Synthesis and simultaneous optimization of multi-heat source multi-pressure evaporation organic Rankine cycle with mixed working fluid

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.

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.597.45 ◽

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.

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Performance Investigation of Solar ORC Using Different Nanofluids

Applied Sciences ◽

10.3390/app9153048 ◽

2019 ◽

Vol 9 (15) ◽

pp. 3048

Author(s):

Reyhaneh Loni ◽

Gholamhassan Najafi ◽

Ezzatollah Askari Asli-Ardeh ◽

Barat Ghobadian ◽

Willem G. Le Roux ◽

...

Keyword(s):

Heat Source ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Heat Transfer Fluid ◽

Working Fluid ◽

Fluid Flow Rate ◽

Different Types ◽

Condenser Temperature ◽

Cubical Cavity ◽

Al2o3 Nanofluid

A parabolic solar dish concentrator, as the heat source of an organic Rankine cycle (ORC), can be used for power generation. Different types of tubular cavity receivers with different nanofluids can be considered for use in the solar dish collector to improve its efficiency. In the current research, an ORC with three different cavity receivers including hemispherical, cubical, and cylindrical are investigated using three nanofluids: Al2O3/oil, CuO/oil, and SiO2/oil. A numerical model is validated using experimental data. The ORC analysis is done for a constant evaporator pressure of 2.5 MPa, and condenser temperature of 38 °C. Methanol is employed as the ORC’s working fluid and a non-regenerative, ideal ORC system with different turbine inlet temperatures is considered. Furthermore, a fixed solar heat transfer fluid flow rate of 60 mL/s and dish diameter of 1.9 m is investigated. Results show that, compared to pure oil, the thermal efficiency of the cavity receivers increases slightly, and the pressure drop increases with the application of nanofluids. Furthermore, results show that the cubical cavity receiver, using oil/Al2O3 nanofluid, is the most efficient choice for application as the investigated solar ORC’s heat source.

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Exergoeconomic comparison and optimization of organic Rankine cycle, trilateral Rankine cycle and transcritical carbon dioxide cycle for heat recovery of low-temperature geothermal water

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650919844647 ◽

2019 ◽

Vol 233 (8) ◽

pp. 1068-1084 ◽

Cited By ~ 5

Author(s):

Afsaneh Noroozian ◽

Abbas Naeimi ◽

Mokhtar Bidi ◽

Mohammad Hossein Ahmadi

Keyword(s):

Sensitivity Analysis ◽

Low Temperature ◽

Heat Source ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Working Fluid ◽

Cost Ratio ◽

Exergetic Efficiency ◽

Geothermal Heat ◽

Product Cost

Depleting fossil fuel resources and the horrible environmental impacts due to burning fossil fuels emphasize the importance of using renewable energy resources such as geothermal and solar energies. This paper compares performance of CO2 transcritical cycle, organic Rankine cycle, and trilateral Rankine cycle using a low-temperature geothermal heat source. Thermodynamic analysis, exergetic analysis, economic analysis, and exergoeconomic analysis are applied for each of the aforementioned cycles. In addition, a sensitivity analysis is performed on the system, and the effects of geothermal heat source temperature, evaporator pinch point temperature, and turbine inlet pressure on the cycle's performance are evaluated. Finally, the systems are optimized in order to minimize product cost ratio and maximize exergetic efficiency by using the genetic algorithm. Results indicate that the maximum thermal efficiency is approximately 13.03% which belongs to organic Rankine cycle with R123 as working fluid. CO2 cycle has the maximum exergetic efficiency, equals to 46.13%. The minimum product cost ratio refers to the organic Rankine cycle with R245fa as working fluid. Moreover, sensitivity analysis shows that increasing geothermal heat source temperature results in higher output power, product cost ratio, and exergy destruction ratio in all cycles.

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

ASME 2020 14th International Conference on Energy Sustainability ◽

10.1115/es2020-1616 ◽

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.

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Experimental Study on the Organic Rankine Cycle Power System Adopting Dual Expanders in Parallel

Volume 3B: Oil and Gas Applications; Organic Rankine Cycle Power Systems; Supercritical CO2 Power Cycles; Wind Energy ◽

10.1115/gt2014-26767 ◽

2014 ◽

Cited By ~ 2

Author(s):

Eunkoo Yoon ◽

Hyun Jun Park ◽

Hyun Dong Kim ◽

Kyung Chun Kim ◽

Sang Youl Yoon

Keyword(s):

Heat Source ◽

Power System ◽

Water Temperature ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Hot Water ◽

