The condenser of a large steam power plant is a heat exchanger in which steam is condensed to liquid water. Assume the condenser to be a shell-and-tube heat exchanger consisting of a single shell and 30,000 tubes, each executing two passes (see figure below). The tubes are of thin wall construction with D-25mm, and steam condenses on their outer surface with an associated convection coefficient ho-11,000W/m.K The heat transfer rate that must be effected by the heat exchanger is q-2x10W, and this is accomplished by passing cooling water through the tubes at a rate of 3x10 kg/s (the flow rate per tube is therefore 1kg/s). The water enters at 20C, while the steam condenses at 50C. What is the temperature of the cooling water emerging from the condenser? What is the required tube length L per pass (NTU method will be used)? We can neglect the thermal resistance of tube material and fouling, as well as the heat transfer between the heat exchanger and surroundings. Properties and data: Cp-4179J/kg.K k=0.613W/m.K Pr-5.83 Water density-997kg/m -855x10 N.S/m 4/5 Nu = 0.023RePr0.4 Condenser: Ch00 NTU (for Cr-Coin Cmax-0)=-In(1-8) Steam q=2x 10W Tube data N = 30,000 D= 0.025 m h, 11,000 W/mK L= length/pass m 1 kg/s The Tel -Tep Water -T = 50C m Tep The 50C - 3 x 10 kg/s T=20C