Analysis of Cogeneration System in Series Circuit Based on Regenerative Organic Rankine Cycle

2012 ◽  
Vol 505 ◽  
pp. 519-523 ◽  
Author(s):  
Kyoung Hoon Kim ◽  
Hyung Jong Ko ◽  
Se Woong Kim
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Inlet Pressure ◽  
Working Fluid ◽  
Combined System ◽  
Working Fluids ◽  
Source Temperature ◽  
Turbine Inlet ◽  
Cogeneration System ◽  
In Series

In this paper thermodynamic performance of a combined heat and power cogeneration system driven by low-temperature source is investigated. The system consists of regenerative Organic Rankine Cycle (ORC) and an additional process heater as a series circuit. Seven working fluids of isobutene, butane, R11, R123, isopentane, normal pentane, and R113 are considered in this work. Special attention is paid to the effects of system parameters such as the turbine inlet pressure or source temperature on the characteristics of the system such as the ratio of mass flow rates, net work production as well as the efficiencies of the first and second laws of thermodynamics for various working fluids. This study finds that higher turbine inlet pressure leads to lower second law efficiency of ORC system but higher that of the combined system. Results also show that the optimum working fluid varies with the source temperature.

A Thermodynamic Analysis of Cogeneration System in Parallel Circuit Based on Organic Rankine Cycle

2012 ◽  
Vol 505 ◽  
pp. 534-538 ◽  
Author(s):  
Kyoung Hoon Kim ◽  
Se Woong Kim ◽  
Hyung Jong Ko
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Inlet Pressure ◽  
Working Fluid ◽  
Second Law ◽  
Low Grade ◽  
Source Temperature ◽  
Turbine Inlet ◽  
Cogeneration System ◽  
Parallel Circuit

The combined heat and power generation system using Organic Rankine Cycle (ORC) has become a promising technology for efficient conversion of low-grade heat source to useful form of energy. In this study thermodynamic performance is investigated for a cogeneration system which consists of ORC power plant and an additional process heater as a parallel circuit. Nine different kinds of fluids of R143a, R22, R134a, R152a, R123, R113, isobutene, butane, and isopentane are considered as a working fluid of ORC. The effects of system parameters such as turbine inlet pressure, source temperature, and process heat load on the system performance including ratio of mass flow rates, net work production, and the first and second law efficiencies of thermodynamics for each fluid. Results show that there exists an optimal turbine inlet pressure to yield maximum net work. The selection of the working fluid for the combined system which assumes the maximum second-law efficiency is dependent on the source temperature level.

Thermodynamic analysis of a wall mounted gas boiler with an organic Rankine cycle and hydrogen production unit

2017 ◽  
Vol 28 (7) ◽  
pp. 725-743 ◽  
Author(s):  
Anahita Moharamian ◽  
Saeed Soltani ◽  
Faramarz Ranjbar ◽  
Mortaza Yari ◽  
Marc A Rosen
Keyword(s):  
Hydrogen Production ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Inlet Pressure ◽  
Pinch Point ◽  
Working Fluids ◽  
Turbine Inlet ◽  
Energy And Exergy ◽  
Cogeneration System ◽  
Net Power Output

A novel cogeneration system based on a wall mounted gas boiler and an organic Rankine cycle with a hydrogen production unit is proposed and assessed based on energy and exergy analyses. The system is proposed in order to have cogenerational functionality and assessed for the first time. A theoretical research approach is used. The results indicate that the most appropriate organic working fluids for the organic Rankine cycle are HFE700 and isopentane. Utilizing these working fluids increases the energy efficiency of the integrated wall mounted gas boiler and organic Rankine cycle system by about 1% and the organic Rankine cycle net power output about 0.238 kW compared to when the systems are separate. Furthermore, increasing the turbine inlet pressure causes the net power output, the organic Rankine cycle energy and exergy efficiencies, and the cogeneration system exergy efficiency to rise. The organic Rankine cycle turbine inlet pressure has a negligible effect on the organic Rankine cycle mass flow rate. Increasing the pinch point temperature decreases the organic Rankine cycle turbine net output power. Finally, increasing the turbine inlet pressure causes the hydrogen production rate to increase; the highest and lowest hydrogen production rates are observed for the working fluids for HFE7000 and isobutane, respectively. Increasing the pinch point temperature decreases the hydrogen production rate. In the cogeneration system, the highest exergy destruction rate is exhibited by the wall mounted gas boiler, followed by the organic Rankine cycle evaporator, the organic Rankine cycle turbine, the organic Rankine cycle condenser, the proton exchange membrane electrolyzer, and the organic Rankine cycle pump, respectively.

