Aluminium with an unknown mass and an initial temperature of 28 °C is to be melted in an arc furnace in 1 hour and 10 minutes. The aluminium has a melting point of 938 K, a specific latent heat of fusion of 458 kJ/kg and specific heat capacity of 1016.22 J/kg.°C. The energy required for the melting process is 180 MJ, the efficiency of the furnace is 85% and the cost of electrical energy is 192c/kWh. 1.3.1 Calculate the mass of the aluminium. 1.3.2 Calculate the active power required by the furnace. 1.3.3 Calculate the operating cost of the furnace for the melting process.
Aluminium with an unknown mass and an initial temperature of 28 °C is to be melted in an arc furnace in 1 hour and 10 minutes. The aluminium has a melting point of 938 K, a specific latent heat of fusion of 458 kJ/kg and specific heat capacity of 1016.22 J/kg.°C. The energy required for the melting process is 180 MJ, the efficiency of the furnace is 85% and the cost of electrical energy is 192c/kWh.
1.3.1 Calculate the mass of the aluminium.
1.3.2 Calculate the active power required by the furnace.
1.3.3 Calculate the operating cost of the furnace for the melting process.
1.4 Determine the total cost of using the following equipment at R2.20/kWh.
A 2500 W Stove for 3 hours;
A 1200 W microwave oven for 30 minutes; Five 11 W CFL light bulbs for one hour;
A 2 kW toaster for 10 minutes;
A 2 kW kettle for 5 minutes.
Step by step
Solved in 4 steps with 4 images
