{"id":48207,"date":"2019-11-08T15:58:41","date_gmt":"2019-11-08T14:58:41","guid":{"rendered":"https:\/\/www.thermal-engineering.org\/o-que-e-eficiencia-termica-de-motores-de-calor-exemplos-definicao\/"},"modified":"2020-01-28T08:23:51","modified_gmt":"2020-01-28T07:23:51","slug":"o-que-e-eficiencia-termica-de-motores-de-calor-exemplos-definicao","status":"publish","type":"post","link":"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-eficiencia-termica-de-motores-de-calor-exemplos-definicao\/","title":{"rendered":"O que \u00e9 efici\u00eancia t\u00e9rmica de motores de calor &#8211; Exemplos &#8211; Defini\u00e7\u00e3o"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-clearfix\">A efici\u00eancia t\u00e9rmica dos motores t\u00e9rmicos projetados ou usados \u200b\u200bhoje em dia tem uma grande variedade.\u00a0A efici\u00eancia t\u00e9rmica de uma usina nuclear t\u00edpica \u00e9 de cerca de um ter\u00e7o (33%).\u00a0Engenharia T\u00e9rmica<\/div>\n<\/div>\n<div class=\"su-divider su-divider-style-dotted\"><\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2>Efici\u00eancia t\u00e9rmica de motores t\u00e9rmicos<\/h2>\n<p>Em geral, a efici\u00eancia dos melhores motores t\u00e9rmicos \u00e9 bastante baixa.\u00a0Em resumo, \u00e9\u00a0<strong>muito dif\u00edcil converter energia t\u00e9rmica em energia mec\u00e2nica<\/strong>\u00a0.\u00a0As efici\u00eancias t\u00e9rmicas geralmente s\u00e3o inferiores a 50% e geralmente muito abaixo.<\/p>\n<figure id=\"attachment_16961\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16961\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-engines-turbines-min.png\"><img loading=\"lazy\" class=\"size-medium wp-image-16961 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-engines-turbines-min-300x222.png\" alt=\"Takaishi, Tatsuo; Numata, Akira; Nakano, Ryouji; Sakaguchi, Katsuhiko (mar\u00e7o de 2008).\" width=\"300\" height=\"222\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-engines-turbines-min-300x222.png\" \/><\/a><figcaption id=\"caption-attachment-16961\" class=\"wp-caption-text\">Takaishi, Tatsuo;\u00a0Numata, Akira;\u00a0Nakano, Ryouji;\u00a0Sakaguchi, Katsuhiko (mar\u00e7o de 2008).\u00a0\u201cAbordagem para motores a diesel e g\u00e1s de alta efici\u00eancia\u201d (PDF).\u00a0Revis\u00e3o t\u00e9cnica Mitsubishi Heavy Industries.\u00a045 (1).\u00a0P\u00e1gina visitada em 2011-02-04.<\/figcaption><\/figure>\n<p>\u00c9 f\u00e1cil produzir energia t\u00e9rmica fazendo o trabalho, por exemplo, por qualquer processo de atrito.\u00a0Mas conseguir trabalho com energia t\u00e9rmica \u00e9 mais dif\u00edcil.\u00a0Est\u00e1 intimamente associado ao\u00a0<a title=\"O que \u00e9 entropia\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/what-is-entropy\/\"><strong>conceito de entropia<\/strong><\/a>\u00a0, que quantifica a energia de uma subst\u00e2ncia que n\u00e3o est\u00e1 mais dispon\u00edvel para realizar um trabalho \u00fatil.\u00a0Por exemplo, a eletricidade \u00e9 particularmente \u00fatil, pois possui\u00a0<strong>entropia\u00a0<\/strong><strong>muito\u00a0<\/strong><strong>baixa<\/strong>\u00a0(\u00e9 altamente solicitada) e pode ser convertida em outras formas de energia com\u00a0<strong>muita efici\u00eancia<\/strong>\u00a0.\u00a0Tenha cuidado ao compar\u00e1-lo com a efici\u00eancia da energia e\u00f3lica ou hidrel\u00e9trica (turbinas e\u00f3licas n\u00e3o s\u00e3o motores de calor), n\u00e3o h\u00e1 convers\u00e3o de energia entre a energia t\u00e9rmica e a mec\u00e2nica.<\/p>\n<p>A efici\u00eancia t\u00e9rmica de v\u00e1rios motores t\u00e9rmicos projetados ou usados \u200b\u200bhoje em dia tem uma grande variedade:<\/p>\n<p><strong>Por exemplo:<\/strong><\/p>\n<p><strong>Transporte<\/strong><\/p>\n<ul>\n<li>Em meados do s\u00e9culo XX, uma\u00a0<strong>locomotiva a vapor<\/strong>\u00a0t\u00edpica\u00a0tinha uma efici\u00eancia t\u00e9rmica de cerca de\u00a0<strong>6%<\/strong>\u00a0.\u00a0Isso significa que para cada 100 MJ de carv\u00e3o queimado, 6 MJ de pot\u00eancia mec\u00e2nica foram produzidos.<\/li>\n<li>Um\u00a0<a title=\"Desmontagem de autom\u00f3veis\" href=\"http:\/\/www.likvidace-vozidla-praha.cz\/\"><strong>motor automotivo a gasolina<\/strong><\/a>\u00a0t\u00edpico\u00a0opera com cerca de\u00a0<strong>25% a 30%<\/strong>\u00a0de efici\u00eancia t\u00e9rmica.\u00a0Cerca de 70-75% \u00e9 rejeitado como calor residual sem ser convertido em trabalho \u00fatil, ou seja, trabalho entregue \u00e0s rodas.<\/li>\n<li>Um\u00a0<strong>motor automotivo a diesel<\/strong>\u00a0t\u00edpico\u00a0opera em torno de\u00a0<strong>30% a 35%<\/strong>\u00a0.