scholarly journals Comparative Analysis of Small-Scale Organic Rankine Cycle Systems for Solar Energy Utilisation

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 829 ◽  
Author(s):  
Ruiqi Wang ◽  
Long Jiang ◽  
Zhiwei Ma ◽  
Abigail Gonzalez-Diaz ◽  
Yaodong Wang ◽  
...  
Keyword(s):  
Solar Energy ◽  
Power Output ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hot Water ◽  
Superior Performance ◽  
Small Scale ◽  
Water Storage Tank ◽  
Solar Thermal Collector ◽  
Cycle Systems

Small-scale organic Rankine cycle (ORC) systems driven by solar energy are compared in this paper, which aims to explore the potential of power generation for domestic utilisation. A solar thermal collector was used as the heat source for a hot water storage tank. Thermal performance was then evaluated in terms of both the conventional ORC and an ORC using thermal driven pump (TDP). It is established that the solar ORC using TDP has a superior performance to the conventional ORC under most working conditions. Results demonstrate that power output of the ORC using TDP ranges from 72 W to 82 W with the increase of evaporating temperature, which shows an improvement of up to 3.3% at a 100 °C evaporating temperature when compared with the power output of the conventional ORC. Energy and exergy efficiencies of the ORC using TDP increase from 11.3% to 12.6% and from 45.8% to 51.3% when the evaporating temperature increases from 75 °C to 100 °C. The efficiency of the ORC using TDP is improved by up to 3.27%. Additionally, the exergy destruction using TDP can be reduced in the evaporator and condenser. The highest exergy efficiency in the evaporator is 96.9%, an improvement of 62% in comparison with that of the conventional ORC, i.e., 59.9%. Thus, the small-scale solar ORC system using TDP is more promising for household application.

Moment Analysis of a Scroll Expander Used in an Organic Rankine Cycle

2014 ◽  
Author(s):  
Amrita Sengupta ◽  
Prashant Kumar ◽  
Pardeep Garg ◽  
Nirmal Hui ◽  
Matthew S. Orosz ◽  
...  
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Expansion Ratio ◽  
Moment Analysis ◽  
Superior Performance ◽  
Working Fluid ◽  
Small Scale ◽  
Inlet Temperature ◽  
Positive Displacement ◽  
Scroll Expander

Recent studies on small-scale power generation with the organic Rankine cycle suggest superior performance of positive displacement type of expanders compared to turbines. Scroll expanders in particular achieve high isentropic efficiencies due to lower leakage and frictional losses. Performance of scroll machines may be enhanced by the use of non-circular involute curves in place of the circular involutes resulting non-uniform wall thickness. In this paper, a detailed moment analysis is performed for such an expander having volumetric expansion ratio of 5 using thermodynamic models proposed earlier by one of the present authors. The working fluid considered in the power cycle is R-245fa with scroll inlet temperature of 125 °C for a gross power output of ∼3.5 kW. The model developed in this paper is verified with an air scroll compressor available in the literature and then applied to an expander. Prediction of small variation of moment with scroll motion recommends use of scroll expander without a flywheel over other positive displacement type of expanders, e.g. reciprocating, where a flywheel is an essential component.

scholarly journals A study of the applicability of a straw-fired batch boiler as a heat source for a small-scale cogeneration unit

2016 ◽  
Vol 37 (4) ◽  
pp. 503-515 ◽  
Author(s):  
Krzysztof Sornek ◽  
Mariusz Filipowicz
Keyword(s):  
Flue Gas ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Electricity Production ◽  
Small Scale ◽  
Gas Temperature ◽  
Wide Range ◽  
Cycle Systems ◽  
Cogeneration System ◽  
Excellent Source

Abstract Straw-fired batch boilers, due to their relatively simple structure and low operating costs, are an excellent source of heat for a wide range of applications. A concept prototype of a cogeneration system with a straw-fired batch boiler was developed. The basic assumptions were based on the principles of the Rankine Cycle and the Organic Rankine Cycle systems with certain design modifications. Using the prototype design of a system that collects high-temperature heat from the boiler, studies were performed. The studies involved an analysis of the flue gas temperature distribution in the area of the oil exchanger, a comparison of the instantaneous power of the boiler’s water and oil circuits for different modes of operation, as well as an analysis of the flue gas. In the proposed system configuration where the electricity production supplements heat generation, the power in the oil circuit may be maintained at a constant level of approx. 20-30 kW. This is possible provided that an automatic fuel supply system is applied. Assuming that the efficiency of the electricity generation system is not less than 10%, it will be possible to generate 2-3 kW of electricity. This value will be sufficient, for an on-site operation of the boiler.

scholarly journals Assessment of a District Trigeneration Biomass Powered Double Organic Rankine Cycle as Primed Mover and Supported Cooling

