Consider a counterflow heat exchanger that must cool 3000 kg/h of mercury from 150of to 128of. the coolant is 1000 kg/h of water, supplied at 70of. if u is 300 w/m2k, complete the design by determining reasoanble value for the area and the exit-water temperature.

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2