\u00a0Em geral, os motores que usam o ciclo Diesel geralmente s\u00e3o mais eficientes.<\/li>\n<li>Em 2014, novos regulamentos foram introduzidos para\u00a0<strong>carros de F\u00f3rmula 1<\/strong>\u00a0.\u00a0Essas regulamenta\u00e7\u00f5es sobre esportes a motor levaram as equipes a desenvolver unidades de pot\u00eancia altamente eficientes.\u00a0Segundo a Mercedes, sua unidade de pot\u00eancia est\u00e1 atingindo\u00a0<strong>mais de 45%<\/strong>\u00a0e quase 50% de efici\u00eancia t\u00e9rmica, ou seja, 45 a 50% da energia potencial do combust\u00edvel \u00e9 entregue \u00e0s rodas.<\/li>\n<li>O motor diesel tem a mais alta efici\u00eancia t\u00e9rmica de qualquer motor de combust\u00e3o pr\u00e1tico.\u00a0<strong>Os motores a diesel de baixa velocidade<\/strong>\u00a0(usados \u200b\u200bem navios) podem ter uma efici\u00eancia t\u00e9rmica superior a\u00a0<strong>50%<\/strong>\u00a0.\u00a0O maior motor diesel do mundo atinge 51,7%.<\/li>\n<\/ul>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<p><strong><span>Engenharia de Energia<\/span><\/strong><\/p>\n<ul>\n<li><strong><span>Convers\u00e3o de energia t\u00e9rmica oce\u00e2nica (OTEC).\u00a0O OTEC<\/span><\/strong><span>\u00a0\u00e9 um motor t\u00e9rmico muito sofisticado que usa a diferen\u00e7a de temperatura entre \u00e1guas do mar mais frias e profundas da superf\u00edcie para acionar uma turbina de baixa press\u00e3o.\u00a0Como a\u00a0<\/span><strong><span>diferen\u00e7a de temperatura \u00e9 baixa<\/span><\/strong><span>\u00a0, cerca de 20 \u00b0 C, sua efici\u00eancia t\u00e9rmica tamb\u00e9m \u00e9 muito baixa,\u00a0<\/span><strong><span>cerca de 3%<\/span><\/strong><span>\u00a0.<\/span><\/li>\n<li><span>Nas modernas\u00a0<\/span><a title=\"Usina nuclear\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/\"><strong><span>usinas nucleares,<\/span><\/strong><\/a><span>\u00a0a efici\u00eancia t\u00e9rmica geral \u00e9 de cerca de\u00a0<\/span><strong><span>um ter\u00e7o<\/span><\/strong><span>\u00a0(33%); portanto, s\u00e3o necess\u00e1rios\u00a0<\/span><strong><span>3000 MWth<\/span><\/strong><span>\u00a0de energia t\u00e9rmica da rea\u00e7\u00e3o de fiss\u00e3o para gerar\u00a0<\/span><strong><span>1000 MWe<\/span><\/strong><span>\u00a0de energia el\u00e9trica.\u00a0Efici\u00eancias mais altas podem ser alcan\u00e7adas aumentando a\u00a0<\/span><strong><span>temperatura<\/span><\/strong><span>\u00a0do\u00a0<\/span><a title=\"Propriedades do Steam - O que \u00e9 o Steam\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-o-steam-propriedades-do-steam-definicao\/\"><span>vapor<\/span><\/a><span>\u00a0.\u00a0Mas isso requer um aumento nas press\u00f5es dentro de caldeiras ou\u00a0<\/span><a title=\"Gerador de vapor\" href=\"https:\/\/www.nuclear-power.com\/steam-generator\/\"><span>geradores de vapor<\/span><\/a><span>.\u00a0No entanto, considera\u00e7\u00f5es metal\u00fargicas imp\u00f5em limites superiores a essas press\u00f5es.\u00a0Em compara\u00e7\u00e3o com outras fontes de energia, a efici\u00eancia t\u00e9rmica de 33% n\u00e3o \u00e9 grande.\u00a0Mas deve-se notar que as usinas nucleares s\u00e3o muito mais complexas que as usinas de combust\u00edveis f\u00f3sseis e \u00e9 muito mais f\u00e1cil queimar combust\u00edveis f\u00f3sseis do que gerar energia a partir\u00a0<\/span><a title=\"Combust\u00edvel nuclear\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/nuclear-fuel\/\"><span>de combust\u00edveis nucleares<\/span><\/a><span>\u00a0.<\/span><\/li>\n<li><span>As usinas subcr\u00edticas de combust\u00edveis f\u00f3sseis, que s\u00e3o operadas sob\u00a0<\/span><strong><span>press\u00e3o cr\u00edtica<\/span><\/strong><span>\u00a0(ou seja, inferiores a 22,1 MPa), podem atingir uma efici\u00eancia de 36 a 40%.<\/span><\/li>\n<li><span>Os\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/reactor-types\/supercritical-water-reactor-scwr\/\"><strong><span>reatores supercr\u00edticos de \u00e1gua<\/span><\/strong><\/a><span>\u00a0s\u00e3o considerados um avan\u00e7o promissor para\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/\"><span>as usinas nucleares<\/span><\/a><span>\u00a0devido \u00e0 sua\u00a0<\/span><strong><span>alta efici\u00eancia t\u00e9rmica<\/span><\/strong><span>\u00a0(~ 45% vs. ~ 33% para as LWRs atuais).<\/span><\/li>\n<li><span>As usinas supercr\u00edticas de combust\u00edveis f\u00f3sseis, que s\u00e3o operadas sob\u00a0<\/span><strong><span>press\u00e3o supercr\u00edtica<\/span><\/strong><span>\u00a0(ou seja, superior a 22,1 MPa), t\u00eam efici\u00eancia em torno de\u00a0<\/span><strong><span>43%<\/span><\/strong><span>\u00a0.