Hot water at 80 oC is carried through a long insulation pipe (average thermal conductivity, k = 0.15 W/mK) with an inner diameter 2 cm and outer diameter 4 cm. Convection heat transfer coefficient of hot water and outside air (at 20 oC) is 150 W/m2K and 12 W/m2K, respectively). (a) Write down the energy balance equation and initial and boundary conditions during initial transient period. [10 pts] (b) solve the equation during steady state operation and find the temperature 1.5 cm from the center of the pipe (halfway between inner and outer surface). [20 pts]

2. Hot water at 80C is carried through a long insulation pipe (average thermal conductivity, k=0.15W/mK ) with an inner diameter 2cm and outer diameter 4cm. Convection heat transfer coefficient of hot water and outside air (at 20C ) is 150W/m2K and 12W/m2K, respectively). (a) Write down the energy balance equation and initial and boundary conditions during initial transient period. [ [10pts] (b) solve the equation during steady state operation and find the temperature 1.5cm from the center of the pipe (halfway between inner and outer surface). [20 pts]