Optimizing the performance of small-scale organic Rankine cycle that utilizes a single-screw expander

Ziviani, Davide; Gusev, Sergei; Lecompte, Steven; Groll, Eckhard A.; Braun, James E.; Horton, W. Travis; Broek, Martijn van den; Paepe, Michel De

doi:10.1016/j.apenergy.2016.12.070

Cited by 59 publications

(19 citation statements)

References 25 publications

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“…This finding is aligned with other studies in the literature which report that for a given size screw expander (i.e. given design VR and volume flow rate), the efficiency is mostly affected by variations in the VR of the device [21]. To predict the piston expander performance at off-design operation, the performance maps generated using an inhouse model have been used, as discussed in Section 2.3.…”

Section: Nominal Expander Design and Sizingsupporting

confidence: 73%

“…[19,20] investigated the performance of ORC engines with scroll expanders and plate/helical coil heat exchangers. Single-stage single screw expanders in off-design operation were also considered by Ziviani et al [21] for smallscale, low-temperature ORC systems, with particular focus on the control strategy of the expander to maximise power output or efficiency. In Ref.…”

Section: Introductionmentioning

confidence: 99%

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Off-design optimisation of organic Rankine cycle (ORC) engines with different heat exchangers and volumetric expanders in waste heat recovery applications

et al. 2019

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Organic Rankine cycle (ORC) engines in real applications experience variable heat-source conditions. In this paper, the off-design performance of small/medium-scale ORC engines recovering heat from a stationary internal combustion engine (ICE) is investigated. Of interest are the employment of screw vs. piston expanders, and two heat exchanger (HEX) architectures. Unlike previous studies where the expander and HEX performance are assumed fixed during offdesign operation, we consider explicitly their varying and interacting characteristics within the overall system. Nominal sizing results reveal indicated isentropic efficiencies >80% for twin-screw and >85% for piston expanders. Following nominal design, ORC engine operation is optimised for ICE part-load (PL) operation. Although the heat transfer coefficients in the evaporator decrease by 30% at PL, the effectiveness increases by 20% due to the larger temperature differences in this component. The screw expander efficiency reduces by up to 3% at off-design operation, whilst that of the piston expander increases by up to 16%. Optimised off-design maps indicate that the ORC engine power output reduces to 77% (piston) or 68% (screw) of full-load when the ICE operates at 60% PL, and that ORC engines with plate HEXs generate 5-11% more power than those with double-pipe HEXs. Under variable ICE operation, smaller ORC engines with piston expanders generate more power than larger engines with screw expanders, highlighting the resilient off-design operation of piston machines. The tool can predict ORC performance over a wide operating envelope and provides performance maps that can be used by operators to optimise ORC engine operation in variable conditions and by ORC vendors to inform component design decisions.

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Section: Nominal Expander Design and Sizingsupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Off-design optimisation of organic Rankine cycle (ORC) engines with different heat exchangers and volumetric expanders in waste heat recovery applications

et al. 2019

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“…System optimization, working fluid selection, and heat transfer enhancement are essential for an ORC system. Hence, various simulation and experimental studies about ORC system design, [8][9][10] optimization of system components, [11][12][13] performance of different expanders, [14][15][16] self-adaptive regulation, [17][18][19] and analysis of actual system operation [20][21][22] are proposed.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on a small-scale pumpless organic Rankine cycle with R1233zd(E) as working fluid at low temperature heat source

Wang

et al. 2019

Int J Energy Res

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Summary This paper focuses on the novelty pumpless organic Rankine cycle (ORC) and its choice of working fluids. Based on the selection criteria, the refrigerant of R1233zd(E) is firstly chosen and investigated in the pumpless ORC system. In the system, the feed pump is removed, and the refrigerant flows back and forth between two heat exchangers, which act as the evaporator or condenser, respectively. The impacts of the heating water temperature and loads on the system performance are studied to find out the best operating conditions. The low‐grade heat source is simulated by an electric boiler. The temperature of the heat resource ranges from 80°C to 100°C with the interval of 5°C. The temperature of the cooling water inlet is 10°C and is kept constant. The largest average power output is 127 W under the condition of 100°C heating water with nine loads. Because the cycle efficiency with heating steam temperature of 100°C cannot be determined, the highest energy and exergy efficiencies are 3.5% and 17.1%, respectively, for heating water of 95°C with seven loads. The experimental results show that the energy and exergy efficiencies increase with the increase of the heating temperature. The power and current outputs increase when the loads increase under the condition of the constant heating water temperature, whereas the voltage output decreases meanwhile. The generating time increases when the loads increase. This phenomenon is mainly caused by the increasing evaporating pressure and decreasing condensing pressure when the loads increases.

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“…Ziviani et al established a nonsymmetric modeling approach to design a single‐screw expander, and the performance was improved significantly. Ziviani et al and Zhang et al adopted a single‐screw expander to build an organic Rankine cycle (ORC) system to recover low‐grade waste heat, and the maximum power outputs of these systems are 11 kW and 10.38 kW, respectively. Wang et al explored the gap sizes between the gate rotor and shell and between the screw and shell.…”

Section: Introductionmentioning

confidence: 99%

The energy performance of a single‐screw compressor for natural gas liquefaction process: Effects of the lubricating oil flow rate

et al. 2019

Int J Energy Res

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Summary An experimental test system including the oil circulation system and the gas circuit system has been designed and built to explore the effects of the lubricating oil flow rate on the performance of a single‐screw compressor, used in a portable natural gas liquefaction process. Outlet pressure, outlet volumetric flow rate, volumetric efficiency, and specific power rate are the parameters for evaluation of the energy performance of the single‐screw compressor. The experimental results indicate that the outlet pressure and outlet volumetric flow rate can be effectively increased by increasing the flow rate of the lubricating oil at different rotational frequencies and that a certain amount of lubricant oil is helpful to improve the volumetric efficiency. In terms of the specific power rate, the optimum oil‐gas ratios are 0.7%, 0.93%, and 1.79%, and the corresponding outlet pressures are 0.45, 0.45, and 0.48 MPa at the conditions of 50, 40, and 30 Hz, respectively.

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Optimizing the performance of small-scale organic Rankine cycle that utilizes a single-screw expander

Cited by 59 publications

References 25 publications

Off-design optimisation of organic Rankine cycle (ORC) engines with different heat exchangers and volumetric expanders in waste heat recovery applications

Off-design optimisation of organic Rankine cycle (ORC) engines with different heat exchangers and volumetric expanders in waste heat recovery applications

Experimental study on a small-scale pumpless organic Rankine cycle with R1233zd(E) as working fluid at low temperature heat source

The energy performance of a single‐screw compressor for natural gas liquefaction process: Effects of the lubricating oil flow rate

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