{"id":476,"date":"2019-04-15T15:15:06","date_gmt":"2019-04-15T20:15:06","guid":{"rendered":"http:\/\/eeppaa.tech\/?page_id=476"},"modified":"2019-04-15T15:28:10","modified_gmt":"2019-04-15T20:28:10","slug":"teg-thermal-electric-generator","status":"publish","type":"page","link":"https:\/\/eeppaa.tech\/?page_id=476","title":{"rendered":"TEG: Thermoelectric Generator"},"content":{"rendered":"\n<div class=\"wp-block-file\"><a href=\"http:\/\/eeppaa.tech\/wp-content\/uploads\/2019\/04\/Thermoelectric-generator.docx\">Download THERMOELECTRIC GENERATOR INFO WITH PHOTOS.<\/a><a href=\"http:\/\/eeppaa.tech\/wp-content\/uploads\/2019\/04\/Thermoelectric-generator.docx\" class=\"wp-block-file__button\" download>Download<\/a><\/div>\n\n\n\n<h1 class=\"wp-block-heading\" style=\"text-align:center\">How does THERMOELECTRIC work?<\/h1>\n\n\n\n<p class=\"wp-block-paragraph\">Strictly speaking, thermoelectric generators take a\ntemperature difference and turn it into electrical power. &nbsp;Amazingly,\nthese materials can also be run in reverse! &nbsp;If you put power into a\nthermoelectric generator you will create a temperature difference. &nbsp;Small\nmini-fridges, for just a few sodas, use thermoelectric generators to\nefficiently cool a few drinks.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><br>\nTo understand how&nbsp;thermoelectric&nbsp;generates\nthe electricity from a temperature difference we have to know a bit about how\nelectrons move in a metal. &nbsp;Metals are good conductors because electrons\ncan move freely within them, similar to a fluid in a pipe. &nbsp;Imagine you\nhave a pipe full of water and you raise one end, what happens? &nbsp;The water\nwill flow down the pipe from the high end to the low end. &nbsp;This is because\nwhen you raised the pipe you increased the potential energy and the water wants\nto flow downhill. &nbsp;In a thermoelectric material the same thing happens to\nthe fluid-like electrons when you heat it.<br>\n<br>\nHeating one end of a thermoelectric material causes the electrons to move away from\nthe hot end toward the cold end. &nbsp;When the electrons go from the hot side\nto the cold side this causes an electrical current, which the&nbsp;PowerPot&nbsp;harnesses to charge USB devices.\n&nbsp;The larger the temperature difference the more electrical current is produced\nand therefore more power generated.<br>\n<br>\nThe tricky part about thermoelectric generators is that as you heat the hot\nside, the cold side of the generator heats up too. &nbsp;In order to generate\npower with the a thermoelectric generator you need both a heat source and a way\nof dissipating heat in order to maintain a temperature difference across the\nthermoelectric materials. This is done with no moving parts by heating water in\nthe&nbsp;PowerPot. &nbsp;Water\nholds several times more heat than aluminum per pound, so it makes a wonderful&nbsp;heatsink. &nbsp;Also,\nwater never gets hotter than 212 F (100 C) at a boil, effectively limiting the\nmaximum temperature of the \u201ccold\u201d side of the thermoelectric generator.\n&nbsp;This is why you always need to have something watery in the&nbsp;PowerPot&nbsp;or else it is possible to overheat the\nthermoelectric generator.<\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\">This rendering shows temperature distribution in the&nbsp;PowerPot&nbsp;during operation with some parts\nremoved for clarity.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">BACKGROUND OF&nbsp;THERMOELECTRICS<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Thermoelectric power is the conversion of a\ntemperature differential directly into electrical power.&nbsp; Thermoelectric\npower results primarily from two physical effects: the&nbsp;<a href=\"http:\/\/en.wikipedia.org\/wiki\/Seebeck_effect#Seebeck_effect\">Seebeck&nbsp;effect<\/a>, and&nbsp;<a href=\"http:\/\/en.wikipedia.org\/wiki\/Peltier_effect#Peltier_effect\">Peltier&nbsp;effect<\/a>.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;Seebeck&nbsp;effect\nis named after&nbsp;<a href=\"http:\/\/en.wikipedia.org\/wiki\/Thomas_Johann_Seebeck\">Thomas J.&nbsp;Seebeck<\/a>, who first\ndiscovered the phenomenon in 1821. &nbsp;Seebeck&nbsp;noticed that when a loop comprised of\ntwo dissimilar materials was heated on one side, an electromagnetic field was\ncreated.&nbsp; He actually discovered the EM field directly with a\ncompass!&nbsp; He noted that the strength of the electromagnetic field, and\ntherefore the voltage, is proportional to the temperature difference between\nthe hot and cold sides of the material.&nbsp; The magnitude of the&nbsp;Seebeck&nbsp;coefficient (S) varies with material\nand temperature of operation.&nbsp; The&nbsp;Seebeck&nbsp;coefficient\nis thus defined as:<\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\">In this equation&nbsp;\u0394V&nbsp;is the voltage difference between the hot and cold sides,&nbsp;\u0394T&nbsp;is the\ntemperature difference between the hot and cold sides.&nbsp; The negative sign\ncomes from the negative charge of the electron, and the conventions of current\nflow.&nbsp; A negative&nbsp;Seebeck&nbsp;coefficient\nresults in electrons being the dominant charge carriers (<a href=\"http:\/\/en.wikipedia.org\/wiki\/N-type_semiconductor\">n-type<\/a>), whereas\nholes are the dominant carrier (<a href=\"http:\/\/en.wikipedia.org\/wiki\/P-type_semiconductor\">p-type<\/a>) in\nmaterials with a positive&nbsp;Seebeck&nbsp;coefficient.&nbsp;\nThe majority charge carriers are said to move away from the heated side toward\nthe cooler side.&nbsp; Minority charge carriers move in the opposite direction,\nbut at a slower rate due to&nbsp;<a href=\"http:\/\/en.wikipedia.org\/wiki\/Phonon_drag\">phonon\ndrag<\/a>&nbsp;and charge carrier diffusion\nrates.&nbsp; Thus, both n-type and p-type materials are required to realize\ncurrent flow in a device.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Things to remember about the&nbsp;Seebeck&nbsp;effect:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Solids\nhave charge carriers that facilitate the flow of electrical power<\/li><li>The\ncharge carriers come in two flavors negative electrons &#8220;n-type&#8221; and\npositive &#8220;holes&#8221; that we use to keep track of mobile positive charge\nin &#8220;p-type&#8221; solids<\/li><li>Heating\none end of a conducting solid pushes on the charge carriers concentration and\nthe distribution of charge creates voltage that can be measured this is called\nthe&nbsp;Seebeck&nbsp;effect<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;Peltier&nbsp;effect\nwas first discovered in 1834 by&nbsp;<a href=\"http:\/\/en.wikipedia.org\/wiki\/Jean_Charles_Athanase_Peltier\" target=\"_blank\" rel=\"noreferrer noopener\">Jean C.A.&nbsp;Peltier<\/a>, for whom it\nwas named.&nbsp;&nbsp;Peltier&nbsp;discovered\nthat whenever a circuit of two dissimilar materials passes current, heat is\nabsorbed at one end of the junction and released at the other.&nbsp; This is a\nlinearly dependent and thermodynamically reversible process, unlike Joule\nheating which is irreversible and quadratic in nature mean.&nbsp; This process\nforms the basis for thermoelectric cooling and temperature control, these are\ncurrently the widest applications of thermoelectric devices.&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, applying a temperature differential the\nreverse process occurs, and current is caused to flow, thereby generating\npower.&nbsp; The figure below shows a&nbsp;TEP&nbsp;device in\nboth cooling and power generation configurations.<\/p>\n\n\n\n\n\n\n\n<p class=\"wp-block-paragraph\">A thermoelectric cooler (left), and power generator\n(right).&nbsp; Current flow is labeled in the direction of the electrons.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The efficiency by which a material is capable of\ngenerating power is governed by the figure of merit (Z).&nbsp; As seen in the\nequation below, the figure of merit is most dependent on the&nbsp;Seebeck&nbsp;coefficient of the material.<\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\">In the above equation, the figure of merit is defined\nin terms of the&nbsp;Seebeck&nbsp;coefficient,\nthe electrical conductivity, and the thermal conductivity.&nbsp; Maximum power\ngeneration requires the minimization of the thermal conductivity, while\nmaximizing the&nbsp;Seebeck&nbsp;coefficient\nand electrical conductivity.&nbsp;<\/p>\n\n\n\n<h1 class=\"wp-block-heading\"><a href=\"http:\/\/powerpractical.com\/collections\/generate\/products\/powerpot5-thermoelectric-generator\">THE POWERPOT | THERMOELECTRIC GENERATOR<\/a><\/h1>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"http:\/\/powerpractical.com\/collections\/generate\/products\/powerpot5-thermoelectric-generator\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;PowerPot&nbsp;is a\nthermoelectric generator that uses heat to generate electricity. &nbsp;The&nbsp;PowerPot&nbsp;has no moving parts or batteries, and\nsince the thermoelectric technology is built into the bottom of the pot it can\nproduce electricity from a wide variety of heat sources. &nbsp;Simply add water\nand place the&nbsp;PowerPot&nbsp;on a\nfire (e.g. wood, propane, butane, alcohol, gas) and it will start generating\nelectricity within seconds. &nbsp;Just plug in the high temperature cable to\nthe back of the pot and watch your USB devices safely charge from a fire.<br>\n<br>\nThe larger the temperature difference between the water in the pot and the\nbottom of the pot, the more electricity the&nbsp;PowerPot&nbsp;will\nproduce. &nbsp;For example, melting snow in the&nbsp;PowerPot&nbsp;is a great way to generate\nelectricity, because snow is so much colder than a flame. &nbsp;However, you\ndon\u2019t have to worry about overpowering your device, because the&nbsp;PowerPot&nbsp;has a built in regulator which insures\nthat you safely charge your USB devices. &nbsp;The regulator outputs 5 volts\n(USB standard) and up to 1000&nbsp;milliAmps&nbsp;of\ncurrent, which is the most any smartphone\/MP3 player on the market can handle.\n&nbsp;This means when you\u2019re charging your USB device with the&nbsp;PowerPot, you will get\nthe same charging time as you would from your wall outlet at home.&nbsp;<a href=\"http:\/\/powerpractical.com\/collections\/generate\/products\/powerpot5-thermoelectric-generator\">Learn\nMore<\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Glossary Of Thermoelectric Terms<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>ACTIVE LOAD<\/strong><br>\nThe amount of heat (in Watts) being generated by the device that is on top of\nthe TE Cooler. Typically, this is the input power of this device (Voltage x\ncurrent).<br>\n<strong>ALUMINA OXIDE<\/strong><br>\nCeramics made of aluminum oxide (Al2O3 ). These ceramics are used on most of\nour standard TECs. A positive of Al2O3 is that it is inexpensive and can be\ndesigned for snap states instead of dice, which considerably reduces production\ncosts. Negative aspects of this material are its lower thermal conductivity and\nit is difficult to use in 3 to 6 stage coolers.<br>\n<strong>AIN<\/strong><br>\n<strong>Aluminum NITRIDE<\/strong><br>\nAl2O3 also a very popular ceramic for it\u2019s high thermal conductivity&nbsp;\nproperties . Typically in the range of 70-200&nbsp; watts\/mk<br>\n<strong>AMBIENT TEMPERATURE<\/strong><br>\nTemperature of the air or environment surrounding a thermoelectric cooling\nsystem; sometimes called room temperature.<br>\n<strong>ASPECT RATIO<\/strong><br>\nThe numerical ratio of the length (height) to cross-sectional area of a\nthermoelectric element. An element\u2019s L\/A aspect ratio is inversely proportional\nto its optimum current.<br>\n<strong>BeO<\/strong>2<br>\nCeramics made of beryllium oxide thermal conductivity of 260&nbsp; watts\/mk.\nTypically used in multistage coolers due to its higher thermal conductivity.\nThe advantages to this material are that it enhances the thermal performance of\nthe TE Cooler as well as makes it easier to assemble because of the high heat\nconductance. Disadvantages are that it is more expensive and BeO22 is toxic\nwhen its dust is inhaled. The dust comes from dicing and sanding of the\nmaterial, both of which are performed on a TE Cooler in its final condition.\nHowever, the risks of BeO2 sometimes prohibit it as an option<br>\nfor commercial use.<br>\n<strong>BISMUTH TELLURIDE ******<\/strong><br>\nA thermoelectric semiconductor Bi2Te3 material that exhibits optimum\nperformance in a \u201croom temperature\u201d range. An alloy of Bismuth Telluride most\noften is used for thermoelectric cooling applications and also power\ngeneration. It is by far the most efficient thermoelectric material presently\nused for power generation in the 250\u00b0C hot side temperature range.<br>\n<strong>LEAD TELLURIDE ******<\/strong><br>\nA Thermo electric material used for high temperature (hot side 500\u00b0C Thermal\nElectric power generation). This material although is well known for it\u2019s power\ngeneration ability is very difficult to find as a module. Sources of this\nmaterial can only be found in completed thermoelectric power generation\nappliances.<br>\n<strong>BISMUTH-ANTIMONY<\/strong><br>\nA thermoelectric semiconductor material that exhibits optimum performance\ncharacteristics at relatively low temperatures.<br>\n<strong>BTU (British Thermal Unit)<\/strong><br>\nThe amount of thermal energy required to raise one pound of water by one\u00b0\nCelsius at a standard temperature of 15\u00bcC.<br>\n<strong>Bonded Heat Sink<\/strong><br>\nA heat sink which has Fins which have been bonded to the base plate.&nbsp; Heat\nsinks constructed in this manner typically have much greater heat dissipation\ncharacteristics and their much lower thermal resistance is far superior to that\nof an extruded heat sink.<br>\n<strong>BURN-IN TEST<\/strong><br>\nA power cycling test performed by repeatedly powering on and off the TE Cooler\nfor short intervals of time. The test is designed to detect latent\nmanufacturing or material defects that would cause premature failure of the TE\nCooler.<br>\n<strong>CASCADE MODULE (MULTISTAGE MODULE)<\/strong><br>\nA thermoelectric cooler configuration whereby one cooler is stacked on top of\nanother so as to be thermally in series. This arrangement makes it possible to\nreach lower temperatures than can be achieved with a single-stage cooler.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Cascade Seebeck Module<\/strong>&nbsp;A Cascade Seebeck module takes advantage\nof large temperature gradients, by exploiting each temperature zone with a\nmaterial that peck efficiency equals that zones temperature. Typically, up to 2\ndifferent materials are thermally stacked (Hot Side to Cold side). The Seebeck\neffect module is constructed using material that is most efficient in that\ntemperature range. Semi-conductors are most efficient when they are exposed to\nspecific temperatures that exploit their targeted peak efficiency.<br>\n<strong>CERAMIC<\/strong><br>\nA patterned substrate, the finished part which goes into a TE Cooler. This\nmaterial conducts heat and insulates electric current. Typically comprised of\nAl2O3 , BeO2 or AIN. At least one side of the ceramic has a metal pattern\nrequired for the operation of the TE Cooler. Al2O3 , AIN, BeO2 Thermal\nConductivity (W\/in C) .051 4.0 6.5 CTE (10-6\/C) 7.0 4.0 9.0<br>\n<strong>CFM (Cubic Feet per Minute)<\/strong><br>\nThe volumetric flow rate of a gas, typically air, expressed in the English\nsystem of units. For thermoelectric applications, this generally refers to the\namount of air passing through the fins of a forced convection heat sink.<br>\n<strong>CLOSED-LOOP TEMPERATURE CONTROLLER<\/strong><br>\nA temperature controlling device having some type of temperature sensor\n(thermocouple, thermistor, RTD, etc.) that will transmit or \u201cfeed back\u201d\ntemperature data to the controller. Based on the returned information, the\ncontroller will automatically adjust its output to maintain the desired\ntemperature.<br>\n<strong>COEFFICIENT OF PERFORMANCE (COP)<\/strong><br>\nA measures of the efficiency of a thermoelectric cooler, device or system.\nMathematically, COP is the total heat transferred through the thermo electric\ndevice divided by the electric input power (COP=Qc\/W). COP sometimes is stated\nas COPR (Coefficient of Performance as a Refrigerator) or as COPH (Coefficient\nof Performance as a Heater).<br>\n<strong>COLD SIDE OF A THERMOELECTRIC MODULE<\/strong><br>\nThe side of a cooler that normally is placed in contact with the object being\ncooled. When the positive and negative cooler leads are connected to the respective\npositive and negative terminals of a DC power source, the cooler\u2019s cold side\nwill absorb heat. Typically, the leads of a TE cooler are attached to the hot\nside.<br>\n<strong>CONDUCTION (THERMAL)<\/strong><br>\nThe transfer of heat within a material caused by a temperature difference\nthrough the material. The actual material may be a solid, liquid or gas (or a\ncombination) where heat will flow by means of direct contact from a high\ntemperature region to a lower temperature region.<br>\n<strong>CONVECTION (THERMAL)<\/strong><br>\nThe transfer of heat by air (gas) movement over a surface. Convection actually\nis a combined heat transfer process that involves elements of conduction,\nmixing action, and energy storage.<br>\n<strong>COUPLE<\/strong><br>\nA pair of thermoelectric elements consisting of one N-type and one P-type\nconnected electrically in series and thermally in parallel. Because the input\nvoltage to a single couple is quite low, a number of couples normally are\njoined together to form a \u201ccooler.\u201d<br>\n<strong>DC<\/strong><br>\nDirect Current is the electricity that comes from a battery or electronics power\nsupply. DC powers TEC but can be stress tested using AC.<br>\n<strong>DELTA-T<\/strong><br>\nThe temperature difference between the cold and hot sides of a thermoelectric\npower&nbsp; generation module. Delta T may also be expressed as \u201cDT\u201d or \u201cDT.\u201d\nThe larger the differential there is the higher output of power achieved !<br>\n<strong>DELTA-T Test For cooling application<\/strong><br>\nTest performed in which the TE Cooler is placed on a temperature controlled\nbase plate (typically 27\u00b0C) and powered at Imax. A thermocouple is pressed onto\nthe top ceramic using a spring plunger and the cold side temperature as well as\nvoltage is measured.<br>\n<strong>DENSITY<\/strong><br>\nThe mass of a material per unit volume, often expressed as pounds per cubic\nfoot or grams per cubic centimeter.<br>\n<strong>DICE<\/strong><br>\nA general term for blocks of the thermoelectric semiconductor material or\n\u201celements\u201d prepared for use in a thermoelectric cooler.<br>\n<strong>EFFICIENCY<\/strong><br>\nFor thermoelectric coolers, mathematical efficiency is the heat pumped by a\ncooler divided by the electrical input power; for thermoelectric generators,\nefficiency is the electrical output power from the cooler divided by the heat\ninput (Qc\/ Qh). To convert to percent, multiply by 100. See definition of\nCoefficient of Performance.<br>\n<strong>ELEMENT<\/strong><br>\nAn individual block of thermo electric semiconductor material. Slicing an ingot\nof TE material into wafers, then dicing these wafers into very tiny, very\nprecise, and accurately sized blocks, which are placed inside a TE Cooler,\nmakes elements. Each TE Cooler has P elements and N elements. Elements are\nsometimes referred to as columns or TE material. See definition of DIE.<br>\n<strong>FIGURE-OF-MERIT (Z factor)<\/strong><br>\nA measure of the overall performance of a thermo electric device or material.\nMaterial having the highest figure-of-merit also has the highest thermoelectric\nperformance. A good thermoelectric material will have a high Z, high Seebeck\ncoefficient and low thermal conductivity and resistively. Unfortunately the\ntesting of figure of merit is not standardized<br>\nso many claims of High-Z cannot be&nbsp; validated.<br>\n<strong>FORCED CONVECTION HEAT SINK<\/strong><br>\nA heat sink that incorporates a fan or blower to actively move air over the\nheat sink\u2019s fins. Greatly improved cooling performance may be realized with a\nforced convection system when compared to a natural convection heat sink.<br>\n<strong>HEAT LOAD<\/strong><br>\nThe quantity of heat presented to a thermoelectric device that must be absorbed\nby the device\u2019s cold side. The term heat load, when used by itself, tends to be\nsomewhat ambiguous and it is preferable to be more specific. Terms such as\nactive heat load, passive heat load or total heat load are more descriptive and\nless uncertain as to meaning.<br>\n<strong>HEAT PUMP<\/strong><br>\nA general term describing a thermoelectric cooling device, often being used as\na synonym for a thermoelectric cooler. In somewhat less common usage, the term\nheat pump has been applied to a thermoelectric device operating in the heating\nmode.<br>\n<strong>HEAT PUMPING CAPACITY<\/strong><br>\nThe amount of heat that a thermoelectric device is capable of pumping at a\ngiven set of operating parameters. Frequently, this term will be used\ninterchangeably with the expression maximum heat pumping capacity. The two\nterms are not strictly synonymous, however, because maximum heat pumping\ncapacity specifically defines the maximum amount of heat that a cooler will\npump at the maximum rated input current and at a zero temperature differential.<br>\n<strong>HEAT SINK<\/strong><br>\nA body that is in contact with a hotter object and that expedites the removal\nof heat from the object. Heat sinks typically are intermediate stages in the\nheat removal process whereby heat flows into a heat sink and then is\ntransferred to an external medium. Common heat sinks include natural (free)\nconvection, forced convection and fluid cooled.<br>\n<strong>HEAT SINK RESISTANCE<\/strong><br>\nAlso referred to as HSR. The thermal path from the hot side of the TE cooler to\nthe ambient, including mounting interfaces, fans, etc., is measure of the\neffectiveness of a heat sink. In other words, how well does the heat sink\nremove the heat from the TE cooler? Its units are \u00b0C\/W and is used to determine\nthe number of degrees the hot side will rise in temperature for a given amount\nof heat that is dumped into it. For example, a heat sink resistance of 0.1\u00b0C\/W\nwill result in a hot side temperature rise of 1\u00b0C when 10 Watts is applied. The\neffectiveness of the heat sink greatly affects the performance of the TE\ncooler. Therefore, the better the heat sink (better is a lower \u00b0C\/W) results in\nless input power to the TE cooler or a colder cold side temperature.<br>\n<strong>HEAT TRANSFER COEFFICIENT<\/strong><br>\nA numerical value that describes the degree of coupling that exists between an\nobject and a cooling or heating fluid. The heat transfer coefficient actually\nis an extremely complex value that encompasses many physical factors.<br>\n<strong>HOT SIDE OF A THERMOELECTRIC MODULE<\/strong><br>\nThe face of a thermoelectric cooler that usually is placed in contact with the\nheat sink. When the positive and negative cooler leads are connected to the\nrespective positive and negative terminals of a DC power source, the cooler\u2019s\nhot side will reject heat. Normally, the wire leads are attached to the hot\nside ceramic substrate.