Chapter 11, Problem 11.11P

A novel heat exchanger concept consists of a largenumber of extruded polypropylene sheets $\left(k=0.17\text{ W/m}\cdot \text{K}\right)$ , each having a fin—like geometry, that aresubsequently stacked and melted together to form theheat exchanger core. Besides being inexpensive, the heatexchanger can be easily recycled at the end of its life.Carbon dioxide at a mean temperature of $10°C$ and pressure of 2 atm flows in the cool channels at a mean velocity of $u_m=0.1\text{ m/s}$ . Air at $\text{3}0°C$ and 2 atm flows at $0.2\text{ m/s}$ in the warm channels. Neglecting thethermal contact resistance at the welded interface, determine the product of the overall heat transfercoefficient and heat transfer area, $UA$ , for a heat exchanger core consisting of 200 cool channels and 200 warm channels.