Hot exhaust gases (carbon dioxide) are cooled from 700 K to 300 K isobarically at 500 kPa. The cooling fluid is countercurrent water flow that enters at 150 kPa and 20ºC and exits as a saturated vapor.
a. Demonstrate that it is reasonable to consider carbon dioxide an ideal gas at these conditions.
b. Calculate the ratio of the mass flow rate of water to that of carbon dioxide.
c. Demonstrate that this is an impossible process by looking at the carbon dioxide and water temperatures at several points along the heat exchanger.