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Encyclopedia > Energy density

Energy density is the amount of energy stored in a given system or region of space per unit volume, or per unit mass, depending on the context. In some cases it is obvious from context which quantity is most useful: for example, in rocketry, energy per unit mass is the most important parameter, but when studying pressurized gas or magnetohydrodynamics the energy per unit volume is more appropriate. In a few applications (comparing, for example, the effectiveness of hydrogen fuel to gasoline) both figures are appropriate and should be called out explicitly. (Hydrogen has a higher energy density per unit mass than does gasoline, but a much lower energy density per unit volume in most applications.) For other uses, see Volume (disambiguation). ... For other uses, see Mass (disambiguation). ... A rocket is a vehicle, missile or aircraft which obtains thrust by the reaction to the ejection of fast moving exhaust from within a rocket engine. ... Magnetohydrodynamics (MHD) (magnetofluiddynamics or hydromagnetics) is the academic discipline which studies the dynamics of electrically conducting fluids. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... Petrol redirects here. ...


Energy density per unit volume has the same physical units as pressure, and in many circumstances is an exact synonym: for example, the energy density of the magnetic field may be expressed as (and behaves as) a physical pressure, and the energy required to compress a gas may be determined by multiplying the pressure of the compressed gas times its final volume. This article is about pressure in the physical sciences. ... Synonyms (in ancient Greek, συν (syn) = plus and όνομα (onoma) = name) are different words with similar or identical meanings. ...

Contents

Energy density in energy storage and in fuel

In energy storage applications, the energy density relates the mass of an energy store to its stored energy. The higher the energy density, the more energy may be stored or transported for the same amount of mass. In the context of fuel selection, that energy density of a fuel is also called the specific energy of that fuel, though in general an engine using that fuel will yield less energy due to inefficiencies and thermodynamic considerations—hence the specific fuel consumption of an engine will be greater than the reciprocal of the specific energy of the fuel. And in general, specific energy and energy density are at odds due to charge screening. Energy storage is the storing of some form of energy that can be drawn upon at a later time to perform some useful operation. ... For other uses, see Mass (disambiguation). ... For other uses, see Fuel (disambiguation). ... The fuel value or relative energy density is the quantity of potential energy in fuel, food or other substance. ... For other uses, see Engine (disambiguation). ... The term inefficiency has several meanings depending on the context in which its used: Economic inefficiency refers to a situation where we could be doing a better job, i. ... Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dynamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ... Specific fuel consumption, often shortened to SFC, is an engineering term that is used to describe the fuel efficiency of an engine design w/ a mechanical output. ... Look up reciprocal in Wiktionary, the free dictionary. ... The shielding effect describes the decrease in attraction between an electron and the nucleus in any atom with more than one electron shell. ...


Gravimetric and volumetric energy density of some fuels and storage technologies (modified from the Gasoline article): Petrol redirects here. ...

