Theoretical and experimental investigation of an organic Rankine cycle for a waste heat recovery system

2009 ◽  
Vol 223 (5) ◽  
pp. 523-533 ◽  
Author(s):  
W Gu ◽  
Y Weng ◽  
Y Wang ◽  
B Zheng
Keyword(s):  
Heat Source ◽  
Entropy Generation ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Entropy Generation Rate ◽  
Working Fluid ◽  
Total Entropy ◽  
Waste Heat Recovery System ◽  
Cycle Efficiency

This article describes and evaluates an organic Rankine cycle (ORC) for a waste heat recovery system by both theoretical and experimental studies. Theoretical analysis of several working fluids shows that cycle efficiency is very sensitive to evaporating pressure, but insensitive to expander inlet temperature. Second law analysis was carried out using R600a as a working fluid and a flow of hot air as a heat source, which is not isothermal, along the evaporator. The result discloses that the evaporator's internal and external entropy generation is the main source of total entropy generation. The effect of the heat source temperature, evaporating pressure, and evaporator size on the entropy generation rate is also presented. The obtained useful power is directly linked to the total entropy generation rate according to the Gouy—Stodola theorem. The ORC testing system was established and operated using R600a as a working fluid and hot water as a heat source. The maximum cycle efficiency of the testing system is 5.2 per cent, and the testing result also proves that cycle efficiency is insensitive to heat source temperature, but sensitive to evaporating pressure. The entropy result also shows that internal and external entropy of the evaporator is the main source of total entropy generation.

scholarly journals Entropy, Entransy and Exergy Analysis of a Dual-Loop Organic Rankine Cycle (DORC) Using Mixture Working Fluids for Engine Waste Heat Recovery

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1301 ◽  
Author(s):  
Shuang Wang ◽  
Wei Zhang ◽  
Yong-Qiang Feng ◽  
Xin Wang ◽  
Qian Wang ◽  
...  
Keyword(s):  
Entropy Generation ◽  
Exergy Analysis ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Working Fluid ◽  
Working Fluids ◽  
Entransy Loss

The exergy, entropy, and entransy analysis for a dual-loop organic Rankine cycle (DORC) using a mixture of working fluids have been investigated in this study. A high-temperature (HT) loop was used to recover waste heat from internal combustion engine in 350 °C, and a low-temperature loop (LT) was used to absorb residual heat of engine exhaust gas and HT loop working fluids. Hexane/toluene, cyclopentane/toluene, and R123/toluene were selected as working fluid mixtures for HT loop, while R245fa/pentane was chosen for LT loop. Results indicated that the variation of entropy generation rate, entransy loss, entransy efficiency, and exergy loss are insensitive to the working fluids. The entransy loss rate and system net power output present the same variation trends, whereas a reverse trend for entropy generation rate and entransy efficiency, while the exergy analysis proved to be only utilized under fixed stream conditions. The results also showed that hexane/toluene is the preferred mixture fluid for DORC.

Working Fluid Selection for an Organic Rankine Cycle for Waste Heat Recovery under Different Heat Source Temperatures

2013 ◽  
Vol 732-733 ◽  
pp. 213-217 ◽  
Author(s):  
Shuang Yang ◽  
Bing Zhang ◽  
Jin Liang Xu ◽  
Wei Zhang ◽  
Chao Xian Wang
Keyword(s):  
Heat Source ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Working Fluid ◽  
Working Fluids ◽  
Working Fluid Selection ◽  
Cycle Efficiency ◽  
Optimum Working

Optimum working conditions of 11 working fluids under different heat source temperatures in an organic Rankine cycle were systematically investigated. Cycle efficiency of each fluid was compared at their optimal operating conditions were then analyzed. R141b appears to be the best choice when the heat source temperature is around 200oC. Heptane is suggested the suitable working fluids for the ORC system when the heat source is 300oC.

scholarly journals Organic Rankine cycle for turboprop engine application

2021 ◽  
pp. 1-21
Author(s):  
G.E. Pateropoulos ◽  
T.G. Efstathiadis ◽  
A.I. Kalfas
Keyword(s):  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Weight Ratio ◽  
Rankine Cycle ◽  
Aircraft Engine ◽  
Working Fluid ◽  
Engine Fuel ◽  
Exhaust Gases ◽  
Waste Heat Recovery System ◽  
Turboprop Engine

ABSTRACT The potential to recover waste heat from the exhaust gases of a turboprop engine and produce useful work through an Organic Rankine Cycle (ORC) is investigated. A thermodynamic analysis of the engine’s Brayton cycle is derived to determine the heat source available for exploitation. The aim is to use the aircraft engine fuel as the working fluid of the organic Rankine cycle in order to reduce the extra weight of the waste heat recovery system and keep the thrust-to-weight ratio as high as possible. A surrogate fuel with thermophysical properties similar to aviation gas turbine fuel is used for the ORC simulation. The evaporator design as well as the weight minimisation and safety of the suggested application are the most crucial aspects determining the feasibility of the proposed concept. The results show that there is potential in the exhaust gases to produce up to 50kW of power, corresponding to a 10.1% improvement of the overall thermal efficiency of the engine.

