Adjusting the pinch point of heat transfer to improve the thermal performance of the organic Rankine cycle

2021 ◽  
Author(s):  
Xinguo Li ◽  
Xiaosong Wu
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Pinch Point

scholarly journals The Exergy Loss Distribution and the Heat Transfer Capability in Subcritical Organic Rankine Cycle

Entropy ◽  
2017 ◽  
Vol 19 (6) ◽  
pp. 256 ◽  
Author(s):  
Chao He ◽  
Youzhou Jiao ◽  
Chaochao Tian ◽  
Zhenfeng Wang ◽  
Zhiping Zhang
Keyword(s):  
Heat Transfer ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Exergy Loss ◽  
Loss Distribution ◽  
Transfer Capability ◽  
Heat Transfer Capability

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

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.

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.

Dynamic Simulation and Optimization of an Experimental Micro-CSP Power Plant

2015 ◽  
Author(s):  
Matthias Mitterhofer ◽  
Matthew Orosz
Keyword(s):  
Control Strategy ◽  
Low Cost ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Economic Benefits ◽  
Solar Thermal ◽  
Small Scale ◽  
Pinch Point ◽  
Simulation And Optimization ◽  
Dynamic Representation

Small scale solar thermal systems are increasingly investigated in the context of decentralized energy supply, due to favorable costs of thermal energy storage (TES) in comparison with battery storage for otherwise economical PV generation. The present study provides the computational framework and results of a one year simulation of a low-cost pilot 3kWel micro-Concentrated Solar Power (micro-CSP) plant with TES. The modeling approach is based on a dynamic representation of the solar thermal loop and a steady state model of the Organic Rankine Cycle (ORC), and is validated to experimental data from a test site (Eckerd College, St. Petersburg, Florida). The simulation results predict an annual net electricity generation of 4.08 MWh/a. Based on the simulation, optimization studies focusing on the Organic Rankine Cycle (ORC) converter of the system are presented, including a control strategy allowing for a variable pinch point in the condenser that offers an annual improvement of 14.0% in comparison to a constant condensation pinch point. Absolute electricity output is increased to 4.65 MWh/a. Improvements are due to better matching to expander performance and lower condenser fan power because of higher pinch points. A method, incorporating this control strategy, is developed to economically optimize the ORC components. The process allows for optimization of the ORC subsystem in an arbitrary environment, e.g. as part of a micro-grid to minimize Levelized electricity costs (LEC). The air-cooled condenser is identified as the driving component for the ORC optimization as its influence on overall costs and performance is of major significance. Application of the optimization process to various locations in Africa illustrates economic benefits of the system in comparison to diesel generation.

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