Comparative performance analysis of low-temperature Organic Rankine Cycle (ORC) using pure and zeotropic working fluids

2013 ◽  
Vol 54 (1) ◽  
pp. 35-42 ◽  
Author(s):  
S. Aghahosseini ◽  
I. Dincer
Keyword(s):  
Performance Analysis ◽  
Low Temperature ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Comparative Performance ◽  
Working Fluids

Performance analysis of low temperature organic Rankine cycle with zeotropic refrigerant by Figure of Merit (FOM)

Energy ◽  
2016 ◽  
Vol 96 ◽  
pp. 96-102 ◽  
Author(s):  
Thoranis Deethayat ◽  
Attakorn Asanakham ◽  
Tanongkiat Kiatsiriroat
Keyword(s):  
Performance Analysis ◽  
Low Temperature ◽  
Figure Of Merit ◽  
Organic Rankine Cycle ◽  
Rankine Cycle

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 A Simple Method of Finding New Dry and Isentropic Working Fluids for Organic Rankine Cycle

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 480 ◽  
Author(s):  
Gábor Györke ◽  
Axel Groniewsky ◽  
Attila Imre
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Electricity Production ◽  
Working Fluid ◽  
Heat Sources ◽  
Simple Method ◽  
Working Fluids ◽  
Temperature Heat

One of the most crucial challenges of sustainable development is the use of low-temperature heat sources (60–200 °C), such as thermal solar, geothermal, biomass, or waste heat, for electricity production. Since conventional water-based thermodynamic cycles are not suitable in this temperature range or at least operate with very low efficiency, other working fluids need to be applied. Organic Rankine Cycle (ORC) uses organic working fluids, which results in higher thermal efficiency for low-temperature heat sources. Traditionally, new working fluids are found using a trial-and-error procedure through experience among chemically similar materials. This approach, however, carries a high risk of excluding the ideal working fluid. Therefore, a new method and a simple rule of thumb—based on a correlation related to molar isochoric specific heat capacity of saturated vapor states—were developed. With the application of this thumb rule, novel isentropic and dry working fluids can be found applicable for given low-temperature heat sources. Additionally, the importance of molar quantities—usually ignored by energy engineers—was demonstrated.

Performance Analysis of Near-Critical and Subcritical Organic Rankine Cycle

2013 ◽  
Vol 448-453 ◽  
pp. 3270-3276
Author(s):  
Yu Ping Wang ◽  
Yi Wu Weng ◽  
Ping Yang ◽  
Lei Tang
Keyword(s):  
Performance Analysis ◽  
Thermophysical Properties ◽  
Thermodynamic Model ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Vapor Generation ◽  
Working Fluids ◽  
The Difference ◽  
Better Than

In this paper, three typical working fluids were selected for the near-critical ORC and subcritical ORC. The difference of performance between the near-critical ORC and subcritical ORC was analyzed by establishing the thermodynamic model. The reason for difference was analyzed in terms of the thermophysical properties. The results indicate that the performance of the near-critical ORC is better than the subcritical ORC. The net absorbed heat, net power and efficiency of the near-critical ORC vary slowly with the vapor generation temperature, which means that the near-critical ORC has good off-design performance. The dry working fluid R236fa is best adapted for the near-critical ORC among the three working fluids. The singular performance of the near-critical ORC depends on the properties of latent heat and type of working fluid in near-critical region.

Analysis of a Combined Power and Ejector Refrigeration Cycle for Low Temperature Heat Sources

2009 ◽  
Author(s):  
Bin Zheng ◽  
Yiwu Weng
Keyword(s):  
Low Temperature ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Refrigeration Cycle ◽  
Heat Sources ◽  
Working Fluids ◽  
Temperature Heat ◽  
Cycle Efficiency

This paper presents a combined power and ejector refrigeration cycle for low temperature heat sources. The proposed cycle combines the organic Rankine cycle and the ejector refrigeration cycle. It can be used as an independent cycle powered by the low temperature sources, such as solar energy, geothermal energy, or as a bottom cycle of the conventional power plant for the recovery of low temperature waste heat. A program was developed to calculate the performance of the combined cycle. Several substances were selected as the working fluids including R113, R123, R245fa, R141b and R600. Simulation results show that R141b has the highest cycle efficiency, followed by R123, R113, R600 and then R245fa. While the working fluids are calculated by per unit, R600 can produce more power and refrigeration outputs due to the large latent heat. Simulations at different generating temperatures, evaporating temperatures and condensing temperatures were also discussed.

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.

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