力学第二定律的分析结果具有一致性,即当指标DMPC增大,换热器中的额外熵产增加,效率升高,而当指标DMPC减少,换热器中的额外熵产降低,效率下降.该评价指标还可作为优化非共沸混合工质ORC换热器中冷热流体温度匹配性能的目标函数,便于进行变温热源驱动ORC非共沸混合工质的组元匹配及配比优化.
Based on the analysis of the temperature matching performance of the heat exchanger between two fluids in variable-temperature heat source driving ORC( Organic Rankine Cycle) with zeotropic refrigerant mixtures, a new criterion DMPC( Standard deviation of temperature matching index) is proposed to evaluate the overall quality of temperature match between two fluids across the heat exchanger. The results deduced by the proposed criterion are consistent with that deduced by the second law,i. e,as the criterion DMPC goes up,the unnecessary entropy generation will increase,while the exergy efficiency of the heat exchanger will decline,and vice verse. This criterion can also be adopted to be the optimization objective for getting a better temperature match between the two heat transfer fluids in heat exchanger.
引文
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