a food processing plant uses pasteruziation and then cooling and refrigeration to avoid spoilage of a liquid product. the pasteurized liquid product has a flow rate of 10m^3/hr and the following properties: density, 1,100 kg/m^3; specific heat capacity, 5 kj/kg C. temperature, 72 degrees C. the plant uses river water at 15 deg C to pre-cool the liquid product after pasteurization to 35 degrees C through a heat exchanger.

Calculate the minimum flow rate (m^3/hr) of river water needed to acheive pre cooling hot, pasteurized liquid prodcut assuming that 10% heat is lost to the surroundings during exchange and that the water temp after cooling should not exceed 25 degrees C.

Part 2. if the flow rate of ther iver upstream of the warm water discharge is 200 m^3/hr, determine the temperature of the river water immediately downstream of the plant water discharge assuming completely mixed conditions and no water losses.