Low grade waste heat recovery with subcritical and supercritical Organic Rankine Cycle based on natural refrigerants and their binary mixtures

Braimakis, Konstantinos; Preißinger, Markus; Brüggemann, Dieter; Karellas, Sotiriοs; Panopoulos, K.D.

doi:10.1016/j.energy.2015.03.092

Cited by 103 publications

(38 citation statements)

References 22 publications

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“…Earlier studies have shown that these mixtures can provide significant thermodynamic benefits in ORC systems [15,[43][44][45], which has motivated their consideration in the present study. Furthermore, pentane and the selected refrigerants are presently being used in actual installations, especially in geothermal ORC plants, such as the one considered here.…”

Section: Resultsmentioning

confidence: 99%

Thermo-Economic and Heat Transfer Optimization of Working-Fluid Mixtures in a Low-Temperature Organic Rankine Cycle System

Oyewunmi

Markides

2016

Energies

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Abstract:In the present paper, we consider the employment of working-fluid mixtures in organic Rankine cycle (ORC) systems with respect to thermodynamic and heat-transfer performance, component sizing and capital costs. The selected working-fluid mixtures promise reduced exergy losses due to their non-isothermal phase-change behaviour, and thus improved cycle efficiencies and power outputs over their respective pure-fluid components. A multi-objective cost-power optimization of a specific low-temperature ORC system (operating with geothermal water at 98 • C) reveals that the use of working-fluid-mixtures does indeed show a thermodynamic improvement over the pure-fluids. At the same time, heat transfer and cost analyses, however, suggest that it also requires larger evaporators, condensers and expanders; thus, the resulting ORC systems are also associated with higher costs. In particular, 50% n-pentane + 50% n-hexane and 60% R-245fa + 40% R-227ea mixtures lead to the thermodynamically optimal cycles, whereas pure n-pentane and pure R-245fa have lower plant costs, both estimated as having ∼14% lower costs per unit power output compared to the thermodynamically optimal mixtures. These conclusions highlight the importance of using system cost minimization as a design objective for ORC plants.

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Section: Resultsmentioning

confidence: 99%

Thermo-Economic and Heat Transfer Optimization of Working-Fluid Mixtures in a Low-Temperature Organic Rankine Cycle System

Oyewunmi

Markides

2016

Energies

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“…Methods without additional components mainly focus on improving the temperature match between heat source, working fluid and environment. In this context, fluid mixtures lead to temperature glide during evaporation and condensation [53][54][55]. For supercritical mode of operation, phase change just occurs in the condenser but not in the heater.…”

Section: Approach For Modular Design Of Orc Unitsmentioning

confidence: 99%

Thermoeconomic Evaluation of Modular Organic Rankine Cycles for Waste Heat Recovery over a Broad Range of Heat Source Temperatures and Capacities

Preißinger

Brüggemann

2017

Energies

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Industrial waste heat recovery by means of an Organic Rankine Cycle (ORC) can contribute to the reduction of CO 2 emissions from industries. Before market penetration, high efficiency modular concepts have to be developed to achieve appropriate economic value for industrial decision makers. This paper aims to investigate modularly designed ORC systems from a thermoeconomic point of view. The main goal is a recommendation for a suitable chemical class of working fluids, preferable ORC design and a range of heat source temperatures and thermal capacities in which modular ORCs can be economically feasible. For this purpose, a thermoeconomic model has been developed which is based on size and complexity parameters of the ORC components. Special emphasis has been laid on the turbine model. The paper reveals that alkylbenzenes lead to higher exergetic efficiencies compared to alkanes and siloxanes. However, based on the thermoeconomic model, the payback periods of the chemical classes are almost identical. With the ORC design, the developed model and the boundary conditions of this study, hexamethyldisiloxane is a suitable working fluid and leads to a payback period of less than 5 years for a heat source temperature of 400 to 600 • C and a mass flow rate of the gaseous waste heat stream of more than 4 kg/s.

