White M. T., Read M. G., Sayma A. I. Comparison between single and cascaded organic Rankine cycle systems accounting for the effects of expansion volume ratio on expander performance / trans. from Engl. M. A. Fedorova
Compared to single-stage organic Rankine cycle (ORC) systems, cascaded ORC systems, in which a high-temperature topping cycle and low-temperature bottoming cycle are coupled together, could have advantages in terms of removing the potential for sub-atmospheric condensation conditions and improvin...
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| Main Author: | |
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| Format: | Article |
| Language: | English |
| Published: |
Omsk State Technical University, Federal State Autonomous Educational Institution of Higher Education
2020-10-01
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| Series: | Омский научный вестник: Серия "Авиационно-ракетное и энергетическое машиностроение" |
| Subjects: | |
| Online Access: | https://www.omgtu.ru/general_information/media_omgtu/journal_of_omsk_research_journal/files/arhiv/2020/%D0%A2.%204,%20%E2%84%96%203%20(%D0%90%D0%A0%D0%B8%D0%AD%D0%9C)/90-100%20%D0%A3%D0%B0%D0%B9%D1%82%20%D0%9C.%20%D0%A2.,%20%D0%A0%D0%B8%D0%B4%20%D0%9C.%20%D0%94%D0%B6.,%20%D0%A1%D0%B0%D0%B9%D0%BC%D0%B0%20A.%20%D0%98..pdf |
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| Summary: | Compared to single-stage organic Rankine cycle (ORC) systems, cascaded ORC systems, in which
a high-temperature topping cycle and low-temperature bottoming cycle are coupled together, could
have advantages in terms of removing the potential for sub-atmospheric condensation conditions and
improving expander performance as the expansion process is effectively divided across two stages.
Moreover, reducing the expansion volume ratio could facilitate the use of volumetric expanders, such as
twin-screw expanders, which, in turn, could facilitate two-phase expansion to be utilised in one, or both,
of the cycles. The aim of this paper is to compare single-stage and cascaded ORC systems, accounting
for the effect of the
expander volume ratio on expander performance. To investigate this, thermodynamic models for single-stage and cascaded ORC systems are developed, which include variable efficiency expander models
for both radial turbines and twin-screw expanders that can estimate the effect of the expansion volume
ratio on the expander isentropic efficiency. Using this model, three different scenarios are compared
for different temperature heat-source temperatures, namely: (i) single-stage ORC systems with vapour-phase expansion obtained using a turboexpander; (ii) single-stage ORC systems operating with a twin-screw expander, with the possibility for two-phase expansion; and (iii) cascaded cycles with either
vapour- or two-phase expansion. The
results from this comparison are used to identify applications where cascaded ORC systems could offer
performance benefits |
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| ISSN: | 2588-0373 2587-764X |