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1030
Author(s):  
Muhammad Tauseef Nasir ◽  
Michael Chukwuemeka Ekwonu ◽  
Yoonseong Park ◽  
Javad Abolfazli Esfahani ◽  
Kyung Chun Kim
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hot Water ◽  
Design Parameters ◽  
Working Fluid ◽  
Small Scale ◽  
Vapor Compression ◽  
Medium Temperature ◽  
Exergetic Analysis ◽  
The Impact

This study presents a combined cooling, heating, and power system powered by biogas, suitable for small scale communities in remote locations. To run such a system, in order to obtain the daily life essentials of electricity, hot water, and cooling, municipal waste can be considered as an option. Furthermore, the organic Rankine cycle part of the organic Rankine cycle powered vapor compression chiller can be used in times of need for additional electric production. The system comprises a medium temperature organic Rankine cycle utilizing M-xylene as its working fluid, and the cooling was covered by an Isobutane vapor compression cycle powered by an R245fa employing organic Rankine cycle. The system analyzed was designated to provide 250 kW of electricity. The energetic and exergetic analysis was performed, considering several system design parameters. The impact of the design parameters in the prime mover has a much greater effect on the whole system. The system proposed can deliver cooling values at the rate between 9.19 and 22 kW and heating values ranging from 879 up to 1255 kW, depending on the design parameter. Furthermore, the second law efficiency of the system was found to be approximately 56% at the baseline conditions and can be increased to 64.5%.

Numerical Investigation on the Performance of a Regenerative Flow Turbine for Small-Scale Organic Rankine Cycle Systems

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Ramin Moradi ◽  
Luca Cioccolanti ◽  
Enrico Bocci ◽  
Mauro Villarini ◽  
Massimiliano Renzi
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Small Scale ◽  
Cfd Analysis ◽  
Cycle Systems ◽  
Mass Flow Rates ◽  
Computational Fluid Dynamics Cfd ◽  
Regenerative Flow ◽  
Operating Points

In this study, the performance characteristics of a regenerative flow turbine (RFT) prototype have been investigated by means of a computational fluid dynamics (CFD) study. The prototype has been initially designed to be used in gas pipelines replacing expansion valves but, because of the intrinsic characteristics of this kind of expander, its use can be extended to other applications like the expansion process in small-scale organic Rankine cycle (ORC) plants. In the first part of this work, the numerical results of the CFD analysis have been validated with the experimental data reported in literature for the same turbine prototype. After the validation of the model, a detailed study has been carried out in order to evaluate specific features of the turbine, focusing the attention on the typical operating conditions of small-scale low-temperature ORC systems. Results have shown that the considered RFT prototype operates with higher isentropic efficiencies (about 32% at 6000 rpm) at lower mass flow rates, while the power output is penalized compared to other operating points. The numerical analysis has also pointed out the high impact of the losses in the leakage flow in the gap between the blade tips and the stripper walls. Therefore, the CFD analysis carried out has provided a thoughtful understanding of the performance of the expander at varying operating conditions and useful insights for the future redesign of this kind of machine for the application in small-scale ORCs.

Approach to Designing a Solar Concentrator for Small Scale Remote Power Application

2010 ◽  
Author(s):  
Khaled Metwally ◽  
Lamyaa A. El-Gabry ◽  
Ahmed Makhlouf
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hot Water ◽  
Heat Transfer Fluid ◽  
Working Fluid ◽  
Small Scale ◽  
Concentrated Solar Power ◽  
Parabolic Trough ◽  
Capstone Project ◽  
Power Application

A small-scale concentrated solar power unit was designed to provide electricity and hot water using an organic Rankine cycle for Egypt as part of an undergraduate capstone project. The system was designed for a target power output of 3 KW. It uses parabolic troughs to heat ethylene glycol used as the heat transfer fluid which absorbs heat in the trough collector and transfers it to the working fluid through a heat exchanger. The system consists of 9 parabolic troughs and a total aperture area of 67 square meters, providing the required 3 KW of energy to the ORC. One parabolic trough was manufactured to test its thermal efficiency according to ASHRAE standard 93-2003 and compare it to its calculated value. A simple microcontroller-based system was used to track the sun.

scholarly journals Experimental Investigation of a 560 Watt Organic Rankine Cycle System using R134a as Working Fluid and Plat Solar Collector as Heat Source

2021 ◽  
Vol 4 (3) ◽  
pp. 169-172
Author(s):  
Awaludin Martin ◽  
Muhammad Nur
Keyword(s):  
Energy Source ◽  
Solar Energy ◽  
Heat Source ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Energy Sources ◽  
Small Scale ◽  
Cycle System

New and renewable energy sources such as solar, geothermal, and waste heat  are energy sources that can be used as a source of energy for Organic Rankine cycle system because the organic Rankine cycle (ORC) requires heat at low temperatures to be used as energy source. The experimental of Organic Rankine Cycle (ORC) systems with solar energy as a heat source was conduct to investigate a small-scale ORC system with R134a as a working fluid by varying the heat source at temperature 75⁰C-95⁰C. The experiment resulted a maximum efficiency, power of system is 4.30%, and 185.9 Watt, where the temperature of heat source is 95⁰C, the pressure and temperature of steam inlet turbine is 1.38 MPa and 67.9oC respectively. Solar energy as the main energy source in the ORC system can reduce energy use up to 49.9% or 4080.8 kJ where the temperature of the water as the heat source in the evaporator is 51°C.

