Energetic optimization of regenerative Organic Rankine Cycle (ORC) configurations

Braimakis, Konstantinos; Karellas, Sotiriοs

doi:10.1016/j.enconman.2017.12.093

Cited by 138 publications

(46 citation statements)

References 40 publications

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“…In order to increase the energy efficiency, different modifications have been proposed to the ORC architecture, several of the proposed improvements aim to optimize the temperature profile, where the organic working fluid follows the external heat source in order to reduce the exergy destroyed in the evaporator and thus increase the general second low efficiency of the system. One of the modifications to the architecture of this system is known as RORC, where research has been carried out to increase the efficiency of the cycle by 9.29%, and from the data obtained from these studies it can also be appreciated that both the RORC and the simple ORC (SORC) work better with drier fluids, where the efficiency of the cycle was also affected by the critical temperature [8][9][10]. These studies are limited to compare only the SORC and RORC cycles, and the double-stage ORC (DORC) study is not integrated with exhaust gases from a natural gas engine as a heat source.…”

Section: Introductionmentioning

confidence: 99%

Thermoeconomic Optimization with PSO Algorithm of Waste Heat Recovery Systems Based on Organic Rankine Cycle System for a Natural Gas Engine

2019

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To contribute to the economic viability of waste heat recovery systems application based on the organic Rankine cycle (ORC) under real operation condition of natural gas engines, this article presents a thermoeconomic optimization results using the particle swarm optimization (PSO) algorithm of a simple ORC (SORC), regenerative ORC (RORC), and double-stage ORC (DORC) integrated to a GE Jenbacher engine type 6, which have not been reported in the literature. Thermoeconomic modeling was proposed for the studied configurations to integrate the exergetic analysis with economic considerations, allowing to reduce the thermoeconomic indicators that most influence the cash flow of the project. The greatest opportunities for improvement were obtained for the DORC, where the results for maximizing net power allowed the maximum value of 99.52 kW, with 85% and 80% efficiencies in the pump and turbine, respectively, while the pinch point temperatures of the evaporator and condenser must be 35 and 16 °C. This study serves as a guide for future research focused on the thermoeconomic performance optimization of an ORC integrated into a natural gas engine.

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Section: Introductionmentioning

confidence: 99%

Thermoeconomic Optimization with PSO Algorithm of Waste Heat Recovery Systems Based on Organic Rankine Cycle System for a Natural Gas Engine

2019

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“…Redesign and optimization of turbines and pumps are examples of these improvement efforts [43][44][45]. The use of a regenerator and operating in supercritical conditions is also often applied to improve the system performance [46][47][48][49][50][51]. When the previous studies are examined in detail, it becomes obvious that there are many studies that reveal the capacity of ORCs to recover waste heat from different sources, but only some of them analyse the probability of using organic Rankine cycles to assist small and medium Energies 2019, 12, 575 3 of 22 scale CHP engines.…”

Section: Introductionmentioning

confidence: 99%

Exergy Analysis and Performance Improvement of a Subcritical/Supercritical Organic Rankine Cycle (ORC) for Exhaust Gas Waste Heat Recovery in a Biogas Fuelled Combined Heat and Power (CHP) Engine Through the Use of Regeneration

2019

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In the present study, a subcritical and supercritical regenerative organic Rankine cycle (rORC) was designed. The designed rORCs assist a combined heat and power (CHP) engine, the fuel of which is biogas produced from anaerobic digestion of domestic wastes in Belgium. R245fa was selected as the working fluid for both the subcritical and supercritical rORC. During the parametric optimisation, the net power production, mass flow rate, exchanged heat in the regenerator, total pump power consumption, thermal and exergetic efficiencies of rORC were calculated for varying turbine inlet temperatures and pressures. After parametric optimisation of the rORC, the results were compared with the results of the previous study, in which only a simple ORC is analysed and parametrically optimised. Moreover, the effect of the regenerator was revealed by examining all results together. Finally, the exergetic analysis of the best performing subcritical and supercritical rORC was performed. Furthermore, the results of the present and previous studies were considered together and it is clearly seen that the subcritical rORC shows the best performance. Consequently, by using the subcritical rORC, the disadvantages of the using simple ORC (low performance) and supercritical cycle (safety, investment) can be eliminated and system performance can be improved.

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“…Numerous studies have been carried out on the application of ORC systems in ICE, which has covered working fluid selection methodologies [12][13][14], exergy and energy analysis [15,16], thermo-economic optimization [17], and comparative analysis of different ORC configurations performance [18]. Regarding the studies on the performance of organic fluids in ORC coupled to ICE, there are those developed by Scaccabarozzi et al [19], who performed tests with 22 working fluids, such as pure fluids, synthetic refrigerants, and binary mixtures, determining that the use of binary mixtures does not lead to a considerable increase in thermal efficiency compared to pure fluids.…”

Section: Introductionmentioning

confidence: 99%

Thermoeconomic Modelling and Parametric Study of a Simple ORC for the Recovery of Waste Heat in a 2 MW Gas Engine under Different Working Fluids

2019

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This paper presents a thermo-economic analysis of a simple organic Rankine cycle (SORC) as a waste heat recovery (WHR) systems of a 2 MW stationary gas engine evaluating different working fluids. Initially, a systematic methodology was implemented to select three organic fluids according to environmental and safety criteria, as well as critical system operational conditions. Then, thermodynamic, exergy, and exergo-economic models of the system were developed under certain defined considerations, and a set of parametric studies are presented considering key variables of the system such as pump efficiency, turbine efficiency, pinch point condenser, and evaporator. The results show the influence of these variables on the combined power of the system (gas engine plus ORC), ORC exergetic efficiency, specific fuel consumption (∆BSFC), and exergo indicators such as the payback period (PBP), levelized cost of energy (LCOE), and the specific investment cost (SIC). The results revealed that heat transfer equipment had the highest exergy destruction cost rates representing 81.25% of the total system cost. On the other hand, sensitivity analyses showed that acetone presented better energetic and exergetic performance when the efficiency of the turbine, evaporator, and condenser pinch point was increased. However, toluene was the fluid with the best results when pump efficiency was increased. In terms of the cost of exergy destroyed by equipment, the results revealed that acetone was the working fluid that positively impacted cost reduction when pump efficiency was improved; and toluene, when turbine efficiency was increased. Finally, the evaporator and condenser pinch point increased all the economic indicators of the system. In this sense, the working fluid with the best performance in economic terms was acetone, when the efficiency of the turbine, pinch condenser, and pinch evaporator was enhanced.

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Energetic optimization of regenerative Organic Rankine Cycle (ORC) configurations

Cited by 138 publications

References 40 publications

Thermoeconomic Optimization with PSO Algorithm of Waste Heat Recovery Systems Based on Organic Rankine Cycle System for a Natural Gas Engine

Thermoeconomic Optimization with PSO Algorithm of Waste Heat Recovery Systems Based on Organic Rankine Cycle System for a Natural Gas Engine

Exergy Analysis and Performance Improvement of a Subcritical/Supercritical Organic Rankine Cycle (ORC) for Exhaust Gas Waste Heat Recovery in a Biogas Fuelled Combined Heat and Power (CHP) Engine Through the Use of Regeneration

Thermoeconomic Modelling and Parametric Study of a Simple ORC for the Recovery of Waste Heat in a 2 MW Gas Engine under Different Working Fluids

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