What is a refrigerator ? Why the expression for coefficient of performance.

Explanation

Refirgerator is thermodynamic device which works exactly to the reverse of Carnot.s heat engine (also called the heat pump).
It this case, heat is abosrbed from cold reservior `(T_(2))` and released to the hot reervoir `(T_(1))`
`alpha=(Q_(2))/(W)=(Q_(2))/(Q_(1)-Q_(2))gt1`
Where `alpha`. is coefficient of performance and `Q_(2)` is the heat extracted from the cold reservoir.