thermal efficiency

American

noun

Thermodynamics.

the ratio of the work output of a heat engine to the heat input expressed in the same units of energy.

thermal efficiency British

noun

the ratio of the work done by a heat engine to the energy supplied to it Compare efficiency

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of thermal efficiency

First recorded in 1905–10

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

In addition to cutting pollution, several experiments reported improvements in brake thermal efficiency.

From Science Daily • Mar. 13, 2026

Water-based cooling systems, especially using mine pools, are ideal for managing heat load due to their thermal efficiency.

From The Wall Street Journal • Mar. 8, 2026

Its homes, which can be customized by combining various-sized modules, range from one to four bedrooms and are solar-powered, built to maximize thermal efficiency and indoor air quality.

From Los Angeles Times • May 9, 2025

Combining these two hybrid technologies has meant F1 engines now have a thermal efficiency of more than 40% - better than a road-going diesel engine.

From BBC • May 19, 2015

Example:—The temperature of the steam admitted to the cylinder of an engine is 340 degrees F., and that of the exhaust steam 220 degrees F. What is the thermal efficiency of the engine?

From Steam Engines Machinery's Reference Series, Number 70 by Anonymous

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023