Which Device Requires Electrical Energy To Produce A Chemical Change

Ratio betwixt the useful output and the input of a machine

Useful output free energy is always lower than input free energy.

Efficiency of power plants, world total, 2008

Energy conversion efficiency ( η ) is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The input, likewise as the useful output may be chemical, electrical power, mechanical work, light (radiations), or rut. ^{[1] [2] [three]}

Overview [edit]

Energy conversion efficiency depends on the usefulness of the output. All or part of the rut produced from burning a fuel may become rejected waste estrus if, for example, work is the desired output from a thermodynamic cycle. Energy converter is an example of an energy transformation. For example, a light seedling falls into the categories energy converter. ${\displaystyle \eta ={\frac {P_{\mathrm {out} }}{P_{\mathrm {in} }}}}$ Even though the definition includes the notion of usefulness, efficiency is considered a technical or physical term. Goal or mission oriented terms include effectiveness and efficacy.

Mostly, energy conversion efficiency is a dimensionless number between 0 and 1.0, or 0% to 100%. Efficiencies may not exceed 100%, e.g., for a perpetual move auto. Nonetheless, other effectiveness measures that tin can exceed i.0 are used for heat pumps and other devices that motility rut rather than convert it.

When talking about the efficiency of heat engines and power stations the convention should be stated, i.e., HHV (a.g.a. Gross Heating Value, etc.) or LCV (a.1000.a. Net Heating value), and whether gross output (at the generator terminals) or cyberspace output (at the power station contend) are being considered. The two are separate but both must be stated. Failure to do so causes endless defoliation.

Related, more specific terms include

• Electrical efficiency, useful power output per electrical power consumed;
• Mechanical efficiency, where ane form of mechanical energy (e.one thousand. potential energy of water) is converted to mechanical energy (work);
• Thermal efficiency or Fuel efficiency, useful heat and/or work output per input free energy such as the fuel consumed;
• 'Total efficiency', e.g., for cogeneration, useful electrical power and heat output per fuel energy consumed. Same as the thermal efficiency.
• Luminous efficiency, that portion of the emitted electromagnetic radiations is usable for homo vision.

Chemical conversion efficiency [edit]

The change of Gibbs energy of a defined chemic transformation at a item temperature is the minimum theoretical quantity of energy required to make that alter occur (if the change in Gibbs energy between reactants and products is positive) or the maximum theoretical energy that might exist obtained from that alter (if the change in Gibbs energy between reactants and products is negative). The energy efficiency of a process involving chemical modify may exist expressed relative to these theoretical minima or maxima.The difference between the change of enthalpy and the change of Gibbs energy of a chemical transformation at a detail temperature indicates the rut input required or the heat removal (cooling) required to maintain that temperature.^[4]

A fuel cell may be considered to be the reverse of electrolysis. For case, an platonic fuel prison cell operating at a temperature of 25 C having gaseous hydrogen and gaseous oxygen every bit inputs and liquid water equally the output could produce a theoretical maximum amount of electrical free energy of 237.129 kJ (0.06587 kWh) per gram mol (18.0154 gram) of h2o produced and would require 48.701 kJ (0.01353 kWh) per gram mol of h2o produced of heat energy to be removed from the cell to maintain that temperature while an ideal electrolysis unit operating at a temperature of 25 C having liquid h2o as the input and gaseous hydrogen and gaseous oxygen equally products would crave a theoretical minimum input of electrical energy of 237.129 kJ (0.06587 kWh) per gram mol (18.0154 gram) of water consumed and would require 48.701 kJ (0.01353 kWh) per gram mol of water produced of heat energy to be added to the unit to maintain that temperature.

Fuel heating values and efficiency [edit]

In Europe the usable energy content of a fuel is typically calculated using the lower heating value (LHV) of that fuel, the definition of which assumes that the h2o vapor produced during fuel combustion (oxidation) remains gaseous, and is non condensed to liquid water so the latent heat of vaporization of that water is non usable. Using the LHV, a condensing boiler tin achieve a "heating efficiency" in backlog of 100% (this does not violate the first law of thermodynamics as long as the LHV convention is understood, just does cause confusion). This is considering the apparatus recovers part of the oestrus of vaporization, which is not included in the definition of the lower heating value of a fuel.^{[ citation needed ]} In the U.South. and elsewhere, the college heating value (HHV) is used, which includes the latent rut for condensing the water vapor, and thus the thermodynamic maximum of 100% efficiency cannot exist exceeded.