Organic Rankine Cycle Optimization With Explicit Designs of Evaporator and Radial Inflow Turbine

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Hasan Eren Bekiloğlu ◽  
Hasan Bedir ◽  
Günay Anlaş
Keyword(s):  
Power Output ◽  
Pressure Ratio ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Working Fluids ◽  
Source Temperature ◽  
Order Preference ◽  
Radial Inflow Turbine ◽  
Net Power Output

Abstract Although there are studies on optimizing organic Rankine cycles (ORCs) through individual components, in this study, for the first time, both evaporator and turbine designs are included in a multiobjective optimization. Twenty-eight working fluids are used to find optimum cycle parameters for three source temperatures (90, 120, and 150 °C). A mean-line radial inflow turbine model is used. Nondominated Sorting Genetic Algorithm II is utilized to minimize total evaporator area per net power output and maximize performance factor simultaneously. The technique for Order Preference by Similarity to Ideal Situation (TOPSIS) procedure is followed to obtain ideal solutions. A group of working fluids with highest net power output is determined for each heat source temperature. Optimized geometric parameters of the evaporator vary in a narrow range independent of the working fluid and the source temperature, but evaporator PPTD and degree of superheating depend on the working fluid. The specific speed, the pressure ratio through the turbine, and the nozzle inlet-to-outlet radius ratio do not change significantly with cycle conditions.

scholarly journals Thermodynamic Performance Analysis of Turbine-Bleeding Organic Rankine Cycle with and without Regeneration

2018 ◽  
Vol 2 (1) ◽  
pp. 23-28
Author(s):  
Keyword(s):  
Performance Analysis ◽  
System Performance ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Inlet Pressure ◽  
Working Fluid ◽  
Low Grade ◽  
System Parameters ◽  
Turbine Inlet ◽  
Thermodynamic Performance

This paper presents a thermodynamic performance analysis of turbine-bleeding organic Rankine cycle (ORC) with and without regeneration using internal heat exchanger based on the first and second thermodynamic laws for the recovery of low-grade finite heat source. The effects of the important system parameters including turbine bleeding pressure, turbine inlet pressure, and working fluid on the system performance were intensively investigated. Results showed that there exists an optimum turbine bleeding pressure for the maximum second-law efficiency. The system performance under the optimal condition is significantly influenced by the turbine inlet pressure, regeneration, and working fluid. The greatest exergy destruction of the system varies depending on the system parameters.

Performance Evaluation of a Small Scale High Efficiency Cogeneration System

2006 ◽  
Author(s):  
Mauro Reini
Keyword(s):  
High Efficiency ◽  
Pressure Ratio ◽  
Organic Rankine Cycle ◽  
Thermodynamic Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Small Scale ◽  
Performance Parameters ◽  
Cogeneration System

In recent years, a big effort has been made to improve microturbines thermal efficiency, in order to approach 40%. Two main options may be considered: i) a wide usage of advanced materials for hot ends components, like impeller and recuperator; ii) implementing more complicated thermodynamic cycle, like combined cycle. In the frame of the second option, the paper deals with the hypothesis of bottoming a low pressure ratio, recuperated gas cycle, typically realized in actual microturbines, with an Organic Rankine Cycle (ORC). The object is to evaluate the expected nominal performance parameters of the integrated-combined cycle cogeneration system, taking account of different options for working fluid, vapor pressure and component’s performance parameters. Both options of recuperated and not recuperated bottom cycles are discussed, in relation with ORC working fluid nature and possible stack temperature for microturbine exhaust gases. Finally, some preliminary consideration about the arrangement of the combined cycle unit, and the effects of possible future progress of gas cycle microturbines are presented.

Scaling a radial flow turbine from air to multiple compressible fluids and performance evaluation using computational fluid dynamics

2020 ◽  
pp. 095765092092207
Author(s):  
K Vijayaraj ◽  
Punit Singh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mach Number ◽  
Radial Flow ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Compressible Fluids ◽  
Working Fluid ◽  
Brayton Cycle ◽  
Working Fluids

Many new turbine designs may take large timelines to prove their worth. For getting duty condition at optimum efficiency, one can always scale speed, diameter, if a very efficient benchmark is available. This paper examines the similarity-based scaling strategy to develop radial inflow turbines for different compressible fluids from a well-established NASA radial flow turbine designed and experimentally tested with air as the working fluid. The NASA 1730 air turbine experimental data have been used as the benchmark here and adopted multiple fluids to understand scaling. The considered fluids are supercritical carbon dioxide for the Brayton cycle, helium for the cryogenic liquefaction cycle, and R143a for the organic Rankine cycle. The uniqueness here is to have three types of cycles, viz. closed-loop Brayton cycle, organic Rankine cycle, and cryogenic helium liquefaction cycle, which employ different working fluids, adapting the same NASA turbine geometry. This paper has described the scaling methodology and presented the simulated turbine performance of SCO2, helium, and R143a using computational fluid dynamics. The dimensionless curves for these fluids are plotted on the corresponding experimental characteristics of the NASA turbine. Out of the three fluids, SCO2 showed the perfect Mach number matching for the flow and torque coefficient curves. The Mach number deviations in the case of helium were small, and the variations were slightly higher for R143a. The efficiencies were the highest for R143a, followed by SCO2 and helium. Thus, the scaling was found to be effective in all cases. Thus, the standard turbomachinery space developed for air as fluid can be used effectively for the development of turboexpanders for various cycles with different working fluids without redesigning the entire shape using similarity-based scaling. The benchmark NASA 1730 turbine has proven this in three special cases. This paper is not against designing new machines but is only trying to say that when such good benchmark machines like NASA 1730 turbine is available; designers must use the power of similitude to adapt it to match new fluids and new conditions.