<br>\n<strong>Imax<\/strong><br>\nCurrent which, the maximum delta T is produced. Generally, it is not a good to\noperate a TE cooler at Imax because the amount of input power increases\nsignificantly without a significant change in delta T. 70 \u2013 80 % of Imax is\nusually an optimal operating condition.<br>\n<strong>INGOT<\/strong><br>\nA cast alloy of thermoelectric material. The ingot is sawed into wafers that\nare then diced into elements.<br>\n<strong>INTERSTAGE TEMPERATURE<\/strong><br>\nThe temperature between specific stages or levels of a multistage or cascade\ncooler.<br>\n<strong>JOULE HEATING<\/strong><br>\nThe passage of an electrical current through a conductor or material due to the\ninternal resistance, resulting in Heat<br>\n<strong>LEAD TELLURIDE<\/strong><br>\nA thermoelectric semiconductor that exhibits its optimum performance within a\ntemperature range of 250-450\u00b0C. Lead Telluride is used most often for\nthermoelectric power generation applications.<br>\n<strong>LIQUID COOLING<\/strong><br>\nA heat sink method involving the use of water or other fluids to carry away\nunwanted heat. When comparing alternative heat-sinking methods, liquid cooled\nheat sinks normally provide the highest thermal performance per unit volume.<br>\n<strong>MAXIMUM HEAT PUMPING CAPACITY (MAXIMUM Qc)<\/strong><br>\nThe maximum quantity of heat that can be absorbed at the cold face of a\nthermoelectric cooler when the temperature differential between the cold and\nhot cooler faces is zero and when the cooler is being operated at its rated\noptimum current. Qmax is one of the significant thermoelectric cooler\/device\nspecifications.<br>\n<strong>MAXIMUM TEMPERATURE DIFFERENTIAL (MAXIMUM Delta T)<\/strong><br>\nThe largest difference that can be obtained between the hot and cold faces of a\nthermoelectric cooler when heat applied to the cold face is effectively zero.\nDTmax or Dmax is one of the significant thermoelectric cooler\/device\nspecifications.<br>\n<strong>METALLIZATION<\/strong><br>\nThe conductive copper pattern printed on the ceramics.<br>\n<strong>MODULE<\/strong><br>\nA thermoelectric cooling component or device fabricated with multiple\nthermoelectric couples that are connected thermally in parallel and\nelectrically in series.<br>\n<strong>MULTISTAGE MODULE (CASCADE MODULE)<\/strong><br>\nA thermoelectric configuration whereby one TEC is mechanically stacked on top\nof another in series. This arrangement makes it possible to reach lower\ntemperatures than can be achieved with a single-stage cooler.<br>\n<strong>NATURAL CONVECTION HEAT SINK<\/strong><br>\nA heat sink from which heat is transferred to the surrounding air by means of\nnatural air currents within the environment. No external fan, blower or other\nappliance is used to facilitate air movement around the heat sink.<br>\n<strong>N-TYPE MATERIAL<\/strong><br>\nThe doping of semiconductor material creating an excess of electrons.<br>\n<strong>OPTIMUM CURRENT<\/strong><br>\nThe specific level of electrical current that will produce the greatest heat\nabsorption by the cold side of a thermal electric cooler. At the optimum\ncurrent, a thermoelectric cooler will be capable of pumping the maximum\nquantity of heat; maximum temperature differential (Delta Tmax) typically\noccurs at a somewhat lower current level.<br>\n<strong>PASSIVE LOADS<\/strong><br>\nThe amount of non-active heat (in Watts) being applied on the TE cooler. This\nincludes conductance through wires that extend from the cold side of the TE\ncooler to the ambient, the convective loads from the surrounding atmosphere\n(note: Convective loads are present in Nitrogen, Argon, and Xenon, but are not\npresent in a vacuum).<br>\n<strong>PELTIER EFFECT<\/strong><br>\nThe phenomenon whereby the passage of an electrical current through a junction\nconsisting of two dissimilar metals results in a cooling effect; when the\ndirection of current flow is reversed heating will occur.<br>\n<strong>P-TYPE MATERIAL<\/strong><br>\nSemiconductor material that is doped so as to have a deficiency of electrons.<br>\nQmax<br>\nThe maximum amount of heat (in Watts) that a TE cooler can pump. This occurs\nwhen the delta T is zero. Only for multistage coolers operating near a Delta\nTmax condition.<br>\n<strong>RESISTIVELY (ELECTRICAL)<\/strong><br>\nResistively is a bulk or inherent property of a material that is unrelated to\nthe physical dimensions of the material. Electrical resistance, on the other\nhand, is an absolute value dependent upon the cross-sectional area (A) and\nLength (L) of the material.<br>\n<strong>SEEBECK EFFECT or SEEBECK Coefficient<\/strong><br>\nThe phenomenon whereby an electrical current will flow in a closed circuit made\nup of two dissimilar metals when the junctions of the metals are maintained at\ntwo different temperatures. A common thermocouple used for temperature\nmeasurement utilizes this principle.<br>\n<strong>SILICON-GERMANIUM<\/strong><br>\nA high temperature thermoelectric semiconductor material that exhibits its\noptimum performance within a temperature range of 500-1000\u00b0C. Silicon-Germanium\nmaterial most often is used for special thermoelectric power generation\napplications that utilize a radioisotope\/nuclear heat source.<br>\n<strong>SINGLE-STAGE MODULE<\/strong><br>\nThe most common type of thermoelectric cooling module using a single layer of\nthermoelectric couples connected electrically in series and thermally in\nparallel. Single-stage coolers will produce a maximum temperature differential\nof approximately 70\u00b0C under a no-load condition.<br>\n<strong>SLICING<\/strong><br>\nThe process of cutting the ingots into wafers.<br>\n<strong>SOLDER<\/strong><br>\nMetals or alloys that melt below 425\u00b0C. Common solders used are: 118\u00b0C 52 In\/48\nSn (mounting); 138\u00b0C 42Sn\/58 Bi (TEC assembly); 183\u00b0C 63 Sn\/37 Pd (TEC\nassembly); 232\u00b0C 95 Sn\/5 Sb (TEC assembly).<br>\n<strong>THERMAL COEFFICIENT OF EXPANSION<\/strong><br>\nA measure of the dimensional change of a material due to a change in\ntemperature. Common measurement units include centimeter per centimeter per\ndegree Celsius and inch per inch per degree Fahrenheit.<br>\n<strong>THERMAL CONDUCTANCE<\/strong><br>\nThe amount of heat a given object will transmit per unit of temperature.\nThermal conductance is independent of the physical dimensions, i.e.,\ncross-sectional area and length of the object. Typical units include watts per\ndegree Celsius and BTU per hour per degree Fahrenheit.<br>\n<strong>THERMAL CONDUCTIVITY<\/strong><br>\nThe amount of heat a material will transmit per unit of temperature based on\nthe material\u2019s cross-sectional area and thickness.<br>\n<strong>THERMAL GREASE<\/strong><br>\nA grease-like material used to enhance heat transfer between two surfaces by\nfilling in the microscopic voids caused by surface roughness. Most thermal\ngreases, also known as Transistor Heat Sink Compound or Thermal Joint Compound,\nare made from silicone grease loaded with zinc oxide. Non-silicone based\ncompounds are also available which in most cases are superior but more\nexpensive than silicone-based alternatives.<br>\n<strong>THERMAL RESISTANCE (HEAT SINK)<\/strong><br>\nA measure of a heat sink\u2019s performance based on the temperature rise per unit\nof applied heat. The best heat sinks have the lowest thermal resistance.<br>\n<strong>THERMAL SHOCK<\/strong><br>\nThermal Shock also is referred to as temperature cycling in some MIL specs. In\na thermal shock test, the TE cooler (not powered throughout test) is placed in\na hot chamber (for example, 85\u00b0C) for a set time (for example, 30 minutes). The\npart is then transferred to the cold chamber (for example, -40\u00b0C) for the same\ntime. This cycle is repeated several times depending on the requirement.<br>\n<strong>THERMOELECTRIC<\/strong><br>\nA term used to denote not only the products produced but also the basic\nscientific principle upon which products are designed.<br>\n<strong>THERMOELECTRIC GENERATOR<\/strong><br>\nA device that directly converts energy into electrical energy based on the\nSeebeck Effect. Bismuth telluride-based thermoelectric generators have very low\nefficiencies (generally not exceeding two or three percent) but may provide\nuseful electrical power in certain applications.<br>\n<strong>THERMOELECTRIC MATERIAL<\/strong><br>\nAn alloy of materials that produce thermoelectric properties.<br>\n<strong>TINNING<\/strong><br>\nApplying solder paste over the copper or tabbed pattern. The bottom ceramic can\nalso be tinned enabling the ability to mount the TEC on a header or heat sink.<br>\n<strong>Vmax<\/strong><br>\nThe optimum voltage the maximum delta T is produced for a thermal electric\ncooling module.<br><\/p>\n\n\n\n<h1 class=\"wp-block-heading\">Stirling\nengine<\/h1>\n\n\n\n<p class=\"wp-block-paragraph\">From Wikipedia, the free encyclopedia<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em>For the&nbsp;<\/em><a href=\"https:\/\/en.wikipedia.org\/wiki\/Adiabatic\"><em>adiabatic<\/em><\/a><em>&nbsp;Stirling\ncycle, see&nbsp;<\/em><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_cycle\"><em>Stirling cycle<\/em><\/a><em>.<\/em><\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Alpha_Stirling.gif\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Alpha-type Stirling engine. There are two cylinders. The expansion cylinder\n(red) is maintained at a high temperature while the compression cylinder (blue)\nis cooled. The passage between the two cylinders contains the regenerator.<\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Stirling_Animation.gif\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Beta-type Stirling engine. There is only one cylinder, hot at one end and\ncold at the other. A loose-fitting displacer shunts the air between the hot and\ncold ends of the cylinder. A power piston at the end of the cylinder drives the\nflywheel.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A&nbsp;<strong>Stirling\nengine<\/strong>&nbsp;is a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_engine\">heat engine<\/a>&nbsp;that operates by cyclic compression\nand expansion of air or other gas (the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Working_fluid\"><em>working fluid<\/em><\/a>) at different temperatures, such\nthat there is a net conversion of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat\">heat<\/a>&nbsp;energy to\nmechanical&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Work_(physics)\">work<\/a>.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-1\"><sup>[1]<\/sup><\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-W.R._Martini_1983,_p.6-2\"><sup>[2]<\/sup><\/a>&nbsp;More specifically, the Stirling\nengine is a closed-cycle regenerative heat engine with a permanently&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Gas\">gaseous<\/a>working fluid.&nbsp;<em>Closed-cycle<\/em>, in\nthis context, means a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermodynamic_system\">thermodynamic\nsystem<\/a>&nbsp;in which\nthe working fluid is permanently contained within the system, and&nbsp;<em>regenerative<\/em>&nbsp;describes\nthe use of a specific type of internal&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_exchanger\">heat exchanger<\/a>&nbsp;and thermal store, known as\nthe&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Regenerative_heat_exchanger\"><em>regenerator<\/em><\/a>. Strictly speaking, the inclusion of\nthe regenerator is what differentiates a Stirling engine from other closed\ncycle&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hot_air_engines\">hot air engines<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Originally\nconceived in 1816 as an industrial prime mover to rival the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Steam_engine\">steam engine<\/a>, its practical use was largely confined to\nlow-power domestic applications for over a century.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-3\"><sup>[3]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Stirling engines\nhave a high efficiency compared to internal combustion engines,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-mpower-4\"><sup>[4]<\/sup><\/a>&nbsp;being able to reach 50%\nefficiency. They are also capable of quiet operation and can use almost any\nheat source. The heat energy source is generated external to the Stirling\nengine rather than by internal combustion as with the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Otto_cycle\">Otto cycle<\/a>&nbsp;or&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Diesel_cycle\">Diesel cycle<\/a>&nbsp;engines. Because the Stirling engine\nis compatible with alternative and renewable energy sources it could become\nincreasingly significant as the price of conventional fuels rises, and also in\nlight of concerns such as depletion of oil supplies and&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Climate_change\">climate change<\/a>. This type of engine is currently\ngenerating interest as the core component of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Micro_combined_heat_and_power\">micro combined\nheat and power<\/a>&nbsp;(CHP)\nunits, in which it is more efficient and safer than a comparable steam engine.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-5\"><sup>[5]<\/sup><\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-6\"><sup>[6]<\/sup><\/a>&nbsp;However, it has a low&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Power-to-weight_ratio\">power-to-weight\nratio<\/a>,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-mpower-4\"><sup>[4]<\/sup><\/a>&nbsp;rendering it more suitable for use in\nstatic installations where space and weight are not at a premium.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Contents<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">&nbsp;&nbsp;[hide]&nbsp;<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Name_and_classification\">1Name and classification<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#History\">2History<\/a><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Invention_and_early_development\">2.1Invention and early development<\/a><\/li><\/ul><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Later_nineteenth_century\">2.2Later nineteenth century<\/a><\/li><\/ul><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Twentieth_century_revival\">2.3Twentieth century revival<\/a><\/li><\/ul><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Functional_description\">3Functional description<\/a><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Key_components\">3.1Key components<\/a><\/li><\/ul><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Configurations\">3.2Configurations<\/a><\/li><\/ul><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Other_developments\">3.3Other developments<\/a><\/li><\/ul><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Theory\">4Theory<\/a><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Operation\">4.1Operation<\/a><\/li><\/ul><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Pressurization\">4.2Pressurization<\/a><\/li><\/ul><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Lubricants_and_friction\">4.3Lubricants and friction<\/a><\/li><\/ul><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Analysis\">5Analysis<\/a><ul><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Comparison_with_internal_combustion_engines\">5.1Comparison with internal combustion engines<\/a><\/li><\/ul><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Applications\">6Applications<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Alternatives\">7Alternatives<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#See_also\">8See also<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#References\">9References<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Bibliography\">10Bibliography<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Further_reading\">11Further reading<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#External_links\">12External links<\/a><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Name\nand classification[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=1\">edit<\/a>]<\/h2>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Stirlingmotor_in_Betrieb.JPG\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Stirling engine running.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/Robert_Stirling\">Robert Stirling<\/a>was a Scottish minister who&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Invented\">invented<\/a>&nbsp;the first\npractical example of a closed cycle&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hot_air_engine\">air engine<\/a>&nbsp;in 1816, and it was suggested\nby&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Fleeming_Jenkin\">Fleeming Jenkin<\/a>&nbsp;as early as 1884 that all such\nengines should therefore generically be called Stirling engines. This naming\nproposal found little favour, and the various types on the market continued to\nbe known by the name of their individual designers or manufacturers, e.g.,\nRider&#8217;s, Robinson&#8217;s, or Heinrici&#8217;s (hot) air engine. In the 1940s, the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Philips\">Philips<\/a>&nbsp;company\nwas seeking a suitable name for its own version of the &#8216;air engine&#8217;, which by\nthat time had been tested with working fluids other than air, and decided upon\n&#8216;Stirling engine&#8217; in April 1945.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-7\"><sup>[7]<\/sup><\/a>&nbsp;However, nearly thirty years later,\nGraham Walker still had cause to bemoan the fact such terms as&nbsp;<em>hot air\nengine<\/em>&nbsp;remained interchangeable with&nbsp;<em>Stirling engine<\/em>,\nwhich itself was applied widely and indiscriminately,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-8\"><sup>[8]<\/sup><\/a>&nbsp;a situation that continues.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-9\"><sup>[9]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Like the steam\nengine, the Stirling engine is traditionally classified as an&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/External_combustion_engine\">external\ncombustion engine<\/a>, as all heat\ntransfers to and from the working fluid take place through a solid boundary\n(heat exchanger) thus isolating the combustion process and any contaminants it\nmay produce from the working parts of the engine. This contrasts with an&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Internal_combustion_engine\">internal\ncombustion engine<\/a>where heat input\nis by combustion of a fuel within the body of the working fluid. Most of the\nmany possible implementations of the Stirling engine fall into the category\nof&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Reciprocating_engine\">reciprocating\npiston engine<\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">History[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=2\">edit<\/a>]<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Invention and early development<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=3\"><strong>edit<\/strong><\/a><strong>]<\/strong><strong><\/strong><\/h3>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Robert_Stirling's_engine_patent.gif\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Illustration from Robert Stirling&#8217;s 1816 patent application of the air\nengine design that later came to be known as the Stirling Engine<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The Stirling\nengine (or Stirling&#8217;s air engine as it was known at the time) was invented and\npatented in 1816.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-10\"><sup>[10]<\/sup><\/a>&nbsp;It followed&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hot_air_engine#History\">earlier attempts\nat making an air engine<\/a>&nbsp;but was\nprobably the first put to practical use when, in 1818, an engine built by\nStirling was employed pumping water in a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Quarry\">quarry<\/a>.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-11\"><sup>[11]<\/sup><\/a>&nbsp;The main subject of Stirling&#8217;s\noriginal patent was a heat exchanger, which he called an &#8220;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Economiser\">economiser<\/a>&#8221; for its enhancement of fuel economy\nin a variety of applications. The patent also described in detail the\nemployment of one form of the economiser in his unique closed-cycle&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hot_air_engine\">air engine<\/a>&nbsp;design<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-12\"><sup>[12]<\/sup><\/a>&nbsp;in which application it is now\ngenerally known as a &#8220;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Regenerator\">regenerator<\/a>&#8220;. Subsequent development by Robert Stirling and his brother&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/James_Stirling_(1800%E2%80%931876)\">James<\/a>, an engineer, resulted in patents\nfor various improved configurations of the original engine including\npressurization, which by 1843, had sufficiently increased power output to drive\nall the machinery at a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Dundee\">Dundee<\/a>&nbsp;iron\nfoundry.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-13\"><sup>[13]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Though it has\nbeen disputed,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-14\"><sup>[14]<\/sup><\/a>&nbsp;it is widely supposed that the inventors\naims were not only to save fuel but also to create a safer alternative to\nthe&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Steam_engine\">steam engines<\/a>of the time,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-15\"><sup>[15]<\/sup><\/a>&nbsp;whose&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Boiler\">boilers<\/a>&nbsp;frequently\nexploded, causing many injuries and fatalities.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-16\"><sup>[16]<\/sup><\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-17\"><sup>[17]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The need for\nStirling engines to run at very high temperatures to maximize power and\nefficiency exposed limitations in the materials of the day, and the few engines\nthat were built in those early years suffered unacceptably frequent failures\n(albeit with far less disastrous consequences than boiler explosions).<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-18\"><sup>[18]<\/sup><\/a>For example, the Dundee foundry engine was\nreplaced by a steam engine after three hot cylinder failures in four years.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-19\"><sup>[19]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Reverend\nStirling filed three patents in relation to hot air engines. The first one in\n1816,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-haestirling1816-20\"><sup>[20]<\/sup><\/a>&nbsp;about an &#8220;Economiser&#8221;, is\nthe predecessor of the regenerator. In this patent (# 4081) he describes the\n&#8220;economiser&#8221; technology and several applications where such technology\ncan be used. Out of them came a new arrangement for a hot air engine. In 1818,\none engine was built to pump water from a quarry in Ayrshire, but due to\ntechnical issues, the engine was abandoned for a time.