Working Fluid ◽

Electric Heater ◽

Shaft Power ◽

Scroll Expanders

This study aims to evaluate the performance of an organic Rankine cycle (ORC) power system adopting dual expanders in parallel by experiment. A dual-expander ORC system was designed to provide competitive advantages over a general single expander ORC system in typical applications with large thermal fluctuation of heat sources such as solar heat, marine waste heat, and etc. The ORC system consists of two scroll expanders installed in parallel, a hydraulic diaphragm type pump to feed and pressurize the working fluid, R-245fa, two plate heat exchangers for the evaporator and the condenser, and two generators with shaft power torque meters. The two scroll expanders were modified from two oil-free air scroll compressors, and were tested in the ORC loop with R245fa. The maximum isentropic efficiency of each expander was measured about 53%, and the shaft power was reached to about 2kW. The hot water was used as heat source, and the water temperature was controlled up to 150 °C by the 100 kW-class electric heater. A circulating air-cooled chiller was utilized for the control of the cooling water temperature. In order to determine the static performance of the system, efficiencies and shaft powers were measured with 130 °C heat source temperature. In addition, performance tests were conducted with various working fluid mass flow rates to control pressure ratios. The characteristics and total thermal efficiency of the dual parallel expander ORC system and optimal operating modes are addressed.

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Utilization of Indonesia’s Hot Spring Sources for Electricity using Kalina Cycle and Organic Rankine Cycle

E3S Web of Conferences ◽

10.1051/e3sconf/20183101002 ◽

2018 ◽

Vol 31 ◽

pp. 01002 ◽

Cited By ~ 1

Author(s):

Grano Prabumukti ◽

Widodo Wahyu Purwanto

Keyword(s):

Heat Source ◽

Thermal Efficiency ◽

Hot Springs ◽

Hot Spring ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Working Fluid ◽

Power Capacity ◽

Spring Temperature ◽

Kalina Cycle

Indonesia posses 40% of the world's geothermal energy sources. The existence of hydrothermal sources is usually characterized by their surface manifestations such as hot springs, geysers and fumarole. Hot spring has a potential to be used as a heat source to generate electricity especially in a rural and isolated area. Hot springs can be converted into electricity by binary thermodynamic cycles such as Kalina cycle and ORC. The aim of this study is to obtain the best performances of cycle configuration and the potential power capacity. Simulation is conducted using UNISIM software with working fluid and its operating condition as the decision variables. The simulation result shows that R1234yf and propene with simple ORC as desired working fluid and cycle configuration. It reaches a maximum thermal efficiency up to 9.6% with a specific turbine inlet pressure. Higher temperature heat source will result a higher thermal efficiency‥ Cycle thermal efficiency varies from 4.7% to 9.6% depends on source of hot spring temperature. Power capacity that can be generated using Indonesia’s hot spring is ranged from 2 kWe to 61.2 kWe. The highest capacity located in Kawah Sirung and the least located in Kaendi.

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

Entropy ◽

10.3390/e23111435 ◽

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.

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Integrated Vapor Compression Chiller with Bottoming Organic Rankine Cycle and Onsite Low-Grade Renewable Energy

Energies ◽

10.3390/en14196401 ◽

2021 ◽

Vol 14 (19) ◽

pp. 6401

Author(s):

Muhammad Tauseef Nasir ◽

Michael Chukwuemeka Ekwonu ◽

Javad Abolfazali Esfahani ◽

Kyung Chun Kim

Keyword(s):

Renewable Energy ◽

Heat Source ◽

Energy Input ◽

Cooling Water ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Sensitivity Analyses ◽

Working Fluid ◽

Inlet Temperature ◽

Low Grade

The present study offers a scheme to improve the performance of existing large-scale chillers. The system involves raising the temperature of the chiller’s cooling water stream using renewable energy sources by incorporating an organic Rankine cycle (ORC). The thermal analysis was conducted by raising the temperature of one-third of the approximately 200 ton chiller’s cooling water. The investigation was considered for ORC evaporator inlet temperature of 90~120 °C by the step of 10 °C. Various working fluids for the different ORC evaporator inlet temperatures were examined. Sensitivity analyses conducted on the degree of superheating, degree of subcooling, condenser saturation temperature, pinch point temperature differences of the ORC evaporator and condenser, and the mass flowrates of the heating and cooling streams were also reported. Genetic algorithm was employed to carry out the optimization. The best options for the ORC working fluid at the heating source ORC evaporator inlet temperatures of 90 °C was found to be DME, presenting an improvement of 48.72% in comparison with the rated coefficient of performance (COP) value of the VCC, with a renewable energy input requirement of 710 kW. At the heat source temperatures of 100 °C and 110 °C, butene, which presented an improvement in the COP equal to 48.76% and 68.85%, respectively, with the corresponding renewable energy requirements of 789.6 kW and 852 kW, was found to be the ideal candidate. Meanwhile, at the heat source inlet temperature of 120 °C, R1233zd (E), representing an improvement of 140.88% with the renewable energy input of around 1061 kW, was determined to be the most favorable ORC working fluid candidate.

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