Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Carnot heat engine
open-in-new
<p>A Carnot heat engine is a theoretical <a href="/facts/Heat_engine/t1gq4r5d">heat engine</a> that operates on the <a href="/facts/Carnot_cycle/cjN9V9q8">Carnot cycle</a>. The basic model for this engine was developed by <a href="/facts/Nicolas_L%C3%A9onard_Sadi_Carnot/atzzIKJB">Nicolas Léonard Sadi Carnot</a> in 1824. The Carnot engine model was graphically expanded by <a href="/facts/Beno%C3%AEt_Paul_%C3%89mile_Clapeyron/108oIBhT">Benoît Paul Émile Clapeyron</a> in 1834 and mathematically explored by <a href="/facts/Rudolf_Clausius/RMgFgY7I">Rudolf Clausius</a> in 1857, work that led to the fundamental thermodynamic concept of <a href="/facts/Entropy/s52IXeFz">entropy</a>. The <a href="/facts/Nicolas_L%C3%A9onard_Sadi_Carnot/atzzIKJB">Carnot</a> engine is the most efficient heat engine which is theoretically possible. The efficiency depends only upon the absolute temperatures of the hot and cold heat reservoirs between which it operates. </p><p>A heat engine acts by transferring energy from a warm region to a cool region of space and, in the process, converting some of that energy to <a href="/facts/Mechanical_work/mbclFPBs">mechanical work</a>. The cycle may also be reversed. The system may be worked upon by an external force, and in the process, it can transfer thermal energy from a cooler system to a warmer one, thereby acting as a <a href="/facts/Refrigerator/TGb5ozLY">refrigerator</a> or <a href="/facts/Heat_pump/JAprSmeL">heat pump</a> rather than a heat engine. </p><p>Every thermodynamic system exists in a particular <a href="/facts/Thermodynamic_state/Rv6m11Pf">state</a>. A <a href="/facts/Thermodynamic_cycle/81AXwUM9">thermodynamic cycle</a> occurs when a <a href="/facts/Thermodynamic_system/VUr0kpWu">system</a> is taken through a series of different states, and finally returned to its initial state. In the process of going through this cycle, the system may perform work on its surroundings, thereby acting as a heat engine. </p><p>The Carnot engine is a theoretical construct, useful for exploring the efficiency limits of other heat engines. An actual Carnot engine, however, would be completely impractical to build. </p>