Reliable and low-cost expanders are fundamental for the competitiveness of small-scale Organic Rankine Cycle (ORC) plants using low-temperature heat sources. Regenerative flow turbines (RFTs) can be considered a low-cost and viable alternative expander, yet their performance needs to be fully investigated. Therefore, the use of an RFT in a micro-scale ORC test bench is investigated in this work through a modelling study. Specifically, three-dimensional CFD simulations are carried out to assess the performance of the considered expander with varying operating conditions and a numerical model of a non-regenerative, small-scale ORC system is developed to investigate its potential in waste heat recovery (WHR) applications. Using R245fa as the working fluid, the CFD analysis shows that the expander achieves a maximum total-to-static isentropic efficiency of about 44% in the investigated operating range. The small-scale ORC system has a net output power in the range 100–600 W and a net cycle efficiency of 1–2.3%. Moreover, a comparison with two scroll expanders having different built-in volume ratios shows that the RFT operates with higher isentropic efficiencies in low mass flow rates and pressure ratios thus highlighting its suitability for low-temperature WHR applications, especially when considerable fluctuations of the heat source are expected.

Investigation on the use of a novel regenerative flow turbine in a micro-scale Organic Rankine Cycle unit / Moradi, Ramin; Habib, Emanuele; Bocci, Enrico; Cioccolanti, Luca. - In: ENERGY. - ISSN 0360-5442. - 210:(2020). [10.1016/j.energy.2020.118519]

Investigation on the use of a novel regenerative flow turbine in a micro-scale Organic Rankine Cycle unit

Moradi, Ramin
Primo
Writing – Original Draft Preparation
;
Habib, Emanuele
Secondo
Writing – Review & Editing
;
Bocci, Enrico
Penultimo
Writing – Review & Editing
;
2020

Abstract

Reliable and low-cost expanders are fundamental for the competitiveness of small-scale Organic Rankine Cycle (ORC) plants using low-temperature heat sources. Regenerative flow turbines (RFTs) can be considered a low-cost and viable alternative expander, yet their performance needs to be fully investigated. Therefore, the use of an RFT in a micro-scale ORC test bench is investigated in this work through a modelling study. Specifically, three-dimensional CFD simulations are carried out to assess the performance of the considered expander with varying operating conditions and a numerical model of a non-regenerative, small-scale ORC system is developed to investigate its potential in waste heat recovery (WHR) applications. Using R245fa as the working fluid, the CFD analysis shows that the expander achieves a maximum total-to-static isentropic efficiency of about 44% in the investigated operating range. The small-scale ORC system has a net output power in the range 100–600 W and a net cycle efficiency of 1–2.3%. Moreover, a comparison with two scroll expanders having different built-in volume ratios shows that the RFT operates with higher isentropic efficiencies in low mass flow rates and pressure ratios thus highlighting its suitability for low-temperature WHR applications, especially when considerable fluctuations of the heat source are expected.
2020
regenerative flow turbine; CFD simulation; small-scale ORC; micro combined heat and power system; low-grade waste heat recovery
01 Pubblicazione su rivista::01a Articolo in rivista
Investigation on the use of a novel regenerative flow turbine in a micro-scale Organic Rankine Cycle unit / Moradi, Ramin; Habib, Emanuele; Bocci, Enrico; Cioccolanti, Luca. - In: ENERGY. - ISSN 0360-5442. - 210:(2020). [10.1016/j.energy.2020.118519]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1435152
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