\u00a0As usinas el\u00e9tricas a carv\u00e3o mais eficientes e tamb\u00e9m muito complexas, operadas a\u00a0<strong>press\u00f5es\u00a0<\/strong><\/span><strong><span>&#8220;ultra-cr\u00edticas&#8221;<\/span><\/strong><span>\u00a0(ou seja, cerca de 30 MPa) e que utilizam reaquecimento em v\u00e1rios est\u00e1gios, atingem cerca de\u00a0<strong>48% de<\/strong>\u00a0efici\u00eancia.<\/span><\/li>\n<li><span>As modernas instala\u00e7\u00f5es de\u00a0<\/span><strong><span>turbina a g\u00e1s de ciclo combinado<\/span><\/strong><span>\u00a0(CCGT), nas quais o ciclo termodin\u00e2mico consiste em\u00a0<\/span><strong><span>dois ciclos de usina<\/span><\/strong><span>\u00a0(por exemplo, o ciclo de Brayton e o ciclo Rankine), podem atingir uma efici\u00eancia t\u00e9rmica de cerca de\u00a0<\/span><strong><span>55%<\/span><\/strong><span>\u00a0, em contraste com um vapor de ciclo \u00fanico usina, limitada a efici\u00eancias em torno de 35 a 45%.<\/span><\/li>\n<\/ul>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\"><\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<h2><span>Efici\u00eancia t\u00e9rmica do ciclo de Brayton<\/span><\/h2>\n<p><span>Vamos assumir o\u00a0<\/span><strong><span>ciclo de Brayton ideal<\/span><\/strong><span>\u00a0que descreve o funcionamento de um\u00a0<strong>motor de calor com\u00a0<\/strong><\/span><strong><span>press\u00e3o constante<\/span><\/strong>\u00a0<span>.\u00a0<strong>Os modernos<\/strong>\u00a0motores de\u00a0<strong>turbina a g\u00e1s<\/strong>\u00a0e os motores a\u00a0<strong>jato de respira\u00e7\u00e3o<\/strong>\u00a0tamb\u00e9m seguem o ciclo de Brayton.\u00a0Esse ciclo consiste em quatro processos termodin\u00e2micos:<\/span><\/p>\n<ol>\n<li>\n<figure id=\"attachment_16843\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16843\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/first-law-example-brayton-cycle.png\"><img loading=\"lazy\" class=\"size-medium wp-image-16843 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/first-law-example-brayton-cycle-300x244.png\" alt=\"primeira lei - exemplo - ciclo de brayton\" width=\"300\" height=\"244\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/first-law-example-brayton-cycle-300x244.png\" \/><\/a><figcaption id=\"caption-attachment-16843\" class=\"wp-caption-text\"><span>O ciclo ideal de Brayton consiste em quatro processos termodin\u00e2micos.\u00a0Dois processos isentr\u00f3picos e dois processos isob\u00e1ricos.<\/span><\/figcaption><\/figure>\n<p><strong><span>compress\u00e3o isentr\u00f3pica<\/span><\/strong><span>\u00a0&#8211; o ar ambiente \u00e9 aspirado para o compressor, onde \u00e9 pressurizado (1 \u2192 2).\u00a0O trabalho necess\u00e1rio para o compressor \u00e9 dado por\u00a0<\/span><strong><span>W\u00a0<\/span><\/strong><strong><sub><span>C<\/span><\/sub><\/strong><strong><span>\u00a0= H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><strong><span>\u00a0.<\/span><\/strong><\/li>\n<li><strong><span>adi\u00e7\u00e3o de calor isob\u00e1rico<\/span><\/strong><span>\u00a0&#8211; o ar comprimido passa por uma c\u00e2mara de combust\u00e3o, onde o combust\u00edvel \u00e9 queimado e o ar ou outro meio \u00e9 aquecido (2 \u2192 3).\u00a0\u00c9 um processo de press\u00e3o constante, j\u00e1 que a c\u00e2mara est\u00e1 aberta para entrar e sair.\u00a0O calor l\u00edquido adicionado \u00e9 dado por\u00a0<\/span><strong><span>Q\u00a0<\/span><\/strong><strong><sub><span>add<\/span><\/sub><\/strong><strong><span>\u00a0= H\u00a0<\/span><\/strong><strong><sub><span>3<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><\/li>\n<li><strong><span>expans\u00e3o isentr\u00f3pica<\/span><\/strong><span>\u00a0&#8211; o ar aquecido e pressurizado se expande na turbina, gasta sua energia.\u00a0O trabalho realizado pela turbina \u00e9 dado por\u00a0<\/span><strong><span>W\u00a0<\/span><\/strong><strong><sub><span>T<\/span><\/sub><\/strong><strong><span>\u00a0= H\u00a0<\/span><\/strong><strong><sub><span>4<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>3<\/span><\/sub><\/strong><\/li>\n<li><strong><span>rejei\u00e7\u00e3o de calor isob\u00e1rica<\/span><\/strong><span>\u00a0&#8211; o calor residual deve ser rejeitado para fechar o ciclo.