The document provides specifications for designing an optimal condenser for a distillation unit, including the vapor flow rate, heat of condensation, available cooling water temperature, cost of cooling water, optimum heat transfer coefficient, cost and life of the heat exchanger. It asks to determine the cooling water flow rate and exit temperature that would result in optimal economic conditions based on these parameters.

1. 12. A condenser for a distillation unit must be designed to condense 2500 kg/h of vapor. The effective condensation temperature for the vapor is 145 o C.The heat of condensation for the vapor is 315000 J/kg. Cooling water is available at 15 o C.The cost of cooling water is $25/1000m 3 .The optimum Heat Transfer Coefficient is 300 W/m 2 K.The cost of the installed heat exchanger is $400/m 2 and life of the equipment is 20 years. The heat capacity of water is 4184 J/kgK. If the condenser is to operate 7200 hrs/yr, determine the cooling water flow rate in kg/hr and exit temperature for optimum economic conditions.

2. Given: T steam = 418 K T 1 = 288 K U = 300 W/m 2 –K H y = 7200 hrs/yr C w = $25/ 1000 m 3 c p = 4184 J/ kg-K C A = $400/m 2 W steam = 2500 kg/hr K f = 1/20 L steam = 315000 J/kg Required: Cooling water Flow Rate, W