Calculation and Optimization of Heat Transfer between the Low Exergy Heat Source and Organic Rankine Cycle Applied to Heat Recovery Systems

2013 ◽  
Vol 597 ◽  
pp. 45-50
Author(s):  
Sławomir Smoleń ◽  
Hendrik Boertz
Keyword(s):  
Heat Transfer ◽  
Heat Source ◽  
Heat Recovery ◽  
Power Plants ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Optimization Procedure ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Total System

One of the key challenges on the area of energy engineering is the system development for increasing the efficiency of primary energy conversion and use. An effective and important measure suitable for improving efficiencies of existing applications and allowing the extraction of energy from previously unsuitable sources is the Organic Rankine Cycle. Applications based on this cycle allow the use of low temperature energy sources such as waste heat from industrial applications, geothermal sources, biomass, fired power plants and micro combined heat and power systems.Working fluid selection is a major step in designing heat recovery systems based on the Organic Rankine Cycle. Within the framework of the previous original study a special tool has been elaborated in order to compare the influence of different working fluids on performance of an ORC heat recovery power plant installation. A database of a number of organic fluids has been developed. The elaborated tool should create a support by choosing an optimal working fluid for special applications and become a part of a bigger optimization procedure by different frame conditions. The main sorting criterion for the fluids is the system efficiency (resulting from the thermo-physical characteristics) and beyond that the date base contains additional information and criteria, which have to be taken into account, like environmental characteristics for safety and practical considerations.The presented work focuses on the calculation and optimization procedure related to the coupling heat source – ORC cycle. This interface is (or can be) a big source of energy but especially exergy losses. That is why the optimization of the heat transfer between the heat source and the process is (besides the ORC efficiency) of essential importance for the total system efficiency.Within the presented work the general calculation approach and some representative calculation results have been given. This procedure is a part of a complex procedure and program for Working Fluid Selection for Organic Rankine Cycle Applied to Heat Recovery Systems.

scholarly journals Economic and Exergo-Advance Analysis of a Waste Heat Recovery System Based on Regenerative Organic Rankine Cycle under Organic Fluids with Low Global Warming Potential

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1317 ◽  
Author(s):  
Guillermo Valencia Ochoa ◽  
Cesar Isaza-Roldan ◽  
Jorge Duarte Forero
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Exhaust Gases ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

The waste heat recovery system (WHRS) is a good alternative to provide a solution to the waste energy emanated in the exhaust gases of the internal combustion engine (ICE). Therefore, it is useful to carry out research to improve the thermal efficiency of the ICE through a WHRS based on the organic Rankine cycle (ORC), since this type of system takes advantage of the heat of the exhaust gases to generate electrical energy. The organic working fluid selection was developed according to environmental criteria, operational parameters, thermodynamic conditions of the gas engine, and investment costs. An economic analysis is presented for the systems operating with three selected working fluids: toluene, acetone, and heptane, considering the main costs involved in the design and operation of the thermal system. Furthermore, an exergo-advanced study is presented on the WHRS based on ORC integrated to the ICE, which is a Jenbacher JMS 612 GS-N of 2 MW power fueled with natural gas. This advanced exergetic analysis allowed us to know the opportunities for improvement of the equipment and the increase in the thermodynamic performance of the ICE. The results show that when using acetone as the organic working fluid, there is a greater tendency of improvement of endogenous character in Pump 2 of around 80%. When using heptane it was manifested that for the turbine there are near to 77% opportunities for improvement, and the use of toluene in the turbine gave a rate of improvement of 70%. Finally, some case studies are presented to study the effect of condensation temperature, the pinch point temperature in the evaporator, and the pressure ratio on the direct, indirect, and fixed investment costs, where the higher investment costs were presented with the acetone, and lower costs when using the toluene as working fluid.