\u00a0O calor l\u00edquido rejeitado \u00e9 dado por\u00a0<\/span><strong><span>Q\u00a0<\/span><\/strong><strong><sub><span>re<\/span><\/sub><\/strong><strong><span>\u00a0= H\u00a0<\/span><\/strong><strong><sub><span>4<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><\/li>\n<\/ol>\n<p><span>Como pode ser visto, podemos descrever e calcular (por exemplo, efici\u00eancia termodin\u00e2mica) esses ciclos (da mesma forma para o\u00a0<\/span><strong><span>ciclo de Rankine<\/span><\/strong><span>\u00a0) usando\u00a0<\/span><a title=\"O que \u00e9 entalpia\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/what-is-enthalpy\/\"><span>entalpias<\/span><\/a><span>\u00a0.<\/span><\/p>\n<p><span>Para calcular a\u00a0<\/span><strong><span>efici\u00eancia t\u00e9rmica<\/span><\/strong><span>\u00a0do\u00a0<\/span><strong><span>ciclo de Brayton<\/span><\/strong><span>\u00a0(compressor \u00fanico e turbina \u00fanica), os engenheiros usam a\u00a0<\/span><strong><span>primeira lei da termodin\u00e2mica<\/span><\/strong><span>\u00a0em termos de entalpia e n\u00e3o em energia interna.<\/span><\/p>\n<p><span>A\u00a0<\/span><a title=\"Primeira lei em termos de entalpia dH = dQ + Vdp\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/first-law-of-thermodynamics\/first-law-in-terms-of-enthalpy-dh-dq-vdp\/\"><span>primeira lei em termos de entalpia<\/span><\/a><span>\u00a0\u00e9:<\/span><\/p>\n<p><em><strong><span>dH = dQ + Vdp<\/span><\/strong><\/em><\/p>\n<p><span>Nesta equa\u00e7\u00e3o, o termo\u00a0<\/span><strong><em><span>Vdp<\/span><\/em><\/strong><span>\u00a0\u00e9 um\u00a0<\/span><strong><span>trabalho de processo de fluxo.\u00a0<\/span><\/strong><span>Este trabalho, \u00a0\u00a0<\/span><strong><em><span>Vdp<\/span><\/em><\/strong><span>\u00a0, \u00e9 usado para\u00a0<\/span><strong><span>sistemas de fluxo aberto,<\/span><\/strong><span>\u00a0como uma\u00a0<\/span><strong><span>turbina<\/span><\/strong><span>\u00a0ou uma\u00a0<\/span><strong><span>bomba<\/span><\/strong><span>\u00a0na qual existe um\u00a0<\/span><strong><span>&#8220;dp&#8221;<\/span><\/strong><span>\u00a0, ou seja, mudan\u00e7a de press\u00e3o.\u00a0N\u00e3o h\u00e1 altera\u00e7\u00f5es no\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/control-volume-control-volume-analysis\/\"><span>volume de controle<\/span><\/a><span>\u00a0.\u00a0Como pode ser visto, essa forma de lei\u00a0<\/span><strong><span>simplifica a descri\u00e7\u00e3o da transfer\u00eancia de energia<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>Existem express\u00f5es em termos de vari\u00e1veis \u200b\u200bmais familiares, como\u00a0<\/span><a href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-temperatura-fisica-definicao\/\"><span>temperatura<\/span><\/a><span>\u00a0e\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-pressure-physics\/\"><span>press\u00e3o<\/span><\/a><span>\u00a0:<\/span><\/p>\n<p><strong><em><span>dH = C\u00a0<\/span><\/em><\/strong><strong><em><sub><span>p<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0dT + V (1-aT) dp<\/span><\/em><\/strong><\/p>\n<p><span>Onde\u00a0<\/span><strong><span>C\u00a0<\/span><\/strong><strong><sub><span>p<\/span><\/sub><\/strong><span>\u00a0\u00e9 a\u00a0<\/span><strong><a title=\"Capacidade t\u00e9rmica - Capacidade t\u00e9rmica espec\u00edfica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/first-law-of-thermodynamics\/heat-capacity\/\"><span>capacidade de calor<\/span><\/a><span>\u00a0a uma press\u00e3o constante<\/span><\/strong><span>\u00a0e\u00a0<\/span><strong><em><span>\u03b1<\/span><\/em><\/strong><span>\u00a0\u00e9 o coeficiente de expans\u00e3o t\u00e9rmica (c\u00fabico).\u00a0Para\u00a0<\/span><strong><span>o g\u00e1s ideal<\/span><\/strong><span>\u00a0\u03b1T = 1 e, portanto:<\/span><\/p>\n<p><strong><em><span>dH = C\u00a0<\/span><\/em><\/strong><strong><em><sub><span>p<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0dT<\/span><\/em><\/strong><\/p>\n<p><strong><span>A press\u00e3o constante<\/span><\/strong><span>\u00a0, a\u00a0<\/span><strong><span>mudan\u00e7a de entalpia<\/span><\/strong><span>\u00a0\u00e9 igual \u00e0\u00a0<\/span><strong><span>energia<\/span><\/strong><span>\u00a0transferida do ambiente atrav\u00e9s do aquecimento:<\/span><\/p>\n<p><strong><span>Processo isob\u00e1rico (Vdp = 0):<\/span><\/strong><\/p>\n<p><strong><span>dH = dQ \u2192 Q = H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><strong><span>\u00a0\u00a0\u00a0\u2192 H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><strong><span>\u00a0=\u00a0<\/span><em><span>C\u00a0<\/span><\/em><\/strong><strong><em><sub><span>P<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0(T\u00a0<\/span><\/em><\/strong><strong><em><sub><span>2<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0&#8211; T\u00a0<\/span><\/em><\/strong><strong><em><sub><span>1<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0)<\/span><\/em><\/strong><\/p>\n<p><strong><span>Na