Question: 1. A hot fluid is to be cooled in a double-pipe heat exchanger from 245°F to 225°F. The cold fluid is heated from 135°F to 220°F.
2. Calculate the heat loss per lineal foot from a 3-in. Schedule 40 steel pip [3.07 in. ID, 3.500 in. OD, k = 25 Btu/(h ft OF)] covered with 1 in. thickness of insulation [k = 0.11 Btu/(h ft °F)]. The pipe transports a fluid at 300°F with an inner heat transfer coefficient of 40 Btu/(h ft OF), [hinside], and is exposed to ambient air at 80°F with an outside heat transfer coefficient of 3 Btu/(h ft2 °F).