Improving the semi-empirical modelling of a single-screw expander for small organic Rankine cycles

Giuffrida, Antonio

doi:10.1016/j.apenergy.2017.02.015

Cited by 63 publications

(36 citation statements)

References 45 publications

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“…Sometimes an additional exhaust pressure drop is modeled [7,24]. Giuffrida used a more advanced model for mechanical losses and considered additional radiative ambient losses for a single screw expander [34]. Also, Ziviani et al [35] investigated a more complex model combining two classical semi-empirical model in series for a single screw expander.…”

Section: Semi-empirical Modelmentioning

confidence: 99%

Experimental investigation and optimal performance assessment of four volumetric expanders (scroll, screw, piston and roots) tested in a small-scale organic Rankine cycle system

Dumont

Parthoens

Dickes

et al. 2018

Energy

103

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Keywords:Modeling Experimental Scroll Screw Piston Roots Volumetric Expander ORC a b s t r a c tThe aim of this paper is to facilitate the selection of the expander for a small-scale organic Rankine cycle based on an experimental comparison of a piston, a screw, a scroll and a roots expander. First, based on a literature review, a comparison between these four technologies of volumetric expansion machines is performed. Afterward, four displacement expanders [2e4 kW] are tested on two similar small-scale ORC unit with fluid R245fa. The maximum effective isentropic efficiencies measured are 53% for the piston expander and the screw expander, 76% for the variable-speed scroll and 48% for the roots machine. However, these performances do not reflect the highest efficiencies achievable by each expander: the test-rig presents experimental limitations in terms of mass flow rate and pressure drop (among others) that restricts the achievable operating conditions. The calibration of semi-empirical models based on the measurements allows to overcome this issue and to predict the isentropic efficiency in optimal conditions despite the limitations of the test-rigs. Based on experimental results, extrapolated prediction of the semi-empirical model and practical considerations, some guidelines are drawn to help the reader to select properly a volumetric expander.

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Section: Semi-empirical Modelmentioning

confidence: 99%

Experimental investigation and optimal performance assessment of four volumetric expanders (scroll, screw, piston and roots) tested in a small-scale organic Rankine cycle system

Dumont

Parthoens

Dickes

et al. 2018

Energy

103

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“…The expander model presented in this section has been adapted following the efforts of Lemort (Vincent Lemort et al, 2009) and Giuffrida (Giuffrida, 2017) for two-phase operation. The model accounts for several sources of power losses; including, suction pressure loss, leakage loss, heat loss and friction loss, using the following initial assumptions:…”

Section: Numerical Model Of the Expandermentioning

confidence: 99%

“…Utilising the above two values in Aspen HYSYS © , it is possible to identify the single-phase properties as well as the vapour fraction, and hence, the node 4 is fully defined. Furthermore, point 4 gives an indication on the level of under/over expansion due to the equation describing the off-design expansion process as (Giuffrida, 2017):…”

Section: Isochoric Expansion (3-4)mentioning

confidence: 99%

“…However, the semi-empirical model, where a selected number of equations best describe the important parameters of the system, represents a proven compromise between the limitations of validity range of the empirical models and the computational demand of the deterministic models. Lemort et al (Vincent Lemort, Quoilin, Cuevas, & Lebrun, 2009) initially presented a semi-empirical model of a scroll expander, which was recently extended by Giuffrida (Giuffrida, 2017) for improvements in the modelled mechanical losses for a single-screw expander utilising the Stribeck's theory. A low error of around 2% in the output power was reported when comparing the expander model to the experimental data.…”

Section: Introductionmentioning

confidence: 99%

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Two-Phase Expander Approach for Next Generation of Heat Recovery Systems

Panesar

Bernagozzi

2019

Int. J. Renew. Energy Dev.

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This study presents the numerical adaptations to the semi-empirical expander model in order to examine the feasibility of piston expanders under off-design and two-phase scenarios. This expander model considers supply valve pressure drop, condensation phenomena, heat losses, leakage losses and friction losses. Using Aspen HYSYS©, the expander model is utilised in simulating the next generation of integrated engine cooling and exhaust heat recovery system for future heavy-duty engines. The heat recovery system utilises water-propanol working fluid mixture and consists of independent high pressure (HP) and low pressure (LP) expander. The results of off‑design and two-phase operation are presented in terms of expander efficiency and the different sources of loss, under two distinctive engine speed-load conditions. The heat recovery system, operating with the LP expander at two-phase and the HP expander at superheated condition, represented the design point condition. At the design point, the system provided 15.9 kW of net power, with an overall conversion efficiency of 11.4%, representing 10% of additional engine crankshaft power. At the extreme off-design condition, the two-phase expander operation improved the system performance as a result of the nullification of leakage losses due to the much denser working fluid. The optimised two-phase operation of the LP expander (x=0.55) and the HP expander (x=0.9) at the extreme-off design condition improved the system power by nearly 50% (17.4 vs. 11.7 kW) compared to the reference state. Finally, adapting piston air motors as two-phase expanders for experimental evaluation and reduction in frictional losses was a recommended research direction. ©2019. CBIORE-IJRED. All rights reserved

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“…To exclude the steam reduction and to use the existed differential pressure, it is proposed to introduce a steam screw-rotor machine (SSRM) in parallel with PRDS 14/1.2. This technical solution will allow simultaneously receiving 0.12 MPa steam and 1,250 kW of electrical energy [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Efficiency of introducing a steam screw-rotor machine to the heating power plant circuit

2019

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The aim of the work is to increase the efficiency of the Nizhnekamsk CHPP-1 (combined heat and power plant) by introducing a steam screw-rotor machine (SSRM) into the thermal circuit. It is proposed to exclude the passage of steam from the exit of the turbine through the pressure reduction and desuperheating station (PRDS) for own needs. Superheated steam is diverted to be sent to a steam screw-rotor machine installed parallel to the PRDS. This technical solution will allow to obtain steam used in low pressure deaerators, as well as electricity for own needs of the CHPP. The article presents the operating parameters, as well as the calculation results of the backpressure turbine. A feasibility study was carried out for the introduction of SSRM into the plant’s thermal circuit: the equivalent fuel and electricity savings for own needs were calculated, as well as the payback period of the project for introducing a steam screw-rotor machine. In the course of the calculations, the following results were obtained: a decrease in the specific consumption of equivalent fuel for the production of 1 kWh of electricity by 1.9 g; saving of equivalent fuel during the implementation of the SSRM will be 13 tons per year, which also entails a reduction in emissions into the environment; Electricity production for own needs is 8100 kWh, the payback period for the project to introduce a steam screw machine in the thermal circuit of a thermal power plant is 5 years.

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Improving the semi-empirical modelling of a single-screw expander for small organic Rankine cycles

Cited by 63 publications

References 45 publications

Experimental investigation and optimal performance assessment of four volumetric expanders (scroll, screw, piston and roots) tested in a small-scale organic Rankine cycle system

Experimental investigation and optimal performance assessment of four volumetric expanders (scroll, screw, piston and roots) tested in a small-scale organic Rankine cycle system

Two-Phase Expander Approach for Next Generation of Heat Recovery Systems

Efficiency of introducing a steam screw-rotor machine to the heating power plant circuit

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