Cold water (cp = 4180 J/kgK) leading to a shower enters a thin-walled double-pipe counter-flow heat exchanger at 15C at a rate of 0.25 kg/s and is heated to 37C by hot water (cp = 4190 J/kgK) that enters at 108C at a rate of 3 kg/s. The overall heat transfer coefficient is 950 W/m2K.Determine the surface area of the heat exchanger using the NTU method. (Round the answer to three decimal places.)