Instructions: Complete the exercise below, providing answers for questions A and B. Type your answers into Word, if possible. Show your work. If you prefer to write the equations on a scratch paper, you can take a picture of your work and insert it into this page. If you take a picture of your written work, please make sure that it is legible and clear. 1. A pilot plant for heating milk is being redesigned. The objective is to heat milk with a volumetric flow rate at V = 900 L/h of milk to 105 C. In the first stage, part of the heat is recovered by means of a plate heat exchanger. In the second stage, the preheated milk (95 C) is to be heated with a double pipe heat exchanger. The heating medium is hot water (125 C) with a volume flow of volume flow of =1500 L/h is available. C Ati2 Atm to1 to2 ti1 Time to1 ti1 ti2 to2 a) Using heat balance for the double pipe heat exchanger, calculate the temperature that the heating medium exits (7.5 points) b) What length of double pipe is required to transfer the calculated heat flow? (7.5 points) Formula collection: Double pipe heat exchanger Symbols: A: Area (m2) Cp: Heat capacity k: Heat transfer coefficient m : Mass flow 0 : Heat flow T: Absolute temperature Energy balance for material flow: ( = .p) 2 = m Cp (1) Energy balance for heat exchanger surface: = kA ATM (A = Tt.d.l) (2) ) Mean temperature difference: (tip-to1)-(t02-til) ATm = (tip-to1) Co2-ti1 (3) In Please use the following values for the calculation: Pskim milk = 998.1 kg/m3, Cp, Skim milk = 3.98kJ/kg:K, Pwater, 100c = 958.4 kg/m3, Cp, Water = 4.2 kJ/kg:K, k = 1935 d = 0.02m W Kimay