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Topic: Heat engines Carnot cycle

	Heat Engines: the Carnot Cycle
		All standard heat engines (steam, gasoline, diesel) work by supplying heat to a gas, the gas then expands in a cylinder and pushes a piston to do its work.
		The analog to having the water flow into buckets at the same height, with no wasteful drop, is to have the heat from the heat supply flow into the gas at the same temperature.
		Carnot’s cycle is around that curved quadrilateral having these four curves as its sides.
	galileo.phys.virginia.edu /classes/152.mf1i.spring02/CarnotEngine.htm (1823 words)

	Carnot heat engine - Wikipedia, the free encyclopedia
		A Carnot heat engine is a hypothetical engine that operates on the reversible Carnot cycle.
		The Carnot engine model was graphically expanded upon by Benoit Paul Émile Clapeyron in 1834 and mathematically elaborated upon by Rudolf Clausius in the 1850s and 60s from which the concept of entropy emerged.
		Carnot realised that in reality it is not possible to build a thermodynamically reversible engine, so real heat engines are less efficient than indicated by Equation 3.
	en.wikipedia.org /wiki/Carnot_heat_engine (845 words)

	Nicolas Léonard Sadi Carnot - Wikipedia, the free encyclopedia
		Born in Paris, Sadi Carnot was the son of the eminent geometer Lazare Nicholas Marguerite Carnot and brother of Hippolyte Carnot.
		Engineers of Carnot's time had tried various mechanical means, such as high pressure steam, or use of some fluid other than steam, to improve the efficiency of engines.
		Perhaps the most important contribution Carnot made to thermodynamics was the process of abstraction of the essential features of the steam engine as it was known in his day into a more general, idealized heat engine.
	en.wikipedia.org /wiki/Nicolas_L%C3%A9onard_Sadi_Carnot (1308 words)

	Sadi Carnot Biography
		Sadi Carnot, a son of the eminent geometer Lazare Nicholas Marguerite Carnot, was the most eminent of Fourier's contemporaries who were interested in the theory of heat.
		Engineers of Carnot's time had tried various mechanical means, such as high pressure of steam or using some fluid other than steam, to maximize the amount of work from engines.
		But Carnot argued correctly that all that mattered, after removing inefficiencies such as friction and heat loss, was to maximize the ratio of the temperature of heat input to the temperature of heat exhaust, see Carnot heat engine.
	www.biographybase.com /biography/Carnot_Sadi.html (274 words)

	Fact Sheets > What are Heat Engines?
		Heat engines cannot convert all the input energy to useful mechanical energy in the same cycle; some amount, in the form of heat, is always not available for the immediate performance of mechanical work.
		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 Stirling cycle engine (also called an "external" combustion engine) differs from the Rankine in that it uses a gas, such as air, helium, or hydrogen, instead of a liquid, as its working fluid.
	www.fact-sheets.com /science-nature/energy/heat_engines (840 words)

	Carnot Cycle
		A thermodynamic process, such as heating or compressing the gas, changes the values of the state variables in a manner which is described by the laws of thermodynamics.
		The work done by a gas and the heat transferred to a gas depend on the beginning and ending states of the gas and on the process used to change the state.
		During the cycle, work W has been produced by the gas, and the amount of work is equal to the area enclosed by the process curves.
	www.grc.nasa.gov /WWW/K-12/airplane/carnot.html (718 words)

	Lecture 42
		209 J of energy is transferred by heat to 1.00 mol of an ideal gas initially at 300 K in a constant-volume process.
		Heat was deposited into the water and the bell, increasing the entropy of both.
		Heat would have to be removed from the water and the bell and spontaneously form into an ordered energy.
	www.uwsp.edu /physastr/kmenning/Phys203/Lect42.html (271 words)

	Carnot Cycle
		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.
		Nicklaus Otto invented an internal combustion engine in 1876 that was the predecessor to the modern gasoline engine.
		Otto’s engine mixed fuel and air before their introduction to the cylinder, and a flame or spark was used to ignite the fuel-air mixture at the appropriate time.
	www.cogeneration.net /Carnot_Cycle.htm (740 words)

	Engines (Site not responding. Last check: 2007-10-22)
		Engines can be found in cars, trucks, motorcycles, planes, boats, ships, trains, lawnmowers, chain saws, model airplanes, portable generators, cranes, augers, drills, and rockets (to give but a few examples).
		A steam-indicator is a device for plotting the pressure in the cylinder of a steam engine as a function of the phase of the engine's working cycle.
		In accordance with the work-energy theorem, this heat lost is less than the heat gained during combustion (the difference between them being equal to the net work done by the gas).
	hypertextbook.com /physics/thermal/engines (1844 words)

	Carnot Cycle
		The most efficient heat engine cycle is the Carnot cycle, consisting of two isothermal processes and two adiabatic processes.
		When the second law of thermodynamics states that not all the supplied heat in a heat engine can be used to do work, the Carnot efficiency sets the limiting value on the fraction of the heat which can be so used.
		It is not a practical engine cycle because the heat transfer into the engine in the isothermal process is too slow to be of practical value.
	hyperphysics.phy-astr.gsu.edu /hbase/thermo/carnot.html (374 words)