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In 1827,\nStirling and his brother James patented a second engine<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-haestirling1827-21\"><sup>[21]<\/sup><\/a>&nbsp;very similar to the Parkinson\nand Crossley&#8217;s air engine,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-haeparkinson1827-22\"><sup>[22]<\/sup><\/a>&nbsp;but having a regenerator. In 1840,\nthe two Stirling brothers patented a third engine, but the changes against the\n1827 patent were minor. Nonetheless in 1842 James Stirling built in the Dundee\nFoundry &#8211; Scotland, two hot air engines.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">James Stirling\ngave a presentation of his engine before the Institution of Civil Engineers in\n1845.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-haestirling1842-23\"><sup>[23]<\/sup><\/a>&nbsp;The first engine of this kind which,\nafter various modifications, was efficiently constructed and heated, had a\ncylinder of 12 inches (approx. 30 cm) in diameter, with a length of stroke of 2\nfeet (approx. 61 cm), and made 40 strokes or revolutions in a minute (40 rpm).\nThis engine moved all the machinery at the Dundee Foundry Company&#8217;s works for\neight or ten months, and was previously found capable of raising 700,000 lbs\none foot in a minute (approx. 21 HP).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Finding this\npower insufficient for their works, the Dundee Foundry Company erected the\nsecond engine, with a cylinder of 16 inches (approx. 40 cm) in diameter, a\nstroke of 4 feet (approx. 1.20 m), and making 28 strokes in a minute. This\nengine has now been in continual operation for upwards of two years, and has\nnot only performed the work of the foundry in the most satisfactory manner, but\nhas been tested (by a friction brake on a third mover) to the extent of lifting\nnearly 1,500,000 lbs (approx. 45 HP).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This gives a\nconsumption of 2.7 lbs. (approx. 1.22 kg) per horse-power per hour; but when\nthe engine was not fully burdened, the consumption was considerably under 2.5\nlbs. (approx. 1.13 kg) per horse-power per hour. This performance was at the\nlevel of the best steam engines whose efficiency was about 10%. After James\nStirling, such efficiency was possible only thanks to the use of the economiser\n(or regenerator).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Later nineteenth century<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=4\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h3>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Ericsson_hot_air_engine.jpg\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A typical late nineteenth\/early twentieth century water pumping engine by\nthe&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Rider-Ericsson_Engine_Company\">Rider-Ericsson\nEngine Company<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Subsequent to\nthe replacement of the Dundee foundry engine there is no record of the Stirling\nbrothers having any further involvement with air engine development, and the\nStirling engine never again competed with steam as an industrial scale power\nsource. (Steam boilers were becoming safer<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-24\"><sup>[24]<\/sup><\/a>&nbsp;and steam engines more\nefficient, thus presenting less of a target for rival prime movers). However,\nbeginning about 1860, smaller engines of the Stirling\/hot air type were\nproduced in substantial numbers for applications in which reliable sources of\nlow to medium power were required, such as pumping air for church organs or\nraising water.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-25\"><sup>[25]<\/sup><\/a>&nbsp;These smaller engines generally\noperated at lower temperatures so as not to tax available materials, and so\nwere relatively inefficient. Their selling point was that unlike steam engines,\nthey could be operated safely by anybody capable of managing a fire.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-26\"><sup>[26]<\/sup><\/a>&nbsp;Several types remained in production\nbeyond the end of the century, but apart from a few minor mechanical\nimprovements the design of the Stirling engine in general stagnated during this\nperiod.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-27\"><sup>[27]<\/sup><\/a><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Twentieth century revival<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=5\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">During the early\npart of the twentieth century the role of the Stirling engine as a\n&#8220;domestic motor&#8221;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-28\"><sup>[28]<\/sup><\/a>&nbsp;was gradually taken over by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Electric_motor\">electric motors<\/a>&nbsp;and small&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Internal_combustion_engine\">internal\ncombustion engines<\/a>. By the late\n1930s, it was largely forgotten, only produced for toys and a few small\nventilating fans.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-29\"><sup>[29]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Around that\ntime,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Philips\">Philips<\/a>&nbsp;was seeking to expand sales of\nits radios into parts of the world where grid electricity and batteries were\nnot consistently available. Philips&#8217; management decided that offering a\nlow-power portable generator would facilitate such sales and asked a group of\nengineers at the company&#8217;s research lab in&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Eindhoven\">Eindhoven<\/a>&nbsp;to evaluate alternative ways of achieving this aim. After a\nsystematic comparison of various&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Prime_mover_(locomotive)\">prime movers<\/a>, the team decided to go forward with\nthe Stirling engine, citing its quiet operation (both audibly and in terms of\nradio interference) and ability to run on a variety of heat sources (common\nlamp oil&nbsp;\u2013 &#8220;cheap and available everywhere&#8221;&nbsp;\u2013 was favored).<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-30\"><sup>[30]<\/sup><\/a>&nbsp;They were also aware that, unlike\nsteam and internal combustion engines, virtually no serious development work\nhad been carried out on the Stirling engine for many years and asserted that\nmodern materials and know-how should enable great improvements.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-31\"><sup>[31]<\/sup><\/a><\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Philips_Stirling_engine.JPG\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Philips MP1002CA Stirling generator of 1951<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">By 1951, the\n180\/200 W generator set designated MP1002CA (known as the &#8220;Bungalow\nset&#8221;) was ready for production and an initial batch of 250 was planned,\nbut soon it became clear that they could not be made at a competitive price.\nAdditionally, the advent of transistor radios and their much lower power\nrequirements meant that the original rationale for the set was disappearing.\nApproximately 150 of these sets were eventually produced.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-32\"><sup>[32]<\/sup><\/a>&nbsp;Some found their way into university\nand college engineering departments around the world<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-33\"><sup>[33]<\/sup><\/a>giving generations of students a\nvaluable introduction to the Stirling engine.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In parallel with\nthe Bungalow set, Philips developed experimental Stirling engines for a wide\nvariety of applications and continued to work in the field until the late\n1970s, but only achieved commercial success with the &#8220;reversed Stirling\nengine&#8221;&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Applications_of_the_Stirling_engine#Stirling_cryocoolers\">cryocooler<\/a>. However, they\nfiled a large number of patents and amassed a wealth of information, which they\nlicensed to other companies and which formed the basis of much of the\ndevelopment work in the modern era.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-34\"><sup>[34]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In 1996, the\nSwedish navy commissioned three&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Gotland-class_submarine\">Gotland-class\nsubmarines<\/a>. On the\nsurface, these boats are propelled by marine diesel engines. However, when\nsubmerged, they use a Stirling-driven generator developed by Swedish\nshipbuilder&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Kockums\">Kockums<\/a>&nbsp;to recharge batteries and provide\nelectrical power for propulsion.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-Kockums-35\"><sup>[35]<\/sup><\/a>&nbsp;A supply of liquid oxygen is carried\nto support burning of diesel fuel to power the engine. Stirling engines are\nalso fitted to the Swedish&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/S%C3%B6dermanland-class_submarine\">S\u00f6dermanland-class\nsubmarines<\/a>, the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Archer-class_submarine\">Archer-class\nsubmarines<\/a>&nbsp;in service\nin Singapore and, license-built by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Kawasaki_Heavy_Industries\">Kawasaki Heavy\nIndustries<\/a>&nbsp;for the\nJapanese&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/S%C5%8Dry%C5%AB-class_submarine\">S\u014dry\u016b-class\nsubmarines<\/a>. In a submarine\napplication, the Stirling engine offers the advantage of being exceptionally\nquiet when running.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Stirling engines\nare frequently used in the dish version of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Concentrated_Solar_Power\">Concentrated\nSolar Power<\/a>&nbsp;systems. A\nmirrored dish similar to a very large satellite dish directs and concentrates\nsunlight onto a thermal receiver, which absorbs and collects the heat and using\na fluid transfers it into the Stirling engine. The resulting mechanical power\nis then used to run a generator or alternator to produce electricity.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-NREL_CSP-36\"><sup>[36]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Stirling engines\nare forming the core component of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Micro_combined_heat_and_power\">micro combined\nheat and power<\/a>&nbsp;(CHP)\nunits, as they are more efficient and safer than a comparable steam engine. CHP\nunits are being installed in people&#8217;s homes.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-BBC_CHP-37\"><sup>[37]<\/sup><\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Functional\ndescription[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=6\">edit<\/a>]<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The engine is\ndesigned so the working gas is generally compressed in the colder portion of\nthe engine and expanded in the hotter portion resulting in a net conversion of\nheat into&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Work_(thermodynamics)\">work<\/a>.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-W.R._Martini_1983,_p.6-2\"><sup>[2]<\/sup><\/a>&nbsp;An internal&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Regenerative_heat_exchanger\">regenerative\nheat exchanger<\/a>&nbsp;increases\nthe Stirling engine&#8217;s thermal efficiency compared to simpler&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hot_air_engine\">hot air engines<\/a>&nbsp;lacking this feature.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Key components<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=7\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h3>\n\n\n\n<table class=\"wp-block-table\"><tbody><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:BetaStirlingTG4web.svg\"><\/a>\n  <\/td><\/tr><tr><td>\n  Cut-away diagram of a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Rhombic_drive\">rhombic drive<\/a>&nbsp;beta configuration Stirling engine design:\n  &nbsp;&nbsp;Hot cylinder wall&nbsp;&nbsp;Cold cylinder wall&nbsp;&nbsp;Coolant inlet and outlet pipes&nbsp;&nbsp;Thermal insulation separating the\n  two cylinder ends&nbsp;&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Displacer\">Displacer<\/a>&nbsp;piston&nbsp;&nbsp;Power piston&nbsp;&nbsp;Linkage crank and flywheels\n  \n  \n  \n  \n  \n  \n  Not shown: Heat source and heat sinks.\n  In this design the displacer piston is constructed without a\n  purpose-built&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Regenerator\">regenerator<\/a>.\n  <\/td><\/tr><\/tbody><\/table>\n\n\n\n<p class=\"wp-block-paragraph\">As a consequence\nof closed cycle operation, the heat driving a Stirling engine must be\ntransmitted from a heat source to the working fluid by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_exchanger\">heat exchangers<\/a>&nbsp;and finally to a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_sink\">heat sink<\/a>. A Stirling engine system has at least one heat source, one heat sink and\nup to five<sup>[<\/sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Please_clarify\"><em><sup>clarification\nneeded<\/sup><\/em><\/a><sup>]<\/sup>&nbsp;heat exchangers. Some types may\ncombine or dispense with some of these.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Heat source<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=8\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:EuroDishSBP_front.jpg\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Point focus parabolic mirror with Stirling engine at its centre and\nits&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Solar_tracker\">solar tracker<\/a>&nbsp;at&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Plataforma_Solar_de_Almer%C3%ADa\">Plataforma Solar\nde Almer\u00eda<\/a>(PSA) in Spain<\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:SolarStirlingEngine.jpg\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/Solar_thermal_energy#Dish_designs\">Dish Stirling<\/a>&nbsp;from SES<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The heat source\nmay be provided by the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Combustion\">combustion<\/a>&nbsp;of a fuel and, since the combustion products do not mix with the\nworking fluid and hence do not come into contact with the internal parts of the\nengine, a Stirling engine can run on fuels that would damage other engines\ntypes&#8217; internals, such as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Landfill_gas\">landfill gas<\/a>, which may contain&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Siloxane\">siloxane<\/a>&nbsp;that could\ndeposit abrasive&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Silicon_dioxide\">silicon dioxide<\/a>&nbsp;in conventional engines.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-LGET-38\"><sup>[38]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Other suitable\nheat sources include&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Concentrated_solar_power\">concentrated\nsolar energy<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Geothermal_energy\">geothermal energy<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Nuclear_power\">nuclear energy<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Waste_heat\">waste heat<\/a>and&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Bioenergy\">bioenergy<\/a>. If solar power is used as a heat source, regular&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Solar_mirror\">solar mirrors<\/a>&nbsp;and solar dishes may be\nutilised. The use of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Fresnel_lens\">Fresnel lenses<\/a>&nbsp;and mirrors has also been advocated,\nfor example in planetary surface exploration.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-39\"><sup>[39]<\/sup><\/a>&nbsp;Solar powered Stirling engines are\nincreasingly popular as they offer an environmentally sound option for\nproducing power while some designs are economically attractive in development\nprojects.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-40\"><sup>[40]<\/sup><\/a><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Heater \/ hot side\nheat exchanger<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=9\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">In small, low\npower engines this may simply consist of the walls of the hot space(s) but\nwhere larger powers are required a greater surface area is needed to transfer\nsufficient heat. Typical implementations are internal and external fins or\nmultiple small bore tubes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Designing\nStirling engine heat exchangers is a balance between high heat transfer with\nlow&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Viscosity\">viscous<\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Darcy%E2%80%93Weisbach_equation\">pumping losses<\/a>, and low dead space (unswept\ninternal volume). Engines that operate at high powers and pressures require\nthat heat exchangers on the hot side be made of alloys that retain considerable\nstrength at high temperatures and that don&#8217;t corrode or&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Creep_(deformation)\">creep<\/a>.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Regenerator<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=10\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Main article:&nbsp;<\/em><a href=\"https:\/\/en.wikipedia.org\/wiki\/Regenerative_heat_exchanger\"><em>Regenerative\nheat exchanger<\/em><\/a><em><\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In a Stirling\nengine, the regenerator is an internal heat exchanger and temporary heat store\nplaced between the hot and cold spaces such that the working fluid passes\nthrough it first in one direction then the other, taking heat from the fluid in\none direction, and returning it in the other. It can be as simple as metal mesh\nor foam, and benefits from high surface area, high heat capacity, low\nconductivity and low flow friction.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-41\"><sup>[41]<\/sup><\/a>&nbsp;Its function is to retain within\nthe&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermodynamic_system\">system<\/a>&nbsp;that heat that would otherwise\nbe exchanged with the environment at temperatures intermediate to the maximum\nand minimum cycle temperatures,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-42\"><sup>[42]<\/sup><\/a>&nbsp;thus enabling the thermal efficiency\nof the cycle (though not of any practical engine<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-43\"><sup>[43]<\/sup><\/a>) to approach the limiting&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Carnot_cycle\">Carnot<\/a>efficiency.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The primary\neffect of regeneration in a Stirling engine is to increase the thermal\nefficiency by &#8216;recycling&#8217; internal heat that would otherwise pass through the\nengine&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Reversible_process_(thermodynamics)\">irreversibly<\/a>. As a secondary effect, increased thermal efficiency yields a higher power\noutput from a given set of hot and cold end heat exchangers. These usually\nlimit the engine&#8217;s heat throughput. In practice this additional power may not\nbe fully realized as the additional &#8220;dead space&#8221; (unswept volume) and\npumping loss inherent in practical regenerators reduces the potential\nefficiency gains from regeneration.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The design\nchallenge for a Stirling engine regenerator is to provide sufficient heat\ntransfer capacity without introducing too much additional internal volume\n(&#8216;dead space&#8217;) or flow resistance. These inherent design conflicts are one of\nmany factors that limit the efficiency of practical Stirling engines. A typical\ndesign is a stack of fine metal&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Wire\">wire<\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Mesh\">meshes<\/a>, with low&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Porosity\">porosity<\/a>&nbsp;to reduce\ndead space, and with the wire axes&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Perpendicular\">perpendicular<\/a>&nbsp;to the gas flow to reduce\nconduction in that direction and to maximize convective heat transfer.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-44\"><sup>[44]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The regenerator\nis the key component invented by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Robert_Stirling\">Robert Stirling<\/a>&nbsp;and its presence distinguishes\na true Stirling engine from any other closed cycle&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hot_air_engine\">hot air engine<\/a>. Many small &#8216;toy&#8217; Stirling engines,\nparticularly low-temperature difference (LTD) types, do not have a distinct\nregenerator component and might be considered hot air engines; however a small\namount of regeneration is provided by the surface of the displacer itself and\nthe nearby cylinder wall, or similarly the passage connecting the hot and cold\ncylinders of an alpha configuration engine.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Cooler \/ cold side\nheat exchanger<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=11\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">In small, low\npower engines this may simply consist of the walls of the cold space(s), but\nwhere larger powers are required a cooler using a liquid like water is needed to\ntransfer sufficient heat.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Heat sink<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=12\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">The larger the\ntemperature difference between the hot and cold sections of a Stirling engine,\nthe greater the engine&#8217;s efficiency. The heat sink is typically the environment\nthe engine operates in, at ambient temperature. In the case of medium to high\npower engines, a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Radiator\">radiator<\/a>&nbsp;is required to transfer the\nheat from the engine to the ambient air. Marine engines have the advantage of\nusing cool ambient sea, lake, or river water, which is typically cooler than\nambient air. In the case of combined heat and power systems, the engine&#8217;s\ncooling water is used directly or indirectly for heating purposes, raising\nefficiency.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Alternatively,\nheat may be supplied at ambient temperature and the heat sink maintained at a\nlower temperature by such means as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Cryogen\">cryogenic fluid<\/a>&nbsp;(see&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Liquid_nitrogen_economy\">Liquid nitrogen\neconomy<\/a>) or iced water.