Integrated Modelling and Multi-Objective Optimization of Organic Rankine Cycle Based on Radial Inflow Turbine

2015 ◽  
Author(s):  
K. Rahbar ◽  
S. Mahmoud ◽  
R. K. Al-Dadah ◽  
N. Moazami
Keyword(s):  
Thermal Efficiency ◽  
Organic Rankine Cycle ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Integrated Modelling ◽  
Working Fluid ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Turbine Efficiency ◽  
Radial Inflow Turbine

This paper presents the integrated modelling and multi-objective optimization of ORC based on radial inflow turbine. With this approach it is possible to replace the constant turbine efficiency with a dynamic efficiency that is unique for each set of cycle operating conditions and working fluid properties. This allows overcoming any arbitrary assumption of the turbine efficiency, unlike the previous literature, and providing a more realistic estimation of the cycle performance. Parametric studies were conducted utilizing the developed model to identify the key input variables that have significant effects on the critical turbine-ORC performance indicators. These variables were then included in the optimization process using DIRECT algorithm to optimize two objective functions as the cycle thermal efficiency and the turbine overall size for five organic fluids. Optimization results predicted that isobutane exhibited the best performance with the maximum cycle thermal efficiency of 13.21% and turbine overall size of 0.1434m while having relatively high turbine isentropic efficiency of 77.03%.

scholarly journals Multi-objective optimization of CuO based organic Rankine cycle operated using R245ca

2019 ◽  
Vol 116 ◽  
pp. 00062 ◽  
Author(s):  
Parth Prajapati ◽  
Vivek Patel
Keyword(s):  
Heat Transfer ◽  
Thermal Efficiency ◽  
Heat Exchangers ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Source Fluid

The present work deals with multi objective optimization of nanofluid based Organic Rankine Cycle (ORC) to utilise waste heat energy. Working fluid considered for the study is R245ca for its good thermodynamic properties and lower Global Warming Potential (GWP) compared to the conventional fluids used in the waste heat recovery system. Heat Transfer Search (HTS) algorithm is used to optimize the objective functions which tends to maximize thermal efficiency and minimize Levelised Energy Cost (LEC). To enhance heat transfer between the working fluid and source fluid, nanoparticles are added to the source fluid. Application of nanofluids in the heat transfer system helps in maximizing recovery of the waste heat in the heat exchangers. Based on the availability and cost, CuO nanoparticles are considered for the study. Effect of Pinch Point Temperature Difference (PPTD) and concentration of nanoparticles in heat exchangers is studied and discussed. Results showed that nanofluids based ORC gives maximum thermal efficiency of 18.50% at LEC of 2.59 $/kWh. Total reduction of 7.11% in LEC can be achieved using nanofluids.

Effect of the Working Fluid on Performance of the ORC and Combined Brayton/ORC Cycle

2017 ◽  
Author(s):  
Alireza Javanshir ◽  
Nenad Sarunac
Keyword(s):  
Thermal Efficiency ◽  
Organic Rankine Cycle ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Working Fluid ◽  
Working Fluids ◽  
Power Cycles ◽  
Topping Cycle ◽  
Selection Of

This study focuses on the power cycles such as organic Rankine cycle (ORC) and combined regenerative Brayton/ORC. The selection of working fluids and power cycles is traditionally conducted by trial and error method and performing a large number of parametric calculations over a range of operating conditions. A methodology for selection of optimal working fluid based on the cycle operating conditions and thermophysical properties of the working fluids was developed in this study. Thermodynamic performance (thermal efficiency and net power output) of a simple subcritical and supercritical ORC was analyzed over a range of operating conditions for a number of working fluids to determine the effect of operating parameters on cycle performance and select the best working fluid. New expressions for thermal efficiency of a simple ORC are proposed. In case of a regenerative Brayton/ORC, the results show that CO2 is the best working fluid for the topping cycle. Depending on the exhaust temperature of the topping cycle, Isobutane, R11 and Ethanol are the preferred working fluids for the bottoming (ORC) cycle, resulting in highest efficiency of the combined cycle. Finally, a performance map is presented as guidance for selection of the best working fluid for specific cycle operating conditions.

scholarly journals Development of a Pattern Recognition Methodology with Thermography and Implementation in an Experimental Study of a Boiler for a WHRS-ORC

2019 ◽  
Author(s):  
Concepción Paz ◽  
Eduardo Suarez ◽  
Miguel Concheiro ◽  
Antonio Diaz
Keyword(s):  
Pattern Recognition ◽  
Wall Temperature ◽  
Waste Heat ◽  
Combustion Engine ◽  
Organic Rankine Cycle ◽  
Exhaust System ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Working Fluid

Waste heat dissipated in the exhaust system in a combustion engine represents a major source of energy to be recovered and converted into useful work. A waste heat recovery system (WHRS) based on an Organic Rankine Cycle (ORC) is a promising approach, and has gained interest in the last few years in an automotive industry interested in reducing fuel consumption and exhaust emissions. Understanding the thermodynamic response of the boiler employed in an ORC plays an important role in steam cycle performance prediction and control system design. The aim of this study is therefore to present a methodology to study these devices by means of pattern recognition with infrared thermography. In addition, the experimental test bench and its operating conditions are described. The methodology proposed identifies the wall coordinates, traces paths, and tracks wall temperature along them in a way that can be exported for subsequent post-processing and analysis. As for the results, through the wall temperature paths on both sides (exhaust gas and working fluid) it was possible to quantitatively estimate the temperature evolution along the boiler and, in particular, the beginning and end of evaporation.

scholarly journals Development of a Pattern Recognition Methodology with Thermography and Implementation in an Experimental Study of a Boiler for a WHRS-ORC

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1680
Author(s):  
Concepción Paz ◽  
Eduardo Suárez ◽  
Miguel Concheiro ◽  
Antonio Diaz
Keyword(s):  
Pattern Recognition ◽  
Wall Temperature ◽  
Waste Heat ◽  
Combustion Engine ◽  
Organic Rankine Cycle ◽  
Exhaust System ◽  
Rankine Cycle ◽  
Operating Conditions ◽  
Cycle Performance ◽  
Working Fluid

Waste heat dissipated in the exhaust system in a combustion engine represents a major source of energy to be recovered and converted into useful work. A waste heat recovery system (WHRS) based on an Organic Rankine Cycle (ORC) is a promising approach, and it gained interest in the last few years in an automotive industry interested in reducing fuel consumption and exhaust emissions. Understanding the thermodynamic response of the boiler employed in an ORC plays an important role in steam cycle performance prediction and control system design. The aim of this study is, therefore, to present a methodology to study these devices by means of pattern recognition with infrared thermography. In addition, the experimental test bench and its operating conditions are described. The methodology proposed identifies the wall coordinates, traces the paths, and tracks the wall temperature along them in a way that can be exported for subsequent post-processing and analysis. As for the results, through the wall temperature paths on both sides (exhaust gas and working fluid), it was possible to quantitatively estimate the temperature evolution along the boiler and, in particular, the beginning and end of evaporation.

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