entropia constante<\/span><\/strong><span>\u00a0, ou seja, no processo isentr\u00f3pico, a\u00a0<\/span><strong><span>mudan\u00e7a de entalpia<\/span><\/strong><span>\u00a0\u00e9 igual ao\u00a0<\/span><strong><span>trabalho do processo de fluxo<\/span><\/strong><span>\u00a0realizado no ou pelo sistema:<\/span><\/p>\n<p><strong><span>Processo isentr\u00f3pico (dQ = 0):<\/span><\/strong><\/p>\n<p><strong><span>dH = Vdp \u2192 W = H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><strong><span>\u00a0\u00a0\u00a0\u00a0\u00a0\u2192 H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><strong><span>\u00a0=\u00a0<\/span><em><span>C\u00a0<\/span><\/em><\/strong><strong><em><sub><span>P<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0(T\u00a0<\/span><\/em><\/strong><strong><em><sub><span>2<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0&#8211; T\u00a0<\/span><\/em><\/strong><strong><em><sub><span>1<\/span><\/sub><\/em><\/strong><strong><em><span>\u00a0)<\/span><\/em><\/strong><\/p>\n<figure id=\"attachment_16843\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16843\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/first-law-example-brayton-cycle.png\"><img loading=\"lazy\" class=\"size-medium wp-image-16843 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/first-law-example-brayton-cycle-300x244.png\" alt=\"primeira lei - exemplo - ciclo de brayton\" width=\"300\" height=\"244\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/first-law-example-brayton-cycle-300x244.png\" \/><\/a><figcaption id=\"caption-attachment-16843\" class=\"wp-caption-text\"><span>O ciclo ideal de Brayton consiste em quatro processos termodin\u00e2micos.\u00a0Dois processos isentr\u00f3picos e dois processos isob\u00e1ricos.<\/span><\/figcaption><\/figure>\n<p><span>A\u00a0<\/span><strong><span>entalpia<\/span><\/strong><span>\u00a0pode ser transformada em uma\u00a0vari\u00e1vel\u00a0<\/span><strong><span>intensiva<\/span><\/strong><span>\u00a0ou\u00a0<\/span><strong><span>espec\u00edfica<\/span><\/strong><span>\u00a0dividindo-se pela\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-mass-and-weight\/what-is-mass\/\"><span>massa<\/span><\/a><span>\u00a0.\u00a0<\/span><strong><span>Os engenheiros usam mais a\u00a0<\/span><\/strong><strong><span>entalpia espec\u00edfica<\/span><\/strong><span>\u00a0na an\u00e1lise termodin\u00e2mica do que a pr\u00f3pria entalpia.\u00a0A efici\u00eancia t\u00e9rmica desse ciclo simples de Brayton, para o g\u00e1s ideal e em termos de entalpias espec\u00edficas, agora pode ser expressa em termos de temperatura:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-brayton-cycle-equation.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-16963 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-brayton-cycle-equation.png\" alt=\"efici\u00eancia t\u00e9rmica do ciclo de Brayton\" width=\"602\" height=\"60\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-brayton-cycle-equation.png\" \/><\/a><\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights  lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spacer\"><\/div>\n<h2><span>Efici\u00eancia t\u00e9rmica do ciclo Rankine<\/span><\/h2>\n<figure id=\"attachment_16026\" class=\"wp-caption alignright\" aria-describedby=\"caption-attachment-16026\"><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Thermodynamic-Cycles-min.png\"><img loading=\"lazy\" class=\"size-medium wp-image-16026 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Thermodynamic-Cycles-min-300x277.png\" alt=\"termodin\u00e2mica de engenharia\" width=\"300\" height=\"277\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/Thermodynamic-Cycles-min-300x277.png\" \/><\/a><figcaption id=\"caption-attachment-16026\" class=\"wp-caption-text\"><span>Ciclo de Rankine &#8211; Termodin\u00e2mica como ci\u00eancia de convers\u00e3o de energia<\/span><\/figcaption><\/figure>\n<p><span>O\u00a0<\/span><strong><span>ciclo Rankine<\/span><\/strong><span>\u00a0descreve de perto os processos em motores t\u00e9rmicos a vapor comumente encontrados na maioria das\u00a0<\/span><strong><span>usinas termel\u00e9tricas<\/span><\/strong><span>\u00a0.