scholarly journals Organic Rankine-cycle power systems working fluids study: Topical report No. 2, Toluene

1987 ◽  
Author(s):  
R.L. Cole ◽  
J.C. Demirgian ◽  
J.W. Allen
Keyword(s):  
Power Systems ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluids

Optimization of Cycle and Expander Design of an Organic Rankine Cycle Unit Using Multi-Component Working Fluids

2016 ◽  
Author(s):  
Andrea Meroni ◽  
Jesper Graa Andreasen ◽  
Leonardo Pierobon ◽  
Fredrik Haglind
Keyword(s):  
Low Temperature ◽  
Power Systems ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Fluid Temperature ◽  
Heat Sources ◽  
Working Fluids ◽  
Turbine Performance ◽  
Temperature Heat

Organic Rankine cycle (ORC) power systems represent attractive solutions for power conversion from low temperature heat sources, and the use of these power systems is gaining increasing attention in the marine industry. This paper proposes the combined optimal design of cycle and expander for an organic Rankine cycle unit utilizing waste heat from low temperature heat sources. The study addresses a case where the minimum temperature of the heat source is constrained and a case where no constraint is imposed. The former case is the waste heat recovery from jacket cooling water of a marine diesel engine onboard a large ship, and the latter is representative of a low-temperature geothermal, solar or waste heat recovery application. Multi-component working fluids are investigated, as they allow improving the match between the temperature profiles in the heat exchangers and, consequently, reducing the irreversibility in the ORC system. This work considers mixtures of R245fa/pentane and propane/isobutane. The use of multi-component working fluids typically results in increased heat transfer areas and different expander designs compared to pure fluids. In order to properly account for turbine performance and design constraints in the cycle calculation, the thermodynamic cycle and the turbine are optimized simultaneously in the molar composition range of each mixture. Such novel optimization approach enables one to identify to which extent the cycle or the turbine behaviour influences the selection of the optimal solution. It also enables one to find the composition for which an optimal compromise between cycle and turbine performance is achieved. The optimal ORC unit employs pure R245fa and provides approximately 200 kW when the minimum hot fluid temperature is constrained. Conversely, the mixture R245fa/pentane (0.5/0.5) is selected and provides approximately 444 kW when the hot fluid temperature is not constrained to a lower value. In both cases, a compact and efficient turbine can be manufactured.

scholarly journals Sizing the thermal energy storage (TES) device for organic Rankine cycle (ORC) power systems

2021 ◽  
Vol 345 ◽  
pp. 00018
Author(s):  
Piotr Kolasiński ◽  
Sindu Daniarta
Keyword(s):  
Energy Storage ◽  
Power Systems ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Thermal Power ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Energy Storage Materials ◽  
Working Fluids ◽  
Storage Materials

Thermal energy storage (TES) became one of the main research topics in modern power engineering. The design of TES devices and systems depend on their application. Different thermal energy storage materials (e.g., solids, liquids, or phase change materials) can be applied in TES devices. The selection of the thermal energy storage material depends mainly on the thermal power and operating temperature range of the TES device. These devices and systems are applied in different energy conversion systems, including solar power plants or combined heat and power (CHP) stations. The application of TES devices is also considered in the case of other industries, such as metallurgy. The possible application of TES devices is particularly promising in the case of organic Rankine cycle (ORC) systems. These systems are often utilizing floating heat sources such as solar energy, waste heat, etc. TES device can be therefore applied as the evaporator of the ORC system in order to stabilize these fluctuations. In this paper, the possible thermal energy storage materials used in TES devices applied in ORCs are discussed. Moreover, the modelling results are reported related to assessment parameters which can be applied to size the TES device for ORC system utilizing different low-boiling working fluids. The thermal properties of working fluids are taken from CoolProp. The function of heat capacity of different TES materials is also provided and the calculation is computed by employing MATLAB. The result shows that based on the simulation, the gradient of the natural characteristic of TES with working fluids (ζ(Tb)) tends to decrease. The presented result in this paper gives a new point of view which can be used by scientists and engineers during the design and implementation of TES evaporators dedicated to ORC power systems.