Wall-plug efficiency, luminous efficiency, and efficacy [edit]

The accented irradiance of four unlike gases when used in a flashtube. Xenon is by far the most efficient of the gases, although krypton is more than effective at a specific wavelength of light.

The sensitivity of the man center to various wavelengths. Assuming each wavelength equals i watt of radiant energy, but the center wavelength is perceived as 685 candelas (i watt of luminous energy), equaling 685 lumens. The vertical colored-lines represent the 589 (yellow) sodium line, and pop 532 nm (green), 671 nm (crimson), 473 nm (blueish), and 405 nm (violet) laser pointers.

A Sankey diagram showing the multiple stages of energy loss between the wall plug and the light output of a fluorescent lamp. The greatest losses occur due to the Stokes shift.

In optical systems such equally lighting and lasers, the free energy conversion efficiency is often referred to as wall-plug efficiency. The wall-plug efficiency is the mensurate of output radiative-energy, in watts (joules per second), per total input electrical energy in watts. The output energy is usually measured in terms of accented irradiance and the wall-plug efficiency is given as a per centum of the total input free energy, with the inverse percentage representing the losses.

The wall-plug efficiency differs from the luminous efficiency in that wall-plug efficiency describes the straight output/input conversion of energy (the corporeality of work that tin can be performed) whereas luminous efficiency takes into business relationship the man eye's varying sensitivity to different wavelengths (how well it can illuminate a space). Instead of using watts, the power of a light source to produce wavelengths proportional to homo perception is measured in lumens. The human eye is virtually sensitive to wavelengths of 555 nanometers (greenish-yellow) merely the sensitivity decreases dramatically to either side of this wavelength, following a Gaussian power-curve and dropping to zero sensitivity at the ruby and violet ends of the spectrum. Due to this the eye does not unremarkably run into all of the wavelengths emitted by a particular light-source, nor does it see all of the wavelengths within the visual spectrum equally. Yellow and dark-green, for instance, make up more than 50% of what the eye perceives every bit being white, even though in terms of radiant energy white-low-cal is made from equal portions of all colors (i.eastward.: a 5 mW green laser appears brighter than a 5 mW red laser, nonetheless the red laser stands-out better against a white background). Therefore, the radiant intensity of a light source may exist much greater than its luminous intensity, meaning that the source emits more than energy than the eye can use. Likewise, the lamp's wall-plug efficiency is ordinarily greater than its luminous efficiency. The effectiveness of a light source to convert electrical energy into wavelengths of visible lite, in proportion to the sensitivity of the human center, is referred to as luminous efficacy, which is measured in units of lumens per watt (lm/w) of electrical input-energy.

Dissimilar efficacy (effectiveness), which is a unit of measurement, efficiency is a unitless number expressed as a percentage, requiring but that the input and output units be of the aforementioned type. The luminous efficiency of a light source is thus the percentage of luminous efficacy per theoretical maximum efficacy at a specific wavelength. The amount of energy carried past a photon of low-cal is adamant past its wavelength. In lumens, this energy is offset past the heart's sensitivity to the selected wavelengths. For example, a green laser pointer can have greater than 30 times the apparent effulgence of a crimson pointer of the aforementioned power output. At 555 nm in wavelength, 1 watt of radiant energy is equivalent to 685 lumens, thus a monochromatic light source at this wavelength, with a luminous efficacy of 685 lm/w, has a luminous efficiency of 100%. The theoretical-maximum efficacy lowers for wavelengths at either side of 555 nm. For example, low-pressure sodium lamps produce monochromatic light at 589 nm with a luminous efficacy of 200 lm/w, which is the highest of any lamp. The theoretical-maximum efficacy at that wavelength is 525 lm/west, so the lamp has a luminous efficiency of 38.i%. Because the lamp is monochromatic, the luminous efficiency nearly matches the wall-plug efficiency of < 40%.^{[5] [6]}