Performance Investigation of Solar Organic Rankine Cycle Systems With and Without Regeneration and With Zeotropic Working Fluid Mixtures for Use in Micro-Cogeneration

2020 ◽  
Author(s):  
Wahiba Yaïci ◽  
Evgueniy Entchev ◽  
Pouyan Talebizadeh Sardari
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
High Efficiency ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Industrial Wastes ◽  
Working Fluid ◽  
Condensation Temperature ◽  
Thermodynamic Performance ◽  
Cycle Efficiency

Abstract Globally there are several viable sources of renewable, low-temperature heat (below 130°C) particularly solar energy, geothermal energy, and energy generated from industrial wastes. Increased exploitation of these low-temperature options has the definite potential of reducing fossil fuel consumption with its attendant very harmful greenhouse gas emissions. Researchers have universally identified the organic Rankine cycle (ORC) as a practicable and promising system to generate electrical power from renewable sources based on its beneficial use of volatile organic fluids as working fluids (WFs). In recent times, researchers have also shown a preference for/an inclination towards deployment of zeotropic mixtures as ORC WFs because of their capacity to improve thermodynamic performance of ORC systems, a feat enabled by better matches of the temperature profiles of the WF and the heat source/sink. This paper demonstrates both the technical feasibility and the notable advantages of using zeotropic mixtures as WFs through a simulation study of an ORC system. The study examines the thermodynamic performance of ORC systems using zeotropic WF mixtures to generate electricity driven by low-temperature solar heat source for building applications. A thermodynamic model is developed with an ORC system both with and excluding a regenerator. Five zeotropic mixtures with varying compositions of R245fa/propane, R245fa/hexane, R245fa/heptane, pentane/hexane and isopentane/hexane are evaluated and compared to identify the best combinations of WF mixtures that can yield high efficiency in their system cycles. The study also investigates the effects of the volumetric flow ratio, and evaporation and condensation temperature glides on the ORC’s thermodynamic performance. Following a detailed analysis of each mixture, R245fa/propane is selected for parametric study to examine the effects of operating parameters on the system’s efficiency and sustainability index. For zeotropic mixtures, results showed that there is an optimal composition range within which binary mixtures are inclined to perform more efficiently than the component pure fluids. In addition, a significant increase in cycle efficiency can be achieved with a regenerative ORC, with cycle efficiency ranging between 3.1–9.8% and 8.6–17.4% for ORC both without and with regeneration, respectively. Results also showed that exploiting zeotropic mixtures could enlarge the limitation experienced in selecting WFs for low-temperature solar organic Rankine cycles.

scholarly journals Configuration Selection of the Multi-Loop Organic Rankine Cycle for Recovering Energy from a Single Source

Entropy ◽  
2021 ◽  
Vol 23 (11) ◽  
pp. 1435
Author(s):  
Youyi Li ◽  
Tianhao Tang
Keyword(s):  
Heat Source ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Optimal Solution ◽  
Rankine Cycle ◽  
Optimal Number ◽  
Exergy Efficiency ◽  
Working Fluid ◽  
Levelized Cost Of Electricity ◽  
Multi Objective

The Organic Rankine Cycle (ORC) is a well-established way to recover energy from a single waste heat source. This paper aims to select the suitable configuration, number of loops, and working fluids for the Multi-Loop ORC (MLORC) by using multi-objective optimization. The thermodynamic and economic performance of MLORC in three various configurations was analyzed. Multi-objective optimizations of the series and parallel MLORC using different working fluid groups were conducted to find the optimal configuration, number of loops, and working fluid combination. The analysis results show that the series–parallel MLORC performed the worst among the three configurations. The optimization results reveal that series MLORC has a higher exergy efficiency than the parallel MLORC. The exergy efficiency of the optimal solution in series dual-loop, triple-loop, and quadruple-loop ORC is 9.3%, 7.98%, and 6.23% higher than that of parallel ORC, respectively. Furthermore, dual-loop is the optimal number of cycles for recovering energy from a single heat source, according to the grey relational grade. Finally, the series dual-loop ORC using cyclohexane\cyclohexane was the suitable configuration for utilizing a single waste heat source. The exergy efficiency and levelized cost of electricity of the series dual-loop ORC with the optimal parameters are 62.18% and 0.1509 $/kWh, respectively.

Working Fluid Selection for Organic Rankine Cycles from a Molecular Structural Point of View

2013 ◽  
Vol 805-806 ◽  
pp. 649-653
Author(s):  
Bing Zhang ◽  
Shuang Yang ◽  
Jin Liang Xu ◽  
Guang Lin Liu
Keyword(s):  
Critical Temperature ◽  
Heat Source ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Point Of View ◽  
Operating Conditions ◽  
Working Fluid ◽  
Working Fluids ◽  
Organic Fluids ◽  
Cycle Efficiency

The optimum working conditions of 11 working fluids under different heat source temperatures for an organic Rankine cycle (ORC) were located in our previous work. In the current work, the system irreversibility of each candidate were calculated and compared at their optimal operating conditions. Obvious variation trends of both the cycle efficiency and irreversibility were found for different types of organic fluids. It is suggested, when selecting working fluid for our ORC system, the critical temperature should be as close as possible to the heat source temperature to achieve high cycle efficiency but avoid large irreversibility. The relationships between the structure of the molecules and the critical temperature of the working fluids are investigated qualitatively and potentially meaningful for the rational selection of proper organic fluids for certain ORCs.