	Heat Engine (Site not responding. Last check: 2007-10-22)
		Heat engine is defined as a device that converts heat energy into mechanical energy or more exactly a system which operates continuously and only heat and work may pass across its boundaries.
		The operation of a heat engine can best be represented by a thermodynamic cycle.
		In case of a reverse heat engine the second law of thermodynamics is as follows: It is impossible to transfer heat from a cooler body to a hotter body without any work input i.e.
	www.taftan.com /thermodynamics/HENGINE.HTM (218 words)

	PHSchool - AP* Lesson Plans (Site not responding. Last check: 2007-10-22)
		Determine the efficiency of a heat engine in terms of heat input and heat output.
		Determine the efficiency of a heat engine in terms of input temperature and output temperature.
		A heat engine absorbs heat at 600 K and expels heat at 200 K. The efficiency of the engine is
	www.phschool.com /advanced/lesson_plans/phys_giancoli_2002/week17.html (848 words)

	Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations
		In this article the author considers the optimum performance at the maximum power output of internally and externally irreversible heat engines of finite size in which heat transfer is proportional to the difference of temperature to an n-power.
		For the case n= 4, which corresponds to radiative heat transfer, the values of design parameters are obtained from the numerical solution of two coupled nonlinear equations.
		For a radiative heat engine of finite size, the upper limit to the optimum efficiency at maximum power output is found to be 0.339.
	www.osti.gov /energycitations/product.biblio.jsp?osti_id=253777 (241 words)

	Carnot Cycle
		The Carnot cycle, named after French engineer Nicolas Leonard Sadi Carnot, is the most efficient cycle possible.
		It consists of four basic reversible processes meaning that the cycle as a whole is also reversible.
		An important conclusion from Carnot cycle analysis is that the maximum theoretical efficiency of heat engines is directly related to:
	www.corrosion-doctors.org /Biographies/carnotcycle.htm (223 words)

	Heat engines (Site not responding. Last check: 2007-10-22)
		Heat engines cannot convert all the input energy to useful mechanical energy in the same cycle; some amount, in the form of heat, is always not available for the immediate performance of mechanical work.
		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 "waste" or rejected heat (to the "sink") can be used for other purposes, including pressurizing a different working fluid, which operates a different heat-engine (vapor turbine) cycle, or simply for heating.
	thermalmotion.net (325 words)

	Heat engine, refrigeration and heat pump cycles approximating the Carnot cycle and apparatus therefor (US5027602)
		Heat engine, refrigeration and heat pump cycles approximating the Carnot cycle and apparatus therefor
		These process approximations, in addition to isothermal heat addition and rejection, enable Carnot heat engine, refrigeration and heat pump cycles to be approximated.
		(c) expanding the heated working fluid provided by step (b) in an expander to produce a work output while the working fluid, during at least an initial portion of the expansion, is in the form of a mixture of fine droplets of saturated liquid in saturated vapour;
	www.delphion.com /details?pn=US05027602__ (635 words)

	Carnot - Understanding Refrigeration
		He proposed the reversible Carnot cycle, and discovered that the efficiency of a heat engine depended only on its input and output temperatures.
		Carnot proposed that work was generated by the passage of caloric from a warmer to a cooler body, with caloric being conserved in the process.
		The temperature at which the heat is supplied from the boiler, and that at which heat is rejected in the condenser would be just like the water levels for the water wheel.
	www.alephzero.co.uk /ref/carnot.htm (397 words)

	IECEC-98-318 (Site not responding. Last check: 2007-10-22)
		In order to involve solar light under non-equilibrium with respect to matter as a motive power within thermodynamics, it is proposed to assume that principle of Carnot formulated for heat engines is also valid for renewable processes (cycles) between an illuminated (source) and a dark (sink) part of a condensed fluid by local optical pumping.
		The problem is to find fundamental restriction of renewable cycles for mechanical energy production by interaction of solar light with matter to estimate perspectives and possible spheres of engineering application several technological processes has been found by action of laser light on liquid.
		Renewable thermodynamics is between the equilibrium radiation thermodynamics and the thermodynamics of heat engines to answer question: why without any machines, the efficiency of conversion is able to be by many orders of magnitude greater than the efficiency of direct mechanical action of light given in framework of equilibrium radiation thermodynamics.
	www.gpi.ru /~sukhodol/free/h1/u1.htm (5585 words)

	Carnot Cycle
		If the heat engine cycles through as a reversible process, the total energy change is zero.
		In a real situation, the processes going on in a heat engine are not actually reversible, so the true efficiency is always less than the Carnot efficiency.
		During the first phase, while heat is transferring energy from the hot reservoir, the temperature of the system remains constant and the process is isothermal.
	physics.tamuk.edu /~suson/html/3333/Carnot.html (1277 words)

