Question

define efficiency of heat energy​

Answer 1

AnSwer :

$\bigstar$Efficiency of heat energy (η) is defined as the fraction of total heat supplied to the engine which is Converted into work.

Mathematically,

${ \sf{\eta = \dfrac{W}{Q_1} = \dfrac{Q_1 - Q_2}{Q_1} = 1 - \dfrac{Q_2}{Q_1} = 1 - \dfrac{T_1}{T_2}}}$

According to this, efficiency is 100% if Q₂ = 0, that is no heat is rejected to the cold reservoir or sink. That is the entire heat aborsbed must be converted to mechanical energy, which is impossible according to second law of thermodynamics.

⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

#sanvi….

Answer 2

For a heat engine, thermal efficiency is the fraction of the energy added by heat ( primary energy) that is converted to net work output (secondary energy). In the case of a refrigeration or heat pump cycle, thermal efficiency is the ratio of net heat output for heating, or removal for cooling, to energy input (the coefficient of performance).