Tutorial ERT 216 1. Water at an average of 70 °F is flowing in a 2-­‐in steel pipe, schedule 40. Steam at 220 °F is condensing on the outside of the pipe. The convective coefficient for the water inside the pipe is h = 500 btu/h.ft2. °F and condensing steam coefficient on the outside is h = 1500 btu/h.ft2. °F. Calculate the heat loss per unit length of 1 ft of pipe using resistance method. ANSWER: 2. A metal steam pipe having an outside diameter of 30 mm has a surface temperature of 400 K and is to be insulated with an insulation having a thickness of 20 mm and k of 0.08 W/m.K. The pipe is exposed to air at 300 K and convection coefficient of 30 W/m.K. a) Calculate the critical radius and the heat loss per m length for the bare pipe b) Calculate the heat loss for the insulated pipe, assuming that the surface temperature of the pipe remain constant. ANSWER: