Glycerin (cp 5 2400 J/kg·K) at 20°C and 0.5 kg/s is to be heated by ethylene glycol (cp 5 2500 J/kg·K) at 60°C in a thin-walled double-pipe parallel-flow heat exchanger. The temperature difference between the two fluids is 15°C at the outlet of the heat exchanger. If the overall heat transfer coefficient is 240 W/m2 ·K and the heat transfer surface area is 3.2 m2 , determine
(a) the rate of heat transfer