scholarly journals Performance comparison of the solar-driven supercritical organic Rankine cycle coupled with the vapour-compression refrigeration cycle

Clean Energy ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 476-491
Author(s):  
Yunis Khan ◽  
Radhey Shyam Mishra
Keyword(s):  
Thermal Efficiency ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Coefficient Of Performance ◽  
Solar Irradiation ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Exergy Destruction ◽  
Cogeneration System ◽  
Vapour Compression

Abstract In this study, a parametric analysis was performed of a supercritical organic Rankine cycle driven by solar parabolic trough collectors (PTCs) coupled with a vapour-compression refrigeration cycle simultaneously for cooling and power production. Thermal efficiency, exergy efficiency, exergy destruction and the coefficient of performance of the cogeneration system were considered to be performance parameters. A computer program was developed in engineering equation-solver software for analysis. Influences of the PTC design parameters (solar irradiation, solar-beam incidence angle and velocity of the heat-transfer fluid in the absorber tube), turbine inlet pressure, condenser and evaporator temperature on system performance were discussed. Furthermore, the performance of the cogeneration system was also compared with and without PTCs. It was concluded that it was necessary to design the PTCs carefully in order to achieve better cogeneration performance. The highest values of exergy efficiency, thermal efficiency and exergy destruction of the cogeneration system were 92.9%, 51.13% and 1437 kW, respectively, at 0.95 kW/m2 of solar irradiation based on working fluid R227ea, but the highest coefficient of performance was found to be 2.278 on the basis of working fluid R134a. It was also obtained from the results that PTCs accounted for 76.32% of the total exergy destruction of the overall system and the cogeneration system performed well without considering solar performance.

scholarly journals Experimental and Techno-Economic Analysis of Solar-Geothermal Organic Rankine Cycle Technology for Power Generation in Nepal

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Suresh Baral
Keyword(s):  
Power Generation ◽  
Heat Source ◽  
Power Output ◽  
Solar Collector ◽  
Hot Spring ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Working Fluids

The current research study focuses on the feasibility of stand-alone hybrid solar-geothermal organic Rankine cycle (ORC) technology for power generation from hot springs of Bhurung Tatopani, Myagdi, Nepal. For the study, the temperature of the hot spring was measured on the particular site of the heat source of the hot spring. The measured temperature could be used for operating the ORC system. Temperature of hot spring can also further be increased by adopting the solar collector for rising the temperature. This hybrid type of the system can have a high-temperature heat source which could power more energy from ORC technology. There are various types of organic working fluids available on the market, but R134a and R245fa are environmentally friendly and have low global warming potential candidates. The thermodynamic models have been developed for predicting the performance analysis of the system. The input parameter for the model is the temperature which was measured experimentally. The maximum temperature of the hot spring was found to be 69.7°C. Expander power output, thermal efficiency, heat of evaporation, solar collector area, and hybrid solar ORC system power output and efficiency are the outputs from the developed model. From the simulation, it was found that 1 kg/s of working fluid could produce 17.5 kW and 22.5 kW power output for R134a and R245fa, respectively, when the geothermal source temperature was around 70°C. Later when the hot spring was heated with a solar collector, the power output produced were 25 kW and 30 kW for R134a and R245fa, respectively, when the heat source was 99°C. The study also further determines the cost of electricity generation for the system with working fluids R134a and R245fa to be $0.17/kWh and $0.14/kWh, respectively. The levelised cost of the electricity (LCOE) was $0.38/kWh in order to be highly feasible investment. The payback period for such hybrid system was found to have 7.5 years and 10.5 years for R245fa and R134a, respectively.

scholarly journals A Simple Method of Finding New Dry and Isentropic Working Fluids for Organic Rankine Cycle

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 480 ◽  
Author(s):  
Gábor Györke ◽  
Axel Groniewsky ◽  
Attila Imre
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Electricity Production ◽  
Working Fluid ◽  
Heat Sources ◽  
Simple Method ◽  
Working Fluids ◽  
Temperature Heat

One of the most crucial challenges of sustainable development is the use of low-temperature heat sources (60–200 °C), such as thermal solar, geothermal, biomass, or waste heat, for electricity production. Since conventional water-based thermodynamic cycles are not suitable in this temperature range or at least operate with very low efficiency, other working fluids need to be applied. Organic Rankine Cycle (ORC) uses organic working fluids, which results in higher thermal efficiency for low-temperature heat sources. Traditionally, new working fluids are found using a trial-and-error procedure through experience among chemically similar materials. This approach, however, carries a high risk of excluding the ideal working fluid. Therefore, a new method and a simple rule of thumb—based on a correlation related to molar isochoric specific heat capacity of saturated vapor states—were developed. With the application of this thumb rule, novel isentropic and dry working fluids can be found applicable for given low-temperature heat sources. Additionally, the importance of molar quantities—usually ignored by energy engineers—was demonstrated.

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