Thermal Efficiency

Thermodynamics · 1824

Equation: η = W_net/Q_in = 1 − Q_out/Q_in
Field: Thermodynamics
Symbols: η thermal efficiency · W_net net work out per cycle · Q_in heat taken from the hot source · Q_out heat rejected to the cold sink
Year: 1824

Significance

What you get for what you burn. Every real cycle's efficiency is this ratio; the Carnot value is what it would be if nothing were wasted. Rankine steam plants manage 33–45 %, combined-cycle gas plants over 60 %, and the difference between them is worth a great deal of fuel.

Machines

Watt Steam Engine Otto Four-Stroke Engine Diesel Engine Gas Turbine (Jet Engine)Steam Turbine Pressurized Water Reactor

Requires

First Law of Thermodynamics

Required By

Carnot Efficiency Otto Cycle Efficiency Diesel Cycle Efficiency Brayton Cycle Efficiency

Referenced by

equation

Brayton Cycle Efficiency Carnot Efficiency Diesel Cycle Efficiency First Law of Thermodynamics Otto Cycle Efficiency

machine

Diesel Engine Gas Turbine (Jet Engine)Otto Four-Stroke Engine Pressurized Water Reactor Steam Turbine Watt Steam Engine

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From the Equations database in Notion, last edited 2026-08-18. This page is the row, rendered by the build; nothing on it is written by hand.