(Notes: Some values may not be precise because of isomers or other irregularities. See Heating value for a comprehensive table of specific energies of important fuels. The symbol ** indicates the item is an energy carrier, not an energy source.)
storage type energy density recovery efficiency
by mass by volume peak practical
MJ/kg MJ/L  %  %
**mass-energy equivalence 89,876,000,000
**binding energy of helium nucleus 675,000,000 8.57x1024
nuclear fusion of hydrogen (energy from the sun) 300,000,000 423,000,000
nuclear fission (of U-235) (Used in Nuclear Power Plants) 77,000,000 1,500,000,000 30% 50%
**liquid hydrogen 143 10.1
**compressed gaseous hydrogen at 700 bar[1] 143 4.7
**gaseous hydrogen at room temperature[citation needed] 143 0.01079
beryllium (toxic) (burned in air) 67.6 125.1
lithium borohydride (burned in air) 65.2 43.4
boron [2] (burned in air) 58.9 137.8
compressed natural gas at 200 bar 53.6[3] 10
gasoline[4] 46.9 34.6
diesel fuel/residential heating oil[5] 45.8 38.7
polyethylene plastic 46.3[6] 42.6
polypropylene plastic 46.3[7] 41.7
gasohol (10% ethanol 90% gasoline) 43.54 28.06
lithium (burned in air) 43.1 23.0
Jet A aviation fuel[8] 42.8 33
biodiesel oil (vegetable oil) 42.20 30.53
DMF (2,5-dimethylfuran) 42[9] 37.8
crude oil (according to the definition of ton of oil equivalent) 41.87 37[10]
polystyrene plastic 41.4[11] 43.5
body fat metabolism 38 35 22-26%[12]
butanol 36.6 29.2
LPG 34.39 22.16
**specific orbital energy of Low Earth orbit 33 (approx.)
graphite (burned in air) 32.7 72.9
anthracite coal 32.5 72.4 36%
silicon (burned in air)[13] 32.2 75.1
aluminum (burned in air) 31.0 83.8
ethanol 30 24
polyester plastic 26.0[14] 35.6
magnesium (burned in air) 24.7 43.0
bituminous coal [15] 24 20
PET pop bottle plastic ?23.5 impure ?
methanol 19.7 15.6
**hydrazine (toxic) combusted to N2+H2O 19.5 19.3
**liquid ammonia (combusted to N2+H2O) 18.6 11.5
PVC plastic (improper combustion toxic) 18.0[16] 25.2
sugars, carbohydrates & proteins metabolism 17 26.2(dextrose) 22-26% [17]
Cl2O7 + CH4 - computed 17.4
lignite coal 14-19
calcium (burned in air) 15.9 24.6
dry cowdung and cameldung 15.5[18]
wood 6–17[19] 1.8–3.2
**liquid hydrogen + oxygen (as oxidizer) (1:8 (w/w), 14.1:7.0 (v/v)) 13.333 5.7
sodium (burned to wet sodium hydroxide) 13.3 12.8
Cl2O7 decomposition - computed 12.2
nitromethane 11.3 12.9
household waste 8-11[20][21]
sodium (burned to dry sodium oxide) 9.1 8.8
iron (burned to iron(III) oxide) 7.4 57.9
Octanitrocubane explosive - computed 7.4
ammonal (Al+NH4NO3 oxidizer) 6.9 12.7
Tetranitromethane + hydrazine explosive - computed 6.6
Hexanitrobenzene explosive - computed 6.5
zinc (burned in air) 5.3 38.0
Teflon plastic (combustion toxic, but flame retardant) 5.1 11.2
iron (burned to iron(II) oxide) 4.9 38.2
**TNT 4.184 6.92
Copper Thermite (Al + CuO as oxidizer) 4.13 20.9
Thermite (powder Al + Fe2O3 as oxidizer) 4.00 [22] 18.4
**compressed air at 300 bar 4 0.14 ?
ANFO 3.88
hydrogen peroxide decomposition (as monopropellant) 2.7 3.8
Lithium Thionyl Chloride Battery 2.5
Regenerative Fuel Cell 1.62[23]
**hydrazine(toxic) decomposition (as monopropellant) 1.6 1.6
**ammonium nitrate decomposition (as monopropellant) 1.4 2.5
Molecular spring ~1
**sodium-sulfur battery ? 1.23[24] ? 85%[25]
**liquid nitrogen 0.77[1] 0.62
**lithium ion battery 0.54–0.72 0.9–1.9 95%[26]
**lithium sulphur battery 0.54-1.44 ?
kinetic energy penetrator 1.9-3.4 30-54
5.56 × 45 mm NATO bullet 0.4-0.8 3.2-6.4
**Zn-air batteries 0.40 to 0.72 ? ? ?
**flywheel 0.5 ? ? 81-94%[www.ccm.nl]
melting ice 0.335 0.335
**zinc-bromine flow battery 0.27–0.306[27]
**compressed air at 20 bar 0.27 ? 64%[28]
**NiMH Battery 0.22[29] 0.36 ? 60% [30]
**NiCd Battery 0.14-0.22 ? ? 80% [31]
**lead acid battery 0.09–0.11[32] 0.14–0.17 ? 75-85%[33]
**commercial lead acid battery pack 0.072-0.079[34] ? ? ?
**vanadium redox battery .09[35] .1188 ? 70-75%
**vanadium bromide redox battery .18[36] .252 ? 81%
**ultracapacitor 0.0206 [37] ? ? ?
**ultracapacitor by EEStor (claimed capacity) 1.0 [38] ? ? ?
**supercapacitor 0.01 ? 98.5% 90%[39]
**capacitor 0.002 [40] ? ? ?
water at 100 m dam height 0.001 0.001 ? 85-90%[41]
**spring power (clock spring), torsion spring 0.0003[42] 0.0006 ?
zero point energy 0 0

