Figure 3 shows an ideal Bell-Coleman air-refrigeration cycle: air leaves the cold chamber at T_{1}, is compressed isentropically to 4 times the pressure, cooled to T_{3} and expanded isentropically back to the chamber pressure. Take c_{p} = 1.005 kJ/kg·K and γ = 1.4. Determine (a) the refrigerating effect per kg of air (answer in kJ/kg) and (b) the COP of the cycle (answer as a number).