Determine the required heat-transfer surface area for a heat exchanger constructed from 10-cm OD tubes. A 95% ethanol solution (c_p = 3.8l0kJ/kg · K), flowing at 6.93 kg/s is cooled from 340 to 312 K by 6.30 kg/s of water that is available at 283 K. The overall heat-transfer coefficient based on outside tube area is 568 W/m² · K. Three different exchanger configurations are of interest:

a. Counterflow, single pass
b. Parallel flow, single pass
c. Cross flow with one tube pass and one shell pass, shell-side fluid mixed