Conclusion: the highest density sources of energy are fusion and fission. Fusion includes energy from the sun which will be available for billions of years (in the form of sunlight) but humans have not learned to make our own sustained fusion power sources. Fission of U-235 in nuclear power plants will be available for thousands of years because of the vast supply of the element on earth[citation needed]. Coal and petroleum are the current primary energy sources in the U.S. but have a much lower energy density. Burning local biomass fuels supplies household energy needs (cooking fires, oil lamps, etc.) worldwide. In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of bonds between atoms, but in which the atoms are arranged differently. ... Heating value (or calorific value) is used to define the amount of heat released during the combustion of a fuel or food. ... The liter (spelled liter in American English and litre in Commonwealth English) is a unit of volume. ... 15ft sculpture of Einsteins 1905 E = mc² formula at the 2006 Walk of Ideas, Germany In physics, mass-energy equivalence is the concept that all mass has an energy equivalence, and all energy has a mass equivalence. ... Binding energy is the energy required to disassemble a whole into separate parts. ... For other uses, see Helium (disambiguation). ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... Sol redirects here. ... An induced nuclear fission event. ... Uranium-235 is an isotope of uranium that differs from the elements other common isotope, uranium-238, by its ability to cause a rapidly expanding fission chain reaction. ... A nuclear power plant (NPP) is a thermal power station in which the heat source is one or more nuclear reactors. ... A heat engine is a physical or theoretical device that converts thermal energy to mechanical output. ... Liquid hydrogen is the liquid state of the element hydrogen. ... General Name, Symbol, Number Hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1 (IA), 1 , s Density, Hardness 0. ... General Name, symbol, number beryllium, Be, 4 Chemical series alkaline earth metals Group, period, block 2, 2, s Appearance white-gray metallic Standard atomic weight 9. ... Lithium Borohydride is known in organic synthesis as a reducing agent for Esters. ... General Name, Symbol, Number boron, B, 5 Chemical series metalloids Group, Period, Block 13, 2, p Appearance black/brown Standard atomic weight 10. ... Typical North America vehicles carry this diamond shape symbol, meaning it is running on compressed natural gas fuel. ... Petrol redirects here. ... This article is about the fuel. ... Heating oil, or burning oil, also known in the United States as No. ... This article does not cite any references or sources. ... Polypropylene lid of a Tic Tacs box, with a living hinge and the resin identification code under its flap Micrograph of polypropylene Polypropylene or polypropene (PP) is a thermoplastic polymer, made by the chemical industry and used in a wide variety of applications, including food packaging, ropes, textiles, stationery, plastic... Gasoline on the left, alcohol on the right at a filling station in Brazil Rising energy prices and global warming have led to increased interest in alternative fuels. ... This article is about the chemical element named Lithium. ... Jet fuel is a type of aviation fuel designed for use in jet-engined aircraft. ... An aviation fuel truck. ... This article is about transesterified plant and animal oils. ... Dimethylformamide, also known under the names N,N-dimethylformamide and DMF, is a clear, water-miscible liquid and common solvent that is often used in chemical reactions. ... Pumpjack pumping an oil well near Sarnia, Ontario Petroleum (from Greek petra – rock and elaion – oil or Latin oleum – oil ) or crude oil is a thick, dark brown or greenish liquid. ... The ton of oil equivalent (TOE) is a unit for measuring energy. ... Polystyrene (IPA: ) is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. ... This article or section is in need of attention from an expert on the subject. ... Butanol may be used as a fuel in an internal combustion engine. ... 45 kg LPG cylinders Spherical Gas Container typically found in Refineries. ... In astrodynamics the specific orbital energy (or vis-viva energy) of an orbiting body traveling through space under standard assumptions is the sum of its potential energy () and kinetic energy () per unit mass. ... A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ... For other uses, see Graphite (disambiguation). ... Anthracite coal Anthracite (Greek Ανθρακίτης, literally a form of coal, from Anthrax [Άνθραξ], coal) is a hard, compact variety of mineral coal that has a high luster. ... Coal Coal (IPA: ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... A heat engine is a physical or theoretical device that converts thermal energy to mechanical output. ... Not to be confused with Silicone. ... Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ... Grain alcohol redirects here. ... SEM picture of a bend in a high surface area polyester fiber with a seven-lobed cross section Polyester is a category of polymers, or, more specifically condensation polymers, which contain the ester functional group in their main chain. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... Ewer from Iran, dated 1180-1210CE. Composed of brass worked in repoussé and inlaid with silver and bitumen. ... Coal Coal (IPA: ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... Polyethylene terephthalate (aka PET, PETE or the obsolete PETP or PET-P) is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination with glass fiber. ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ... Hydrazine is the chemical compound with formula N2H4. ... For other uses, see Ammonia (disambiguation). ... PVC may refer to the following: Polyvinyl chloride, a plastic Premature ventricular contraction, irregular heartbeat Permanent virtual circuit, a term used in telecommunications and computer networks Param Vir Chakra, Indias highest military honor. ... Polyvinyl chloride Polyvinyl chloride, (IUPAC Polychloroethene) commonly abbreviated PVC, is a widely used thermoplastic polymer. ... This article or section is in need of attention from an expert on the subject. ... A space-filling model of glucose Glucose, a simple monosaccharide sugar, is one of the most important carbohydrates and is used as a source of energy in animals and plants. ... Dichlorine heptoxide, Cl2O7, is a chlorine oxide. ... The simplest hydrocarbon, methane, is a gas with a chemical formula of CH4. ... Coal Coal is a fossil fuel extracted from the ground by mining. ... For other uses, see Calcium (disambiguation). ... Cow dung is the faeces of the bovine species. ... Animal manure is often a mixture of animals feces and bedding straw, as in this example from a stable. ... For other uses, see Wood (disambiguation). ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) pale blue (liquid) Standard atomic weight 15. ... An oxidizing agent is a substance that oxidizes another substance in electrochemistry or redox chemical reactions in general. ... For sodium in the diet, see Edible salt. ... Flash point Non-flammable. ... Dichlorine heptoxide, Cl2O7, is a chlorine oxide. ... Flash point 35 °C R/S statement R: S: RTECS number PA9800000 Related compounds Related nitro compounds nitroethane Related compounds methyl nitrite methyl nitrate Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references Nitromethane is an organic... Mixed municipal waste, Hiriya, Tel Aviv Municipal solid waste (MSW) is a waste type that includes predominantly household waste (domestic waste) with sometimes the addition of commercial wastes collected by a municipality within a given area. ... For sodium in the diet, see Edible salt. ... Sodium oxide is a chemical compound with the formula Na2O. It is used in ceramics and glasses. ... For other uses, see Iron (disambiguation). ... Iron(III) oxide — also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply rust — is one of the several oxide compounds of iron, and has paramagnetic properties. ... Octanitrocubane is a shock-insensitive high explosive. ... Ammonal is an explosive mixture of ammonium nitrate, aluminium dust and stearic acid. ... Related Compounds Other anions Ammonium nitrite; ammonium perchlorate Other cations Sodium nitrate; potassium nitrate; hydroxylammonium nitrate Related compounds Nitrous oxide Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references The chemical compound ammonium nitrate, the nitrate of... An oxidizing agent is a substance that oxidizes another substance in electrochemistry or redox chemical reactions in general. ... Tetranitromethane or TNM is an organic oxidizer with chemical formula C(NO2)4. ... Hydrazine is the chemical compound with formula N2H4. ... Hexanitrobenzene is a high-density explosive compound with chemical formula C6N6O12, obtained by oxidizing the amine group of pentanitroaniline with hydrogen peroxide in sulfuric acid. ... General Name, symbol, number zinc, Zn, 30 Chemical series transition metals Group, period, block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ... Teflon is the brand name of a polymer compound discovered by Roy J. Plunkett (1910-1994) of DuPont in 1938 and introduced as a commercial product in 1946. ... For other uses, see Iron (disambiguation). ... Iron(II) oxide, also called ferrous oxide, is a black-colored powder with the chemical formula FeO. It consists of the element iron in the oxidation state of 2 bonded to oxygen. ... R-phrases S-phrases Related Compounds Related compounds picric acid hexanitrobenzene Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Trinitrotoluene (TNT) is a chemical compound with the formula C6H2(NO2)3CH3. ... A thermite mixture using Iron (III) Oxide A thermite mixture using Iron (II,III) Oxide A thermite reaction is a type of aluminothermic reaction in which aluminium metal is oxidized by the oxide of another metal, most commonly iron oxide. ... Copper(II) oxide or cupric oxide (CuO) is the higher oxide of copper. ... An oxidizing agent is a substance that oxidizes another substance in electrochemistry or redox chemical reactions in general. ... A thermite mixture using Iron (III) Oxide A thermite mixture using Iron (II,III) Oxide A thermite reaction is a type of aluminothermic reaction in which aluminium metal is oxidized by the oxide of another metal, most commonly iron oxide. ... Iron(III) oxide — also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply rust — is one of the several oxide compounds of iron, and has paramagnetic properties. ... An oxidizing agent is a substance that oxidizes another substance in electrochemistry or redox chemical reactions in general. ... Compressed Air Energy Storage (CAES) refers to the compression of air during periods of low energy demand, for use in meeting periods of higher demand. ... ANFO stands for ammonium nitrate/fuel oil (most often diesel fuel, sometimes