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Displacer<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=13\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">The displacer is\na special-purpose&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Piston\">piston<\/a>, used in Beta and Gamma type\nStirling engines, to move the working gas back and forth between the hot and\ncold heat exchangers. Depending on the type of engine design, the displacer may\nor may not be sealed to the cylinder, i.e. it may be a loose fit within the\ncylinder, allowing the working gas to pass around it as it moves to occupy the\npart of the cylinder beyond.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Configurations<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=14\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">There are three\nmajor types of Stirling engines, that are distinguished by the way they move\nthe air between the hot and cold areas:<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>The&nbsp;<strong>alpha<\/strong>&nbsp;configuration\nhas two power pistons, one in a hot cylinder, one in a cold cylinder, and the\ngas is driven between the two by the pistons; it is typically in a V-formation\nwith the pistons joined at the same point on a crankshaft.<\/li><li>The&nbsp;<strong>beta<\/strong>&nbsp;configuration\nhas a single cylinder with a hot end and a cold end, containing a power piston\nand a &#8216;displacer&#8217; that drives the gas between the hot and cold ends. It is\ntypically used with a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Rhombic_drive\">rhombic drive<\/a>&nbsp;to achieve\nthe phase difference between the displacer and power pistons, but they can be\njoined 90 degrees out of phase on a crankshaft.<\/li><li>The&nbsp;<strong>gamma<\/strong>&nbsp;configuration\nhas two cylinders: one containing a displacer, with a hot and a cold end, and\none for the power piston; they are joined to form a single space with the same\npressure in both cylinders; the pistons are typically in parallel and joined 90\ndegrees out of phase on a crankshaft.<\/li><\/ol>\n\n\n\n<h4 class=\"wp-block-heading\">Alpha\nconfiguration operation<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=15\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">An&nbsp;<strong>alpha\nStirling<\/strong>&nbsp;contains two power pistons in separate cylinders, one hot and\none cold. The hot cylinder is situated inside the high temperature&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_exchanger\">heat exchanger<\/a>&nbsp;and the cold cylinder is\nsituated inside the low temperature heat exchanger. This type of engine has a\nhigh power-to-volume ratio but has technical problems because of the usually\nhigh temperature of the hot piston and the durability of its seals.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-45\"><sup>[45]<\/sup><\/a>&nbsp;In practice, this piston usually\ncarries a large insulating head to move the seals away from the hot zone at the\nexpense of some additional dead space. The crank angle has a major effect on\nefficiency and the best angle frequently must be found experimentally. An angle\nof 90\u00b0 frequently locks.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The following\ndiagrams do not show internal heat exchangers in the compression and expansion\nspaces, which are needed to produce power. A&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Regenerative_heat_exchanger\">regenerator<\/a>would be placed in the pipe\nconnecting the two cylinders.<\/p>\n\n\n\n<table class=\"wp-block-table\"><tbody><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Alpha_Stirling_frame_12.svg\"><\/a>\n  <br>\n  1. Most of the working gas is in the hot cylinder and has more contact with\n  the hot cylinder&#8217;s walls. This results in overall heating of the gas. Its\n  pressure increases and the gas expands. Because the hot cylinder is at its\n  maximum volume and the cold cylinder is at the top of its stroke (minimum\n  volume), the volume of the system is increased by expansion into the cold\n  cylinder.\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Alpha_Stirling_frame_16.svg\"><\/a>\n  <br>\n  2. The system is at its maximum volume and the gas has more contact with the\n  cold cylinder. This cools the gas, lowering its pressure. Because of flywheel\n  momentum or other piston pairs on the same shaft, the hot cylinder begins an\n  upstroke reducing the volume of the system.\n  <\/td><\/tr><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Alpha_Stirling_frame_4.svg\"><\/a>\n  <br>\n  3. Almost all the gas is now in the cold cylinder and cooling continues. This\n  continues to reduce the pressure of the gas and cause contraction. Because\n  the hot cylinder is at minimum volume and the cold cylinder is at its maximum\n  volume, the volume of the system is further reduced by compression of the\n  cold cylinder inwards.\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Alpha_Stirling_frame_8.svg\"><\/a>\n  <br>\n  4. The system is at its minimum volume and the gas has greater contact with\n  the hot cylinder. The volume of the system increases by expansion of the hot\n  cylinder.\n  <\/td><\/tr><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Alpha_Stirling.gif\"><\/a><br>\n  The complete alpha type Stirling cycle. Note that if the application of heat\n  and cold is reversed, the engine runs in the opposite direction without any\n  other changes.\n  <\/td><\/tr><\/tbody><\/table>\n\n\n\n<h4 class=\"wp-block-heading\">Beta configuration\noperation<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=16\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">A&nbsp;<strong>beta\nStirling<\/strong>&nbsp;has a single power piston arranged within the same cylinder\non the same shaft as a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#Displacer\">displacer<\/a>&nbsp;piston. The displacer piston is a loose fit and does not extract any\npower from the expanding gas but only serves to shuttle the working gas between\nthe hot and cold heat exchangers. When the working gas is pushed to the hot end\nof the cylinder it expands and pushes the power piston. When it is pushed to\nthe cold end of the cylinder it contracts and the momentum of the machine,\nusually enhanced by a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Flywheel\">flywheel<\/a>, pushes the\npower piston the other way to compress the gas. Unlike the alpha type, the beta\ntype avoids the technical problems of hot moving seals, as the power piston is\nnot in contact with the hot gas.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-46\"><sup>[46]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Again, the\nfollowing diagrams do not show any internal heat exchangers or a regenerator,\nwhich would be placed in the gas path around the displacer. If a regenerator is\nused in a beta engine, it is usually in the position of the displacer and\nmoving, often as a volume of wire mesh.<\/p>\n\n\n\n<table class=\"wp-block-table\"><tbody><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Beta_Stirling_frame_12.png\"><\/a>\n  <br>\n  1. Power piston (dark grey) has compressed the gas, the displacer piston\n  (light grey) has moved so that most of the gas is adjacent to the hot heat\n  exchanger.\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Beta_Stirling_frame_16.png\"><\/a>\n  <br>\n  2. The heated gas increases in pressure and pushes the power piston to the\n  farthest limit of the&nbsp;<strong>power stroke<\/strong>.\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Beta_Stirling_frame_4.png\"><\/a>\n  <br>\n  3. The displacer piston now moves, shunting the gas to the cold end of the\n  cylinder.\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Beta_Stirling_frame_8.png\"><\/a>\n  <br>\n  4. The cooled gas is now compressed by the flywheel momentum. This takes less\n  energy, since its pressure drops when it is cooled.\n  <\/td><\/tr><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Stirling_Animation.gif\"><\/a><br>\n  The complete beta type Stirling cycle\n  <\/td><\/tr><\/tbody><\/table>\n\n\n\n<h4 class=\"wp-block-heading\">Gamma\nconfiguration operation<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=17\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">A&nbsp;<strong>gamma\nStirling<\/strong>&nbsp;is simply a beta Stirling with the power piston mounted in a\nseparate cylinder alongside the displacer piston cylinder, but still connected\nto the same flywheel. The gas in the two cylinders can flow freely between them\nand remains a single body. This configuration produces a lower&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Compression_ratio\">compression ratio<\/a>because of the volume of the\nconnection between the two but is mechanically simpler and often used in\nmulti-cylinder Stirling engines.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Other types<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=18\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">Other Stirling\nconfigurations continue to interest engineers and inventors.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<strong>rotary\nStirling<\/strong>&nbsp;engine seeks to convert power from the Stirling cycle\ndirectly into torque, similar to the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Rotary_combustion_engine\">rotary\ncombustion engine<\/a>. No practical\nengine has yet been built but a number of concepts, models and patents have\nbeen produced, such as the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Quasiturbine\">Quasiturbine engine<\/a>.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-47\"><sup>[47]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A hybrid between\npiston and rotary configuration is a double acting engine. This design rotates\nthe displacers on either side of the power piston. In addition to giving great\ndesign variability in the heat transfer area, this layout eliminates all but\none external seal on the output shaft and one internal seal on the piston.\nAlso, both sides can be highly pressurized as they balance against each other.<\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Solar_Miller_Style_Stirling_layout.JPG\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Top view of two rotating displacer powering the horizontal piston.\nRegenerators and radiator removed for clarity<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Another alternative\nis the&nbsp;<strong>Fluidyne engine<\/strong>(<strong>Fluidyne heat pump<\/strong>), which uses\nhydraulic pistons to implement the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_cycle\">Stirling cycle<\/a>. The work produced by a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Fluidyne_engine\">Fluidyne engine<\/a>&nbsp;goes into pumping the liquid.\nIn its simplest form, the engine contains a working gas, a liquid, and two\nnon-return valves.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<strong>Ringbom\nengine<\/strong>&nbsp;concept published in 1907 has no rotary mechanism or linkage\nfor the displacer. This is instead driven by a small auxiliary piston, usually\na thick displacer rod, with the movement limited by stops.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-48\"><sup>[48]<\/sup><\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-49\"><sup>[49]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<strong>two-cylinder\nStirling with Ross yoke<\/strong>&nbsp;is a two-cylinder stirling engine (positioned\nat 0\u00b0, not 90\u00b0) connected using a special yoke. The engine configuration\/yoke\nsetup was invented by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Andy_Ross_(engineer)&amp;action=edit&amp;redlink=1\">Andy Ross<\/a>.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-50\"><sup>[50]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<strong>Franchot\nengine<\/strong>&nbsp;is a double acting engine invented by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Charles-Louis-F%C3%A9lix_Franchot&amp;action=edit&amp;redlink=1\">Charles-Louis-F\u00e9lix Franchot<\/a>&nbsp;(<a href=\"https:\/\/de.wikipedia.org\/wiki\/Charles-Louis-F%C3%A9lix_Franchot\">de<\/a>)&nbsp;in the nineteenth century. In a\ndouble acting engine, the pressure of the working fluid acts on both sides of\nthe piston. One of the simplest forms of a double acting machine, the Franchot\nengine consists of two pistons and two cylinders, and acts like two separate\nalpha machines. In the Franchot engine, each piston acts in two gas phases,\nwhich makes more efficient use of the mechanical components than a single\nacting alpha machine. However, a disadvantage of this machine is that one\nconnecting rod must have a sliding seal at the hot side of the engine, which is\ndifficult when dealing with high pressures and temperatures<sup>[<\/sup><a href=\"https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed\"><em><sup>citation needed<\/sup><\/em><\/a><sup>]<\/sup>.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Free-piston\nStirling engines<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=19\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Free-Piston_Configurations.jpg\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Various free-piston Stirling configurations\u2026 F. &#8220;free cylinder&#8221;,\nG. Fluidyne, H. &#8220;double-acting&#8221; Stirling (typically 4 cylinders)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Free-piston Stirling<\/strong>engines include\nthose with&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Fluidyne_engine\">liquid pistons<\/a>&nbsp;and those with diaphragms as\npistons. In a free-piston device, energy may be added or removed by an\nelectrical&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Linear_alternator\">linear\nalternator<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Pump\">pump<\/a>&nbsp;or other\ncoaxial device. This avoids the need for a linkage, and reduces the number of\nmoving parts. In some designs, friction and wear are nearly eliminated by the\nuse of non-contact&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Gas_bearing\">gas bearings<\/a>&nbsp;or very precise suspension through\nplanar&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Spring_(device)\">springs<\/a>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Four basic steps\nin the cycle of a&nbsp;<strong>free-piston<\/strong>&nbsp;Stirling engine are:<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>The power piston\nis pushed outwards by the expanding gas thus doing work. Gravity plays no role\nin the cycle.<\/li><li>The gas volume\nin the engine increases and therefore the pressure reduces, which causes a\npressure difference across the displacer rod to force the displacer towards the\nhot end. When the displacer moves, the piston is almost stationary and\ntherefore the gas volume is almost constant. This step results in the constant\nvolume cooling process, which reduces the pressure of the gas.<\/li><li>The reduced\npressure now arrests the outward motion of the piston and it begins to\naccelerate towards the hot end again and by its own inertia, compresses the now\ncold gas, which is mainly in the cold space.<\/li><li>As the pressure\nincreases, a point is reached where the pressure differential across the\ndisplacer rod becomes large enough to begin to push the displacer rod (and\ntherefore also the displacer) towards the piston and thereby collapsing the\ncold space and transferring the cold, compressed gas towards the hot side in an\nalmost constant volume process. As the gas arrives in the hot side the pressure\nincreases and begins to move the piston outwards to initiate the expansion step\nas explained in (1).<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">In the early\n1960s, W.T. Beale invented a free piston version of the Stirling engine to\novercome the difficulty of lubricating the crank mechanism.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-51\"><sup>[51]<\/sup><\/a>&nbsp;While the invention of the basic free\npiston Stirling engine is generally attributed to Beale, independent inventions\nof similar types of engines were made by E.H. Cooke-Yarborough and C. West at\nthe Harwell Laboratories of the UKAERE.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-52\"><sup>[52]<\/sup><\/a>&nbsp;G.M. Benson also made important early\ncontributions and patented many novel free-piston configurations.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-53\"><sup>[53]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The first known\nmention of a Stirling cycle machine using freely moving components is a British\npatent disclosure in 1876.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-54\"><sup>[54]<\/sup><\/a>&nbsp;This machine was envisaged as a\nrefrigerator (i.e., the&nbsp;<em>reversed<\/em>&nbsp;Stirling cycle). The first\nconsumer product to utilize a free piston Stirling device was a portable\nrefrigerator manufactured by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Twinbird_Corporation\">Twinbird\nCorporation<\/a>&nbsp;of Japan\nand offered in the US by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Coleman_Company\">Coleman<\/a>in 2004.<\/p>\n\n\n\n<h5 class=\"wp-block-heading\">Flat Stirling\nengine[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=20\">edit<\/a>]<\/h5>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:FlatStirlingEngine800x242.gif\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Cutaway of the flat Stirling engine: 10 &#8211; Hot cylinder. 11 &#8211; A volume of\nhot cylinder. 12 &#8211; B volume of hot cylinder. 17 &#8211; Warm piston diaphragm. 18 &#8211;\nHeating medium. 19 &#8211; Piston rod. 20 &#8211; Cold cylinder. 21 &#8211; A Volume of cold\ncylinder. 22 &#8211; B Volume of cold cylinder. 27 &#8211; Cold piston diaphragm. 28 &#8211;\nCoolant medium. 30 &#8211; Working cylinder. 31 &#8211; A volume of working cylinder. 32 &#8211;\nB volume of working cylinder. 37 &#8211; Working piston diaphragm. 41 &#8211; Regenerator\nmass of A volume. 42 &#8211; Regenerator mass of B volume. 48 &#8211; Heat accumulator. 50\n&#8211; Thermal insulation. 60 &#8211; Generator. 63 &#8211; Magnetic circuit. 64 &#8211; Electrical\nwinding. 70 &#8211; Channel connecting warm and working cylinders.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Design of the\nflat double-acting Stirling engine solves the drive of a displacer with the help\nof the fact that areas of the hot and cold pistons of the displacer are\ndifferent. The drive does so without any mechanical transmission. Using\ndiaphragms eliminates friction and need for lubricants. When the displacer is\nin motion, the generator holds the working piston in the limit position, which\nbrings the engine working cycle close to an ideal Stirling cycle. The ratio of\nthe area of the heat exchangers to the volume of the machine increases by the\nimplementation of a flat design. Flat design of the working cylinder\napproximates thermal process of the expansion and compression closer to the\nisothermal one. The disadvantage is a large area of the thermal insulation\nbetween the hot and cold space.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-55\"><sup>[55]<\/sup><\/a><\/p>\n\n\n\n<h5 class=\"wp-block-heading\">Thermoacoustic\ncycle[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=21\">edit<\/a>]<\/h5>\n\n\n\n<p class=\"wp-block-paragraph\">Thermoacoustic\ndevices are very different from Stirling devices, although the individual path\ntravelled by each working gas molecule does follow a real&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_cycle\">Stirling cycle<\/a>. These devices include the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermoacoustic_hot_air_engine\">thermoacoustic\nengine<\/a>&nbsp;and&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermoacoustic_refrigeration\">thermoacoustic\nrefrigerator<\/a>. High-amplitude\nacoustic&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Standing_wave\">standing waves<\/a>&nbsp;cause compression and expansion\nanalogous to a Stirling power piston, while out-of-phase acoustic&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Travelling_wave\">travelling waves<\/a>&nbsp;cause displacement along a\ntemperature&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Gradient\">gradient<\/a>, analogous to a Stirling displacer\npiston. Thus a thermoacoustic device typically does not have a displacer, as\nfound in a beta or gamma Stirling.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Other developments<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=22\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Starting in\n1986, Infinia Corporation began developing both highly reliable pulsed\nfree-piston Stirling engines, and thermoacoustic coolers using related\ntechnology. The published design uses flexural bearings and hermetically sealed\nHelium gas cycles, to achieve tested reliabilities exceeding 20 years. As of\n2010, the corporation had amassed more than 30 patents, and developed a number\nof commercial products for both combined heat and power, and solar power.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-56\"><sup>[56]<\/sup><\/a>&nbsp;More recently,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/NASA\">NASA<\/a>&nbsp;has\nconsidered&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_radioisotope_generator\">nuclear-decay\nheated Stirling Engines<\/a>&nbsp;for\nextended missions to the outer solar system.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-57\"><sup>[57]<\/sup><\/a>&nbsp;At the 2012 Cable-Tec Expo put on by\nthe Society of Cable Telecommunications Engineers, Dean Kamen took the stage\nwith Time Warner Cable Chief Technology Officer Mike LaJoie to announce a new\ninitiative between his company Deka Research and the SCTE. Kamen refers to it\nas a Stirling engine.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-58\"><sup>[58]<\/sup><\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-59\"><sup>[59]<\/sup><\/a><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Theory[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=23\">edit<\/a>]<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Main article:&nbsp;<\/em><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_cycle\"><em>Stirling cycle<\/em><\/a><em><\/em><\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:Stirling_Cycle_color.png\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Pressure_volume_diagram\">pressure\/volume\ngraph<\/a>&nbsp;of the\nidealized Stirling cycle<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The idealised\nStirling cycle consists of four&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermodynamic_processes\">thermodynamic\nprocesses<\/a>acting on the\nworking fluid:<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Isothermal\">Isothermal<\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermal_expansion\">expansion<\/a>. The expansion-space and associated\nheat exchanger are maintained at a constant high temperature, and the gas\nundergoes near-isothermal expansion absorbing heat from the hot source.<\/li><li>Constant-volume\n(known as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Isometric_process\">isovolumetric<\/a>&nbsp;or&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Isochoric_process\">isochoric<\/a>) heat-removal. The gas is passed\nthrough the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Regenerative_heat_exchanger\">regenerator<\/a>, where it\ncools, transferring heat to the regenerator for use in the next cycle.