Efficiency Enhancement of a Small Scale Closed Solar Thermal Brayton Cycle by a Combined Simple Organic Rankine Cycle

2012 ◽  
Author(s):  
H. Riazi ◽  
N. A. Ahmed
Keyword(s):  
Power Output ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Solar Thermal ◽  
Small Scale ◽  
Brayton Cycle ◽  
Efficiency Enhancement ◽  
Power Cycles ◽  
Micro Turbine ◽  
Net Power Output

In this paper efficiency enhancement of a small scale closed solar thermal Brayton cycle is investigated by combining it to a simple organic Rankine cycle. Brayton power cycles are generally known as the enabling technology for high temperature solar power towers due to their higher efficiencies compared to other power cycles. Unlike conventional solar-thermal plants, which concentrate the sun’s energy to generate steam for driving a turbine, the Brayton thermodynamic does not use water. Instead, the concentrated solar energy is used to heat compressed air, which then expands through a gas turbine to generate power. Irreversible loss in compressor and turbine, the operating temperature of solar collector and recuperator effectiveness are the main features that limit the net power output of the system which should be considered and analyzed. The exhaust of the gas turbine is still at high temperature that should be cooled down before entering the compressor. Thus, this heat can be utilized to operate a low temperature Rankine cycle and increase the system efficiency and power generation. Operating points of off the shelf micro-turbines and steam turbine with parabolic solar dish concentrator of various concentrating ratios are considered. Thermodynamic analysis is applied, by using the first and second law of thermodynamics, to obtain the optimum temperature of solar collector, minimum irreversibility rates to maximize the efficiency and net power output of the system at various steady-state conditions. Results show that for the closed solar thermal Brayton cycle the maximum overall first law efficiency of the system can be increased of more than 5% by combining a simple Rankine cycle to recover the exhaust heat and a significant 20% increase in the second law efficicency. The system efficiency is related to the solar concentration ratio with an optimum operating temperature and the choice of micro-turbine. On this basis, both the overall efficiency and the total output power may reach their maximum value by optimizing the pressure ratio. In a small scale closed solar thermal Brayton cycle combined by a Rankine cycle with a micro turbine operating at its highest compressor efficiency, the operating conditions can be optimized in such a way that the system produces maximum net power output or having the highest overall efficiency.

scholarly journals Assessment of a Geothermal Combined System with an Organic Rankine Cycle and Multi-effect Distillation Desalination

2022 ◽  
Author(s):  
Aida Farsi ◽  
Marc A. Rosen
Keyword(s):  
Environmental Impact ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Hot Water ◽  
Exergy Destruction ◽  
Destruction Rate ◽  
Sustainability Analysis ◽  
Environment Temperature ◽  
Cycle Systems ◽  
Reference Environment

AbstractAn analysis is reported of a geothermal-based electricity-freshwater system in which an organic Rankine cycle is integrated with a multi-effect distillation desalination unit. The system is driven by geothermal hot water extracted from the production well. Mass, energy, entropy, and exergy rate balances are written for all system components, as are energy and exergy efficiency expressions for each subsystem. The exergy destruction rate associated with the temperature and chemical disequilibrium of the freshwater and brine with the reference environment are taken into account to reveal accurate results for irreversibility sources within the desalination process. The developed thermodynamic model is simulated using thermodynamic properties of the working fluids (i.e., ammonia, seawater, distillate, and brine) at each state point. A sustainability analysis is performed that connects exergy and environmental impact concepts. That assessment expresses the extent of the contribution of the system to sustainable development and reduced environmental impact, using exergy methods. Results of the sustainability analysis indicate that, with an increase in the reference environment temperature from 20 to 35 $$^\circ{\rm C}$$ ∘ C , the exergy destruction rate decreases for the multi-effect distillation and organic Rankine cycle systems respectively from 6474 to 4217 kW and from 16,270 to 13,459 kW. Also, the corresponding sustainability index for the multi-effect distillation and organic Rankine cycle systems increases from 1.16 to 1.2 and 1.5–1.6, respectively, for the same increase in reference environment temperature.

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