kerosene or even molasses). ... R-phrases , , , , S-phrases , , , ,, , , , Flash point Non-flammable Related Compounds Related compounds Water Ozone Hydrazine Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in... A (usually liquid) rocket propellant that can be used by itself, without the need for a second component. ... A fuel cell is an electrochemical device similar to a battery, but differing from the latter in that it is designed for continuous replenishment of the reactants consumed; i. ... Hydrazine is the chemical compound with formula N2H4. ... A (usually liquid) rocket propellant that can be used by itself, without the need for a second component. ... Related Compounds Other anions Ammonium nitrite; ammonium perchlorate Other cations Sodium nitrate; potassium nitrate; hydroxylammonium nitrate Related compounds Nitrous oxide Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references The chemical compound ammonium nitrate, the nitrate of... A (usually liquid) rocket propellant that can be used by itself, without the need for a second component. ... illustrative example of C-C length molecular energy dependece, numerical accuracy is not garanted illustrative example of C-C-C angle molecular energy dependece, numerical accuracy is not garanted illustrative example of C-C-C-C torsion molecular energy dependence, numerical accuracy is not garanted Molecular spring is device or... A NaS battery is a type of battery constructed from sodium (Na) and sulfur (S). ... A liquid nitrogen (LN2) economy is a hypothetical proposal for a future economy in which the primary form of energy storage and transport is liquid nitrogen. ... Lithium ion batteries (sometimes abbreviated Li-Ion or Li-On) are a type of rechargeable battery commonly used in consumer electronics. ... Soviet ammunition BM 15 of 125mm French anti-tank round with its sabot APFSDS at point of separation of sabot. ... 5. ... Zinc-air batteries, also called “zinc-air fuel cells,“ are non-rechargeable electro-chemical batteries powered by the oxidation of zinc with oxygen from the air. ... NASA G2 flywheel Flywheel Energy Storage (FES) works by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy. ... The latent heat of fusion of a substance is the amount of energy per unit mass required to turn a specified amount of the substance in its solid phase at its melting point to a liquid at the same temperature. ... The zinc-bromine flow battery is a type of hybrid flow battery. ... Compressed Air Energy Storage (CAES) refers to the compression of air during periods of low energy demand, for use in meeting periods of higher demand. ... A nickel metal hydride battery, abbreviated NiMH, is a type of rechargeable battery similar to a nickel-cadmium (NiCd) battery but has a hydrogen-absorbing alloy for the anode instead of cadmium. ... The nickel-cadmium battery (commonly abbreviated NiCd and pronounced nye-cad) is a popular type of rechargeable battery for portable electronics and toys using the metals nickel (Ni) and cadmium (Cd) as the active chemicals. ... Lead-acid batteries, invented in 1859 by French physicist Gaston Planté, are the most commonly used rechargeable batteries today. ... The vanadium redox ( and redox flow ) battery was first patented by the University of New South Wales in Australia in 1986. ... The vanadium redox (and redox flow) battery in its present form (with sulphuric acid electrolytes) was patented by the University of New South Wales in Australia in 1986 . ... An Ultracapacitor is a capacitor that has an unusually large amount of energy storage capability relative to its size when compared to common capacitors. ... An Ultracapacitor is a capacitor that has an unusually large amount of energy storage capability relative to its size when compared to common capacitors. ... A supercapacitor or an ultracapacitor is an electrochemical capacitor that has an unusually large amount of energy storage capability relative to its size when compared to common capacitors. ... See Capacitor (component) for a discussion of specific types. ... Hydroelectricity is electricity produced by hydropower. ... Springs A spring is a flexible elastic object used to store mechanical energy. ... This article or section does not adequately cite its references or sources. ... In a quantum mechanical system such as the particle in a box or the quantum harmonic oscillator, the lowest possible energy is called the zero-point energy. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... In general fission is a splitting or breaking up of any substance into parts. ... Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ... A nuclear power plant (NPP) is a thermal power station in which the heat source is one or more nuclear reactors. ... Coal Coal (IPA: ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... Pumpjack pumping an oil well near Lubbock, Texas Ignacy Łukasiewicz - inventor of the refining of kerosene from crude oil. ... See biomass (ecology) for the use of the term in ecology, where it refers to the cumulation of living matter Switchgrass, a tough plant used in the biofuel industry in the United States Rice chaff. ... Cook stoves, sometimes referred to as biomass cook stoves, are the most common way of cooking and heating food in developing countries. ... Antique bronze oil lamp with Christian symbol (replica) A terra-cotta oil lamp, Antique oil lamp (replica) An oil lamp is a simple vessel used to produce light continuously for a period of time from a fuel source. ...