<\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Isothermal\">Isothermal<\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Compression_ratio\">compression<\/a>. The compression space and\nassociated heat exchanger are maintained at a constant low temperature so the\ngas undergoes near-isothermal compression rejecting heat to the cold sink<\/li><li>Constant-volume\n(known as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Isometric_process\">isovolumetric<\/a>&nbsp;or&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Isochoric_process\">isochoric<\/a>) heat-addition. The gas passes back\nthrough the regenerator where it recovers much of the heat transferred in\nprocess 2, heating up on its way to the expansion space.<\/li><\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Theoretical&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermal_efficiency\">thermal\nefficiency<\/a>&nbsp;equals\nthat of the hypothetical&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Carnot_cycle\">Carnot cycle<\/a>&nbsp;\u2013 i.e. the highest efficiency\nattainable by any heat engine. However, though it is useful for illustrating\ngeneral principles, the ideal cycle deviates substantially from practical\nStirling engines.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-60\"><sup>[60]<\/sup><\/a>It has been argued that its indiscriminate\nuse in many standard books on engineering thermodynamics has done a disservice\nto the study of Stirling engines in general.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-61\"><sup>[61]<\/sup><\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-62\"><sup>[62]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Other real-world\nissues reduce the efficiency of actual engines, because of limits of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Convective_heat_transfer\">convective heat\ntransfer<\/a>, and&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Fluid_dynamics#Viscous_vs_inviscid_flow\">viscous flow<\/a>&nbsp;(friction). There are also\npractical mechanical considerations, for instance a simple kinematic linkage\nmay be favoured over a more complex mechanism needed to replicate the idealized\ncycle, and limitations imposed by available materials such as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Ideal_gas\">non-ideal<\/a>&nbsp;properties of the working gas,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermal_conductivity\">thermal\nconductivity<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Tensile_strength\">tensile strength<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Creep_(deformation)\">creep<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Flexural_strength\">rupture strength<\/a>, and&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Melting_point\">melting point<\/a>. A question that often arises is\nwhether the ideal cycle with isothermal expansion and compression is in fact\nthe correct ideal cycle to apply to the Stirling engine. Professor C. J. Rallis\nhas pointed out that it is very difficult to imagine any condition where the\nexpansion and compression spaces may approach&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Isothermal\">isothermal<\/a>&nbsp;behavior and it is far more realistic to imagine these spaces\nas&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Adiabatic\">adiabatic<\/a>.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-63\"><sup>[63]<\/sup><\/a>An ideal analysis where the expansion and\ncompression spaces are taken to be&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Adiabatic\">adiabatic<\/a>&nbsp;with&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Isothermal\">isothermal<\/a>&nbsp;heat exchangers and perfect\nregeneration was analyzed by Rallis and presented as a better ideal yardstick\nfor Stirling machinery. He called this cycle the &#8216;pseudo-Stirling cycle&#8217; or\n&#8216;ideal adiabatic Stirling cycle&#8217;. An important consequence of this ideal cycle\nis that it does not predict Carnot efficiency. A further conclusion of this\nideal cycle is that maximum efficiencies are found at lower compression ratios,\na characteristic observed in real machines. In an independent work, T.\nFinkelstein also assumed adiabatic expansion and compression spaces in his\nanalysis of Stirling machinery&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-64\"><sup>[64]<\/sup><\/a><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Operation<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=24\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Since the\nStirling engine is a closed cycle, it contains a fixed mass of gas called the\n&#8220;working fluid&#8221;, most commonly&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Air\">air<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hydrogen\">hydrogen<\/a>&nbsp;or&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Helium\">helium<\/a>. In normal\noperation the engine is sealed and no gas enters or leaves the engine. No\nvalves are required, unlike other types of piston engines. The Stirling engine,\nlike most heat engines, cycles through four main processes: cooling,\ncompression, heating and expansion. This is accomplished by moving the gas back\nand forth between hot and cold&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_exchangers\">heat exchangers<\/a>, often with a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Regenerative_heat_exchanger\">regenerator<\/a>&nbsp;between the heater and cooler.\nThe hot heat exchanger is in thermal contact with an external heat source, such\nas a fuel burner, and the cold heat exchanger is in thermal contact with an\nexternal heat sink, such as air fins. A change in gas temperature causes a\ncorresponding change in gas pressure, while the motion of the piston makes the\ngas alternately expand and compress.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The gas follows\nthe behaviour described by the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Gas_laws\">gas laws<\/a>, which describe\nhow a gas&#8217;s&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Pressure\">pressure<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Temperature\">temperature<\/a>&nbsp;and&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Volume\">volume<\/a>&nbsp;are\nrelated. When the gas is heated the pressure rises (because it is in a sealed\nchamber) and this pressure then acts on the power&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Piston\">piston<\/a>&nbsp;to produce\na power stroke. When the gas is cooled the pressure drops and this drop means\nthat the piston needs to do less work to compress the gas on the return stroke.\nThe difference in work between the strokes yields a net positive power output.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The ideal\nStirling cycle is unattainable in the real world (as with any heat engine);\nefficiencies of 50% have been reached,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-mpower-4\"><sup>[4]<\/sup><\/a>&nbsp;similar to the maximum figure\nfor Diesel cycle engines.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-65\"><sup>[65]<\/sup><\/a>&nbsp;The efficiency of Stirling machines\nis also linked to the environmental temperature; higher efficiency is obtained\nwhen the weather is cooler, thus making this type of engine less interesting in\nplaces with warmer climates. As with other external combustion engines,\nStirling engines can use heat sources other than from combustion of fuels.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">When one side of\nthe piston is open to the atmosphere, the operation is slightly different. As\nthe sealed volume of working gas comes in contact with the hot side, it\nexpands, doing work on both the piston and on the atmosphere. When the working\ngas contacts the cold side, its pressure drops below atmospheric pressure and\nthe atmosphere pushes on the piston and does work on the gas.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To summarize,\nthe Stirling engine uses the temperature difference between its hot end and\ncold end to establish a cycle of a fixed mass of gas, heated and expanded, and\ncooled and compressed, thus converting thermal&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Energy\">energy<\/a>&nbsp;into\nmechanical energy. The greater the temperature difference between the hot and\ncold sources, the greater the thermal efficiency. The maximum theoretical\nefficiency is equivalent to that of the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Carnot_cycle\">Carnot cycle<\/a>, but the efficiency of real engines is\nless than this value because of friction and other losses.<\/p>\n\n\n\n\n\n<p class=\"wp-block-paragraph\">Video showing the compressor and displacer of a very small Stirling Engine\nin action<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Very low-power\nengines have been built that run on a temperature difference of as little as\n0.5 K.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-66\"><sup>[66]<\/sup><\/a>&nbsp;A&nbsp;<strong>displacer type stirling\nengine<\/strong>has one piston and one displacer. A temperature difference is\nrequired between the top and bottom of the large cylinder to run the engine. In\nthe case of the&nbsp;<strong>low-temperature difference<\/strong>(LTD) stirling engine,\nthe temperature difference between one&#8217;s hand and the surrounding air can be\nenough to run the engine. The power piston in the displacer type stirling\nengine is tightly sealed and is controlled to move up and down as the gas\ninside expands. The displacer, on the other hand, is very loosely fitted so\nthat air can move freely between the hot and cold sections of the engine as the\npiston moves up and down. The displacer moves up and down to cause most of the\ngas in the displacer cylinder to be either heated, or cooled. Note that in the\nfollowing description of the cycle the heat source at the bottom (the engine\nwould run equally well with the heat source at the top):<\/p>\n\n\n\n<ol class=\"wp-block-list\"><li>When the\ndisplacer is near the top of the large cylinder; most of the gas is in the\nlower section and will be heated by the heat source and it expands. This\nincreases the pressure, which forces the piston up, powering the flywheel. The\nturning of the flywheel then moves the displacer down.<\/li><li>When the\ndisplacer is near the bottom of the large cylinder; most of the gas is in the\nupper section and will cooled and contract causing the pressure to decrease,\nwhich in turn moves the piston down, imparting more energy to the flywheel.<\/li><\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Pressurization<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=25\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In most high\npower Stirling engines, both the minimum pressure and mean pressure of the\nworking fluid are above atmospheric pressure. This initial engine\npressurization can be realized by a pump, or by filling the engine from a\ncompressed gas tank, or even just by sealing the engine when the mean\ntemperature is lower than the mean&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Operating_temperature\">operating\ntemperature<\/a>. All of these\nmethods increase the mass of working fluid in the thermodynamic cycle. All of\nthe heat exchangers must be sized appropriately to supply the necessary heat\ntransfer rates. If the heat exchangers are well designed and can supply the\nheat&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Flux\">flux<\/a>&nbsp;needed for convective&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_transfer\">heat transfer<\/a>, then the engine, in a first\napproximation, produces power in proportion to the mean pressure, as predicted\nby the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/West_number\">West number<\/a>, and&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Beale_number\">Beale number<\/a>. In practice, the maximum pressure is also\nlimited to the safe pressure of the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Pressure_vessel\">pressure vessel<\/a>. Like most aspects of Stirling\nengine design, optimization is&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Multivariable_calculus\">multivariate<\/a>, and often has conflicting\nrequirements.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-A.J._Organ_1997,_p-67\"><sup>[67]<\/sup><\/a>&nbsp;A difficulty of pressurization is\nthat while it improves the power, the heat required increases proportionately\nto the increased power. This heat transfer is made increasingly difficult with\npressurization since increased pressure also demands increased thicknesses of\nthe walls of the engine, which, in turn, increase the resistance to heat\ntransfer.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Lubricants and friction<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=26\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h3>\n\n\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/File:STM_Stirling_Generator_set.jpg\"><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A modern Stirling engine and generator set with 55 kW electrical output,\nfor combined heat and power applications<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">At high\ntemperatures and pressures, the oxygen in air-pressurized crankcases, or in the\nworking gas of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hot_air_engines\">hot air engines<\/a>, can combine with the engine&#8217;s\nlubricating oil and explode. At least one person has died in such an explosion.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-Hargreaves-68\"><sup>[68]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Lubricants can\nalso clog heat exchangers, especially the regenerator. For these reasons,\ndesigners prefer non-lubricated, low-<a href=\"https:\/\/en.wikipedia.org\/wiki\/Coefficient_of_friction\">coefficient of\nfriction<\/a>&nbsp;materials\n(such as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Rulon_(plastic)\">rulon<\/a>&nbsp;or&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Graphite\">graphite<\/a>), with\nlow&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Normal_force\">normal forces<\/a>&nbsp;on the moving parts, especially\nfor sliding seals. Some designs avoid sliding surfaces altogether by using\ndiaphragms for sealed pistons. These are some of the factors that allow\nStirling engines to have lower maintenance requirements and longer life than\ninternal-combustion engines.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Analysis[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=27\">edit<\/a>]<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Comparison with internal combustion\nengines<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=28\"><strong>edit<\/strong><\/a><strong>]<\/strong><strong><\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In contrast to\ninternal combustion engines, Stirling engines have the potential to use&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Renewable_heat\">renewable heat<\/a>sources more easily, and to be\nquieter and more reliable with lower maintenance. They are preferred for\napplications that value these unique advantages, particularly if the cost per\nunit energy generated is more important than the capital cost per unit power.\nOn this basis, Stirling engines are cost competitive up to about 100&nbsp;kW.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-autogenerated1-69\"><sup>[69]<\/sup><\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Compared to\nan&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Internal_combustion_engine\">internal\ncombustion engine<\/a>&nbsp;of the\nsame power rating, Stirling engines currently have a higher&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Capital_cost\">capital cost<\/a>&nbsp;and are usually larger and heavier.\nHowever, they are more efficient than most internal combustion engines.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-70\"><sup>[70]<\/sup><\/a>&nbsp;Their lower maintenance requirements\nmake the overall&nbsp;<em>energy<\/em>&nbsp;cost comparable. The&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermal_efficiency\">thermal\nefficiency<\/a>&nbsp;is also\ncomparable (for small engines), ranging from 15% to 30%.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-autogenerated1-69\"><sup>[69]<\/sup><\/a>&nbsp;For applications such as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Micro-CHP\">micro-CHP<\/a>, a Stirling engine is often preferable to an internal combustion engine.\nOther applications include&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Water_pump\">water pumping<\/a>,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Astronautics\">astronautics<\/a>, and electrical generation from plentiful\nenergy sources that are incompatible with the internal combustion engine, such\nas solar energy, and&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Biomass\">biomass<\/a>&nbsp;such as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Zero_waste_agriculture\">agricultural\nwaste<\/a>&nbsp;and\nother&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Waste\">waste<\/a>&nbsp;such as domestic refuse. However,\nStirling engines are generally not price-competitive as an automobile engine,\nbecause of high cost per unit power, low&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Power_density\">power density<\/a>, and high material costs.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Basic analysis\nis based on the closed-form Schmidt analysis.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-71\"><sup>[71]<\/sup><\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-72\"><sup>[72]<\/sup><\/a><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Advantages<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=29\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<ul class=\"wp-block-list\"><li>Stirling engines can run directly on any available heat\nsource, not just one produced by combustion, so they can run on heat from\nsolar, geothermal, biological, nuclear sources or waste heat from industrial\nprocesses.<\/li><li>A continuous combustion process can be used to supply\nheat, so those emissions associated with the intermittent combustion processes\nof a reciprocating internal combustion engine can be reduced.<\/li><li>Some types of Stirling engines have the bearings and\nseals on the cool side of the engine, where they require less lubricant and\nlast longer than equivalents on other reciprocating engine types.<\/li><li>The engine mechanisms are in some ways simpler than other\nreciprocating engine types. No valves are needed, and the burner system can be\nrelatively simple. Crude Stirling engines can be made using common household\nmaterials.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-73\"><sup>[73]<\/sup><\/a><\/li><li>A Stirling engine uses a single-phase working fluid that\nmaintains an internal pressure close to the design pressure, and thus for a\nproperly designed system the risk of explosion is low. In comparison, a steam\nengine uses a two-phase gas\/liquid working fluid, so a faulty overpressure\nrelief valve can cause an explosion.<\/li><li>In some cases, low operating pressure allows the use of\nlightweight cylinders.<\/li><li>They can be built to run quietly and without an air\nsupply, for&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Air-independent_propulsion\">air-independent\npropulsion<\/a>&nbsp;use in\nsubmarines.<\/li><li>They start easily (albeit slowly, after warmup) and run\nmore efficiently in cold weather, in contrast to the internal combustion, which\nstarts quickly in warm weather, but not in cold weather.<\/li><li>A Stirling engine used for pumping water can be\nconfigured so that the water cools the compression space. This increases\nefficiency when pumping cold water.<\/li><li>They are extremely flexible. They can be used as CHP (<a href=\"https:\/\/en.wikipedia.org\/wiki\/Combined_heat_and_power\">combined heat\nand power<\/a>) in the winter\nand as coolers in summer.<\/li><li>Waste heat is easily harvested (compared to waste heat\nfrom an internal combustion engine), making Stirling engines useful for\ndual-output heat and power systems.<\/li><li>In 1986 NASA built a Stirling automotive engine and\ninstalled it in a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Chevrolet_Celebrity\">Chevrolet\nCelebrity<\/a>. Fuel economy\nwas improved 45% and emissions were greatly reduced. Acceleration (power\nresponse) was equivalent to the standard internal combustion engine. This\nengine, designated the Mod II, also nullifies arguments that Stirling engines\nare heavy, expensive, unreliable, and demonstrate poor performance.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-NASA,_Automotive_Stirling_Engine-74\"><sup>[74]<\/sup><\/a>&nbsp;A catalytic converter, muffler\nand frequent oil changes are not required.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-NASA,_Automotive_Stirling_Engine-74\"><sup>[74]<\/sup><\/a><\/li><\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">Disadvantages<strong>[<\/strong><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=30\"><strong>edit<\/strong><\/a><strong>]<\/strong><\/h4>\n\n\n\n<h5 class=\"wp-block-heading\">Size and cost\nissues[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=31\">edit<\/a>]<\/h5>\n\n\n\n<ul class=\"wp-block-list\"><li>Stirling engine designs require&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_exchanger\">heat exchangers<\/a>&nbsp;for heat\ninput and for heat output, and these must contain the pressure of the working\nfluid, where the pressure is proportional to the engine power output. In\naddition, the expansion-side heat exchanger is often at very high temperature,\nso the materials must resist the corrosive effects of the heat source, and have\nlow&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Creep_(deformation)\">creep<\/a>. Typically\nthese material requirements substantially increase the cost of the engine. The\nmaterials and assembly costs for a high temperature heat exchanger typically\naccounts for 40% of the total engine cost.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-Hargreaves-68\"><sup>[68]<\/sup><\/a><\/li><li>All thermodynamic cycles require large temperature\ndifferentials for efficient operation. In an external combustion engine, the\nheater temperature always equals or exceeds the expansion temperature. This\nmeans that the metallurgical requirements for the heater material are very\ndemanding. This is similar to a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Gas_turbine\">Gas turbine<\/a>, but is in contrast to an&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Otto_engine\">Otto engine<\/a>or&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Diesel_engine\">Diesel engine<\/a>, where the\nexpansion temperature can far exceed the metallurgical limit of the engine\nmaterials, because the input heat source is not conducted through the engine,\nso engine materials operate closer to the average temperature of the working\ngas. The Stirling cycle is not actually achievable, the real cycle in Stirling\nmachines is less efficient than the theoretical Stirling cycle, also the\nefficiency of the Stirling cycle is lower where the ambient temperatures are\nmild, while it would give its best results in a cool environment, such as\nnorthern countries&#8217; winters.