The temperature inside a refrigerator is t₂°C and the room temperature is t₁°C. The amount of heat delivered to the room for each joule of electrical energy consumed ideally will be : 

\(\frac{t_1 + 273}{t_1 - t_2}\)

K = \(\frac{Q_2}{W}\) 

   = \(\frac{1}{\frac{t_1}{t_2}-1}\)

Q₂ = \(\frac{t_2 W}{t_1 - t_2}\) 

Q1 = W + Q₂

     = \(\frac{t_1 + 273}{t_1 - t_2}\)