Development and analysis of a packaged Trilateral Flash Cycle system for low grade heat to power conversion applications

Bianchi, Giuseppe; McGinty, Rebecca; Oliver, D. A.; Brightman, Derek; Zaher, Obadah; Tassou, S.A.; Miller, Jeremy; Jouhara, Hussam

doi:10.1016/j.tsep.2017.09.009

Cited by 37 publications

(13 citation statements)

References 27 publications

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“…The energy recovery unit has been designed based on a bottoming Trilateral Flash Cycle; the first law analysis and the working fluid selection is presented in [23]. The theoretical system performance, i.e., the one resulting from the cycle analysis carried out in [23], are summarized in Table 2, where the net power output is the difference between expansion and pumping powers while the cycle thermal efficiency is the ratio between net power output and the heat gain, all of them expressed as absolute enthalpy differences. The working fluid at the end of the heat recovery phase was assumed to be in saturated liquid conditions.…”

Section: Resultsmentioning

confidence: 99%

“…Table 3 shows the simulation results at the design point, which also served as reference for the off-design analysis. Compared to the initial layout presented in [23], where one third of the flow rate was sent to the pump through an additional connection on the receiver, in the one-dimensional model an additional condenser was considered. This explains the discrepancy in the cold water flow rate between Tables 2 and 3.…”

Section: Tfc Systemmentioning

confidence: 99%

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One-Dimensional Modelling of a Trilateral Flash Cycle System with Two-Phase Twin-Screw Expanders for Industrial Low-Grade Heat to Power Conversion

Bianchi

Marchionni

Kennedy

et al. 2019

Designs

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This paper provides an overview of a one-dimensional modelling methodology for equipment and systems for heat to power conversion based on a staggered grid space discretization and implemented in the commercial software GT-SUITE®. Particular attention is given to a newly developed modelling procedure for twin-screw machines that is based on a chamber modelling approach and considers leakage paths between cells and with the casing. This methodology is then applied to a low-grade heat to power conversion system based on a Trilateral Flash Cycle (TFC) equipped with two parallel two-phase twin-screw expanders and a control valve upstream of the machines to adapt the fluid quality for an optimal expander operation. The standalone expander model is used to generate performance maps of the machine, which serve as inputs for the TFC system model. Parametric analyses are eventually carried out to assess the impact of several operating parameters of the TFC unit on the recovered power and cycle thermal efficiency. The study shows that the most influencing factors on the TFC system’s performance are the inlet temperature of the heat source and the expander speed. While the first depends on the topping industrial process, the expander speed can be used to optimize and control the TFC system operation also in transient or off-design operating conditions.

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Section: Resultsmentioning

confidence: 99%

Section: Tfc Systemmentioning

confidence: 99%

One-Dimensional Modelling of a Trilateral Flash Cycle System with Two-Phase Twin-Screw Expanders for Industrial Low-Grade Heat to Power Conversion

Bianchi

Marchionni

Kennedy

et al. 2019

Designs

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“…For these reasons, these units are suitable for ultra-low temperature WHR applications, from 200 °C down to 70 °C Furthermore, because of the two-phase expansion, volumetric machines are usually adopted since they guarantee a higher adiabatic efficiency. The size of these machines, however, limits the maximum thermal capacity of the waste heat source exploitable, which can go up to 5 MW [26,27]. For capacities lower than 1 MW, ORC systems are more competitive [26].…”

Section: Benchmark Of Supercritical Co 2 Heat To Power Cyclesmentioning

confidence: 99%

“…The size of these machines, however, limits the maximum thermal capacity of the waste heat source exploitable, which can go up to 5 MW [26,27]. For capacities lower than 1 MW, ORC systems are more competitive [26].…”

Section: Benchmark Of Supercritical Co 2 Heat To Power Cyclesmentioning

confidence: 99%

Review of supercritical carbon dioxide (sCO2) technologies for high-grade waste heat to power conversion

2020

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In the European Industry, 275 TWh of thermal energy is rejected into the environment at temperatures beyond 300 °C. To recover some of this wasted energy, bottoming thermodynamic cycles using supercritical carbon dioxide (sCO 2) as working fluid are a promising technology for the conversion of the waste heat into power. CO 2 is a non-flammable and thermally stable compound, and due to its favourable thermo-physical properties in the supercritical state, can lead to high cycle efficiencies and a substantial reduction in size compared to alternative heat to power conversion technologies. In this work, a brief overview of the sCO 2 power cycle technology is presented. The main concepts behind this technology are highlighted, including key technological challenges with the major components such as turbomachinery and heat exchangers. The discussion focuses on heat to power conversion applications and benefits of the experience gained from the design and construction of a 50 kWe sCO 2 test facility at Brunel University London. A comparison between sCO 2 power cycles and conventional heat to power conversion systems is also provided. In particular, the operating ranges of sCO 2 and other heat to power systems are reported as a function of the waste heat source temperature and available thermal power. The resulting map provides insights for the preliminary selection of the most suitable heat to power conversion technology for a given industrial waste heat stream.

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“…To solve this problem, simulations and experiments of two-phase expanders were carried out. Both the reciprocating expanders and twin-screw expanders were suggested as possible candidates [20,21].…”

Section: Introductionmentioning

confidence: 99%

Influence of evaporating rate on two-phase expansion in the piston expander with cyclone separator

Wang

Zhang

et al. 2020

Therm sci

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The trilateral flash cycle shows a greater potentiality in moderate to low grade heat utilization systems due to its potentiality of obtaining high exergy efficiency, compared to the conventional thermodynamic cycles such as the organic Rankine cycles and the Kalina cycle. The main difference between the trilateral flash cycle and the conventional thermodynamic cycles is that the superheated vapor expansion process is replaced by the two-phase expansion process. The two-phase expansion process actually consists of a flashing of the inlet stream into a vapor and a liquid phase. Most simulations assume an equilibrium model with an instantaneous flashing. Yet, the experiments of pool flashing indicate that there is a flash evaporating rate. The mechanism of this process still remains unclear. In this paper, the flash evaporating rate is introduced into the model of the two-phase expansion process in the reciprocating expander with a cyclone separator. As such, the obtained results reveal the influence of evaporating rate on the efficiency of the two-phase expander.

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Development and analysis of a packaged Trilateral Flash Cycle system for low grade heat to power conversion applications

Cited by 37 publications

References 27 publications

One-Dimensional Modelling of a Trilateral Flash Cycle System with Two-Phase Twin-Screw Expanders for Industrial Low-Grade Heat to Power Conversion

One-Dimensional Modelling of a Trilateral Flash Cycle System with Two-Phase Twin-Screw Expanders for Industrial Low-Grade Heat to Power Conversion

Review of supercritical carbon dioxide (sCO2) technologies for high-grade waste heat to power conversion

Influence of evaporating rate on two-phase expansion in the piston expander with cyclone separator

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