A novel design for a condenser consists of a tube of thermal conductivity 200W/m · K with longitudinal fins snugly fitted into a larger tube. Condensing refrigerant at 45°C flows axially through the inner tube, while water at a flow rate of 0.012 kg/s passes through the six channels around the inner tube. The pertinent diameters are D1 = 10 mm. D2 = 14 mm, and D3 = 50 mm, while the fin thickness is t = 2 mm. Assume that the convection coefficient associated with the condensing refrigerant is extremely large. Determine the heat removal rate per unit tube length in a section of the tube for which the water is at 15°C.