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“…The results show that the critical temperature of working fluids is much higher than the temperature of the heat source cause low vapor densities while the critical temperature of working fluids is lower than the heat source temperature cause low thermodynamic performance. Braimakis et al [23] investigated subcritical ORC system and supercritical ORC system using five natural refrigerants for a waste heat recovery organic Rankine cycle. They have calculated the several technical parameters such as the turbine size and rotational speed.…”

Section: Introductionmentioning

confidence: 99%

Comparative Thermodynamic Assessment of Various Super- and Trans-Critical Working Fluids for Low Temperature Power Generation Applications

Özcan¹,

Seyitoğlu²

2017

Journal of Polytechnic

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Bu makaleye şu şekilde atıfta bulunabilirsiniz (To cite to this article): Ozcan H. and Seyıtoglu S. S., "Comparative thermodynamic assessment of various super-and trans-critical working fluids for low temperature power generation applications", Politeknik Dergisi, 20(4): 915-921, (2017). Politeknik Dergisi, 2017; 20 (4) : 915-921 Journal of Polytechnic, 2017; 20 (4) ABSTRACTRecently, energy need is exponentially increasing in the world while energy sources are decreasing rapidly. Therefore, this issue requires energy sources to be used more efficiently and urges professionals to utilize energy from low temperature energy sources such as waste heat and low temperature renewable sources. In this study, energy and exergy analyses of several clean working fluids are comparatively studied in several organic Rankine cycle configurations. CO2, N2O, and SF6 fluids are compared with the conventional R23 in three ORC configurations, namely the basic ORC cycle, regenerative ORC cycle, and reheat and regenerative ORC cycle, respectively. Effects of various selected system and environmental parameters on the system performances are comprehensively investigated. Even though R23 shows the best energy and exergy performances than those of other investigated working fluids at low-temperature applications, N2O and CO2 provide a clean solution to high GWP (global warming potential) R23 with similar performance characteristics at low and high temperature power generation applications.Keywords: Organic rankine cycle, energy, exergy, R23, CO2, N2O, SF6. ÖZSon zamanlarda, enerji ihtiyacı dünyada katlanarak artarken enerji kaynakları hızla azalmaktadır. Bu yüzden, bu konu enerji kaynaklarının daha verimli kullanılması ve uzmanları atık ısı ve düşük sıcaklık yenilenebilir enerji kaynakları gibi düşük sıcaklık kaynaklarının kullanmalarını gerektirir. Bu çalışmada, birbirinden farklı temiz akışkanların enerji ve ekserji analizleri farklı organik Rankine çevrim konfigürasyonlarında karşılaştırmalı olarak incelenmiştir. CO2, N2O ve SF6 akışkanları geleneksel R23 akışkanı ile sırasıyla temel organik Rankine çevirimi, ara buhar almalı organik Rankine çevrimi ve ara ısıtmalı-ara buhar almalı organik Rankine çevrimlerinde karşılaştırılmıştır. Çeşitli seçilmiş sistemlerin ve çevresel parametrelerin sistem performanslarına etkileri kapsamlı olarak incelenmiştir.Anahtar Kelimeler: Organik rankine çevrimi, enerji, ekserji, R23, CO2, N2O, SF6.

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Low grade waste heat recovery with subcritical and supercritical Organic Rankine Cycle based on natural refrigerants and their binary mixtures

Cited by 103 publications

References 22 publications

Thermo-Economic and Heat Transfer Optimization of Working-Fluid Mixtures in a Low-Temperature Organic Rankine Cycle System

Thermo-Economic and Heat Transfer Optimization of Working-Fluid Mixtures in a Low-Temperature Organic Rankine Cycle System

Thermoeconomic Evaluation of Modular Organic Rankine Cycles for Waste Heat Recovery over a Broad Range of Heat Source Temperatures and Capacities

Comparative Thermodynamic Assessment of Various Super- and Trans-Critical Working Fluids for Low Temperature Power Generation Applications

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