2. 2. Determine the optimum economic thickness of insulation that should be used under the following conditions: saturated steam is being passed continuously in a horizontal 1” Sch 40 steel pipe. The temperature of the steam is valued at $0.0035/kg. the pipe is to be insulated with a material that has a thermal conductivity of 0.06W/mK. The cost of the installed insulation per m of pipe length is $200x, where x is the thickness of the insulation in meters. Annual fixed charges including maintenance amount to 20% of the initial installed cost. The total length of the pipe is 250 m, and the average temperature of the surroundings is 27degC. Heat transfer coefficient at the outside of the insulation may be assumed constant for all insulation thickness.