Calculations for luminous efficiency become more complex for lamps that produce white calorie-free or a mixture of spectral lines. Fluorescent lamps have college wall-plug efficiencies than depression-pressure sodium lamps, but only have half the luminous efficacy of ~ 100 lm/w, thus the luminous efficiency of fluorescents is lower than sodium lamps. A xenon flashtube has a typical wall-plug efficiency of 50–70%, exceeding that of near other forms of lighting. Because the flashtube emits large amounts of infrared and ultraviolet radiations, only a portion of the output energy is used by the eye. The luminous efficacy is therefore typically around 50 lm/w. However, not all applications for lighting involve the human being eye nor are restricted to visible wavelengths. For laser pumping, the efficacy is not related to the human eye so information technology is non called "luminous" efficacy, but rather simply "efficacy" as it relates to the assimilation lines of the laser medium. Krypton flashtubes are frequently chosen for pumping Nd:YAG lasers, even though their wall-plug efficiency is typically only ~ 40%. Krypton'south spectral lines better match the absorption lines of the neodymium-doped crystal, thus the efficacy of krypton for this purpose is much higher than xenon; able to produce upward to twice the light amplification by stimulated emission of radiation output for the same electric input.^{[seven] [8]} All of these terms refer to the amount of energy and lumens as they exit the low-cal source, disregarding whatsoever losses that might occur within the lighting fixture or subsequent output optics. Luminaire efficiency refers to the total lumen-output from the fixture per the lamp output.^[9]

With the exception of a few calorie-free sources, such every bit incandescent low-cal bulbs, virtually light sources have multiple stages of energy conversion between the "wall plug" (electrical input point, which may include batteries, direct wiring, or other sources) and the final light-output, with each stage producing a loss. Low-pressure sodium lamps initially convert the electrical energy using an electrical ballast, to maintain the proper current and voltage, only some energy is lost in the ballast. Similarly, fluorescent lamps too convert the electricity using a ballast (electronic efficiency). The electricity is then converted into light free energy by the electrical arc (electrode efficiency and discharge efficiency). The light is so transferred to a fluorescent blanket that only absorbs suitable wavelengths, with some losses of those wavelengths due to reflection off and manual through the blanket (transfer efficiency). The number of photons absorbed by the blanket will not match the number then reemitted equally fluorescence (quantum efficiency). Finally, due to the phenomenon of the Stokes shift, the re-emitted photons volition take a longer wavelength (thus lower free energy) than the absorbed photons (fluorescence efficiency). In very similar manner, lasers also experience many stages of conversion betwixt the wall plug and the output discontinuity. The terms "wall-plug efficiency" or "free energy conversion efficiency" are therefore used to denote the overall efficiency of the energy-conversion device, deducting the losses from each stage, although this may exclude external components needed to operate some devices, such every bit coolant pumps.^{[x] [11]}

Example of energy conversion efficiency [edit]

Conversion procedure	Conversion blazon	Energy efficiency
Electricity generation
Gas turbine	Chemical to electric	up to 40%
Gas turbine plus steam turbine (combined bicycle)	Chemical to thermal+electrical (cogeneration)	up to 63.08%[12] In December 2017, GE claimed >64% in its latest 826 MW 9HA.02 establish, up from 63.seven%. They said this was due to advances in additive manufacturing and combustion. Their press release said that they planned to achieve 65% by the early on 2020s.[13] [ self-published source ]
Water turbine	Gravitational to electrical	upwards to 95%[14] [ self-published source ] (practically achieved)
Wind turbine	Kinetic to electrical	upward to fifty% (HAWT in isolation,[15] up to 25%–40% HAWTs in close proximity, upwards to 35%–40% VAWT in isolation, up to 41%–47% VAWT series-subcontract.[xvi] 3128 HAWTs older than 10 years in Kingdom of denmark showed that half had no decrease, while the other one-half saw a production decrease of one.2% per year.[17] Theoretical limit= 16/27= 59%)
Solar cell	Radiative to electric	half-dozen–xl% (applied science-dependent, 15–20% nigh ofttimes, median degradation for x-Si technologies in the 0.5–0.half-dozen%/year[18] range with the hateful in the 0.8–0.9%/year range. Hetero-interface engineering (HIT) and microcrystalline silicon (µc-Si) technologies, although not equally plentiful, showroom degradation effectually 1%/year and resemble thin-film products more closely than x-Si.[19] space-stack limit: 86.viii% concentrated[20] 68.vii% unconcentrated[21])
Fuel jail cell	Chemical to thermal+electric (cogeneration)	The energy efficiency of a fuel prison cell is more often than not between xl and sixty%; all the same, if waste heat is captured in a cogeneration scheme, efficiencies of upward to 85% can be obtained.[22]
World average fossil fuel electricity generation power institute as of 2008 [23]	Chemical to electrical	Gross output 39%, Net output 33%
Electricity storage
Lithium-ion bombardment	Chemical to electric/reversible	80–90% [24]
Nickel-metal hydride bombardment	Chemical to electric/reversible	66% [25]
Lead-acid battery	Chemical to electrical/reversible	50–95% [26]
Pumped-storage hydroelectricity	gravitational to electrical/reversible	70–85% [27]
Engine/motor
Combustion engine	Chemic to kinetic	x–50%[28]
Electric motor	Electrical to kinetic	70–99.99% (> 200 W); fifty–90% (10–200 Westward); 30–60% (< 10 Due west)
Turbofan	Chemical to kinetic	20-40%[29]
Natural process
Photosynthesis	Radiative to chemical	0.1% (average)[30] to 2% (best);[31] upwardly to 6% in principle[32] (see main: Photosynthetic efficiency)
Muscle	Chemic to kinetic	14–27%
Appliance
Household refrigerator	Electrical to thermal	depression-stop systems ~ 20%; loftier-finish systems ~ xl–50%
Incandescent light bulb	Electrical to radiative	0.7–5.1%,[33] 5–10%[ citation needed ]
Light-emitting diode (LED)	Electrical to radiative	4.2–53%[34] [ failed verification ] [ dubious – discuss ]
Fluorescent lamp	Electrical to radiative	8.0–15.6%,[33] 28%[35]
Low-pressure sodium lamp	Electric to radiative	15.0–29.0%,[33] xl.5%[35]
Metal-halide lamp	Electrical to radiative	9.5–17.0%,[33] 24%[35]
Switched-mode power supply	Electrical to electrical	currently upward to 96% practically
Electric shower	Electrical to thermal	90–95% (multiply past the energy efficiency of electricity generation to compare with other h2o-heating systems)
Electric heater	Electrical to thermal	~100% (essentially all energy is converted into heat, multiply past the energy efficiency of electricity generation to compare with other heating systems)
Others
Firearm	Chemic to kinetic	~thirty% (.300 Militarist ammunition)
Electrolysis of water	Electrical to chemic	50–seventy% (lxxx–94% theoretical maximum)