Energy density (how much energy you can carry) does not tell you about energy conversion efficiency (net output per input) or embodied energy (what the energy output costs to provide, as harvesting, refining, distributing, and dealing with pollution all use energy). Like any process occurring on a large scale, intensive energy use creates environmental impacts: for example, global warming, nuclear waste storage, and deforestation are a few of the consequences of supplying our growing energy demands from fossil fuels, nuclear fission, or biomass. Energy conversion efficiency is the ratio between the useful output of an energy conversion machine and the input, in energy terms. ... Embodied Energy refers to the quantity of energy required to manufacture, and supply to the point of use, a product, material or service. ... The energy industry is a generic term for all of the industries involved the production and sale of energy, including fuel extraction, manufacturing fuel and refining, and fuel distribution. ... A refinery is composed of a group of chemical engineering unit processes and unit operations used for refining certain materials or converting raw material into products of value. ... Air pollution Pollution is the introduction of pollutants (whether chemical substances, or energy such as noise, heat, or light) into the environment to such a point that its effects become harmful to human health, other living organisms, or the environment. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Political Punk band from Victorville, Ca WWW.MYSPACE.COM/NUCLEARWASTEX ... This article is about the process of deforestation in the environment. ...


By dividing by 3.6 the figures for megajoules per kilogram can be converted to kilowatt-hours per kilogram. Unfortunately, the useful energy available by extraction from an energy store is always less than the energy put into the energy store, as explained by the laws of thermodynamics. No single energy storage method boasts the best in specific power, specific energy, and energy density. Peukert's Law describes how the amount of energy we get out depends how quickly we pull it out. The laws of thermodynamics, in principle, describe the specifics for the transport of heat and work in thermodynamic processes. ... In engineering, specific power (sometimes also power per unit mass or power density) refers to the amount of power delivered by an energy source, divided by some measure of the sources size or mass. ... The fuel value or relative energy density is the quantity of potential energy in fuel, food or other substance. ... Peukerts Law defines a way to measure the capacity of a Battery (electricity) over a range of discharge rates. ...


