In a one-shell and eight-tube pass heat exchanger, the temperature of water flowing at rate of 50,000 lbm/h is raised from 70°F to 150°F. Hot air (c_p = 0.25 Btu/lbm·°F) that flows on the tube side enters the heat exchanger at 600°F and exits at 300°F. If the convection heat transfer coefficient on the outer surface of the tubes is 30 Btu/h·ft²·°F, determine the surface area of the heat exchanger using both LMTD and ε - NTU methods. Account for the possible fouling resistance of 0.0015 and 0.001 h·ft²·°F/Btu on water and air side, respectively.