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Topic: Rankine cycle

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In the News (Mon 19 Aug 19)

  Rankine Cycle with Regeneration
The Carnot cycle is maximally efficient, in part, because it receives all of its heat addition at the same temperature, which is the highest temperature in the cycle.
Also shown is the percent gain in power output of the modified cycle when supplied with the same heat as the unmodified Rankine cycle and the mean temperatures of heat addition for both cycles.
For a Rankine cycle where the steam enters the boiler as a superheated gas, we can never achieve the efficiency of the Carnot cycle, even with an infinite number of regeneration stages.
www.qrg.northwestern.edu /thermo/design-library/regen/regen.html   (1709 words)

  Rankine Cycle
The Rankine cycle is the ideal prototype of steam engines in use today.
The cycle is 1) water heated at constant pressure 2) evaporated to saturated vapor 3 superheated to gas 4) expanded 5) exhausted to condenser 6) condensed.
The automobile Rankine cycle is the complete cycle including the boiler, throttle, engine, condenser and compression.
ghlin2.greenhills.net /~apatter/rankine.html   (135 words)

  Rankine cycle - Wikipedia, the free encyclopedia
Like other thermodynamic cycles, the maximum efficiency of the Rankine cycle is given by calculating the maximum efficiency of the Carnot cycle.
Rankine cycles describe the operation of steam heat engines commonly found in power generation plants.
The regenerative Rankine cycle is so named because after emerging from the condenser (possibly as a subcooled liquid) the working fluid is heated by steam tapped from the hot portion of the cycle.
en.wikipedia.org /wiki/Rankine_cycle   (659 words)

 Thermodynamic Power Cycles
There are four power cycles that are generally used in the generation of electricity; the Rankine cycle, the Brayton cycle, the Otto cycle, and the Diesel cycle.
Rankine cycle plants have a long life span, and all parts of the system are reliable and require relatively little maintenance.
The two cycles are similar in theory, with one major difference; the Otto cycle is a spark-ignition cycle, whereas the Diesel cycle is a compression ignition cycle.
www.me.gatech.edu /energy/brett/four.htm   (1990 words)

 Rankine cycle and working fluid therefor - Patent 6233938
There has been a consensus in the industry that organics as alternative Rankine cycle working fluids are inherently unstable and therefore their utility is limited to low temperature power cycles such as geothermal, solar or other novel and limited applications, e.g.
I have carefully analyzed the bottoming cycle to determine what improvements were needed which would enable a warmed (by deareation) working fluid to still extract enough heat to bring the hot gas down to the desired, minimum stack temperature, while operating with a single pressure boiler.
In a typical bottoming cycle of a conventional combined gas and steam cycle system, the mass flow rate ratio of working fluid to gas in the heat recovery boiler is typically in the range of 0.12 to 0.15.
www.freepatentsonline.com /6233938.html   (5262 words)

 Fact Sheets > What are Heat Engines?
Practical heat engines operate on less efficient cycles (such as the Rankine, Brayton, or Stirling) but in general, the highest thermal efficiency is achieved when the input temperature is as high as possible and the sink temperature is as low as possible.
The Rankine cycle system uses a liquid that evaporates when heated and expands to produce work, such as turning a turbine, which when connected to a generator, produces electricity.
This new technology is similar to the Rankine cycle except that it heats two fluids, such as ammonia and water, instead of one.
www.fact-sheets.com /science-nature/energy/heat_engines   (840 words)

 Brayton Cycle
A turbine operates on the principal of the Brayton Cycle, which is defined as a constant pressure cycle, with four basic operations which it accomplishes simultaneously and continuously for an uninterrupted flow of power.
The Rankine cycle is a thermodynamic cycle used to generate electricity in many power stations, and is the real-world approach to the Carnot cycle.
An Organic Rankine cycle uses a heated chemical instead of steam as found in the Rankine Cycle.
www.cogeneration.net /Brayton_Cycle.htm   (823 words)

 William Rankine - A Leader in Early Thermodynamics
In 1836, while attending the University of Edinburgh, Rankine was awarded a gold medal for his essay on the undulating theory of light, and in 1838, he won another medal for his essay on methods of investigation.
Rankine's research led him to a theory of steam engines and to expand and modify William Froude's theory on the rolling of ships among waves.
Rankine is perhaps best remembered for the Rankine cycle which describes the changes in pressure and temperature of water in a steam engine.
www.suite101.com /article.cfm/biographies_scientists/101664   (463 words)

