To cool a summer home without using a vapor compression refrigeration cycle, air is routed through a plastic pipe (k=0.15 w/m*k, d_inner=0.15m, d_outer=0.17m) that is submerged in an adjoining body of water. the water temperature is nominally at t_infinity=17 degrees celsius and has a convection coefficient of h=1500w/m^2*k is maintained at the outer surface of the pipe. if air from the home enters at t_m, i=29 degrees celsius and a volumetric flow rate of v_i=0.025 m^3/s, what pipe length, l, is needed to provide a discharge temperature of t_m, o=21 degrees celsius?