0.35 kg/s of ethyl benzene is to be cooled from 90°c to 55°c in the annulus of a double pipe heat exchanger. the two steel pipes are 1 ¼ in and 2 in nominal size. a cooling stream of water, in the inner tube, is available at a temperature of 27°c. calculate the mass flowrate of water required if the outlet temperature of water is 45°c, the lmtd, the overall heat transfer coefficient based on outside surface, and the total surface area of the exchanger. if the effective exchanger length is not to exceed 8 ft, calculate the number of tubes required. also, do the calculations for both cocurrent flow and countercurrent flow. use reliable literature source for the physical properties.