An ammonia refrigerator produces 30 tonnes of ice from and at 0 °C in 24 hours. The temperature range of the compressor is 25 °C to −15 °C. The vapour is dry saturated at the end of compression and an expansion valve is used. The actual COP is 60 % of the theoretical value. Calculate the power required to drive the compressor (in kW). Latent heat of ice = 335 kJ/kg. Properties of ammonia: at 25 °C, h_{f} = 298.9, h_{g} = 1465.84 kJ/kg, s_{f} = 1.1242, s_{g} = 5.0391 kJ/kg·K; at −15 °C, h_{f} = 112.34, h_{g} = 1426.54 kJ/kg, s_{f} = 0.4572, s_{g} = 5.5490 kJ/kg·K.