scholarly journals Thermodynamic, Economic and Sustainability Analysis of Solar Organic Rankine Cycle System with Zeotropic Working Fluid Mixtures for Micro-Cogeneration in Buildings

2020 ◽  
Vol 10 (21) ◽  
pp. 7925
Author(s):  
Wahiba Yaïci ◽  
Evgueniy Entchev ◽  
Pouyan Talebizadehsardari ◽  
Michela Longo
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Optimum Operating ◽  
Working Fluid ◽  
Condensation Temperature ◽  
Fluid Mixtures ◽  
Thermodynamic Performance ◽  
Cycle Efficiency

Globally there are several viable sources of renewable, low-temperature heat (below 130 °C), particularly solar energy, geothermal energy, and energy generated from industrial wastes. Increased exploitation of these low-temperature options has the definite potential of reducing fossil fuel consumption with its attendant very harmful greenhouse gas emissions. Researchers have universally identified the organic Rankine cycle (ORC) as a practicable and suitable system to generate electrical power from renewable sources based on its beneficial usage of volatile organic fluids as working fluids (WFs). In recent times, researchers have also shown a preference towards deployment of zeotropic mixtures as ORC WFs because of their capacity to improve thermodynamic performance of ORC systems, a feat enabled through the greater matching of the temperature profiles of the WF and the heat source/sink. This paper demonstrates the thermodynamic, economic and sustainability feasibility, and the notable advantages of using zeotropic mixtures as WFs through a simulation study of an ORC system. The study examines first the thermodynamic performance of ORC systems using zeotropic mixtures to generate electricity powered by a low-temperature solar heat source for building applications. A thermodynamic model is developed with a solar-driven ORC system both with and excluding a regenerator. Twelve zeotropic mixtures with varying compositions are evaluated and compared to identify the best combinations of mixtures that can yield high performance and high efficiency in their system cycles. The study also examines the effects of the volume flow ratio, and evaporation and condensation temperature glides on the ORC’s thermodynamic performance. Following a detailed analysis of each mixture, R245fa/propane and butane/propane are selected for parametric study to investigate the influence of operating parameters on the system’s efficiency and sustainability index. For zeotropic mixtures, results disclosed that there is an optimal composition range within which binary mixtures are inclined to perform more efficiently than the component pure fluids. In addition, a substantial enhancement in cycle efficiency can be obtained by a regenerative ORC, with cycle efficiency ranging between 3.1–9.8% and 8.6–17.4% for ORC both without and with regeneration, respectively. Results also revealed that exploiting zeotropic mixtures could enlarge the limitation experienced in selecting WFs for low-temperature solar ORCs. Moreover, a detailed economic with a sensitivity analysis of the solar ORC system was performed to evaluate the cost of the electricity and other economic criteria. The outcome of this investigation should be useful in the thermo-economic feasibility assessments of solar-driven ORC systems using working fluid mixtures to find the optimum operating range for maximum performance and minimum cost.

scholarly journals Thermo-Economic Performance of an Organic Rankine Cycle System Recovering Waste Heat Onboard an Offshore Service Vessel

2020 ◽  
Vol 8 (5) ◽  
pp. 351 ◽  
Author(s):  
ChunWee Ng ◽  
Ivan C. K. Tam ◽  
Dawei Wu
Keyword(s):  
Entropy Generation ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Simple Cycle ◽  
Entropy Generation Rate ◽  
Fuel Saving ◽  
Maritime Industry ◽  
Design Data ◽  
Cycle System

Recent regulatory developments in the global maritime industry have signalled an increased emphasis on the improvement of energy efficiency onboard ships. Among the various efficiency enhancement options, recovering waste heat using the organic Rankine cycle (ORC) has been studied and identified as a promising one in many earlier studies. In this paper, a marine application of ORC for waste heat recovery will be discussed by performing the first law thermodynamic analysis based on the operating profile and machinery design data of an offshore service vessel (OSV) and defining four standard cycle configurations that include simple, recuperated, dual heat source, and with intermediate heating. The use of five hydrocarbon working fluids that are suitable for shipboard usage comprising cyclopentane, n-heptane, n-octane, methanol and ethanol are examined. The economic analysis found that annual fuel saving between 5% and 9% is possible and estimated a specific installation cost of $5000–8000 USD/kW. Among the various options, the methanol ORC in a simple cycle configuration is found to have the shortest payback time relatively balancing between annual fuel saving and total module cost. Finally, the simple cycle ORC running on methanol is further examined using the second law entropy generation analysis and it is found that the heat exchangers in the system accounted for nearly 95% of the overall entropy generation rate and further work is recommended to reduce this in the future.

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