scholarly journals Thermal performance comparison of Rankine cycle, reheat cycle and regenerative cycle with the same initial and final parameters

2021 ◽  
Vol 245 ◽  
pp. 03015
Author(s):  
Yarong Wang ◽  
Peirong Wang
Keyword(s):  
Thermal Efficiency ◽  
Thermal Cycle ◽  
Power Plants ◽  
Mechanical Energy ◽  
Rankine Cycle ◽  
Performance Comparison ◽  
Factors Affecting ◽  
Working Medium ◽  
Generation Cost ◽  
Regenerative Cycle

The conversion between thermal energy and mechanical energy can be realized through the thermal cycle of working medium in a series of power plants. For the thermodynamic analysis of the thermal cycle, it mainly analyzes the thermal efficiency and steam consumption rate of the cycle to analyze the main factors affecting the thermal efficiency of the cycle, and the measures to improve the thermal efficiency, in order to reduce the fuel consumption and reduce the power generation cost.

Progress of Closed-Cycle OTEC and Study of a New Cycle of OTEC

2011 ◽  
Vol 354-355 ◽  
pp. 275-278
Author(s):  
Wei Min Liu ◽  
Feng Yun Chen ◽  
Yi Qiang Wang ◽  
Wei Jun Jiang ◽  
Ji Guang Zhang
Keyword(s):  
Temperature Difference ◽  
Thermal Efficiency ◽  
Rankine Cycle ◽  
Ammonia Solution ◽  
Ocean Temperature ◽  
Closed Cycle ◽  
Kalina Cycle ◽  
Cycle System ◽  
Working Medium ◽  
Regenerative Cycle

OTEC has the advantages of large reserves, renewable, stable and clean without pollution. However the smaller ocean temperature-difference results in the lower thermal efficiency. Based on the research of Rankine cycle, Kalina cycle, Uehara cycle, a new closed-cycle system (GuoHai cycle) has been studied, this cycle system uses ammonia-water mixtures as working medium. Indirect regenerative cycle and poor ammonia solution regenerative cycle is adopted in order to improve the thermal efficiency of the system.

scholarly journals Analysis of Factors Affecting Thermodynamic Efficiency in Generation III+ PWR Nuclear Power Plants.

2017 ◽  
Vol 4 ◽  
pp. 141-154
Author(s):  
Marcus Vitlin ◽  
Miroshan Naicker ◽  
Augustine Frederick Gardner
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Rankine Cycle ◽  
Steam Temperature ◽  
Factors Affecting ◽  
Electrical Efficiency ◽  
Balance Of Plant ◽  
The Impact ◽  
The Relationship

Generation III+ reactors are the latest generation of Nuclear Power Plants to enter the market. The key evolution in these reactors is the introduction of stringent safety standards. This is done through thorough incident scenario analysis and preparation, resulting in the addition of novel active and passive auxiliary safety systems, affecting the power consumption in the balance of plant. This paper analyses the parameters of PWR power plants of similar design, to determine the parameters for optimal efficiency, regarding gross and net electrical output, determining the impact the balance of plant has on this efficiency. While two of the three main factors affecting the Rankine cycle – boiler pressure and steam temperature – behaved as theoretically expected, there was a notable point of departure with the third parameter – condenser pressure. The relationship between steam temperature and gross electrical efficiency was linear across all reactors but the relation between the steam temperature and the net electrical efficiency ceased to be linear for secondary loop steam temperatures above 290°C. The relationship between boiler pressure and both gross and net electrical efficiency was linear, proving the Rankine cycle. A relationship was not observed between the condenser pressure and either the gross or net electrical efficiency

Estimation of the efficiency of the thermal cycle of a piston internal combustion engine

2021 ◽  
pp. 18-22
Keyword(s):  
Internal Combustion Engine ◽  
Thermal Cycle ◽  
Power Plants ◽  
Combustion Engine ◽  
Mechanical Energy ◽  
Heat Content ◽  
Internal Combustion ◽  
Working Fluid ◽  
Heat Cycle ◽  
Hybrid Power Plant