\u00a0As fontes de calor usadas nessas usinas s\u00e3o geralmente a combust\u00e3o de combust\u00edveis f\u00f3sseis, como carv\u00e3o, g\u00e1s natural ou tamb\u00e9m a\u00a0<\/span><strong><span>fiss\u00e3o nuclear<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>Uma\u00a0<\/span><a title=\"Usina nuclear\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/\"><strong><span>usina<\/span><\/strong><\/a><span>\u00a0nuclear (\u00a0<a title=\"Usina nuclear\" href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/\"><strong>usina<\/strong><\/a>\u00a0nuclear) parece uma usina termel\u00e9trica padr\u00e3o, com uma exce\u00e7\u00e3o.\u00a0A fonte de calor na usina nuclear \u00e9 um\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-power-plant\/nuclear-reactor\/\"><strong><span>reator nuclear<\/span><\/strong><\/a><span>\u00a0.\u00a0Como \u00e9 t\u00edpico em todas as centrais t\u00e9rmicas convencionais, o calor \u00e9 usado para gerar\u00a0<\/span><a title=\"Propriedades do Steam - O que \u00e9 o Steam\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-o-steam-propriedades-do-steam-definicao\/\"><span>vapor<\/span><\/a><span>\u00a0que aciona uma turbina a vapor conectada a um gerador que produz eletricidade.<\/span><\/p>\n<p><span>Normalmente, a maioria das\u00a0<\/span><strong><span>usinas nucleares<\/span><\/strong><span>\u00a0opera\u00a0<\/span><strong><span>turbinas a vapor de condensa\u00e7\u00e3o de v\u00e1rios est\u00e1gios<\/span><\/strong><span>\u00a0.\u00a0Nessas turbinas, o est\u00e1gio de alta press\u00e3o recebe\u00a0<\/span><a href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-o-steam-propriedades-do-steam-definicao\/\"><span>vapor<\/span><\/a><span>\u00a0(esse vapor \u00e9 quase saturado &#8211; x = 0,995 &#8211; ponto C na figura;\u00a0<\/span><strong><span>6 MPa<\/span><\/strong><span>\u00a0; 275,6 \u00b0 C) de um gerador de vapor e o esgota para o separador-reaquecedor de umidade (ponto D )\u00a0O vapor deve ser reaquecido para evitar danos que possam ser causados \u200b\u200b\u00e0s p\u00e1s da turbina a vapor por vapor de\u00a0<\/span><a title=\"Qualidade de Vapor - Fra\u00e7\u00e3o de Secura\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/materials-nuclear-engineering\/properties-steam-what-is-steam\/vapor-quality-dryness-fraction\/\"><span>baixa qualidade<\/span><\/a><span>\u00a0.\u00a0O reaquecedor aquece o vapor (ponto D) e, em seguida, o vapor \u00e9 direcionado para o est\u00e1gio de baixa press\u00e3o da turbina a vapor, onde se expande (pontos E a F).\u00a0O vapor exaurido condensa no condensador e est\u00e1 a uma press\u00e3o bem abaixo da atmosf\u00e9rica (press\u00e3o absoluta de<\/span><strong><span>0,008 MPa<\/span><\/strong><span>\u00a0) e est\u00e1 em um estado parcialmente condensado (ponto F), tipicamente com uma qualidade pr\u00f3xima a 90%.<\/span><\/p>\n<p><span>Nesse caso, geradores de vapor, turbinas a vapor, condensadores e bombas de \u00e1gua de alimenta\u00e7\u00e3o constituem um motor t\u00e9rmico, sujeito \u00e0s limita\u00e7\u00f5es de efici\u00eancia impostas pela\u00a0<a title=\"Segunda Lei da Termodin\u00e2mica\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-a-segunda-lei-da-termodinamica-definicao\/\"><strong>segunda lei da termodin\u00e2mica<\/strong><\/a>\u00a0.\u00a0No caso ideal (sem atrito, processos revers\u00edveis, design perfeito), este motor t\u00e9rmico teria uma\u00a0<a title=\"Efici\u00eancia de Carnot - Efici\u00eancia do mecanismo de calor de Carnot\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/second-law-of-thermodynamics\/carnot-efficiency-efficiency-of-carnot-heat-engine\/\">efici\u00eancia<\/a>\u00a0de\u00a0<a title=\"Efici\u00eancia de Carnot - Efici\u00eancia do mecanismo de calor de Carnot\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/second-law-of-thermodynamics\/carnot-efficiency-efficiency-of-carnot-heat-engine\/\">Carnot<\/a>\u00a0de<\/span><\/p>\n<p><span>= 1 &#8211; T\u00a0<\/span><sub><span>frio<\/span><\/sub><span>\u00a0\/ T\u00a0<\/span><sub><span>quente<\/span><\/sub><span>\u00a0= 1 &#8211; 315\/549 = 42,6%<\/span><\/p>\n<p><span>onde a temperatura do reservat\u00f3rio quente \u00e9 de 275,6 \u00b0 C (548,7 K), a temperatura do reservat\u00f3rio frio \u00e9 de 41,5 \u00b0 C (314,7 K).\u00a0Mas a usina nuclear \u00e9 o\u00a0<\/span><strong><span>verdadeiro motor t\u00e9rmico<\/span><\/strong><span>\u00a0, no qual os processos termodin\u00e2micos s\u00e3o de alguma forma irrevers\u00edveis.\u00a0Eles n\u00e3o s\u00e3o feitos infinitamente devagar.\u00a0Em dispositivos reais (como turbinas, bombas e compressores), um atrito mec\u00e2nico e perdas de calor causam mais perdas de efici\u00eancia.