In a dairy operation, milk at a flow rate of 250 L/h and a cow-body temperature of 38.6 oC must be chilled to a safe-to-store temperature of 13 oC or less. Ground water at 10 oC is available at a flow rate of 0.72 m3/h. The density and specific heat of milk are 1030 kg/m3 and 3860 J/kg∙K, respectively. a) By using NTU method, determine the UA product of a counterflow heat exchanger required for the chilling process. Determine the length of the exchanger if the inner pipe has a50-mm diameter and the overall heat transfer coefficient is U = 1000 W/m2∙K.
b) Determine the outlet temperature of the water.