Authors Rusinov R.V., Hoodorozhkov S.I., Dobretsov R.Yu., [email protected]. Estimation of the efficiency of the thermal cycle of a piston internal combustion engine The article proposes a simplified technique for the operational assessment of the efficiency of the heat cycle of a piston internal combustion engine. A feature of the developed computational model is the release of the amount of heat consumed for the production of only mechanical energy in the form of a separate component of the heat balance of the cycle. The value of this component is determined by calculation (or according to the results of experiments) in advance, which makes it possible to reduce the number of pre(determined initial data. The methodology is based on a mathematical description of thermodynamic processes occurring during the development of the thermal cycle of an engine with ignition of the working mixture from compression (diesel engine), which allows it to be expanded to new engines of design, including those operating under electronic control. The objects for the application of the calculation method can be diesel engines installed on transport vehicles, both individually and as part of a hybrid power plant, as well as engines of stationary or transportable power plants. The very principle underlying the model can be implemented for engines of other purposes and other thermal cycles. Keywords: heat cycle; the working process; diesel; heat content of the working fluid; expansion

scholarly journals Design analysis of ORC micro-turbines making use of thermal energy of oceans

2013 ◽  
Vol 20 (2) ◽  
pp. 48-60 ◽  
Author(s):  
Marian Piwowarski
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Power Plants ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Design Parameters ◽  
Thermal Energy Conversion ◽  
Working Medium ◽  
Ocean Thermal Energy ◽  
Cycle Efficiency

Abstract The article presents the results of the analysis of energy conversion cycles making use of thermal energy of oceans. The objects of analysis were two cases of closed Organic Rankine Cycle (ORC) power plants, which were: the cycle in which the vapour of the working medium was produced by warm oceanic water in the circum-equatorial zone, and the so-called “arctic” cycle in which this vapour was produced by non-frozen water in the circumpolar zone. Between ten and twenty low-boiling media were examined for which operating parameters were optimised to obtain the highest cycle efficiency. A preliminary design of an ORC turbine which was obtained by optimising basic design parameters is included. It has been proved that realisation of the Ocean Thermal Energy Conversion (OTEC) cycle is possible both in the warm and permanently frozen regions. The results of the calculations have also revealed that the efficiency of the OTEC cycle is higher in the circumpolar zone. Selecting a low-boiling medium and designing a highly efficient turbine operating in both abovementioned regimes is technically realisable.

Electrical Power Generation: Fossil Fuels

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Fossil Fuels ◽  
Turbine Blades ◽  
Electrical Power ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Steam Temperature

Nearly all electrical power is generated by rotating a coil in a magnetic field. In most cases, the coil is turned by a steam turbine operating according to the Rankine cycle. Water is boiled and heated to make high-pressure steam, which drives the turbine. The thermal efficiency is about 30–35%, and is limited by the highest steam temperature tolerated by the turbine blades. Alternatively, a gas turbine operating according to the Brayton cycle can be used. Much higher turbine inlet temperatures are possible, and the thermal efficiency is higher, typically 40%. Combined cycle generation, in which the hot exhaust from a gas turbine drives a Rankine cycle, can achieve thermal efficiencies of almost 60%. Substitution of coal-fired by combined cycle natural gas power plants can result in significant reductions in CO2 emissions.

Evaluation of the Effect of Firing Temperature, Cycle, Engine Configuration, Components, and Bottoming Cycle on the Overall Thermal Efficiency of an Indirectly Coal-Fired Gas Turbine Based Power Plant

2006 ◽  
Author(s):  
Richard P. Johnston
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Working Fluid ◽  
Turbine Engine ◽  
Combined Cycle Plant ◽  
Plant Power