<\/span><\/p>\n<p><span>Para calcular a\u00a0<\/span><strong><span>efici\u00eancia t\u00e9rmica<\/span><\/strong><span>\u00a0do\u00a0<\/span><strong><span>ciclo Rankine<\/span><\/strong><span>\u00a0mais simples\u00a0(sem reaquecer), os engenheiros usam a\u00a0<\/span><a title=\"Primeira lei em termos de entalpia dH = dQ + Vdp\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/laws-of-thermodynamics\/first-law-of-thermodynamics\/first-law-in-terms-of-enthalpy-dh-dq-vdp\/\"><strong><span>primeira lei da termodin\u00e2mica em termos de entalpia<\/span><\/strong><\/a><span>\u00a0e n\u00e3o em energia interna.<\/span><\/p>\n<p><span>A primeira lei em termos de entalpia \u00e9:<\/span><\/p>\n<p><em><strong><span>dH = dQ + Vdp<\/span><\/strong><\/em><\/p>\n<p><span>Nesta equa\u00e7\u00e3o, o termo\u00a0<\/span><strong><em><span>Vdp<\/span><\/em><\/strong><span>\u00a0\u00e9 um\u00a0<\/span><strong><span>trabalho de processo de fluxo.\u00a0<\/span><\/strong><span>Este trabalho, \u00a0\u00a0<\/span><strong><em><span>Vdp<\/span><\/em><\/strong><span>\u00a0, \u00e9 usado para\u00a0<\/span><strong><span>sistemas de fluxo aberto,<\/span><\/strong><span>\u00a0como uma\u00a0<\/span><strong><span>turbina<\/span><\/strong><span>\u00a0ou uma\u00a0<\/span><strong><span>bomba<\/span><\/strong><span>\u00a0na qual existe um\u00a0<\/span><strong><span>&#8220;dp&#8221;<\/span><\/strong><span>\u00a0, ou seja, mudan\u00e7a de press\u00e3o.\u00a0N\u00e3o h\u00e1 altera\u00e7\u00f5es no\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/fluid-dynamics\/control-volume-control-volume-analysis\/\"><span>volume de controle<\/span><\/a><span>\u00a0.\u00a0Como pode ser visto, essa forma de lei\u00a0<\/span><strong><span>simplifica a descri\u00e7\u00e3o da transfer\u00eancia de energia<\/span><\/strong><span>\u00a0.\u00a0<\/span><strong><span>A press\u00e3o constante<\/span><\/strong><span>\u00a0, a\u00a0<\/span><strong><span>mudan\u00e7a de entalpia<\/span><\/strong><span>\u00a0\u00e9 igual \u00e0\u00a0<\/span><strong><span>energia<\/span><\/strong><span>\u00a0transferida do ambiente atrav\u00e9s do aquecimento:<\/span><\/p>\n<p><strong><span>Processo isob\u00e1rico (Vdp = 0):<\/span><\/strong><\/p>\n<p><strong><span>dH = dQ \u2192 Q = H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><\/p>\n<p><strong><span>Na entropia constante<\/span><\/strong><span>\u00a0, ou seja, no processo isentr\u00f3pico, a\u00a0<\/span><strong><span>mudan\u00e7a de entalpia<\/span><\/strong><span>\u00a0\u00e9 igual ao\u00a0<\/span><strong><span>trabalho do processo de fluxo<\/span><\/strong><span>\u00a0realizado no ou pelo sistema:<\/span><\/p>\n<p><strong><span>Processo isentr\u00f3pico (dQ = 0):<\/span><\/strong><\/p>\n<p><strong><span>dH = Vdp \u2192 W = H\u00a0<\/span><\/strong><strong><sub><span>2<\/span><\/sub><\/strong><strong><span>\u00a0&#8211; H\u00a0<\/span><\/strong><strong><sub><span>1<\/span><\/sub><\/strong><\/p>\n<p><span>\u00c9 \u00f3bvio que ser\u00e1 muito \u00fatil na an\u00e1lise de ambos os ciclos termodin\u00e2micos usados \u200b\u200bna engenharia de energia, ou seja, no ciclo de Brayton e no ciclo de Rankine.<\/span><\/p>\n<p><span>A\u00a0<\/span><strong><span>entalpia<\/span><\/strong><span>\u00a0pode ser transformada em uma\u00a0vari\u00e1vel\u00a0<\/span><strong><span>intensiva<\/span><\/strong><span>\u00a0ou\u00a0<\/span><strong><span>espec\u00edfica<\/span><\/strong><span>\u00a0dividindo-se pela\u00a0<\/span><a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-mass-and-weight\/what-is-mass\/\"><span>massa<\/span><\/a><span>\u00a0.\u00a0<\/span><strong><span>Os engenheiros usam mais a\u00a0<\/span><\/strong><strong><span>entalpia espec\u00edfica<\/span><\/strong><span>\u00a0na an\u00e1lise termodin\u00e2mica do que a pr\u00f3pria entalpia.\u00a0Ele \u00e9 tabulado nas\u00a0<\/span><a title=\"Tabelas de Vapor - Propriedades Espec\u00edficas da \u00c1gua e Vapor\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/steam-tables\/\"><strong><span>tabelas de vapor,<\/span><\/strong><\/a><span>\u00a0juntamente com o\u00a0<\/span><a title=\"O que \u00e9 volume espec\u00edfico\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/thermodynamic-properties\/what-is-specific-volume\/\"><span>volume\u00a0<\/span><\/a><a title=\"Energia interna espec\u00edfica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/internal-energy-thermal-energy\/specific-internal-energy\/\"><span>espec\u00edfico<\/span><\/a><span>\u00a0e\u00a0<a title=\"Energia interna espec\u00edfica\" href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/internal-energy-thermal-energy\/specific-internal-energy\/\">a energia interna espec\u00edfica<\/a>\u00a0.