<\/li><li>Dissipation of waste heat is especially complicated\nbecause the coolant temperature is kept as low as possible to maximize thermal\nefficiency. This increases the size of the radiators, which can make packaging\ndifficult. Along with materials cost, this has been one of the factors limiting\nthe adoption of Stirling engines as automotive prime movers. For other\napplications such as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Ship#Propulsion\">ship propulsion<\/a>&nbsp;and stationary&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Microgeneration\">microgeneration<\/a>&nbsp;systems\nusing&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Cogeneration\">combined heat\nand power<\/a>&nbsp;(CHP)\nhigh&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Power_density\">power density<\/a>&nbsp;is not\nrequired.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-BBC_CHP-37\"><sup>[37]<\/sup><\/a><\/li><\/ul>\n\n\n\n<h5 class=\"wp-block-heading\">Power and torque\nissues[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=32\">edit<\/a>]<\/h5>\n\n\n\n<ul class=\"wp-block-list\"><li>Stirling engines, especially those that run on small\ntemperature differentials, are quite large for the amount of power that they\nproduce (i.e., they have low&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Power_density\">specific power<\/a>). This is\nprimarily due to the heat transfer coefficient of gaseous convection, which\nlimits the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_flux\">heat flux<\/a>&nbsp;that can\nbe attained in a typical cold heat exchanger to about 500&nbsp;W\/(m<sup>2<\/sup>\u00b7K),\nand in a hot heat exchanger to about 500\u20135000&nbsp;W\/(m<sup>2<\/sup>\u00b7K).<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-A.J._Organ_1997,_p-67\"><sup>[67]<\/sup><\/a>&nbsp;Compared with internal\ncombustion engines, this makes it more challenging for the engine designer to\ntransfer heat into and out of the working gas. Because of the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermal_efficiency\">thermal\nefficiency<\/a>&nbsp;the\nrequired heat transfer grows with lower temperature difference, and the heat\nexchanger surface (and cost) for 1&nbsp;kW output grows with (1\/\u0394T)<sup>2<\/sup>.\nTherefore, the specific cost of very low temperature difference engines is very\nhigh. Increasing the temperature differential and\/or pressure allows Stirling\nengines to produce more power, assuming the heat exchangers are designed for\nthe increased heat load, and can deliver the convected heat flux necessary.<\/li><li>A Stirling engine cannot start instantly; it literally\nneeds to &#8220;warm up&#8221;. This is true of all external combustion engines,\nbut the warm up time may be longer for Stirlings than for others of this type\nsuch as&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Steam_engine\">steam engines<\/a>. Stirling\nengines are best used as constant speed engines.<\/li><li>Power output of a Stirling tends to be constant and to\nadjust it can sometimes require careful design and additional mechanisms. Typically,\nchanges in output are achieved by varying the displacement of the engine (often\nthrough use of a&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Swashplate\">swashplate<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Crankshaft\">crankshaft<\/a>&nbsp;arrangement), or by changing\nthe quantity of working fluid, or by altering the piston\/displacer phase angle,\nor in some cases simply by altering the engine load. This property is less of a\ndrawback in hybrid electric propulsion or &#8220;base load&#8221; utility\ngeneration where constant power output is actually desirable.<\/li><\/ul>\n\n\n\n<h5 class=\"wp-block-heading\">Gas choice issues[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=33\">edit<\/a>]<\/h5>\n\n\n\n<p class=\"wp-block-paragraph\">The gas used\nshould have a low&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_capacity\">heat capacity<\/a>, so that a given amount of\ntransferred heat leads to a large increase in pressure. Considering this issue,\nhelium would be the best gas because of its very low heat capacity. Air is a\nviable working fluid,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-75\"><sup>[75]<\/sup><\/a>&nbsp;but the oxygen in a highly\npressurized air engine can cause fatal accidents caused by lubricating oil\nexplosions.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-Hargreaves-68\"><sup>[68]<\/sup><\/a>Following one such accident Philips\npioneered the use of other gases to avoid such risk of explosions.<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Hydrogen\">Hydrogen<\/a>&#8216;s low&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Viscosity\">viscosity<\/a>&nbsp;and high&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermal_conductivity\">thermal\nconductivity<\/a>&nbsp;make it\nthe most powerful working gas, primarily because the engine can run faster than\nwith other gases. However, because of hydrogen absorption, and given the high\ndiffusion rate associated with this low&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Molecular_weight\">molecular weight<\/a>&nbsp;gas,\nparticularly at high temperatures, H<sub>2<\/sub>&nbsp;leaks through the solid\nmetal of the heater. Diffusion through carbon steel is too high to be\npractical, but may be acceptably low for metals such as aluminum, or even\nstainless steel. Certain ceramics also greatly reduce diffusion.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hermetic_seal\">Hermetic<\/a>&nbsp;pressure vessel seals are\nnecessary to maintain pressure inside the engine without replacement of lost\ngas. For high temperature differential (HTD) engines, auxiliary systems may\nrequired to maintain high pressure working fluid. These systems can be a gas\nstorage bottle or a gas generator. Hydrogen can be generated by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Electrolysis\">electrolysis<\/a>&nbsp;of water, the action of steam\non red hot carbon-based fuel, by gasification of hydrocarbon fuel, or by the\nreaction of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Acid\">acid<\/a>&nbsp;on metal.\nHydrogen can also cause the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hydrogen_embrittlement\">embrittlement<\/a>of metals.\nHydrogen is a flammable gas, which is a safety concern if released from the\nengine.<\/li><li>Most technically advanced Stirling engines, like those\ndeveloped for United States government labs, use&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Helium\">helium<\/a>&nbsp;as the working gas, because it\nfunctions close to the efficiency and power density of hydrogen with fewer of\nthe material containment issues. Helium is&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Inert_gas\">inert<\/a>, and hence not flammable. Helium is\nrelatively expensive, and must be supplied as bottled gas. One test showed\nhydrogen to be 5% (absolute) more efficient than helium (24% relatively) in the\nGPU-3 Stirling engine.<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-76\"><sup>[76]<\/sup><\/a>&nbsp;The researcher Allan Organ\ndemonstrated that a well-designed air engine is theoretically just as&nbsp;<em>efficient<\/em>as\na helium or hydrogen engine, but helium and hydrogen engines are several times\nmore&nbsp;<em>powerful per unit volume<\/em>.<\/li><li>Some engines use&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Air\">air<\/a>&nbsp;or&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Nitrogen\">nitrogen<\/a>&nbsp;as the working fluid. These\ngases have much lower power density (which increases engine costs), but they\nare more convenient to use and they minimize the problems of gas containment\nand supply (which decreases costs). The use of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Compressed_air\">compressed air<\/a>&nbsp;in contact\nwith flammable materials or substances such as lubricating oil introduces an\nexplosion hazard, because compressed air contains a high&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Partial_pressure\">partial pressure<\/a>&nbsp;of&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Oxygen\">oxygen<\/a>. However, oxygen can be removed from\nair through an oxidation reaction or bottled nitrogen can be used, which is\nnearly inert and very safe.<\/li><li>Other possible lighter-than-air gases include:&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Methane\">methane<\/a>, and&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Ammonia\">ammonia<\/a>.<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Applications[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=34\">edit<\/a>]<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><em>Main article:&nbsp;<\/em><a href=\"https:\/\/en.wikipedia.org\/wiki\/Applications_of_the_Stirling_engine\"><em>Applications of the Stirling engine<\/em><\/a><em><\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Applications of\nthe Stirling engine range from heating and cooling to underwater power systems.\nA Stirling engine can function in reverse as a heat pump for heating or\ncooling. Other uses include combined heat and power, solar power generation,\nStirling cryocoolers, heat pump, marine engines, low power aviation engines,<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_note-Model_Aircraft-77\"><sup>[77]<\/sup><\/a>&nbsp;and low temperature difference\nengines.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Alternatives[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=35\">edit<\/a>]<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Alternative\nthermal energy harvesting devices include the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermogenerator\">thermogenerator<\/a>. Thermogenerators allow less\nefficient conversion (5-10%) but may be useful in situations where the end\nproduct must be electricity, and where a small conversion device is a critical\nfactor.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">See\nalso[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=36\">edit<\/a>]<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Beale_number\">Beale number<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Bore_(engine)\">Bore<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Cogeneration\">Cogeneration<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Distributed_generation\">Distributed generation<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Fluidyne_engine\">Fluidyne engine<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Quasiturbine\">Quasiturbine<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Relative_cost_of_electricity_generated_by_different_sources\">Relative cost of electricity\ngenerated by different sources<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Schmidt_number#Stirling_engines\">Schmidt number<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_radioisotope_generator\">Stirling\nradioisotope generator<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stroke_(engine)\">Stroke<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermomechanical_generator\">Thermomechanical\ngenerator<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/West_Number\">West Number<\/a><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">References[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=37\">edit<\/a>]<\/h2>\n\n\n\n<ol class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-1\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;&#8220;Stirling\nEngines&#8221;, G. Walker (1980), Clarenden Press, Oxford, page 1: &#8220;A\nStirling engine is a mechanical device which operates on a *closed*\nregenerative thermodynamic cycle, with cyclic compression and expansion of the\nworking fluid at different temperature levels.&#8221;<ol><li>^&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-W.R._Martini_1983,_p.6_2-0\">Jump up to:<strong><em><sup>a<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-W.R._Martini_1983,_p.6_2-1\"><strong><em><sup>b<\/sup><\/em><\/strong><\/a>&nbsp;W.R. Martini (1983), p.6<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-3\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;T.\nFinkelstein; A.J. Organ (2001), Chapters 2&amp;3<\/li><\/ol><ol><li>^&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-mpower_4-0\">Jump up to:<strong><em><sup>a<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-mpower_4-1\"><strong><em><sup>b<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-mpower_4-2\"><strong><em><sup>c<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"http:\/\/www.mpoweruk.com\/stirling_engine.htm\"><em>&#8220;The Stirling Engine&#8221;<\/em><\/a>.&nbsp;mpoweruk.com.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-5\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Sleeve\nnotes from A.J. Organ (2007)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-6\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;F.\nStarr (2001)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-7\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;C.M.\nHargreaves (1991), Chapter 2.5<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-8\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Graham\nWalker (1971) Lecture notes for Stirling engine symposium at Bath University.\nPage 1.1 &#8220;Nomenclature&#8221;<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-9\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/www.stirlingbuilder.com\/survey\/survey-results\"><em>&#8220;Previous Survey Results \u2013 StirlingBuilder.com&#8221;<\/em><\/a>.&nbsp;stirlingbuilder.com.&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20140526022227\/http:\/www.stirlingbuilder.com\/survey\/survey-results\"><em>Archived<\/em><\/a>&nbsp;from the\noriginal on 26 May 2014.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-10\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;R.\nSier (1999)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-11\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;T.\nFinkelsteinl; A.J. Organ (2001), Chapter 2.2<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-12\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;English\npatent 4081 of 1816&nbsp;<em>Improvements for diminishing the consumption of\nfuel and in particular an engine capable of being applied to the moving<\/em>&nbsp;(of)&nbsp;<em>machinery\non a principle entirely new.<\/em>&nbsp;as reproduced in part in C.M. Hargreaves\n(1991), Appendix B, with full transcription of text in R. Sier (1995), p.??<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-13\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;R.\nSier (1995), p. 93<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-14\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;A.J.\nOrgan (2008a)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-15\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Excerpt\nfrom a paper presented by&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/James_Stirling_(1800%E2%80%931876)\">James Stirling<\/a>&nbsp;in June\n1845 to the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Institution_of_Civil_Engineers\">Institution of\nCivil Engineers<\/a>. As reproduced in R. Sier (1995),\np.92.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-16\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;A.\nNesmith (1985)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-17\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;R.\nChuse; B. Carson (1992), Chapter 1<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-18\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;R.\nSier (1995), p.94<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-19\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;T.\nFinkelstein; A.J. Organ (2001), p.30<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-haestirling1816_20-0\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/hotairengines.org\/stirling-engines-inventors\/stirling\/the-stirling-engine-of-1816\/the-economiser\"><em>&#8220;Stirling patent of 1816&#8221;<\/em><\/a>.&nbsp;hotairengines.org.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-haestirling1827_21-0\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/hotairengines.org\/stirling-engines-inventors\/stirling\/the-stirling-engine-of-1827\/book-galloway\"><em>&#8220;The Stirling Engine of\n1827&#8221;<\/em><\/a>.&nbsp;hotairengines.org.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-haeparkinson1827_22-0\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/hotairengines.org\/stirling-engines-inventors\/parkinson-and-crossley\/predecessor-of-stirling-engine\"><em>&#8220;The Parkinson and Crossley&#8217;s\nHot Air Engine of 1827&#8221;<\/em><\/a>.&nbsp;hotairengines.org.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-haestirling1842_23-0\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/hotairengines.org\/stirling-engines-inventors\/stirling\/the-stirling-engine-of-1842\/complete-description\"><em>&#8220;The 1842 Stirling Engine\npresented by James Stirling&#8221;<\/em><\/a>.&nbsp;hotairengines.org.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-24\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Hartford\nSteam Boiler (a)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-25\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;T.\nFinkelstein; A.J. Organ (2001), Chapter 2.4<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-26\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;The\n1906 Rider-Ericsson Engine Co. catalog claimed that &#8220;any gardener or\nordinary domestic can operate these engines and no licensed or experienced\nengineer is required&#8221;.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-27\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;T.\nFinkelstein; A.J. Organ (2001), p.64<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-28\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;T.\nFinkelstein; A. J. Organ (2001), p. 34<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-29\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;T.\nFinkelstein; A. J. Organ (2001), p. 55<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-30\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;C.\nM. Hargreaves (1991), p. 28\u201330<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-31\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<em>Philips\nTechnical Review<\/em>&nbsp;(1947), Vol. 9, No. 4, p. 97.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-32\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;C.\nM. Hargreaves (1991), p. 61<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-33\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Letter\ndated March 1961 from Research and Control Instruments Ltd. London WC1 to North\nDevon Technical College, offering &#8220;remaining stocks&#8230; to institutions\nsuch as yourselves&#8230; at a special price of \u00a375 nett&#8221;<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-34\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;C.\nM. Hargreaves (1991), p. 77<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-Kockums_35-0\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Kockums\n(a)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-NREL_CSP_36-0\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/www.nrel.gov\/learning\/re_csp.html\"><em>&#8220;Learning about renewable energy&#8221;<\/em><\/a>. NREL \u2013\nNational Renewable Energy Laboratory.&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20160502171536\/http:\/www.nrel.gov\/learning\/re_csp.html\"><em>Archived<\/em><\/a>from the\noriginal on 2 May 2016<em>.\nRetrieved&nbsp;<\/em><em>25 April<\/em><em>2016<\/em>.<\/li><\/ol><ol><li>^&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-BBC_CHP_37-0\">Jump up to:<strong><em><sup>a<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-BBC_CHP_37-1\"><strong><em><sup>b<\/sup><\/em><\/strong><\/a>&nbsp;BBC News (2003), &#8220;The boiler is based on the Stirling\nengine, dreamed up by the Scottish inventor Robert Stirling in 1816. [\u2026] The\ntechnical name given to this particular use is Micro Combined Heat and Power or\nMicro CHP.&#8221;<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-LGET_38-0\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Dudek, Jerzy; Klimek,\nPiotr; Ko\u0142odziejak, Grzegorz; Niemczewska, Joanna; Zaleska-Bartosz, Joanna\n(2010).&nbsp;<a href=\"https:\/\/www.globalmethane.org\/Data\/1022_LFG-Handbook.pdf\"><em>&#8220;Landfill Gas Energy\nTechnologies&#8221;<\/em><\/a>&nbsp;(PDF).&nbsp;Global Methane Initiative. Instytut\nNafty i Gazu \/ US Environmental Protection Agency.&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20150725064554\/https:\/www.globalmethane.org\/Data\/1022_LFG-Handbook.pdf\"><em>Archived<\/em><\/a>&nbsp;(PDF)from\nthe original on 25 July 2015<em>.\nRetrieved&nbsp;<\/em><em>24 July<\/em><em>2015<\/em>.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-39\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;W.H.\nBrandhorst; J.A. Rodiek (2005)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-40\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;B.\nKongtragool; S. Wongwises (2003)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-41\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/e-futures.group.shef.ac.uk\/publications\/pdf\/140_4%20Erardo%20Elizondo.pdf\"><em>&#8220;Archived copy&#8221;<\/em><\/a>&nbsp;(PDF).&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20140526013415\/http:\/e-futures.group.shef.ac.uk\/publications\/pdf\/140_4%20Erardo%20Elizondo.pdf\"><em>Archived<\/em><\/a>&nbsp;(PDF)&nbsp;from\nthe original on 26 May 2014<em>.\nRetrieved&nbsp;<\/em><em>25 May<\/em><em>&nbsp;2014<\/em>.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-42\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;A.J.\nOrgan (1992), p.58<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-43\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Stirling\nCycle Engines, A J Organ (2014), p.4<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-44\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;K.\nHirata (1998)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-45\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;M.Keveney\n(2000a)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-46\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;M.\nKeveney (2000b)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-47\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Quasiturbine\nAgence (a)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-48\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;&#8220;Ringbom\nStirling Engines&#8221;, James R. Senft, 1993, Oxford University Press<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-49\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Ossian\nRingbom (of Borg\u00e5, Finland)&nbsp;<a href=\"http:\/\/patimg1.uspto.gov\/.piw?Docid=00856102&amp;homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D0856102.PN.%2526OS%3DPN%2F0856102%2526RS%3DPN%2F0856102&amp;PageNum=&amp;Rtype=&amp;SectionNum=&amp;idkey=NONE&amp;Input=View+first+page\">&#8220;Hot-air engine&#8221;<\/a>&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20151017032339\/http:\/patimg1.uspto.gov\/.piw?Docid=00856102&amp;homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D0856102.PN.