Efficiency

Efficiency, abbreviated as \(\eta\) (Greek symbol eta), a dimensionless number, is expressed in percentage and always less than 100%.  Efficiency is a measure of how effectively a system or process converts inputs into outputs.  It quantifies the ratio of useful output or work obtained from a system to the total input or energy supplied to the system.  In general, efficiency is a measure of how well a system performs in achieving its intended purpose while minimizing waste or losses.

Efficiency is an important factor in various fields, including energy production, manufacturing, transportation, and sustainability.  Improving efficiency can lead to reduced waste, increased productivity, cost savings, and a more sustainable use of resources.

 

Energy Efficiency formula
\( \eta \;=\;  ( E_o \;/\; E_i ) \;100 \)     (Energy Efficiency) \( E_o \;=\;  \eta \; E_i \;/\; 100 \) \( E_i \;=\;   E_o \; 100 \;/\; \eta \)
Symbol	English	Metric
\( \eta \)  (Greek symbol eta) = Energy Efficiency	\(dimensionless\)	\(dimensionless\)
\( E_o \) = Output Energy	\(ft-lbf\)	\(J\)
\( E_i \) = Input Energy	\(ft-lbf\)	\(J\)

 

Work Efficiency formula
\( \eta \;=\; ( W_o \;/\; W_i ) \; 100 \)     (Work Efficiency) \( W_o \;=\;  \eta \; W_i \;/\; 100 \) \( W_i \;=\;  W_o \; 100 \;/\; \eta \)
Symbol	English	Metric
\( \eta \)  (Greek symbol eta) = Work Efficiency	\(dimensionless\)	\(dimensionless\)
\( W_o \) = Output Work	\(ft-lbf\)	\(J\)
\( W_i \) = Input Work	\(ft-lbf\)	\(J\)