Energy density of electric and magnetic fields

Electric and magnetic fields store energy. In a vacuum, the (volumetric) energy density (in SI units) is given by In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field. ... Magnetic field lines shown by iron filings In physics, the space surrounding moving electric charges, changing electric fields and magnetic dipoles contains a magnetic field. ...

 U = frac{varepsilon_0}{2} mathbf{E}^2 + frac{1}{2mu_0} mathbf{B}^2 ,

where E is the electric field and B is the magnetic induction. In the context of magnetohydrodynamics, the physics of conductive fluids, the magnetic energy density behaves like an additional pressure that adds to the gas pressure of a plasma. Electromagnetic induction is the production of an electrical potential difference (or voltage) across a conductor situated in a changing magnetic field. ... Magnetohydrodynamics (MHD) (magnetofluiddynamics or hydromagnetics) is the academic discipline which studies the dynamics of electrically conducting fluids. ... This article is about pressure in the physical sciences. ... Kinetic theory attempts to explain macroscopic properties of gases, as pressure, temperature, or volume, by considering their molecular composition and motion. ... For other uses, see Plasma. ...


In normal (linear) substances, the energy density (in SI units) is

 U = frac{1}{2} ( mathbf{E} cdot mathbf{D} + mathbf{H} cdot mathbf{B} ) ,

where D is the electric displacement and H is the magnetic field. Magnetic field lines shown by iron filings In physics, the space surrounding moving electric charges, changing electric fields and magnetic dipoles contains a magnetic field. ...


Energy density of empty space

In physics, "vacuum energy" or "zero-point energy" is the volumetric energy density of empty space. More recent developments have expounded on the concept of energy in empty space. A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... Vacuum energy is an underlying background energy that exists in space even when devoid of matter (known as free space). ... In physics, the zero-point energy is the lowest possible energy that a quantum mechanical physical system may possess and is the energy of the ground state of the system. ...


Modern physics is commonly classified into two fundamental theories: quantum field theory and general relativity. Quantum field theory takes quantum mechanics and special relativity into account, and it's a theory of all the forces and particles except gravity. General relativity is a theory of gravity, but it is incompatible with quantum mechanics. Currently these two theories have not yet been reconciled into one unified description, though research into "quantum gravity" seeks to bridge this divide. Modern physics may refer to: Quantum mechanics Theory of relativity 20th-century physics in general See also History of physics This is a disambiguation page: a list of articles associated with the same title. ... Quantum field theory (QFT) is the quantum theory of fields. ... For a less technical and generally accessible introduction to the topic, see Introduction to general relativity. ... For a less technical and generally accessible introduction to the topic, see Introduction to quantum mechanics. ... For a less technical and generally accessible introduction to the topic, see Introduction to special relativity. ... Gravity is a force of attraction that acts between bodies that have mass. ... Quantum gravity is the field of theoretical physics attempting to unify quantum mechanics, which describes three of the fundamental forces of nature, with general relativity, the theory of the fourth fundamental force: gravity. ...


In general relativity, the cosmological constant is proportional to the energy density of empty space, and can be measured by the curvature of space. It is subsequently related to the age of the universe, as energy expands outwards with time its density changes. For a less technical and generally accessible introduction to the topic, see Introduction to general relativity. ... In physical cosmology, the cosmological constant (usually denoted by the Greek capital letter lambda: Λ) was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe. ...


Quantum field theory considers the vacuum ground state not to be completely empty, but to consist of a seething mass of virtual particles and fields. These fields are quantified as probabilities—that is, the likelihood of manifestation based on conditions. Since these fields do not have a permanent existence, they are called vacuum fluctuations. In the Casimir effect, two metal plates can cause a change in the vacuum energy density between them which generates a measurable force. In physics, a virtual particle is a particle which exists for such a short time and space that its energy and momentum do not have to obey the usual relationship. ... The magnitude of an electric field surrounding two equally charged (repelling) particles. ... In physics, the Casimir effect is a physical force exerted between separate objects, which is due to neither charge, gravity, nor the exchange of particles, but instead is due to resonance of all-pervasive energy fields in the intervening space between the objects. ...


