A poorly insulated counter-flow double-tube heat exchanger is used to cool ethylene glycol (cp = 2.56 kJ/(kg.K) flowing at a rate of 2 kg/s from 80 to 40 C using water (cp= 4.18 kJ/(kg.K)) that enters at 22 C and leaves at 55 C. The outer surface of the heat exchanger loses heat to the surroundings (Tsurr = 20 C) at the rate of 20 kW. Determine: (a) the rate of heat transfer between the ethylene glycol stream and water stream; (b) the mass flow rate of the water stream; (c) the rate of entropy generation in the heat exchanger. Ethylene glycol inlet Water outlet Outer tube Outer surface of heat exchanger Inner tube water inlet Ethylene glycol outlet Figure 1. Schematic of heat exchanger showing inlet and outlet for water and ethylene glycol.