	Ask Leo - Adding Heat Back to Carnot Cycle
		Carnot’s principle can readily be generalized to include engines that receive heat transfer over a range of temperatures and reject heat over a (normally different) range of temperatures.
		A heat engine may undergo changes in its state in the course of a cycle, but return to its initial state, thereby undergoing no net change in its state.
		A heat engine operating in reverse, such as a refrigerator, can cause heat transfer from a thermal reservoir to another thermal reservoir at a higher temperature.
	www.simtherg.com /askleo2.html (911 words)

	Clan Stirling Online! News (Site not responding. Last check: 2007-10-22)
		He soon became concerned about the danger the workers in his parish faced from steam engines, which frequently exploded because ofthe poor quality of the iron boiler plate available at the time, and decided to improve the design of an existing air engine in the hope that it would provide a safer alternative.
		The theoretical basis of Stirling's engine, the Stirling cycle, would not be fully understood until the work of Sadi Carnot (1796 - 1832).
		Carnot produced (and published in 1825) a general theory of heat engines, the Carnot cycle, of which the Stirling cycle is a similar case.
	s88173292.onlinehome.us /Main/news/news.shtml (1413 words)

	Heat Engine Projects
		theorem which says that a maximum efficiency of heat engine can be obtained by a reversible engine, and that efficiency depends only on the temperatures of the hot and the cool sources of the engine.
		A heat exchanger is used to boil water and a closed cycle generator system using a turbine then operates a generator or alternator.
		Sterling Thermal Power has developed a thermally driven powerplant comprised of a heat collector, an evaporator for vaporizing a heated refrigerant, an ORC rotary valved piston engine for converting the heated refrigerant vapor into power, a condenser for condensing the vaporous refrigerant exhaust, and Sterling's proprietary motorless feedpump for recycling the spent refrigerant for re-use.
	www.redrok.com /engine.htm (3562 words)

	HumCooler: The Carnot Cycle (Site not responding. Last check: 2007-10-22)
		Sadi Carnot (1796-1832) was a French physicist who was interested in the steam engine, and spent most of his life trying to improve it.
		Carnot's theory describes the best efficiency that a heat engine can achieve, appropriately called the Carnot efficiency.
		Any real heat engine can only approximate it, but the Carnot efficiency is a useful goal, and the efficiency of a real heat engine is often compared to the Carnot efficiency as a standard.
	stuff.mit.edu /people/howitt/humcool/sci8.html (177 words)

	PGP Teaching Resources
		A perception of the Carnot cycle (© unknown student).
		Heat capacities of ideal gases, adiabatic processes in ideal gases
		The Second Law, thermal efficiency of heat engines, Carnot cycle, entropy, irreversible processes, fundamental thermodynamic relationship
	newton.ex.ac.uk /teaching/resources/pgp/index.html (78 words)

	Heat Engines and the Carnot Cycle
		A heat engine is a cyclic process that absorbs heat and does work on the surroundings.
		As we have said, the Carnot cycle is a heat engine.
		Even though the Carnot cycle is idealized the general principles of heat engines remain the same.
	www.chem.arizona.edu /~salzmanr/480a/480ants/carnot/carnot.html (936 words)

	Carnot Engines, Heat Pumps, and Refrigerators
		The enclosed area (and therefore the mechanical work done) will depend on the two temperatures ("height") and on the amount of heat transferred, which depends in turn on the extent of the isothermal compression or expansion ("width"), during which heat must be transferred to maintain the constant temperature.
		For a heat engine, the efficiency is the ratio of useful work performed to the heat energy consumed from the high-temperature reservoir:
		For a Carnot machine functioning as a heat pump, the "effectiveness" is the ratio of the energy delivered to the high-temperature reservoir to the work required to force the machine around its cycle (the energy consumed and paid for):
	oak.cats.ohiou.edu /~piccard/phys202/carnot/carnot.html (864 words)

	Rankine Cycle
		This approach provides our customers with superior performance, decreased operating expenses and increased return on investment.
		History of the Carnot Cycle, Organic Rankine Cycle and Brayton Cycle
		Background Information and History of Rudolph Diesel and Sadi Carnot
	www.cogeneration.net /Rankine_Cycle.htm (830 words)

	Engineering at Birmingham: Module - Fluid Flow, Thermodynamics and Heat Transfer
		Applications of principles to engineering problems, including flow measurement by orifice, Venturi, Pitot tube, rotameter and weirs.
		Carnot cycle and some other theoretical cycles including refrigeration.
		Practical problems involving forced convection, resistances in series, overall heat transfer coefficients, Design of simple heat exchangers, log-mean temperature differences.
	www.eng.bham.ac.uk /metallurgy/ug/fluidflow.htm (317 words)

	Triode designs with longitudinal magnetic field
		The thermionic energy converter as a topping cycle for more efficient heat engines—new triode designs with a longitudinal magnetic field
		A new concept for converting heat energy to electrical energy using thermionic energy converters (TECs) is proposed.
		It has potential for increasing the Carnot efficiency to an unprecedented 80% when the TEC is combined as a topping cycle with a conventional external combustion engine.
	stacks.iop.org /0022-3727/38/782 (358 words)

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