See too [edit]

• Cost of electricity by source
• Energy efficiency (disambiguation)
• EROEI
• Exergy efficiency
• Figure of merit
• Oestrus of combustion
• International Electrotechnical Commission
• Perpetual motion
• Sensitivity (electronics)
• Solar cell efficiency
• Coefficient of performance

References [edit]

1. ^ Energy Glossary, California Free energy Commission (Accessed: April iii, 2021)
2. ^ What is efficiency?, NASA, Cryogenics and Fluids Co-operative (Accessed: April three, 2021)
3. ^ Efficiency, J.M.K.C. Donev et al. (2020). Energy Instruction - Efficiency (Accessed: Apr 3, 2021)
4. ^ Denbigh, G. "The Principles of Chemical Equilibrium with Applications in Chemical science and Chemical Engineering", Cambridge University Printing, Cambridge (1966)
5. ^ Applied Atomic Collision Physics, Book 5 past H. S. W. Massey, Due east. W. McDaniel, B. Bederson -- Bookish Press 1982 Page 383
6. ^ "Efficacy Limits for Solid-Land White Light Sources".
7. ^ Advanced Optical Instruments and Techniques by Daniel Malacara Hernández [es] -- CRC Printing 2018 Page 589
8. ^ Solid-state light amplification by stimulated emission of radiation applied science by Walter Koechner – Springer-Verlag 1965 Page 335
9. ^ Understanding LED Illumination by M. Nisa Khan -- CRC Press 2014 Page 21--23
10. ^ "Wall-plug Efficiency".
11. ^ Handbook of Luminescent Semiconductor Materials by Leah Bergman, Jeanne Fifty. McHale -- CRC Press 2012 Page 270
12. ^ "GE-Powered Plant Awarded World Tape Efficiency by Guinness". Power Engineering. 2018-03-27. Retrieved 2021-10-04 .
13. ^ "HA technology now available at industry-commencement 64 percent efficiency" (Press release). GE Power. December 4, 2017.
14. ^ "Heavy Metal: Building A Huge Hydropower Plant Involves Steady Hands And A Boatload Of Finesse | GE News". world wide web.ge.com . Retrieved 2021-x-04 .
15. ^ "Enercon E-family, 330 Kw to seven.v MW, Wind Turbine Specification" (PDF). Archived from the original (PDF) on 16 May 2011.
16. ^ Hansen, Joachim Toftegaard; Mahak, Mahak; Tzanakis, Iakovos (2021-02-05). Written at Faculty of Applied science, Design and Environment, Oxford Brookes University, College Cl, Wheatley, Oxford, OX33 1HX, UK. "Numerical modelling and optimization of vertical axis current of air turbine pairs: A scale upward approach". Renewable Free energy. sixth floor, 1 Appold Street London EC2A 2UT, UK: Elsevier Ltd. (published June 2021). 171: 1371–1381. doi:10.1016/j.renene.2021.03.001. {{cite journal}}: CS1 maint: location (link)
17. ^ Sanne Wittrup (1 November 2013). "11 års vinddata afslørede overraskende produktionsnedgang" [eleven years of wind data shows surprising product subtract]. Ingeniøren (in Danish). Archived from the original on 25 October 2018.
18. ^ Jordan, Dirk C.; Kurtz, Sarah R. (13 Oct 2011). "Photovoltaic Deposition Rates -- An Analytical Review" (PDF). Progress in Photovoltaics: Inquiry and Applications. National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway Golden CO 80401 USA: John Wiley & Sons, Ltd. (published 2012-06-01). 21 (1): 12–29. doi:10.1002/pip.1182. OSTI 1045052. Retrieved 2021-10-15 . {{cite journal}}: CS1 maint: location (link) CS1 maint: url-status (link)
