A refrigerant using refrigerant R-12 as the working fluid operates on vapourcompression cycle between \(273 \mathrm{~K}\) and \(313 \mathrm{~K}\). Compute the following:

(i) COP of the vapour-compression cycle

(ii) Refrigerating effect

(iii) COP of an ideal Carnot refrigerator

(iv) Work of compression Given that Enthalpy of saturated vapour at \(273 \mathrm{~K}, H_{1}=187 \mathrm{~kJ} / \mathrm{kg}\)

Enthalpy of saturated liquid at \(313 \mathrm{~K}, H_{3}=H_{4}=74 \mathrm{~kJ} / \mathrm{kg}\)

Enthalpy of superheated vapour at \(273 \mathrm{~K}, H_{2}=204 \mathrm{~kJ} / \mathrm{kg}\).