Consider that you are an engineer in a dairy operation and you are about to design a counter-flow DPHE to cool and keep milk at safe-to-store temperature. Milk with a flow rate of 250LPH at cowbody temperature 38.6C must be chilled to a safe-to-store temperature at 13C or less. Groundwater at 10C is available at a flow rate of 720LPH. The density and the specific heat of the milk are 1,030 kg/m3 and 3,860J/kgK, respectively. a) Assuming thin-wall DPHE, calculate the length of the heat exchanger needed to achieve the required cooling of milk if the inner pipe diameter is 50-mm and the overall heat transfer coefficient U=1,000W/m2K b) Calculate new milk outlet temperature if the cold water flow rate is doubled, but the rest of the parameters are kept the same as in part a). c) Calculate new milk outlet temperature for the case when cold water flow is halved, but the rest of the parameters are kept the same as in part a)