Thermal efficiency

In <a href="/facts/Thermodynamics/q4hIx3yP">thermodynamics</a>, the thermal efficiency (
 
 
 
 
 η
 
 
 t
 h
 
 
 
 
 
 {\displaystyle \eta _{\rm {th}}}
 
) is a <a href="/facts/Dimensionless_quantity/TINrpQIq">dimensionless</a> performance measure of a device that uses <a href="/facts/Thermal_energy/eVaKAC7K">thermal energy</a>, such as an <a href="/facts/Internal_combustion_engine/Ju4BXzj0">internal combustion engine</a>, <a href="/facts/Steam_turbine/scacVXsB">steam turbine</a>, <a href="/facts/Steam_engine/f7hN8vzm">steam engine</a>, <a href="/facts/Boiler/uPqTq0I6">boiler</a>, <a href="/facts/Furnace_(house_heating)/UBIUG3c0">furnace</a>, <a href="/facts/Refrigerator/TGb5ozLY">refrigerator</a>, <a href="/facts/Air_conditioning/bK2sIKQd">ACs</a> etc.
For a <a href="/facts/Heat_engine/t1gq4r5d">heat engine</a>, thermal efficiency is the ratio of the net work output to the heat input; in the case of a <a href="/facts/Heat_pump_and_refrigeration_cycle/yW0gnSvL">heat pump</a>, thermal efficiency (known as the <a href="/facts/Coefficient_of_performance/35m7j66C">coefficient of performance</a> or COP) is the ratio of net heat output (for heating), or the net heat removed (for cooling) to the energy input (external work). The efficiency of a heat engine is fractional as the output is always less than the input while the COP of a heat pump is more than 1. These values are further restricted by the <a href="/facts/Carnot%27s_theorem_(thermodynamics)/MtLN7MfQ">Carnot theorem</a>.

Thermal efficiency open-in-new

Thermal efficiency