\u00a0A efici\u00eancia t\u00e9rmica desse ciclo simples de Rankine e em termos de entalpias espec\u00edficas seria:<\/span><\/p>\n<p><a href=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-rankine-cycle-equation.png\"><img loading=\"lazy\" class=\"aligncenter size-full wp-image-16962 lazy-loaded\" src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-rankine-cycle-equation.png\" alt=\"efici\u00eancia t\u00e9rmica do ciclo Rankine\" width=\"535\" height=\"68\" data-lazy-type=\"image\" data-src=\"https:\/\/thermal-engineering.org\/wp-content\/uploads\/2019\/05\/thermal-efficiency-rankine-cycle-equation.png\" \/><\/a><\/p>\n<p><span>\u00c9 uma equa\u00e7\u00e3o muito simples e, para determinar a efici\u00eancia t\u00e9rmica, voc\u00ea pode usar os dados das\u00a0<\/span><strong><span>tabelas de vapor<\/span><\/strong><span>\u00a0.<\/span><\/p>\n<p><span>Nas modernas usinas nucleares, a efici\u00eancia t\u00e9rmica geral \u00e9 de cerca de\u00a0<\/span><strong><span>um ter\u00e7o<\/span><\/strong><span>\u00a0(33%); portanto, s\u00e3o necess\u00e1rios\u00a0<\/span><strong><span>3000 MWth<\/span><\/strong><span>\u00a0de energia t\u00e9rmica da rea\u00e7\u00e3o de fiss\u00e3o para gerar\u00a0<\/span><strong><span>1000 MWe<\/span><\/strong><span>\u00a0de energia el\u00e9trica.\u00a0O motivo est\u00e1 na temperatura do vapor relativamente baixa (\u00a0<\/span><strong><span>6 MPa<\/span><\/strong><span>\u00a0; 275,6 \u00b0 C).\u00a0Efici\u00eancias mais altas podem ser alcan\u00e7adas aumentando a\u00a0<\/span><strong><span>temperatura<\/span><\/strong><span>do vapor.\u00a0Mas isso requer um aumento nas press\u00f5es dentro de caldeiras ou geradores de vapor.\u00a0No entanto, considera\u00e7\u00f5es metal\u00fargicas imp\u00f5em limites superiores a essas press\u00f5es.\u00a0Em compara\u00e7\u00e3o com outras fontes de energia, a efici\u00eancia t\u00e9rmica de 33% n\u00e3o \u00e9 grande.\u00a0Mas deve-se notar que as usinas nucleares s\u00e3o muito mais complexas que as usinas de combust\u00edveis f\u00f3sseis e \u00e9 muito mais f\u00e1cil queimar combust\u00edveis f\u00f3sseis do que gerar energia a partir de combust\u00edveis nucleares.\u00a0As usinas subcr\u00edticas de combust\u00edveis f\u00f3sseis, que s\u00e3o operadas sob\u00a0<\/span><strong><span>press\u00e3o cr\u00edtica<\/span><\/strong><span>\u00a0(ou seja, inferiores a 22,1 MPa), podem atingir uma efici\u00eancia de 36 a 40%.<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<p>&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;.<\/p>\n<p>Este artigo \u00e9 baseado na tradu\u00e7\u00e3o autom\u00e1tica do artigo original em ingl\u00eas. Para mais informa\u00e7\u00f5es, consulte o artigo em ingl\u00eas. Voc\u00ea pode nos ajudar. Se voc\u00ea deseja corrigir a tradu\u00e7\u00e3o, envie-a para: translations@nuclear-power.com ou preencha o formul\u00e1rio de tradu\u00e7\u00e3o on-line. Agradecemos sua ajuda, atualizaremos a tradu\u00e7\u00e3o o mais r\u00e1pido poss\u00edvel. Obrigado.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A efici\u00eancia t\u00e9rmica dos motores t\u00e9rmicos projetados ou usados \u200b\u200bhoje em dia tem uma grande variedade.\u00a0A efici\u00eancia t\u00e9rmica de uma usina nuclear t\u00edpica \u00e9 de cerca de um ter\u00e7o (33%).\u00a0Engenharia T\u00e9rmica Efici\u00eancia t\u00e9rmica de motores t\u00e9rmicos Em geral, a efici\u00eancia dos melhores motores t\u00e9rmicos \u00e9 bastante baixa.\u00a0Em resumo, \u00e9\u00a0muito dif\u00edcil converter energia t\u00e9rmica em energia &#8230; <a title=\"O que \u00e9 efici\u00eancia t\u00e9rmica de motores de calor &#8211; Exemplos &#8211; Defini\u00e7\u00e3o\" class=\"read-more\" href=\"https:\/\/www.thermal-engineering.org\/pt-br\/o-que-e-eficiencia-termica-de-motores-de-calor-exemplos-definicao\/\" aria-label=\"More on O que \u00e9 efici\u00eancia t\u00e9rmica de motores de calor &#8211; Exemplos &#8211; Defini\u00e7\u00e3o\">Ler mais<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[14],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v15.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>O que \u00e9 efici\u00eancia t\u00e9rmica de motores de calor - Exemplos - Defini\u00e7\u00e3o<\/title>\n<meta name=\"description\" content=\"A efici\u00eancia t\u00e9rmica dos motores t\u00e9rmicos projetados ou usados hoje em dia tem uma grande variedade. 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