Performance Assessments of Organic Rankine Cycle With Internal Heat Exchanger Based on Exergetic Approach

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Nurettin Yamankaradeniz ◽  
Ali Husnu Bademlioglu ◽  
Omer Kaynakli
Keyword(s):  
Heat Exchanger ◽  
Organic Rankine Cycle ◽  
Internal Heat ◽  
Rankine Cycle ◽  
Performance Assessments ◽  
Evaporator Temperature ◽  
Pinch Point ◽  
Internal Heat Exchanger ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis

This study makes energy and exergy analysis of a sample organic Rankine cycle (ORC) with a heat exchanger which produces energy via a geothermal source with a temperature of 140 °C. R600a is preferred as refrigerant to be used in the cycle. The changes in exergy destructions (of irreversibility) and exergy efficiencies in each cycle element are calculated in the analyses made based on the effectiveness of heat exchanger used in cycle and evaporator temperature changing between 60 and 120 °C for fixed pinch point temperature differences in evaporator and condenser. Parameters showing system performance are assessed via second law approach. Effectiveness of heat exchanger and temperature of evaporator are taken into consideration within the scope of this study, and energy and exergy efficiencies of cycle are enhanced maximum 6.87% and 6.21% respectively. Similarly, exergy efficiencies of evaporator, heat exchanger, and condenser are increased 4%, 82%, and 1.57%, respectively, depending on the effectiveness of heat exchanger and temperature of evaporator.

Study on the Performance of the Organic Rankine Cycle System with Internal Heat Exchanger under Vehicle Engine Various Operating Conditions

2013 ◽  
Vol 856 ◽  
pp. 349-356 ◽  
Author(s):  
Kai Yang ◽  
Hong Guang Zhang ◽  
Zhen Wang ◽  
Jian Zhang ◽  
Fu Bin Yang ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Diesel Engine ◽  
High Speed ◽  
Organic Rankine Cycle ◽  
Internal Heat ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Combined System ◽  
Cycle System ◽  
Internal Heat Exchanger

Through experiment, the variation of the exhaust energy of the vehicle diesel engine is studied, a set of vehicle diesel engine-organic Rankine cycle (ORC) combined system with internal heat exchanger (IHE) is designed, the zeotropic mixtures R416A is used as the working fluids for the ORC system with IHE, by theoretical analysis and numerical calculation, the variation of the vehicle diesel engine-ORC combined system with IHE under entire operating conditions of the diesel engine is studied, the calculation results show that, when engine is operating at high speed and high torque, the performance of the vehicle diesel engine-ORC combined system with IHE is higher.

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.

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