Potential LHV performance of an indirect coal-fired gas turbine-based combined cycle plant is explored and compared to the typical LHV 35–38 % thermal efficiencies achievable with current coal-fired Rankine Cycle power plants. Plant performance with a baseline synchronous speed, single spool 25:1 pressure ratio gas turbine with a Rankine bottoming cycle was developed. A coal-fired High Temperature Advanced Furnace (HITAF) supplying 2000° F. (1093° C.) hot pressurized air for the gas turbine was modeled for the heat source. The HITAF concept along with coal gas for supplemental heating, are two important parts of the clean coal technology program for power plants. [1,2] From this baseline power plant arrangement, different gas turbine engine configurations with two pressure ratios are evaluated. These variations include a dual spool concentric shaft gas turbine, dual spool non-concentric shaft arrangement, intercooler, liquid metal loop re-heater, free power turbine (FPT) and post HITAF duct burner (DB). A dual pressure Heat Recovery Steam Generator (HRSG) with varying steam pressures to fit conditions is used for each engine. A novel steam generating method employing flash tank technology is applied when a water-cooled intercooler is incorporated. A halogenated hydrocarbon working fluid is also evaluated for lower temperature sub-bottoming Rankine cycle equipment. Current technology industrial gas turbine component performance levels are applied to these various engines to produce a range of LHV gross gas turbine thermal efficiency estimates. These estimates range from the lower thirties to over forty percent. Overall LHV combined cycle plant gross thermal efficiencies range from nearly forty to over fifty percent. All arrangements studied would produce significant improvements in thermal efficiency compared to current coal-fired Rankine cycle power plants. Regenerative inter-cooling, free power turbines, and dual-spool non-concentric shaft gas turbine arrangements coupled with post-HITAF duct burners produced the highest gas turbine engine and plant efficiency results. These advanced engine configurations should also produce operational benefits such as easier starting and much improved part power efficiency over the baseline engine arrangement. An inter-turbine liquid metal re-heat loop reduced engine thermal efficiency but did increase plant power output and efficiency for the example studied. Use of halogenated hydrocarbons as a working fluid would add to plant power output, but at the cost of significant additional plant equipment.

scholarly journals Teach Second Law of Thermodynamics via Analysis of Flow through Packed Beds and Consolidated Porous Media

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 116 ◽  
Author(s):  
Rajinder Pal
Keyword(s):  
Porous Media ◽  
Entropy Generation ◽  
Power Plants ◽  
Mechanical Energy ◽  
Fluid Velocity ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Packed Beds ◽  
Factors Affecting ◽  
Flow Through

The second law of thermodynamics is indispensable in engineering applications. It allows us to determine if a given process is feasible or not, and if the given process is feasible, how efficient or inefficient is the process. Thus, the second law plays a key role in the design and operation of engineering processes, such as steam power plants and refrigeration processes. Nevertheless students often find the second law and its applications most difficult to comprehend. The second law revolves around the concepts of entropy and entropy generation. The feasibility of a process and its efficiency are directly related to entropy generation in the process. As entropy generation occurs in all flow processes due to friction in fluids, fluid mechanics can be used as a tool to teach the second law of thermodynamics and related concepts to students. In this article, flow through packed beds and consolidated porous media is analyzed in terms of entropy generation. The link between entropy generation and mechanical energy dissipation is established in such flows in terms of the directly measurable quantities such as pressure drop. Equations are developed to predict the entropy generation rates in terms of superficial fluid velocity, porous medium characteristics, and fluid properties. The predictions of the proposed equations are presented and discussed. Factors affecting the rate of entropy generation in flow through packed beds and consolidated porous media are identified and explained.

scholarly journals Thermal Efficiency of Combined Cycle Power Plant

2018 ◽  
Vol 8 (3) ◽  
Author(s):  
R. Rajesh ◽  
P. S. Kishore
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Waste Heat ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Heat Recovery Boiler ◽  
Brayton Cycle ◽  
Single Cycle ◽  
Working Medium ◽  
Temperature And Pressure