scholarly journals Assessment of Methods for Performance Comparison of Pure and Zeotropic Working Fluids for Organic Rankine Cycle Power Systems

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1783 ◽  
Author(s):  
Jesper Graa Andreasen ◽  
Martin Ryhl Kærn ◽  
Fredrik Haglind
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Power Systems ◽  
Temperature Difference ◽  
Power Output ◽  
Heat Exchangers ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluids ◽  
Net Power Output

In this paper, we present an assessment of methods for estimating and comparing the thermodynamic performance of working fluids for organic Rankine cycle power systems. The analysis focused on how the estimated net power outputs of zeotropic mixtures compared to pure fluids are affected by the method used for specifying the performance of the heat exchangers. Four different methods were included in the assessment, which assumed that the organic Rankine cycle systems were characterized by the same values of: (1) the minimum pinch point temperature difference of the heat exchangers; (2) the mean temperature difference of the heat exchangers; (3) the heat exchanger thermal capacity ( U ¯ A ); or (4) the heat exchanger surface area for all the considered working fluids. The second and third methods took into account the temperature difference throughout the heat transfer process, and provided the insight that the advantages of mixtures are more pronounced when large heat exchangers are economically feasible to use. The first method was incapable of this, and deemed to result in optimistic estimations of the benefits of using zeotropic mixtures, while the second and third method were deemed to result in conservative estimations. The fourth method provided the additional benefit of accounting for the degradation of heat transfer performance of zeotropic mixtures. In a net power output based performance ranking of 30 working fluids, the first method estimates that the increase in the net power output of zeotropic mixtures compared to their best pure fluid components is up to 13.6%. On the other hand, the third method estimates that the increase in net power output is only up to 2.56% for zeotropic mixtures compared to their best pure fluid components.

scholarly journals Prospects of the use of nanofluids as working fluids for organic Rankine cycle power systems

2017 ◽  
Vol 129 ◽  
pp. 160-167 ◽  
Author(s):  
Maria E. Mondejar ◽  
Jesper G. Andreasen ◽  
Maria Regidor ◽  
Stefano Riva ◽  
Georgios Kontogeorgis ◽  
...  
Keyword(s):  
Power Systems ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluids

scholarly journals Comparative investigation of working fluids for an organic Rankine cycle with geothermal water

2015 ◽  
Vol 36 (2) ◽  
pp. 75-84
Author(s):  
Yan-Na Liu ◽  
Song Xiao
Keyword(s):  
Power Generation ◽  
Pressure Ratio ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Comparative Investigation ◽  
Geothermal Water ◽  
Thermodynamic Investigation ◽  
Working Fluids ◽  
Temperature Heat ◽  
Input Pressure

AbstractIn this paper, the thermodynamic investigation on the use of geothermal water (130 °C as maximum) for power generation through a basic Rankine has been presented together with obtained main results. Six typical organic working fluids (i.e., R245fa, R141b, R290, R600, R152a, and 134a) were studied with modifying the input pressure and temperature to the turbine. The results show that there are no significant changes taking place in the efficiency for these working fluids with overheating the inlet fluid to the turbine, i.e., efficiency is a weak function of temperature. However, with the increasing of pressure ratio in the turbine, the efficiency rises more sharply. The technical viability is shown of implementing this type of process for recovering low temperature heat resource.

A new understanding on thermal efficiency of organic Rankine cycle: Cycle separation based on working fluids properties

2018 ◽  
Vol 157 ◽  
pp. 169-175 ◽  
Author(s):  
Yongzhen Wang ◽  
Jun Zhao ◽  
Guibing Chen ◽  
Shuai Deng ◽  
Qingsong An ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluids
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