Some believe that vacuum energy might be the "dark energy" (also called quintessence) associated with the cosmological constant in general relativity, thought to be similar to a negative force of gravity (or antigravity). Observations that the expanding universe appears to be accelerating seem to support the cosmic inflation theory—first proposed by Alan Guth in 1981—in which the nascent universe passed through a phase of exponential expansion driven by a negative vacuum energy density (positive vacuum pressure). In physical cosmology, dark energy is a hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe. ... Look up Quintessence in Wiktionary, the free dictionary. ... AntiGravity is a group of New York gymnasts/performance artists. ... In physical cosmology, cosmic inflation is the idea that the nascent universe passed through a phase of exponential expansion that was driven by a negative-pressure vacuum energy density. ... Alan Harvey Guth (born February 27, 1947) is a physicist and cosmologist. ...


Energy density of food

Energy density is the amount of energy (kilojoules or calories) per amount of food, with food amount being measured in grams or milliliters of food. Energy density is thus expressed in cal/g, kcal/g, J/g, kJ/g, cal/mL, kcal/mL, J/mL, or kJ/mL. This is the energy released when the food is metabolised by a healthy organism when it ingests the food (see food energy for calculation) and the food is metabolized with oxygen, into waste products such as carbon dioxide and water. Typical values of food energy density for high energy-density foods, such as a hamburger, would be 2.5 kcal/g. Purified fats and oils contain the highest energy densities—about 9 kcal/g. What is popularly referred to as the number of "calories" in a portion of food is therefore technically the number of kilocalories in the portion. A kilojoule (abbreviation: kJ) is a unit of energy equal to 1000 joules. ... Etymology: French calorie, from Latin calor (heat), from calere (to be warm). ... Food energy is the amount of energy in food that is available through digestion. ... A few of the metabolic pathways in a cell. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... A calorie refers to a unit of energy. ...


See also

Energy Portal

Image File history File links Crystal_128_energy. ... A Figure of merit is a quantity used to characterize the performance of a device relative to other devices of the same type. ... While all CO2 gas output ratios are calculated to within a less than 1% margin of error (assuming total oxidation of the carbon content of fuel), ratios preceded by a Tilde (~) indicate a margin of error of up to (but no greater than) 9%. Ratios listed do not include emissions... It has been suggested that this article or section be merged with Heating value. ... Heating value (or calorific value) is used to define the amount of heat released during the combustion of a fuel or food. ... A rechargeable lithium polymer Nokia mobile phone battery. ... Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. ... Vacuum energy is an underlying background energy that exists in space even when devoid of matter (known as free space). ...

External references

Zero point energy

  1. Eric Weisstein's world of physics: energy density [43]
  2. Baez physics: Is there a nonzero cosmological constant? [44]; What's the Energy Density of the Vacuum?.
  3. Introductory review of cosmic inflation [45]
  4. An exposition to inflationary cosmology [46]

Density data

  • ^  "Aircraft Fuels." Energy, Technology and the Environment Ed. Attilio Bisio. Vol. 1. New York: John Wiley and Sons, Inc., 1995. 257-259

Energy storage

Books

  • The Inflationary Universe: The Quest for a New Theory of Cosmic Origins by Alan H. Guth (1998) ISBN 0-201-32840-2
  • Cosmological Inflation and Large-Scale Structure by Andrew R. Liddle, David H. Lyth (2000) ISBN 0-521-57598-2
  • Richard Becker, "Electromagnetic Fields and Interactions", Dover Publications Inc., 1964

References

  1. ^ C. Knowlen, A.T. Mattick, A.P. Bruckner and A. Hertzberg, "High Efficiency Conversion Systems for Liquid Nitrogen Automobiles", Society of Automotive Engineers Inc, 1988.

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