Now a day’s power generation is most important for every country. This power is generated by some thermal cycles. But single cycle cannot be attain complete power requirements and its efficiency also very low so that to fulfill this requirements to combine two or more cycles in a single power plant then we can increase the efficiency of the power plant. Its increased efficiency is more than that of if the plant operated on single cycle. In which we are using two different cycles and these two cycles are operated by means of different working mediums. These type of power plants we can called them like combined cycle power plants. In combined cycle power plants above cycle is known as topping cycle and below cycle is known as bottoming cycle. The above cycle generally brayton cycle which uses air as a working medium. When the power generation was completed the exhaust gas will passes in to the waste heat recovery boiler. Another cycle also involved in bottoming cycle. This cycle works on the basis on rankine cycle. In which steam is used as working medium. The main component in bottoming cycle is waste heat recovery boiler. It will receive exhaust heat from the gas turbine and converts water in to steam. The steam used for generating power by expansion on steam turbine. Combined cycle power plants are mostly used in commercial power plants.In this paper we are analyzing one practical combined cycle power plant. In practical conditions due to some losses it can not be generates complete power. So that we are invistigated why it is not give that much of power and the effect of various operating parameters such as maximum temperature and pressure of rankine cycle, gas turbine inlet temperature and pressure ratio of Brayton cycle on the net output work and thermal efficiency of the combine cycle power plant.The outcome of this work can be utilized in order to facilitate the design of a combined cycle with higher efficiency and output work. Mathematical calculations and simple graphs in ms excel, and auto cad has been carried out to study the effects and influences of the above mentioned parameters on the efficiency and work output.

Performance Comparison of Gas Turbine Cycle Combined With Supercritical CO2 Recompression and Regenerative Cycle

2018 ◽  
Author(s):  
Yuqi Han ◽  
Weilin Zhuge ◽  
Yangjun Zhang ◽  
Haoxiang Chen
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Supercritical Co2 ◽  
Performance Comparison ◽  
Maximum Temperature ◽  
Micro Gas Turbine ◽  
Coupling Methods ◽  
Gas Turbine Cycle ◽  
Recompression Cycle ◽  
Regenerative Cycle

With the aim to recover waste heat from a specific micro gas turbine (MGT), and improve the thermal efficiency and the system compactness, simulation models of regenerative gas turbine cycle combined with supercritical CO2 recompression cycle and supercritical CO2 regenerative cycle respectively are developed. The influence of the introduction of the gas turbine recuperator with three cycle coupling methods on the thermal efficiency of the system is discussed. Compare to the micro gas turbine system combined with supercritical CO2 regenerative cycle, the improved system can increase the thermal efficiency and the output power by 3.32 percent point and 10.54% respectively. The impact on system performance of cycle parameters, including split ratio, the maximum temperature of the bottoming cycle, the recuperator effectiveness of the bottoming cycle and the hot side outlet temperature of the intermediate heat exchanger have been analyzed and optimized. From the viewpoints of the thermal efficiency and the heat transfer area, performance comparison between two bottoming cycles with different coupling methods is done. The multi-objective optimization study shows that the regenerative gas turbine cycle coupled in series with supercritical CO2 recompression cycle performs better than that coupled in parallel with supercritical CO2 regenerative cycle in terms of thermal efficiency.

An analysis of a thermal power plant working on a Rankine cycle: A theoretical investigation

2008 ◽  
Vol 19 (1) ◽  
pp. 77-83 ◽  
Author(s):  
R.K. Kapooria ◽  
S. Kumar ◽  
K.S. Kasana
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Carnot Cycle ◽  
Steam Power ◽  
Factors Affecting ◽  
Steam Power Plants ◽  
Effi Ciency ◽  
Cycle Efficiency

Today, most of the electricity produced throughout the world is from steam power plants. However, electricity is being produced by some other power generation sources such as hydropower, gas power, bio-gas power, solar cells, etc. One newly devel-oped method of electricity generation is the Magneto hydro dynamic power plant. This paper deals with steam cycles used in power plants. Thermodynamic analysis of the Rankine cycle has been undertaken to enhance the efficiency and reli-ability of steam power plants. The thermodynamic deviations resulting in non-ideal or irreversible func-tioning of various steam power plant components have been identified. A comparative study between the Carnot cycle and Rankine cycle efficiency has been analyzed resulting in the introduction of regen-eration in the Rankine cycle. Factors affecting effi-ciency of the Rankine cycle have been identified and analyzed for improved working of thermal power plants.

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