Effect of Subcooling on Thermal Performance of Organic Rankine Cycle With Zeotropic Mixture in Geothermal Power Generation
Organic Rankine cycle (ORC) is the main way to generate electricity by using medium-low temperature (< 150℃) geothermal heat. In actual operation, zeotropic mixture tends to condense to the subcooling state. This paper analyzed the effect of subcooling on thermal performance of ORCs using zeotrop...
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Editorial Department of Power Generation Technology
2020-04-01
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| Series: | 发电技术 |
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| Online Access: | https://www.pgtjournal.com/EN/10.12096/j.2096-4528.pgt.19098 |
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| author | Ran CHEN Qiang LIU Dongyu MENG |
| author_facet | Ran CHEN Qiang LIU Dongyu MENG |
| author_sort | Ran CHEN |
| collection | DOAJ |
| description | Organic Rankine cycle (ORC) is the main way to generate electricity by using medium-low temperature (< 150℃) geothermal heat. In actual operation, zeotropic mixture tends to condense to the subcooling state. This paper analyzed the effect of subcooling on thermal performance of ORCs using zeotropic mixture as working fluid. The mathematics model of the ORC and the ORC with internal heat exchanger (IHE) were established, and then the evaporation pressure was optimized to maximize the net power output. Moreover, the system exergy analysis was also conducted. The results show that the condensation subcooling affects the temperature profile match between the working fluid and the heat sink. Limited by the pinch point temperature difference, the condensation pressure rises with the subcooling increasing. The subcooling also changes the heat allocation between the preheater and evaporator, the optimal evaporation pressure also increases as the subcooling increases. When the subcooling is 2℃, the net power output can be reduced by 4.36% for isobutene/isopentane (0.4:0.6) which is the most affected by the subcooling. The IHE recovers the waste heat of expander exhaust to preheat the working fluid, as a result, the net power output of the subcooled ORC system can be increased by 0.55%. The subcooling causes a significant increase in the condenser exergy destruction that can be reduced by 24.7% using the recuperative ORC system. |
| format | Article |
| id | doaj-art-df039fde21b64b16af55bdc58aa58e79 |
| institution | Kabale University |
| issn | 2096-4528 |
| language | English |
| publishDate | 2020-04-01 |
| publisher | Editorial Department of Power Generation Technology |
| record_format | Article |
| series | 发电技术 |
| spelling | doaj-art-df039fde21b64b16af55bdc58aa58e792024-11-09T02:04:14ZengEditorial Department of Power Generation Technology发电技术2096-45282020-04-0141219019710.12096/j.2096-4528.pgt.19098fdjs-41-2-190Effect of Subcooling on Thermal Performance of Organic Rankine Cycle With Zeotropic Mixture in Geothermal Power GenerationRan CHEN0Qiang LIU1Dongyu MENG2State Key Laboratory of Petroleum Resources and Prospecting(China University of Petroleum-Beijing), Changping District, Beijing 102249, ChinaState Key Laboratory of Petroleum Resources and Prospecting(China University of Petroleum-Beijing), Changping District, Beijing 102249, ChinaState Key Laboratory of Petroleum Resources and Prospecting(China University of Petroleum-Beijing), Changping District, Beijing 102249, ChinaOrganic Rankine cycle (ORC) is the main way to generate electricity by using medium-low temperature (< 150℃) geothermal heat. In actual operation, zeotropic mixture tends to condense to the subcooling state. This paper analyzed the effect of subcooling on thermal performance of ORCs using zeotropic mixture as working fluid. The mathematics model of the ORC and the ORC with internal heat exchanger (IHE) were established, and then the evaporation pressure was optimized to maximize the net power output. Moreover, the system exergy analysis was also conducted. The results show that the condensation subcooling affects the temperature profile match between the working fluid and the heat sink. Limited by the pinch point temperature difference, the condensation pressure rises with the subcooling increasing. The subcooling also changes the heat allocation between the preheater and evaporator, the optimal evaporation pressure also increases as the subcooling increases. When the subcooling is 2℃, the net power output can be reduced by 4.36% for isobutene/isopentane (0.4:0.6) which is the most affected by the subcooling. The IHE recovers the waste heat of expander exhaust to preheat the working fluid, as a result, the net power output of the subcooled ORC system can be increased by 0.55%. The subcooling causes a significant increase in the condenser exergy destruction that can be reduced by 24.7% using the recuperative ORC system.https://www.pgtjournal.com/EN/10.12096/j.2096-4528.pgt.19098geothermal power generationorganic rankine cycle (orc)zeotropic mixturesubcoolinginternal heat exchanger (ihe)thermal performance |
| spellingShingle | Ran CHEN Qiang LIU Dongyu MENG Effect of Subcooling on Thermal Performance of Organic Rankine Cycle With Zeotropic Mixture in Geothermal Power Generation 发电技术 geothermal power generation organic rankine cycle (orc) zeotropic mixture subcooling internal heat exchanger (ihe) thermal performance |
| title | Effect of Subcooling on Thermal Performance of Organic Rankine Cycle With Zeotropic Mixture in Geothermal Power Generation |
| title_full | Effect of Subcooling on Thermal Performance of Organic Rankine Cycle With Zeotropic Mixture in Geothermal Power Generation |
| title_fullStr | Effect of Subcooling on Thermal Performance of Organic Rankine Cycle With Zeotropic Mixture in Geothermal Power Generation |
| title_full_unstemmed | Effect of Subcooling on Thermal Performance of Organic Rankine Cycle With Zeotropic Mixture in Geothermal Power Generation |
| title_short | Effect of Subcooling on Thermal Performance of Organic Rankine Cycle With Zeotropic Mixture in Geothermal Power Generation |
| title_sort | effect of subcooling on thermal performance of organic rankine cycle with zeotropic mixture in geothermal power generation |
| topic | geothermal power generation organic rankine cycle (orc) zeotropic mixture subcooling internal heat exchanger (ihe) thermal performance |
| url | https://www.pgtjournal.com/EN/10.12096/j.2096-4528.pgt.19098 |
| work_keys_str_mv | AT ranchen effectofsubcoolingonthermalperformanceoforganicrankinecyclewithzeotropicmixtureingeothermalpowergeneration AT qiangliu effectofsubcoolingonthermalperformanceoforganicrankinecyclewithzeotropicmixtureingeothermalpowergeneration AT dongyumeng effectofsubcoolingonthermalperformanceoforganicrankinecyclewithzeotropicmixtureingeothermalpowergeneration |