Advanced Turbine Cycles with Organic Media

Piwowarski, Marian; Kosowski, Krzysztof

doi:10.3390/en13061327

Cited by 3 publications

(5 citation statements)

References 17 publications

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Section: Resultsmentioning

confidence: 99%

“…For power plants with isothermal turbines, this growth is as high as 3.6 points for c3cc6 up to 10.1 percent points for R1233zd. The comparison of the efficiency for power plants with isothermal and adiabatic expansion is presented in Figure 9 for subcritical live vapor parameters [19] and in Figure 10 for supercritical parameters. In the case of supercritical parameters, due to a higher value of the initial pressure, we observe higher cycle efficiency than for the power plants with subcritical parameters.…”

Section: Resultsmentioning

confidence: 99%

“…As a result, these installations achieve an efficiency of about 10%, and only exceptionally can they reach about 20% thanks to the use of various modifications [16]. It is possible to increase the efficiency of the cycle by increasing the upper temperature [17] and modifying the installation structure, e.g., by adding an additional cycle [18] or by using an additional heater [19]. As in the case of steam turbines, efficiency can be increased by using an inter-stage superheater [20], regenerators [21,22] or by using a parallel evaporator [23].…”

Section: Introductionmentioning

confidence: 99%

“…Our team has successfully designed, built and tested an experimental isothermal turbine. The photo of its model and the experimental stand is presented in [19]. Therefore, the obtained results can be of great relevance in future designs.…”

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Organic Supercritical Thermodynamic Cycles with Isothermal Turbine

Piwowarski,

Kosowski,

Richert

2023

Energies

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Organic Rankine cycles (ORC) are quite popular, but the overall efficiencies of these plants are rather very low. Numerous studies have been conducted in many scientific centers and research centers to improve the efficiency of such cycles. The research concerns both the modification of the cycle and the increase in the parameters of the medium at the inlet to the turbine. However, the efficiency of even these modified cycles rarely exceeds 20%. The plant modifications and the optimization of the working medium parameters, as a rule, lead to cycles with the high pressure and high temperature of live vapor and with a regenerator (heat exchanger) for the heating, vaporization and superheating of the medium. A new modified cycle with supercritical parameters of the working medium and with a new type of turbine has been described and calculated in the paper. For the first time, the isothermal turbine is proposed for supercritical organic cycles, though this solution is known as the Ericsson cycle for gas turbines. The innovative cycle and the usual ORC plants are characterized by almost identical block diagrams, while in the proposed cycle, the work of the turbine is obtained as a result of isothermal expansion and not in an adiabatic process. The analysis has been performed for 11 different working media and two cycles. The calculations have shown that power plants with isothermal expansion achieve better efficiency than cycles with adiabatic turbines. For example, the rise in efficiency changes from 8 percentage points for R245fa up to 10 percentage points for acetone. The calculations have proved that it is possible to obtain efficiency exceeding 50% for organic power plants. This is an outstanding result compared with modern steam and gas turbine units.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Organic Supercritical Thermodynamic Cycles with Isothermal Turbine

Piwowarski,

Kosowski,

Richert

2023

Energies

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“…20% [25]. It is possible to improve the cycle efficiency by increasing the upper temperature and modifying the plant design [26,27]. Despite very considerable developments in distributed energy and alternative energy sources, it should be concluded that high-efficiency power plants with steam turbines set to supercritical parameters, combined gas-steam cycle power plants, and nuclear power plants [28] will be developed in terms of high installed capacities.…”

Section: Introductionmentioning

confidence: 99%

Technical and Economic Analysis of the Supercritical Combined Gas-Steam Cycle

et al. 2021

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Combined cycle power plants are characterized by high efficiency, now exceeding 60%. The record-breaking power plant listed in the Guinness Book of World Records is the Nishi-Nagoya power plant commissioned in March 2018, located in Japan, and reaching the gross efficiency of 63.08%. Research and development centers, energy companies, and scientific institutions are taking various actions to increase this efficiency. Both the gas turbine and the steam turbine of the combined cycle are modified. The main objective of this paper is to improve the gas-steam cycle efficiency and to reach the efficiency that is higher than in the record-breaking Nishi-Nagoya power plant. To do so, a number of numerical calculations were performed for the cycle design similar to the one used in the NishiNagoya power plant. The paper assumes the use of the same gas turbines as in the reference power plant. The process of recovering heat from exhaust gases had to be organized so that the highest capacity and efficiency were achieved. The analyses focused on the selection of parameters and the modification of the cycle design in the steam part area in order to increase overall efficiency. As part of the calculations, the appropriate selection of the most favorable thermodynamic parameters of the steam at the inlet to the high-pressure (HP) part of the turbine (supercritical pressure) allowed the authors to obtain the efficiency and the capacity of 64.45% and about 1.214 GW respectively compared to the reference values of 63.08% and 1.19 GW. The authors believe that efficiency can be improved further. One of the methods to do so is to continue increasing the high-pressure steam temperature because it is the first part of the generator into which exhaust gases enter. The economic analysis revealed that the difference between the annual revenue from the sale of electricity and the annual fuel cost is considerably higher for power plants set to supercritical parameters, reaching approx. USD 14 million per annum. It is proposed that investments in adapting components of the steam part to supercritical parameters may be balanced out by a higher profit.

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Subcritical Thermodynamic Cycles with Organic Medium and Isothermal Expansion

Kosowski

Piwowarski

2020

Energies

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The efficiencies of the Organic Rankine Cycle (ORC) are not very high and only very seldom do they exceed 20%. The increase and optimization of initial parameters and certain modifications of the thermodynamic cycle make it possible to overcome these drawbacks. A new modified cycle has been described and analyzed in detail in the paper. Similarly to the Ericsson cycle for gas turbines, isothermal expansion in the turbine is suggested for the power plant with organic media. The new cycle and the typical ORC power plants have the same block diagram. The only difference is that expansion in the proposed cycle occurs not adiabatically but as an isothermal process. The thermodynamic calculations have been carried out for 11 various fluids and 4 different cycles. The obtained results have clearly shown that cycles with isothermal expansion (isothermal turbines) are characterized by remarkably higher efficiency than typical power plants with adiabatic turbines. The increase in efficiency varies from 6 to 12 percent points for cycles with saturated live vapor and from 4 to 7 percent points for cycles with superheated live vapor. The performed analyses have shown that it is possible to achieve a very high efficiency (over 45%) of organic cycle, which is a very competitive value. In such cases the proposed power plants can achieve an efficiency which is higher than that of modern steam turbine plants with supercritical parameters.

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Advanced Turbine Cycles with Organic Media

Cited by 3 publications

References 17 publications

Organic Supercritical Thermodynamic Cycles with Isothermal Turbine

Organic Supercritical Thermodynamic Cycles with Isothermal Turbine

Technical and Economic Analysis of the Supercritical Combined Gas-Steam Cycle

Subcritical Thermodynamic Cycles with Organic Medium and Isothermal Expansion

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