19. ^ Jordan, Dirk C.; Kurtz, Sarah R.; VanSant, Kaitlyn; Newmiller, Jeff (seven February 2016). "Compendium of photovoltaic degradation rates: Photovoltaic degradation rates". Progress in Photovoltaics: Research and Applications. National Renewable Energy Laboratory (NREL), Gilt, CO (United States): John Wiley & Sons, Ltd. (published 2016-02-07). 24 (7): 978–989. doi:10.1002/pip.2744. ISSN 1062-7995. OCLC 640902675. OSTI 1259256. Retrieved 2021-10-xv . {{cite journal}}: CS1 maint: url-status (link)
20. ^ De Vos, A. (1980). "Detailed balance limit of the efficiency of tandem solar cells". Journal of Physics D: Applied Physics. 13 (5): 839–846. Bibcode:1980JPhD...13..839D. doi:10.1088/0022-3727/13/5/018.
21. ^ A. De Vos & H. Pauwels (1981). "On the Thermodynamic Limit of Photovoltaic Free energy Conversion". Appl. Phys. 25 (2): 119–125. Bibcode:1981ApPhy..25..119D. doi:10.1007/BF00901283. S2CID 119693148.
22. ^ "Types of Fuel Cells" Archived 9 June 2010 at the Wayback Machine. Department of Energy EERE website, accessed 4 Baronial 2011
23. ^ IEC/OECD 2008 Energy Residual for World Archived 2013-07-24 at the Wayback Machine, accessdate 2011-06-08
24. ^ Valøen, Lars Ole and Shoesmith, Marking I. (2007). The effect of PHEV and HEV duty cycles on bombardment and battery pack performance (PDF). 2007 Plug-in Highway Electric Vehicle Conference: Proceedings. Retrieved eleven June 2010.
25. ^ "NiMH Bombardment Charging Basics". PowerStream.com.
26. ^ PowerSonic, Technical Manual (PDF), p. nineteen, retrieved Jan 2014
27. ^ Pumped Hydro Storage, Energy Storage Association, feb 2012.
28. ^ "Motivations for Promoting Clean Diesels" (PDF). US Department Of Energy. 2006. Archived from the original (PDF) on Oct seven, 2008.
29. ^ "11.five Trends in thermal and propulsive efficiency". web.mit.edu . Retrieved 2016-10-26 .
30. ^ Govindjee, What is photosynthesis?
31. ^ The Dark-green Solar Collector; converting sunlight into algal biomass Wageningen University project (2005—2008)
32. ^ Miyamoto K. "Chapter 1 - Biological energy production". Renewable biological systems for alternative sustainable energy production (FAO Agricultural Services Bulletin - 128). Nutrient and Agriculture Organisation of the United Nations. Retrieved 2009-01-04 .
33. ^ ^{a b c d} Luminous efficacy#Lighting efficiency
34. ^ "All in ane LED Lighting Solutions Guide". PhilipsLumileds.com. Philips. 2012-10-04. p. 15. Archived from the original (PDF) on 2013-03-31. Retrieved 2015-11-18 .
35. ^ ^{a b c} Calorie-free Pollution Handbook. Springer. 2004. ISBN9781402026652.

External links [edit]

• The Intelligent Free energy - Europe program: the EU'south tool for funding action towards a more energy intelligent Europe
• Does it make sense to switch to LED ?

Source: https://en.wikipedia.org/wiki/Energy_conversion_efficiency

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