Air enters the core of a finned tube PTFE heat exchanger of the type shown in Figure 10.4 at 2 atm and 150°C.. The air mass flow rate is 10 kg/s and flows perpendicular to the tubes. The core is 0.5 m long with a 0.30 m2 frontal area. The height of the core is 0.5 m. Water at 15°C and at a flow rate of 50 kg/s flows inside the tubes. Air-side data are given on Figure 10.4. For water-side data, assume that σw = 0.129, Dh = 0.373 cm, and water-side heat transfer area/total volume = 138 m2 /m3. When consider this problem as a rating problem, calculate:
a. The airside and waterside heat transfer coefficients
b. Overall heat transfer coefficient based on the outer (airside) surface area
c. Total heat transfer rate and outlet temperatures of air and water.
