Saturated liquid benzene flowing at a rate of 5 kg/s is to be cooled from 75°C to 45°C by using a source of cold water (c_p = 4187 J/kg · K) flowing at 3.5 kg/s and 15°C through a 20-mmdiameter tube of negligible wall thickness. The overall heat transfer coefficient of the heat exchanger is estimated to be 750 W/m² · K. If the specific heat of the liquid benzene is 1839 J/kg · K and assuming that the capacity ratio and effectiveness remain the same, determine the heat exchanger surface area for the following four heat exchangers:

(a) Parallel flow,

(b) Counter flow,

(c) Shell and tube heat exchanger with 2-shell passes and 40-tube passes,

(d) Cross-flow heat exchanger with one fluid mixed (liquid benzene) and other fluid unmixed (water).