%2526OS%3DPN%2F0856102%2526RS%3DPN%2F0856102&amp;PageNum=&amp;Rtype=&amp;SectionNum=&amp;idkey=NONE&amp;Input=View+first+page\">Archived<\/a>&nbsp;17 October\n2015 at the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Wayback_Machine\">Wayback Machine<\/a>. U.S. Patent\nno. 856,102 (filed: 17 July 1905; issued: 4 June 1907).<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-50\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/www.animatedengines.com\/ross.shtml\"><em>&#8220;Animated Engines&#8221;<\/em><\/a>.&nbsp;animatedengines.com.&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20111111115813\/http:\/www.animatedengines.com\/ross.shtml\"><em>Archived<\/em><\/a>&nbsp;from the\noriginal on 11 November 2011.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-51\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;&#8220;Free-Piston\nStirling Engines&#8221;, G. Walker et al., Springer 1985, reprinted by Stirling\nMachine World, West Richland WA<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-52\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;&#8220;The\nThermo-mechanical Generator&#8230;&#8221;, E.H. Cooke-Yarborough, (1967) Harwell\nMemorandum No. 1881 and (1974) Proc. I.E.E., Vol. 7, pp. 749-751<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-53\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;G.M.\nBenson (1973 and 1977)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-54\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;D.\nPostle (1873)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-55\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;&#8220;<a href=\"http:\/\/patentscope.wipo.int\/search\/en\/detail.jsf?docId=WO2012062231&amp;recNum=1&amp;maxRec=1&amp;office=&amp;prevFilter=&amp;sortOption=&amp;queryString=PCT%2FCZ2011%2F000108&amp;tab=PCT+Biblio\">DOUBLE ACTING DISPLACER WITH SEPARATE\nHOT AND COLD SPACE AND THE HEAT ENGINE WITH A DOUBLE ACTING DISPLACE<\/a>&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20150114100725\/http:\/patentscope.wipo.int\/search\/en\/detail.jsf?docId=WO2012062231&amp;recNum=1&amp;maxRec=1&amp;office=&amp;prevFilter=&amp;sortOption=&amp;queryString=PCT%2FCZ2011%2F000108&amp;tab=PCT+Biblio\">Archived<\/a>14 January 2015\nat the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Wayback_Machine\">Wayback Machine<\/a>.&#8221;\nWO\/2012\/062231 PCT\/CZ2011\/000108<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-56\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/www.infiniacorp.com\/accomplishments.html\">Infinia web site<\/a>&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20130110021806\/http:\/www.infiniacorp.com\/accomplishments.html\">Archived<\/a>&nbsp;10 January\n2013 at the&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Wayback_Machine\">Wayback Machine<\/a>., accessed\n2010-12-29<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-57\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Schimdt,\nGeorge.&nbsp;<a href=\"http:\/\/newfrontiers.larc.nasa.gov\/PDF_FILES\/09_NF_PPC_Schmidt.pdf\">Radio Isotope Power Systems for the\nNew Frontier<\/a>. Presentation to New Frontiers\nProgram Pre-proposal Conference. 13 November 2003. (Accessed 2012-Feb-3)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-58\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Mari Silbey.&nbsp;<a href=\"http:\/\/www.smartplanet.com\/blog\/report\/new-alliance-could-make-cable-a-catalyst-for-cleaner-power\/364?tag=search-river\"><em>&#8220;New alliance could make cable a\ncatalyst for cleaner power&#8221;<\/em><\/a>.&nbsp;ZDNet.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-59\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/www.dekaresearch.com\/stirling.shtml\"><em>&#8220;Archived copy&#8221;<\/em><\/a>.&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20121125082843\/http:\/www.dekaresearch.com\/stirling.shtml\"><em>Archived<\/em><\/a>&nbsp;from the\noriginal on 25 November 2012<em>.\nRetrieved&nbsp;<\/em><em>28 November<\/em><em>&nbsp;2012<\/em>.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-60\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;A.\nRomanelli&nbsp;<a href=\"https:\/\/arxiv.org\/pdf\/1704.01611.pdf\">Alternative thermodynamic cycle for\nthe Stirling machine<\/a>, American Journal of Physics 85, 926\n(2017)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-61\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;T.\nFinkelstein; A.J. Organ (2001), Page 66 &amp; 229<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-62\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;A.J.\nOrgan (1992), Chapter 3.1 \u2013 3.2<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-63\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Rallis\nC. J., Urieli I. and Berchowitz D.M. A New Ported Constant Volume External Heat\nSupply Regenerative Cycle, 12th IECEC, Washington DC, 1977, pp 1534\u20131537.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-64\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Finkelstein,\nT. Generalized Thermodynamic Analysis of Stirling Engines. Paper 118B, Society\nof Automotive Engineers, 1960.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-65\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;<a href=\"http:\/\/www.mpoweruk.com\/piston_engines.htm\">http:\/\/www.mpoweruk.com\/piston_engines.htm<\/a>Section heading\n&#8220;Energy Conversion Efficiency&#8221;<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-66\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;&#8220;An\nIntroduction to Low Temperature Differential Stirling Engines&#8221;, James R.\nSenft, 1996, Moriya Press<\/li><\/ol><ol><li>^&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-A.J._Organ_1997,_p_67-0\">Jump up to:<strong><em><sup>a<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-A.J._Organ_1997,_p_67-1\"><strong><em><sup>b<\/sup><\/em><\/strong><\/a>&nbsp;A.J. Organ (1997), p.??<\/li><\/ol><ol><li>^&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-Hargreaves_68-0\">Jump up to:<strong><em><sup>a<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-Hargreaves_68-1\"><strong><em><sup>b<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-Hargreaves_68-2\"><strong><em><sup>c<\/sup><\/em><\/strong><\/a>&nbsp;C.M. Hargreaves (1991), p.??<\/li><\/ol><ol><li>^&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-autogenerated1_69-0\">Jump up to:<strong><em><sup>a<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-autogenerated1_69-1\"><strong><em><sup>b<\/sup><\/em><\/strong><\/a>&nbsp;WADE (a)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-70\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Krupp\nand Horn. Earth: The Sequel. p. 57<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-71\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Z.\nHerzog (2008)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-72\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;K.\nHirata (1997)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-73\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;MAKE:\nMagazine (2006)<\/li><\/ol><ol><li>^&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-NASA,_Automotive_Stirling_Engine_74-0\">Jump up to:<strong><em><sup>a<\/sup><\/em><\/strong><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-NASA,_Automotive_Stirling_Engine_74-1\"><strong><em><sup>b<\/sup><\/em><\/strong><\/a>&nbsp;Nightingale,\nNoel P. (October 1986).&nbsp;<a href=\"https:\/\/ntrs.nasa.gov\/archive\/nasa\/casi.ntrs.nasa.gov\/19880002196.pdf\"><em>&#8220;Automotive Stirling Engine: Mod\nII Design Report&#8221;<\/em><\/a>&nbsp;(PDF).&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/NASA\"><em>NASA<\/em><\/a>.&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20170429223941\/https:\/ntrs.nasa.gov\/archive\/nasa\/casi.ntrs.nasa.gov\/19880002196.pdf\"><em>Archived<\/em><\/a>&nbsp;(PDF)&nbsp;from\nthe original on 29 April 2017.<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-75\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;A.J.\nOrgan (2008b)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-76\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;L.G.\nThieme (1981)<\/li><\/ol><ol><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine#cite_ref-Model_Aircraft_77-0\"><strong>Jump up<\/strong><strong>^<\/strong><\/a>&nbsp;Mcconaghy, Robert\n(1986). &#8220;Design of a Stirling Engine for Model Aircraft&#8221;.&nbsp;IECEC:\n490\u2013493.<\/li><\/ol><\/li><\/ol>\n\n\n\n<h2 class=\"wp-block-heading\">Bibliography[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=38\">edit<\/a>]<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>S. Backhaus; G. Swift (2003).&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20080801212651\/http:\/www.lanl.gov\/mst\/engine\/\"><em>&#8220;Acoustic Stirling Heat Engine:\nMore Efficient than Other No-Moving-Parts Heat Engines&#8221;<\/em><\/a>. Los Alamos\nNational Laboratory. Archived from&nbsp;<a href=\"http:\/\/www.lanl.gov\/mst\/engine\/\"><em>the original<\/em><\/a>&nbsp;on 2008-08-01<em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>BBC News (2003-10-31).&nbsp;<a href=\"http:\/\/news.bbc.co.uk\/2\/hi\/programmes\/working_lunch\/3231549.stm\"><em>&#8220;Power from the people&#8221;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>W.T. Beale (1971). &#8220;Stirling Cycle Type Thermal\nDevice&#8221;,&nbsp;<a href=\"http:\/\/v3.espacenet.com\/textdoc?DB=EPODOC&amp;IDX=US3552120\"><em>US patent 3552120<\/em><\/a>. Granted to\nResearch Corp, 5 January 1971.<\/li><li>G.M. Benson (1977). &#8220;Thermal\nOscillators&#8221;,&nbsp;<a href=\"http:\/\/v3.espacenet.com\/textdoc?DB=EPODOC&amp;IDX=US4044558\"><em>US patent 4044558<\/em><\/a>. Granted to New\nProcess Ind, 30 August 1977 .<\/li><li>G.M. Benson (1973). &#8220;Thermal\nOscillators&#8221;.&nbsp;Proceedings of the 8th IECEC. Philadelphia: American\nSociety of Mechanical Engineers. pp.&nbsp;182\u2013189.<\/li><li>H.W. Brandhorst; J.A. Rodiek (2005).&nbsp;<a href=\"http:\/\/pdf.aiaa.org\/preview\/CDReadyMIAF05_1429\/PVIAC-05-C3.P.05.pdf\"><em>&#8220;A 25 kW Solar Stirling Concept\nfor Lunar Surface Exploration&#8221;<\/em><\/a>&nbsp;(PDF). In International\nAstronautics Federation.&nbsp;Proceedings of the 56th International\nAstronautical Congress. IAC-05-C3.P.05<em>. Retrieved&nbsp;<\/em><em>2012-03-18<\/em>.<\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Carbon_Trust\"><em>Carbon Trust<\/em><\/a>&nbsp;(2007).&nbsp;<a href=\"http:\/\/www.carbontrust.com\/resources\/reports\/technology\/micro-chp-accelerator\"><em>&#8220;Micro-CHP Accelerator&nbsp;\u2014\nInterim Report&nbsp;\u2014 Executive summary&#8221;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>March 19,<\/em><em>2012<\/em>.<\/li><li>E.H. Cooke-Yarborough; E. Franklin; J. Geisow; R.\nHowlett; C.D. West (1974). &#8220;Harwell Thermo-Mechanical\nGenerator&#8221;.&nbsp;Proceedings of the 9th IECEC. San Francisco: American\nSociety of Mechanical Engineers. pp.&nbsp;1132\u20131136.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Bibcode\"><em>Bibcode<\/em><\/a>:<a href=\"http:\/\/adsabs.harvard.edu\/abs\/1974iece.conf.1132C\"><em>1974iece.conf.1132C<\/em><\/a>.<\/li><li>E.H. Cooke-Yarborough (1970). &#8220;Heat\nEngines&#8221;,&nbsp;<a href=\"http:\/\/v3.espacenet.com\/textdoc?DB=EPODOC&amp;IDX=US3548589\"><em>US patent 3548589<\/em><\/a>. Granted to\nAtomic Energy Authority UK, 22 December 1970.<\/li><li>E.H. Cooke-Yarborough (1967). &#8220;A Proposal for a\nHeat-Powered Nonrotating Electrical Alternator&#8221;,&nbsp;<em>Harwell Memorandum\nAERE-M881<\/em>.<\/li><li>R. Chuse; B. Carson (1992).&nbsp;Pressure Vessels, The\nASME Code Simplified. McGraw\u2013Hill.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/International_Standard_Book_Number\"><em>ISBN<\/em><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/0-07-010939-7\"><em>0-07-010939-7<\/em><\/a>.<\/li><li>T. Finkelstein; A.J. Organ (2001).&nbsp;Air Engines.\nProfessional Engineering Publishing.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/International_Standard_Book_Number\"><em>ISBN<\/em><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/1-86058-338-5\"><em>1-86058-338-5<\/em><\/a>.<\/li><li>C.M. Hargreaves (1991).&nbsp;The Philips Stirling\nEngine.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Elsevier_Science\"><em>Elsevier Science<\/em><\/a>.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/International_Standard_Book_Number\"><em>ISBN<\/em><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/0-444-88463-7\"><em>0-444-88463-7<\/em><\/a>.<\/li><li>J. Harrison (2008).&nbsp;<a href=\"http:\/\/www.claverton-energy.com\/what-is-microgeneration.html\"><em>&#8220;What is micro generation?&#8221;<\/em><\/a>. Claverton\nEnergy Research Group<em>.\nRetrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Hartford_Steam_Boiler\"><em>Hartford Steam\nBoiler<\/em><\/a>.&nbsp;<a href=\"http:\/\/www.hsb.com\/about.asp?id=50\"><em>&#8220;Hartford Steam Boiler: Steam\nPower and the Industrial Revolution&#8221;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>J. Hasci (2008).&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20090106155529\/http:\/www.createthefuturecontest.com\/pages\/view\/entriesdetail.html?entryID=1329\"><em>&#8220;Modified Stirling Engine With\nGreater Power Density&#8221;<\/em><\/a>.&nbsp;Create the Future Design Contest.\nNASA &amp; SolidWorks. Archived from&nbsp;<a href=\"http:\/\/www.createthefuturecontest.com\/pages\/view\/entriesdetail.html?entryID=1329\"><em>the original<\/em><\/a>&nbsp;on 6\nJanuary 2009<em>. Retrieved&nbsp;<\/em><em>19 January<\/em><em>&nbsp;2009<\/em>.<\/li><li>Z. Herzog (2008).&nbsp;<a href=\"http:\/\/mac6.ma.psu.edu\/stirling\/simulations\/isothermal\/schmidt.html\"><em>&#8220;Schmidt Analysis&#8221;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>K. Hirata (1998).&nbsp;<a href=\"http:\/\/www.nmri.go.jp\/eng\/khirata\/stirling\/docpaper\/sekkeie.html\"><em>&#8220;Design and manufacturing of a\nprototype engine&#8221;<\/em><\/a>. National Maritime Research Institute<em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>K. Hirata (1997).&nbsp;<a href=\"http:\/\/www.bekkoame.ne.jp\/~khirata\/academic\/schmidt\/schmidt.htm\"><em>&#8220;Schmidt Theory For Stirling\nEngines&#8221;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>K. Hirata.&nbsp;<a href=\"http:\/\/www.bekkoame.ne.jp\/~khirata\/academic\/kiriki\/models\/plm_top.html\"><em>&#8220;Palm Top Stirling Engine&#8221;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>M. Keveney (2000a).&nbsp;<a href=\"http:\/\/www.animatedengines.com\/vstirling.shtml\"><em>&#8220;Two Cylinder Stirling Engine&#8221;<\/em><\/a>.\nanimatedengines.com<em>.\nRetrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>M. Keveney (2000b).&nbsp;<a href=\"http:\/\/www.animatedengines.com\/stirling.shtml\"><em>&#8220;Single Cylinder Stirling Engine&#8221;<\/em><\/a>.\nanimatedengines.com<em>.\nRetrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>Kockums.&nbsp;<a href=\"http:\/\/www.kockums.se\/products\/kockumsstirlingm.html\"><em>&#8220;The Stirling Engine: An Engine for\nthe Future&#8221;<\/em><\/a><em>.\nRetrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>B. Kongtragool; S. Wongwises (2003). &#8220;A review of\nsolar-powered Stirling engines and low temperature differential Stirling\nengines&#8221;.&nbsp;Renewable and Sustainable Energy Reviews.&nbsp;<strong>7<\/strong>&nbsp;(2):\n131\u2013154.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Digital_object_identifier\"><em>doi<\/em><\/a>:<a href=\"https:\/\/doi.org\/10.1016%2FS1364-0321%2802%2900053-9\"><em>10.1016\/S1364-0321(02)00053-9<\/em><\/a>.<\/li><li>D. Liao.&nbsp;<a href=\"http:\/\/www.logicsys.com.tw\/wrkbas.htm\"><em>&#8220;The Working Principles&#8221;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>W.R. Martini (1983).&nbsp;<a href=\"https:\/\/ntrs.nasa.gov\/archive\/nasa\/casi.ntrs.nasa.gov\/19830022057_1983022057.pdf\"><em>&#8220;Stirling Engine Design Manual\n(2nd ed)&#8221;<\/em><\/a>&nbsp;(17.9&nbsp;MB PDF). NASA<em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Micro-Star_International\"><em>Micro-Star\nInternational<\/em><\/a>&nbsp;(2008).&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20080913215446\/http:\/global.msi.com.tw\/index.php?func=newsdesc&amp;news_no=591\"><em>&#8220;World&#8217;s First Powerless Air\nCooler on a Mainboard!&#8221;<\/em><\/a>. Archived from&nbsp;<a href=\"http:\/\/global.msi.com.tw\/index.php?func=newsdesc&amp;news_no=591\"><em>the original<\/em><\/a>&nbsp;on 13\nSeptember 2008<em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>A. Nesmith (1985).&nbsp;<a href=\"http:\/\/www.asme.org\/Communities\/History\/Resources\/Long_Arduous_March_Toward.cfm\"><em>&#8220;A Long, Arduous March Toward\nStandardization&#8221;<\/em><\/a>. Smithsonian Magazine<em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>A.J. Organ (2008a).&nbsp;<a href=\"http:\/\/web.me.com\/allan.j.o\/Communicable_Insight\/1818_and_all_that.html\"><em>&#8220;1818 and All That&#8221;<\/em><\/a>. Communicable\nInsight<em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>A.J. Organ (2008b).&nbsp;<a href=\"http:\/\/web.me.com\/allan.j.o\/Communicable_Insight\/Why_air.html\"><em>&#8220;Why Air?&#8221;<\/em><\/a>. Communicable\nInsight<em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>A.J. Organ (2007).&nbsp;The Air Engine: Stirling Cycle\nPower for a Sustainable Future. Woodhead Publishing.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/International_Standard_Book_Number\"><em>ISBN<\/em><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/1-84569-231-4\"><em>1-84569-231-4<\/em><\/a>.<\/li><li>A.J. Organ (1997).&nbsp;The Regenerator and the Stirling\nEngine. Wiley.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/International_Standard_Book_Number\"><em>ISBN<\/em><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/1-86058-010-6\"><em>1-86058-010-6<\/em><\/a>.<\/li><li>A.J. Organ (1992).&nbsp;Thermodynamics and Gas Dynamics\nof the Stirling Cycle Machine. Cambridge University Press.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/International_Standard_Book_Number\"><em>ISBN<\/em><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/0-521-41363-X\"><em>0-521-41363-X<\/em><\/a>.<\/li><li>PASCO Scientific (1995).&nbsp;<a href=\"ftp:\/\/ftp.pasco.com\/Support\/Documents\/English\/SE\/SE-8575\/012-06055A.pdf\"><em>&#8220;Instruction Manual and Experiment\nGuide for the PASCO scientific Model SE-8575&#8221;<\/em><\/a>&nbsp;(PDF)<em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>D. Postle (1873). &#8220;Producing Cold for Preserving\nAnimal Food&#8221;,&nbsp;<em>British Patent 709<\/em>, granted 26 February 1873.<\/li><li>Precer Group.&nbsp;<a href=\"http:\/\/www.precer.com\/Files\/Precer_Data_Sheet_D.pdf\"><em>&#8220;Solid Biofuel-Powered Vehicle\nTechnology&#8221;<\/em><\/a>&nbsp;(PDF)<em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>Quasiturbine Agence.&nbsp;<a href=\"http:\/\/quasiturbine.promci.qc.ca\/ETypeStirling.htm\"><em>&#8220;Quasiturbine Stirling&nbsp;\u2013 Hot Air\nEngine&#8221;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>R. Sier (1999).&nbsp;Hot Air Caloric and Stirling\nEngines: A History.&nbsp;<strong>1<\/strong>&nbsp;(1st (Revised) ed.). L.A. Mair.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/International_Standard_Book_Number\"><em>ISBN<\/em><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/0-9526417-0-4\"><em>0-9526417-0-4<\/em><\/a>.<\/li><li>R. Sier (1995).&nbsp;Reverend Robert Stirling D.D: A\nBiography of the Inventor of the Heat Economiser and Stirling Cycle Engine. L.A\nMair.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/International_Standard_Book_Number\"><em>ISBN<\/em><\/a>&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:BookSources\/0-9526417-0-4\"><em>0-9526417-0-4<\/em><\/a>.<\/li><li>F. Starr (2001).&nbsp;<a href=\"http:\/\/www.ingenia.org.uk\/ingenia\/issues\/issue8\/Starr.pdf\"><em>&#8220;Power for the People: Stirling\nEngines for Domestic CHP&#8221;<\/em><\/a>&nbsp;(PDF).&nbsp;Ingenia&nbsp;(8):\n27\u201332<em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/World_Alliance_for_Decentralized_Energy\"><em>WADE<\/em><\/a>.&nbsp;<a href=\"http:\/\/www.localpower.org\/deb_tech_se.html\"><em>&#8220;Stirling Engines&#8221;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-18<\/em>.<\/li><li>L.G. Thieme (1981).&nbsp;<a href=\"https:\/\/ntrs.nasa.gov\/archive\/nasa\/casi.ntrs.nasa.gov\/19810023544_1981023544.pdf\"><em>&#8220;High-power baseline and\nmotoring test results for the GPU-3 Stirling engine&#8221;<\/em><\/a>&nbsp;(14.35&nbsp;MB\nPDF). NASA.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Office_of_Scientific_and_Technical_Information\"><em>OSTI<\/em><\/a>&nbsp;<a href=\"https:\/\/www.osti.gov\/energycitations\/product.biblio.jsp?osti_id=6321358\"><em>6321358<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>Y. Timoumi; I. Tlili; S.B. Nasrallah (2008).\n&#8220;Performance Optimization of Stirling Engines&#8221;.&nbsp;Renewable\nEnergy.&nbsp;<strong>33<\/strong>(9): 2134\u20132144.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Digital_object_identifier\"><em>doi<\/em><\/a>:<a href=\"https:\/\/doi.org\/10.1016%2Fj.renene.2007.12.012\"><em>10.1016\/j.renene.2007.12.012<\/em><\/a>.<\/li><li>G. Walker (1971). &#8220;Lecture notes for Stirling engine\nseminar&#8221;,&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/University_of_Bath\">University of\nBath<\/a>. Reprinted in\n1978.<\/li><li>C.D. West (1970). &#8220;Hydraulic Heat\nEngines&#8221;,&nbsp;<em>Harwell Momorandum AERE-R6522<\/em>.<\/li><li>S.K. Wickham (2008).&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20110522195440\/http:\/www.unionleader.com\/article.aspx?articleId=1b081989-f67b-458e-8e42-913c8568fb36\"><em>&#8220;Kamen&#8217;s Revolt&#8221;<\/em><\/a>. Union Leader.\nArchived from&nbsp;<a href=\"http:\/\/www.unionleader.com\/article.aspx?articleId=1b081989-f67b-458e-8e42-913c8568fb36\"><em>the original<\/em><\/a>&nbsp;on 22 May\n2011<em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>MAKE: Magazine (2006).&nbsp;<a href=\"http:\/\/makezine.com\/images\/07\/stirlingengine.pdf\"><em>&#8220;Two Can Stirling Engine&#8221;<\/em><\/a>(PDF)<em>. Retrieved&nbsp;<\/em><em>2012-03-18<\/em>.<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Further\nreading[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=39\">edit<\/a>]<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>R.C. Belaire (1977). &#8220;Device for decreasing the\nstart-up time for stirling engines&#8221;,&nbsp;<a href=\"http:\/\/v3.espacenet.com\/publicationDetails\/biblio?CC=US&amp;NR=4057962&amp;KC=&amp;FT=E\"><em>US patent 4057962<\/em><\/a>. Granted to\nFord Motor Company, 15 November 1977.<\/li><li>P.H. Ceperley (1979). &#8220;A pistonless Stirling\nengine\u2014The traveling wave heat engine&#8221;.&nbsp;Journal of the Acoustical\nSociety of America.&nbsp;<strong>66<\/strong>&nbsp;(5): 1508\u20131513.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Bibcode\"><em>Bibcode<\/em><\/a>:<a href=\"http:\/\/adsabs.harvard.edu\/abs\/1979ASAJ...66.1508C\"><em>1979ASAJ&#8230;66.1508C<\/em><\/a>.&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/Digital_object_identifier\"><em>doi<\/em><\/a>:<a href=\"https:\/\/doi.org\/10.1121%2F1.383505\"><em>10.1121\/1.383505<\/em><\/a>.<\/li><li>P. Fette.