A heat exchanger is to be designed to condense an organic vapour at a rate of 500 kg / min which is available at its saturation temperature of 355 K. Cooling water at 286 K is available at a flowrate of 60 kg/s. The overall heat transfer coefficient is 475 W/m2.K. The latent heat of condensation of the organic vapour is 600 kJ/kg. Calculate the number of tubes required if 25 mm outer diameter, 2 mm thick and 4.87 m long tubes are available. Find the number of tube passes if the cooling water velocity (tube side) should not exceed 2 m/s. You will need to use the concept of mass flowrate. The number of tubes is number of tubes in each pass X Number of passes