Impact of molecular structure of working fluids on performance of organic Rankine cycles (ORCs)

2017 ◽  
Vol 1 (5) ◽  
pp. 1098-1111 ◽  
Author(s):  
Maciej Z. Lukawski ◽  
Jefferson W. Tester ◽  
Ronald DiPippo
Keyword(s):  
Molecular Structure ◽  
Power Plants ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Molecular Structures ◽  
Working Fluids ◽  
Organic Rankine Cycles

Performance of organic Rankine cycle (ORC) power plants can be predicted based on the molecular structures of working fluids.

Performance Analysis of Supercritical Organic Rankine Cycles

2013 ◽  
Vol 781-784 ◽  
pp. 2411-2414
Author(s):  
Jian Qiang Gao ◽  
Xin Sun ◽  
Nan Nan Xue ◽  
Hai Kun Xing
Keyword(s):  
Performance Analysis ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Low Grade ◽  
High Grade ◽  
System Efficiency ◽  
Working Fluids ◽  
Organic Rankine Cycles ◽  
High System ◽  
Organic Fluids

Supercritical Rankine cycles using organic fluids as working fluids in converting low-grade energy to high-grade power energy are investigated in the study. The main purpose is to identify suitable working fluids which may yield high system efficiencies in a supercritical Organic Rankine Cycle (ORC) system. R123, R134a, R152a, R22, and R245fa are used for the research. Results show that: at a constant superheating of expansion outlet, system efficiency improves with the increasing of evaporation pressure for all the working fluids and supercritical ORC has a higher efficiency than sub-ORC process. Furthermore, R152a performs the best compared with other refrigerants and is suitable for SORC system.

scholarly journals Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

Energies ◽  
2016 ◽  
Vol 9 (5) ◽  
pp. 322 ◽  
Author(s):  
Jesper Andreasen ◽  
Martin Kærn ◽  
Leonardo Pierobon ◽  
Ulrik Larsen ◽  
Fredrik Haglind
Keyword(s):  
Power Plants ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Multi Objective Optimization ◽  
Working Fluids ◽  
Multi Objective

scholarly journals Effects of evaporation parameters on recuperative transcritical organic Rankine cycle using binary mixture fluids

2020 ◽  
Author(s):  
Jui-Ching Hsieh ◽  
Chu-Hong Cheng
Keyword(s):  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Specific Power ◽  
Second Law ◽  
Inlet Temperature ◽  
Negative Effects ◽  
Critical Temperatures ◽  
Working Fluids ◽  
Organic Rankine Cycles ◽  
Positive Effect

Abstract In this study, thermodynamic analysis was performed on basic and recuperative transcritical organic Rankine cycles by using five pure and six mixed fluids. The effects of evaporation parameters on the first- and second-law efficiencies (ηI and ηII) as well as power output were investigated. The results indicate that a recuperator had a positive effect on the ηI and ηII and negative effects on the specific power. The total irreversibility of the system was improved by the recuperator. However, the total irreversibility considerably increased with an increase in the expander inlet temperature (Texp,in) due to the significant increase in irreversibility in the condenser, particularly for working fluids with low critical temperatures, namely R134a, R1234yf and R290, and low proportions of R245fa and R600a in mixed fluids. For both the pure and mixed fluids, the specific power linearly increased with an increase in the expander inlet pressure (Pexp,in) and Texp,in. However, with an increase in Pexp,in, the ηI and ηII first increased and then decreased. Finally, for ηI and ηII, the effect of the recuperator increased with an increase in Texp,in even though the recuperator had a relatively small effect on the working fluids with high critical temperature, especially when Pexp,in was high.

Selection of Working Fluids for Low-Temperature Power Generation Organic Rankine Cycles System

2012 ◽  
Vol 557-559 ◽  
pp. 1509-1513 ◽  
Author(s):  
Zhong He Han ◽  
Yi Da Yu
Keyword(s):  
Low Temperature ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Heat Sources ◽  
Working Fluids ◽  
Cycle System ◽  
Organic Rankine Cycles ◽  
Organic Fluids ◽  
Cycle Efficiency

A Rankine cycle using organic fluids as working fluids, called organic Rankine cycle (ORC), is potentially feasible in recovering low enthalpy containing heat sources. The choices of fluids should meet the requirement of environment, safety, critical pressure and critical temperature etc. Under the proposed working conditions, R600a, R245fa, R236fa, R236ea, R227ea are chosen as the working fluids of the low-temperature Rankine cycle system, then those fluids are investigated and compared from cycle efficiency, work ratio, exergy efficiency, irreversible loss. The results show that R245fa is an available and effective working fluid for low-temperature Rankine cycle.

Aerodynamic Considerations in the Thermodynamic Analysis of Organic Rankine Cycles

2014 ◽  
Author(s):  
Maria E. Mondejar ◽  
Marcus Thern ◽  
Magnus Genrup
Keyword(s):  
Thermodynamic Analysis ◽  
Equations Of State ◽  
Organic Rankine Cycle ◽  
Thermodynamic Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Working Fluids ◽  
Turbine Efficiency ◽  
Cycle Simulation ◽  
Organic Rankine Cycles

Due to the increasing interest of producing power from renewable and non-conventional resources, organic Rankine cycles are finding their place in today’s thermal energy mix. The main influencers on the efficiency of an organic Rankine cycle are the working fluid and the expander. Therefore most of the research done up to date turns around the selection of the best performance working media and the optimization of the expansion unit design. However, few studies consider the interaction of the working fluids in the turbine design, and how this fact can affect the overall thermodynamic cycle analysis. In this work we aim at including the aerodynamic behavior of the working fluids and their effect on the turbine efficiency in the thermodynamic analysis of an organic Rankine cycle. To that end, we proposed a method for the estimation of the characteristics of an axial in-flow turbine in an organic Rankine cycle simulation model. The code developed for the characterization of the turbine behavior under the working fluid properties evaluated the irreversibilities associated to the aerodynamic losses in the turbine. The organic Rankine cycle was analyzed by using IPSEpro process simulator. A set of candidate working fluids composed of selected organofluorines and organochlorines was chosen for the analysis. The thermophysical properties of the fluids were estimated with the equations of state implemented in Refprop. Results on the energy and exergy overall performances of the cycle were analyzed for a case study with standard source and sink temperatures. For each fluid the number of stages and geometry of the turbine were optimized. It was observed that some working fluids that could initially be considered as advantageous from a thermodynamic point of view, had an unfavorable impact on the turbine efficiency, thus increasing the irreversibilities of the cycle. We concluded that if the influence of the working fluid on the turbine performance is underestimated, the real performance of the organic Rankine cycle could show unexpected deviations from the theoretical results.

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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