&nbsp;<a href=\"http:\/\/home.germany.net\/101-276996\/etatherm.htm\"><em>&#8220;About the Efficiency of the\nRegenerator in the Stirling Engine and the Function of the Volume Ratio V<sub>max<\/sub>\/V<sub>min<\/sub>&#8220;<\/em><\/a><em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>P. Fette.&nbsp;<a href=\"http:\/\/home.germany.net\/101-276996\/english.htm\"><em>&#8220;A Twice Double Acting \u03b1-Type Stirling\nEngine Able to Work with Compound Fluids Using Heat Energy of Low to Medium\nTemperatures&#8221;<\/em><\/a><em>.\nRetrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>D. Haywood.&nbsp;<a href=\"http:\/\/www.occc.edu\/gholland\/Thermo\/Stirling_Intro.pdf\"><em>&#8220;An Introduction to Stirling-Cycle\nMachine&#8221;<\/em><\/a>&nbsp;(PDF)<em>. Retrieved&nbsp;<\/em><em>2013-12-20<\/em>.<\/li><li>Z. Herzog (2006).&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20070403174124\/http:\/mac6.ma.psu.edu\/stirling\/\"><em>&#8220;Stirling Engines&#8221;<\/em><\/a>. Mont Alto: Pennsylvania\nState University. Archived from&nbsp;<a href=\"http:\/\/mac6.ma.psu.edu\/stirling\/\"><em>the original<\/em><\/a>&nbsp;on 2007-04-03<em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>F. Kyei-Manu; A. Obodoako (2005).&nbsp;<a href=\"http:\/\/www.engin.swarthmore.edu\/academics\/courses\/e90\/2005_6\/E90Proposal\/FK_AO.pdf\"><em>&#8220;Solar Stirling-Engine Water\nPump Proposal Draft&#8221;<\/em><\/a>&nbsp;(PDF)<em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>Lund University, Department of Energy Science: Division\nof Combustion Engines.&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20080419062324\/http:\/www.vok.lth.se\/~ce\/Research\/stirling\/stirling_en.htm\"><em>&#8220;Stirling Engine Research&#8221;<\/em><\/a>. Archived\nfrom&nbsp;<a href=\"http:\/\/www.vok.lth.se\/~ce\/Research\/stirling\/stirling_en.htm\"><em>the original<\/em><\/a>&nbsp;on 19 April\n2008<em>. Retrieved&nbsp;<\/em><em>2009-01-19<\/em>.<\/li><li>D. Phillips (1994).&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20090119035229\/http:\/www.airsport-corp.com\/fourpartstirling.html\"><em>&#8220;Why Aviation Needs the Stirling\nEngine&#8221;<\/em><\/a>. Archived from&nbsp;<a href=\"http:\/\/www.airsport-corp.com\/fourpartstirling.html\"><em>the original<\/em><\/a>&nbsp;on 19\nJanuary 2009<em>. Retrieved&nbsp;<\/em><em>19 January<\/em><em>&nbsp;2009<\/em>.<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">External\nlinks[<a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=edit&amp;section=40\">edit<\/a>]<\/h2>\n\n\n\n<table class=\"wp-block-table\"><tbody><tr><td>\n  \n  <\/td><td>\n  Wikimedia Commons has media related\n  to&nbsp;<a href=\"https:\/\/commons.wikimedia.org\/wiki\/Category:Stirling_engines\"><strong><em>Stirling engines<\/em><\/strong><\/a>.\n  <\/td><\/tr><\/tbody><\/table>\n\n\n\n<table class=\"wp-block-table\"><tbody><tr><td>\n  \n  <\/td><td>\n  Look up&nbsp;<a href=\"https:\/\/en.wiktionary.org\/wiki\/Stirling_engine\"><strong><em>Stirling\n  engine<\/em><\/strong><\/a>&nbsp;in\n  Wiktionary, the free dictionary.\n  <\/td><\/tr><\/tbody><\/table>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/www.youtube.com\/watch?v=75wUYbVyTeY\">NASA Stirling Engine Based Nuclear Power Plant For\nLunar Use<\/a>&nbsp;on&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/YouTube\">YouTube<\/a><\/li><li><a href=\"https:\/\/curlie.org\/Science\/Technology\/Energy\/Devices\/External_Combustion_Engines\/Stirling_Engines\">Stirling engine<\/a>&nbsp;at Curlie\n(based on&nbsp;<a href=\"https:\/\/en.wikipedia.org\/wiki\/DMOZ\">DMOZ<\/a>)<\/li><li>I. Urieli (2008).&nbsp;<a href=\"https:\/\/web.archive.org\/web\/20100630062833\/http:\/www.ent.ohiou.edu\/~urieli\/stirling\/me422.html\">Stirling Cycle Machine Analysis 2008\nWinter Syllabus<\/a><\/li><li>How to build your Stirling engine (2017).&nbsp;<a href=\"http:\/\/sesusa.org\/SEDAF.htm\">Stirling\nEngines: Design and Fabrication<\/a><\/li><li><a href=\"http:\/\/www.bekkoame.ne.jp\/~khirata\/academic\/simple\/simplee.htm\">Simple Performance Prediction Method\nfor Stirling Engine<\/a><\/li><li>Shockwave3D models:&nbsp;<a href=\"http:\/\/touch3d.net\/stirling_b.html\">Beta Stirling<\/a>&nbsp;and&nbsp;<a href=\"http:\/\/touch3d.net\/stirling_ltd.html\">LTD<\/a><\/li><li><a href=\"http:\/\/hotairengines.org\/\">Inquiry into the Hot Air Engines of\nthe 19th Century<\/a><\/li><\/ul>\n\n\n\n<table class=\"wp-block-table\"><tbody><tr><td>\n  [<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine\">hide<\/a>]<strong><\/strong>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Template:Thermodynamic_cycles\">v<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Template_talk:Thermodynamic_cycles\">t<\/a><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Template:Thermodynamic_cycles&amp;action=edit\">e<\/a>\n  \n  \n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Thermodynamic_cycle\"><strong>Thermodynamic cycles<\/strong><\/a><strong><\/strong>\n  <\/td><\/tr><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/External_combustion\"><strong>External<\/strong><strong><br>\n  <\/strong><strong>combustion<\/strong><\/a><strong><\/strong>\n  <\/td><td>\n  \n   \n    \n    Without\n    phase change<br>\n    (<a href=\"https:\/\/en.wikipedia.org\/wiki\/Hot_air_engine\">hot air engines<\/a>)\n    \n    \n    <a href=\"https:\/\/en.wikipedia.org\/wiki\/Brayton_cycle#Reverse_Brayton_cycle\">Bell Coleman<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Brayton_cycle\">Brayton \/\n    Joule<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Carnot_cycle\">Carnot<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Ericsson_cycle\">Ericsson<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_cycle\">Stirling<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Pseudo_Stirling_cycle\">Stirling (pseudo \/ adiabatic)<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stoddard_cycle\">Stoddard<\/a>\n    \n    \n    \n    \n    \n    \n    \n   \n   \n    \n    With phase change\n    \n    \n    <a href=\"https:\/\/en.wikipedia.org\/wiki\/Kalina_cycle\">Kalina<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Hygroscopic_cycle\">Hygroscopic<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Rankine_cycle\">Rankine<\/a>&nbsp;(<a href=\"https:\/\/en.wikipedia.org\/wiki\/Organic_Rankine_cycle\">Organic Rankine<\/a>)<a href=\"https:\/\/en.wikipedia.org\/wiki\/Regenerative_cycle\">Regenerative<\/a>\n    \n    \n    \n    \n   \n  \n  <\/td><\/tr><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Internal_combustion\"><strong>Internal combustion<\/strong><\/a><strong><\/strong>\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Atkinson_cycle\">Atkinson<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Brayton_cycle\">Brayton \/ Joule<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Diesel_cycle\">Diesel<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Expander_cycle\">Expander<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Gas-generator_cycle\">Gas-generator<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Homogeneous_charge_compression_ignition\">Homogeneous charge compression\n  ignition<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Lenoir_cycle\">Lenoir<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Miller_cycle\">Miller<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Otto_cycle\">Otto<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Scuderi_cycle\">Scuderi<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Staged_combustion_cycle\">Staged combustion<\/a>\n  \n  \n  \n  \n  \n  \n  \n  \n  \n  \n  <\/td><\/tr><tr><td>\n  <strong>Mixed<\/strong>\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Combined_cycle\">Combined<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/High-efficiency_hybrid_cycle\">HEHC<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Mixed\/dual_cycle\">Mixed \/ Dual<\/a>\n  \n  \n  <\/td><\/tr><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_pump_and_refrigeration_cycle\"><strong>Refrigeration<\/strong><\/a><strong><\/strong>\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Hampson%E2%80%93Linde_cycle\">Hampson\u2013Linde<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Kleemenko_cycle\">Kleemenko<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Pulse_tube_refrigerator\">Pulse tube<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Regenerative_cooling\">Regenerative cooling<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Transcritical_cycle\">Transcritical<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Absorption_refrigerator\">Vapor absorption<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Vapor-compression_refrigeration\">Vapor-compression<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Siemens_cycle\">Siemens<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Vuilleumier_cycle\">Vuilleumier<\/a>\n  \n  \n  \n  \n  \n  \n  \n  \n  <\/td><\/tr><tr><td>\n  <strong>Uncategorized<\/strong>\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Barton_evaporation_engine\">Barton<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Humphrey_cycle\">Humphrey<\/a>\n  \n  <\/td><\/tr><tr><td>\n  [<a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine\">show<\/a>]<strong><\/strong>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Template:Heat_engines\">v<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Template_talk:Heat_engines\">t<\/a><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Template:Heat_engines&amp;action=edit\">e<\/a>\n  \n  \n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Heat_engine\"><strong>Heat engines<\/strong><\/a><strong><\/strong>\n  <\/td><td>&nbsp;<\/td><\/tr><tr><\/tr><\/tbody><\/table>\n\n\n\n<table class=\"wp-block-table\"><tbody><tr><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Help:Authority_control\"><strong>Authority control<\/strong><\/a><strong><\/strong>\n  <\/td><td>\n  <a href=\"https:\/\/en.wikipedia.org\/wiki\/Library_of_Congress_Control_Number\">LCCN<\/a>:&nbsp;<a href=\"http:\/\/id.loc.gov\/authorities\/subjects\/sh85128168\">sh85128168<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Integrated_Authority_File\">GND<\/a>:&nbsp;<a href=\"https:\/\/d-nb.info\/gnd\/4128005-2\">4128005-2<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/Biblioth%C3%A8que_nationale_de_France\">BNF<\/a>:&nbsp;<a href=\"http:\/\/catalogue.bnf.fr\/ark:\/12148\/cb12378418h\">cb12378418h<\/a>&nbsp;<a href=\"http:\/\/data.bnf.fr\/ark:\/12148\/cb12378418h\">(data)<\/a><a href=\"https:\/\/en.wikipedia.org\/wiki\/National_Diet_Library\">NDL<\/a>:&nbsp;<a href=\"https:\/\/id.ndl.go.jp\/auth\/ndlna\/01170814\">01170814<\/a>\n  \n  \n  \n  <\/td><\/tr><\/tbody><\/table>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/en.wikipedia.org\/wiki\/Help:Category\">Categories<\/a>:&nbsp;<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Category:Cooling_technology\">Cooling technology<\/a><\/li><\/ul>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Category:Heat_pumps\">Heat pumps<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Category:Stirling_engines\">Stirling engines<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Category:Hot_air_engines\">Hot air engines<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Category:Piston_engines\">Piston engines<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Category:Scottish_inventions\">Scottish inventions<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Category:External_combustion_engines\">External combustion engines<\/a><\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Navigation menu<\/h2>\n\n\n\n<ul class=\"wp-block-list\"><li>Not logged in<\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:MyTalk\">Talk<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:MyContributions\">Contributions<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CreateAccount&amp;returnto=Stirling+engine\">Create account<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Special:UserLogin&amp;returnto=Stirling+engine\">Log in<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine\">Article<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Talk:Stirling_engine\">Talk<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Stirling_engine\">Read<\/a><\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>More<\/strong><\/h3>\n\n\n\n<h3 class=\"wp-block-heading\">Search<\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Main_Page\">Main page<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Portal:Contents\">Contents<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Portal:Featured_content\">Featured content<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Portal:Current_events\">Current\nevents<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:Random\">Random article<\/a><\/li><li><a href=\"https:\/\/donate.wikimedia.org\/wiki\/Special:FundraiserRedirector?utm_source=donate&amp;utm_medium=sidebar&amp;utm_campaign=C13_en.wikipedia.org&amp;uselang=en\">Donate to Wikipedia<\/a><\/li><li><a href=\"https:\/\/shop.wikimedia.org\/\">Wikipedia store<\/a><\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Interaction<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Help:Contents\">Help<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Wikipedia:About\">About Wikipedia<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Community_portal\">Community portal<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:RecentChanges\">Recent changes<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Contact_us\">Contact page<\/a><\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Tools<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:WhatLinksHere\/Stirling_engine\">What links here<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:RecentChangesLinked\/Stirling_engine\">Related changes<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Wikipedia:File_Upload_Wizard\">Upload file<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Special:SpecialPages\">Special\npages<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;oldid=824866157\">Permanent\nlink<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;action=info\">Page information<\/a><\/li><li><a href=\"https:\/\/www.wikidata.org\/wiki\/Special:EntityPage\/Q186212\">Wikidata item<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CiteThisPage&amp;page=Stirling_engine&amp;id=824866157\">Cite this page<\/a><\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Print\/export<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Special:Book&amp;bookcmd=book_creator&amp;referer=Stirling+engine\">Create a book<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Special:ElectronPdf&amp;page=Stirling+engine&amp;action=show-download-screen\">Download as PDF<\/a><\/li><li><a href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Stirling_engine&amp;printable=yes\">Printable\nversion<\/a><\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>In other projects<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/commons.wikimedia.org\/wiki\/Category:Stirling_engines\">Wikimedia Commons<\/a><\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Languages<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/ar.wikipedia.org\/wiki\/%D9%85%D8%AD%D8%B1%D9%83_%D8%B3%D8%AA%D9%8A%D8%B1%D9%84%D9%8A%D9%86%D8%BA\">\u0627\u0644\u0639\u0631\u0628\u064a\u0629<\/a><\/li><li><a href=\"https:\/\/be.wikipedia.org\/wiki\/%D0%A0%D1%83%D1%85%D0%B0%D0%B2%D1%96%D0%BA_%D0%A1%D1%82%D1%8B%D1%80%D0%BB%D1%96%D0%BD%D0%B3%D0%B0\">\u0411\u0435\u043b\u0430\u0440\u0443\u0441\u043a\u0430\u044f<\/a><\/li><li><a href=\"https:\/\/be-x-old.wikipedia.org\/wiki\/%D0%A0%D1%83%D1%85%D0%B0%D0%B2%D1%96%D0%BA_%D0%A1%D1%82%D1%8B%D1%80%D0%BB%D1%96%D0%BD%D0%B3%D0%B0\">\u0411\u0435\u043b\u0430\u0440\u0443\u0441\u043a\u0430\u044f (\u0442\u0430\u0440\u0430\u0448\u043a\u0435\u0432\u0456\u0446\u0430)\u200e<\/a><\/li><li><a href=\"https:\/\/bg.wikipedia.org\/wiki\/%D0%94%D0%B2%D0%B8%D0%B3%D0%B0%D1%82%D0%B5%D0%BB_%D0%BD%D0%B0_%D0%A1%D1%82%D1%8A%D1%80%D0%BB%D0%B8%D0%BD%D0%B3\">\u0411\u044a\u043b\u0433\u0430\u0440\u0441\u043a\u0438<\/a><\/li><li><a href=\"https:\/\/bs.wikipedia.org\/wiki\/Stirlingov_motor\">Bosanski<\/a><\/li><li><a href=\"https:\/\/br.wikipedia.org\/wiki\/Keflusker_Stirling\">Brezhoneg<\/a><\/li><li><a href=\"https:\/\/ca.wikipedia.org\/wiki\/Motor_Stirling\">Catal\u00e0<\/a><\/li><li><a href=\"https:\/\/cs.wikipedia.org\/wiki\/Stirling%C5%AFv_motor\">\u010ce\u0161tina<\/a><\/li><li><a href=\"https:\/\/da.wikipedia.org\/wiki\/Stirlingmotor\">Dansk<\/a><\/li><li><a href=\"https:\/\/de.wikipedia.org\/wiki\/Stirlingmotor\">Deutsch<\/a><\/li><li><a href=\"https:\/\/es.wikipedia.org\/wiki\/Motor_Stirling\">Espa\u00f1ol<\/a><\/li><li><a href=\"https:\/\/eo.wikipedia.org\/wiki\/Stirling-motoro\">Esperanto<\/a><\/li><li><a href=\"https:\/\/fa.wikipedia.org\/wiki\/%D9%85%D9%88%D8%AA%D9%88%D8%B1_%D8%A7%D8%B3%D8%AA%D8%B1%D9%84%DB%8C%D9%86%DA%AF\">\u0641\u0627\u0631\u0633\u06cc<\/a><\/li><li><a href=\"https:\/\/fr.wikipedia.org\/wiki\/Moteur_Stirling\">Fran\u00e7ais<\/a><\/li><li><a href=\"https:\/\/ko.wikipedia.org\/wiki\/%EC%8A%A4%ED%84%B8%EB%A7%81_%EA%B8%B0%EA%B4%80\">\ud55c\uad6d\uc5b4<\/a><\/li><li><a href=\"https:\/\/hy.wikipedia.org\/wiki\/%D5%8D%D5%BF%D5%AB%D5%BC%D5%AC%D5%AB%D5%B6%D5%A3%D5%AB_%D5%B7%D5%A1%D6%80%D5%AA%D5%AB%D5%B9\">\u0540\u0561\u0575\u0565\u0580\u0565\u0576<\/a><\/li><li><a href=\"https:\/\/hi.wikipedia.org\/wiki\/%E0%A4%B8%E0%A5%8D%E0%A4%9F%E0%A4%B0%E0%A5%8D%E0%A4%B2%E0%A4%BF%E0%A4%82%E0%A4%97_%E0%A4%87%E0%A4%82%E0%A4%9C%E0%A4%A8\">\u0939\u093f\u0928\u094d\u0926\u0940<\/a><\/li><li><a href=\"https:\/\/hr.wikipedia.org\/wiki\/Stirlingov_motor\">Hrvatski<\/a><\/li><li><a href=\"https:\/\/io.wikipedia.org\/wiki\/Stirling_motoro\">Ido<\/a><\/li><li><a href=\"https:\/\/id.wikipedia.org\/wiki\/Motor_bakar_stirling\">Bahasa Indonesia<\/a><\/li><li><a href=\"https:\/\/it.wikipedia.org\/wiki\/Motore_Stirling\">Italiano<\/a><\/li><li><a href=\"https:\/\/he.wikipedia.org\/wiki\/%D7%9E%D7%A0%D7%95%D7%A2_%D7%A1%D7%98%D7%99%D7%A8%D7%9C%D7%99%D7%A0%D7%92\">\u05e2\u05d1\u05e8\u05d9\u05ea<\/a><\/li><li><a href=\"https:\/\/lt.wikipedia.org\/wiki\/Stirlingo_variklis\">Lietuvi\u0173<\/a><\/li><li><a href=\"https:\/\/hu.wikipedia.org\/wiki\/Stirling-motor\">Magyar<\/a><\/li><li><a href=\"https:\/\/nl.wikipedia.org\/wiki\/Stirlingmotor\">Nederlands<\/a><\/li><li><a href=\"https:\/\/ja.wikipedia.org\/wiki\/%E3%82%B9%E3%82%BF%E3%83%BC%E3%83%AA%E3%83%B3%E3%82%B0%E3%82%A8%E3%83%B3%E3%82%B8%E3%83%B3\">\u65e5\u672c\u8a9e<\/a><\/li><li><a href=\"https:\/\/no.wikipedia.org\/wiki\/Stirlingmotor\">Norsk<\/a><\/li><li><a href=\"https:\/\/pnb.wikipedia.org\/wiki\/%D8%B3%D9%B9%D8%B1%D9%84%D9%86%DA%AF_%D8%A7%D9%86%D8%AC%D9%86\">\u067e\u0646\u062c\u0627\u0628\u06cc<\/a><\/li><li><a href=\"https:\/\/pl.wikipedia.org\/wiki\/Silnik_Stirlinga\">Polski<\/a><\/li><li><a href=\"https:\/\/pt.wikipedia.org\/wiki\/Motor_Stirling\">Portugu\u00eas<\/a><\/li><li><a href=\"https:\/\/ro.wikipedia.org\/wiki\/Motorul_Stirling\">Rom\u00e2n\u0103<\/a><\/li><li><a href=\"https:\/\/ru.wikipedia.org\/wiki\/%D0%94%D0%B2%D0%B8%D0%B3%D0%B0%D1%82%D0%B5%D0%BB%D1%8C_%D0%A1%D1%82%D0%B8%D1%80%D0%BB%D0%B8%D0%BD%D0%B3%D0%B0\">\u0420\u0443\u0441\u0441\u043a\u0438\u0439<\/a><\/li><li><a href=\"https:\/\/sq.wikipedia.org\/wiki\/Motori_Stirling\">Shqip<\/a><\/li><li><a href=\"https:\/\/simple.wikipedia.org\/wiki\/Stirling_engine\">Simple English<\/a><\/li><li><a href=\"https:\/\/sk.wikipedia.org\/wiki\/Stirlingov_motor\">Sloven\u010dina<\/a><\/li><li><a href=\"https:\/\/sl.wikipedia.org\/wiki\/Stirlingov_motor\">Sloven\u0161\u010dina<\/a><\/li><li><a href=\"https:\/\/sr.wikipedia.org\/wiki\/%D0%A1%D1%82%D0%B8%D1%80%D0%BB%D0%B8%D0%BD%D0%B3%D0%BE%D0%B2_%D0%BC%D0%BE%D1%82%D0%BE%D1%80\">\u0421\u0440\u043f\u0441\u043a\u0438 \/ srpski<\/a><\/li><li><a href=\"https:\/\/sh.wikipedia.org\/wiki\/Stirlingov_motor\">Srpskohrvatski \/ \u0441\u0440\u043f\u0441\u043a\u043e\u0445\u0440\u0432\u0430\u0442\u0441\u043a\u0438<\/a><\/li><li><a href=\"https:\/\/fi.wikipedia.org\/wiki\/Stirlingmoottori\">Suomi<\/a><\/li><li><a href=\"https:\/\/sv.wikipedia.org\/wiki\/Stirlingmotor\">Svenska<\/a><\/li><li><a href=\"https:\/\/te.wikipedia.org\/wiki\/%E0%B0%B8%E0%B1%8D%E0%B0%9F%E0%B0%BF%E0%B0%B0%E0%B1%8D%E0%B0%B2%E0%B0%BF%E0%B0%82%E0%B0%97%E0%B1%8D_%E0%B0%AF%E0%B0%82%E0%B0%A4%E0%B1%8D%E0%B0%B0%E0%B0%82\">\u0c24\u0c46\u0c32\u0c41\u0c17\u0c41<\/a><\/li><li><a href=\"https:\/\/th.wikipedia.org\/wiki\/%E0%B9%80%E0%B8%84%E0%B8%A3%E0%B8%B7%E0%B9%88%E0%B8%AD%E0%B8%87%E0%B8%A2%E0%B8%99%E0%B8%95%E0%B9%8C%E0%B8%AA%E0%B9%80%E0%B8%95%E0%B8%AD%E0%B8%A3%E0%B9%8C%E0%B8%A5%E0%B8%B4%E0%B8%87\">\u0e44\u0e17\u0e22<\/a><\/li><li><a href=\"https:\/\/tr.wikipedia.org\/wiki\/Stirling_motoru\">T\u00fcrk\u00e7e<\/a><\/li><li><a href=\"https:\/\/uk.wikipedia.org\/wiki\/%D0%94%D0%B2%D0%B8%D0%B3%D1%83%D0%BD_%D0%A1%D1%82%D1%96%D1%80%D0%BB%D1%96%D0%BD%D0%B3%D0%B0\">\u0423\u043a\u0440\u0430\u0457\u043d\u0441\u044c\u043a\u0430<\/a><\/li><li><a href=\"https:\/\/vi.wikipedia.org\/wiki\/%C4%90%E1%BB%99ng_c%C6%A1_Stirling\">Ti\u1ebfng Vi\u1ec7t<\/a><\/li><li><a href=\"https:\/\/zh.wikipedia.org\/wiki\/%E6%96%AF%E7%89%B9%E6%9E%97%E5%8F%91%E5%8A%A8%E6%9C%BA\">\u4e2d\u6587<\/a><\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.wikidata.org\/wiki\/Special:EntityPage\/Q186212#sitelinks-wikipedia\">Edit links<\/a><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>This page was last edited on 10 February 2018, at\n00:17.<\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"<p>How does THERMOELECTRIC work? Strictly speaking, thermoelectric generators take a temperature difference and turn it into electrical power. &nbsp;Amazingly, these materials can also be run in reverse! &nbsp;If you put [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_EventAllDay":false,"_EventTimezone":"","_EventStartDate":"","_EventEndDate":"","_EventStartDateUTC":"","_EventEndDateUTC":"","_EventShowMap":false,"_EventShowMapLink":false,"_EventURL":"","_EventCost":"","_EventCostDescription":"","_EventCurrencySymbol":"","_EventCurrencyCode":"","_EventCurrencyPosition":"","_EventDateTimeSeparator":"","_EventTimeRangeSeparator":"","_EventOrganizerID":[],"_EventVenueID":[],"_OrganizerEmail":"","_OrganizerPhone":"","_OrganizerWebsite":"","_VenueAddress":"","_VenueCity":"","_VenueCountry":"","_VenueProvince":"","_VenueState":"","_VenueZip":"","_VenuePhone":"","_VenueURL":"","_VenueStateProvince":"","_VenueLat":"","_VenueLng":"","_VenueShowMap":false,"_VenueShowMapLink":false,"footnotes":""},"class_list":["post-476","page","type-page","status-publish","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/eeppaa.tech\/index.php?rest_route=\/wp\/v2\/pages\/476","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/eeppaa.tech\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/eeppaa.tech\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/eeppaa.tech\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/eeppaa.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=476"}],"version-history":[{"count":6,"href":"https:\/\/eeppaa.tech\/index.php?rest_route=\/wp\/v2\/pages\/476\/revisions"}],"predecessor-version":[{"id":487,"href":"https:\/\/eeppaa.tech\/index.php?rest_route=\/wp\/v2\/pages\/476\/revisions\/487"}],"wp:attachment":[{"href":"https:\/\/eeppaa.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=476"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}