 Power From the Sun - Chapter 12
The most common power cycle used in solar power systems is the Rankine cycle.  This cycle combines constant-pressure heat addition and rejection processes with adiabatic reversible compression and expansion processes.  It utilizes a working fluid that changes phase during the heat-transfer processes to provide essentially isothermal heat addition and rejection.
Often during this expansion process, the vapor reaches saturation conditions and a mixture of saturated liquid and saturated vapor forms in the expander.  The requirement to superheat the vapor from state 3' to 3 is defined by the amount of moisture that is permitted in the expander exhaust from state 4 to 4'.
Pumps.  The pump in a Rankine cycle is needed to raise the pressure of the liquid leaving the condenser to the pressure of the vapor generator.
www.powerfromthesun.net /chapter12/Chapter12new.htm   (3693 words)

 SDI CONVERSION CYCLES - Nuclear Thermal Propulsion
Indirect Rankine systems use a liquid (typically lithium in liquid metal reactors) that is heated by the reactor or other power source, which then passes through a heat exchanger to vaporize a working fluid (potassium in liquid metal reactors) in a secondary loop, which in turn is passed through turbomachinery and a condenser.
The primary advantage of the Rankine Cycle is high efficiency, and isothermal heat rejection, which minimizes the area of a radiator for a given operating temperature.
The fact that the Rankine cycle is based on the use of working fluids that are present in both liquid and vapor phases adds a further element of complexity.
www.fas.org /nuke/space/c06sdi_3.htm   (6046 words)

 OTEC Beck - Ocean Thermal Energy Conversion Non-Rankine
Both operate on the principle defined by the Rankine Cycle, in which a refrigerant or water vapor (steam) is expanded through a turbine and the exhausting vapor is condensed by cold water pumped from great ocean depths.
Both (open and closed cycles) operate on the principle defined by the Rankine Cycle, in which a refrigerant or water vapor (steam) is expanded through a turbine and the exhausting vapor is condensed by cold water pumped from great ocean depths.
In Claude's open cycle, most of the available temperature is lost in throttling to a low pressure to produce flashed steam, leaving little for the turbine, and that steam is at such a low pressure, high specific volume that "ordinary" steam turbines are of no use.
otecbeck.com /index.html   (1103 words)

 Compact, Recuperated, Binary-Fluid Rankine-Cycle Engine
The described binary-fluid Rankine cycle has higher efficiency and smaller volume than Rankine cycles with single-component working fluids.
It has nearly the same efficiency but much smaller volume than the binary-fluid Kalina Rankine cycle, which entails the use of separators and additional heat exchangers to vary the proportions of ammonia and water in the working fluid at various points in the cycle.
In so doing, the recuperator recycles some of the heat that would otherwise be dumped out through the condenser as waste heat; thus, the main effect of the recuperator is to increase the energy-conversion efficiency.
www.nasatech.com /Briefs/Sept00/LEW16834.html   (568 words)

 Heat cycle patent invention
Due to the foregoing, it is possible to provide a heat cycle, which is provided with a refrigerating cycle and a Rankine cycle which are changeable each other, in which an incomplete start at the time of Rankine cycle can be reduced and a deterioration of the cycle efficiency can be reduced.
Alternatively, this Rankine cycle device can be used as an automotive power generating device in which waste heat of an internal combustion engine of an automobile is recovered so as to generate automotive power.
The prior application further includes: components to compose a Rankine cycle device to provide a waste heat recovery operation mode (Rankine cycle operation) in which the refrigerant is made to flow in the order of the liquid pump 32.fwdarw.the vapor generator 30.fwdarw.the reversible rotary machine 10.fwdarw.the radiator 11.
www.freshpatents.com /Heat-cycle-dt20051201ptan20050262858.php   (1216 words)

 ..: Distributed Energy | Technology Review :..
The Rankine cycle is the heat-engine operating cycle used by all steam engines since the start of the industrial age.
A regenerative Rankine cycle utilizes steam from the hot portion of the cycle (phase 2 to 3 and phase 3 to 4) to reheat the liquid cooled by the condenser, to greatly increase the efficiency of the work performed by the system.
Since a potential waste-heat source of a Rankine cycle heat engine is less intense and more diffuse than the direct heat of a fuel-burning boiler, working fluid other than water is needed to efficiently capture and use this energy, which brings us to organic working fluids.
www.distributedenergy.com /de_0511_tech.html   (2857 words)

 Freepower ORC Electricity Company General FAQs
The Rankine cycle was invented by William Rankine in the mid 19th Century, and used as a thermodynamic standard for rating the performance of steam turbines.
Rankine was elected a Fellow of the Royal Society in 1853 and became Professor of Civil engineering and Mechanics at the University of Glasgow in 1855.
An Organic Rankine Cycle uses a heated chemical instead of steam, as used in the original Rankine Cycle.
www.freepower.co.uk /FAQ-general.htm   (711 words)

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