NTU - HX - GATE ME '09

In a parallel flow heat exchanger operating under a steady state, the heat capacity rates (product of specific heat at constant pressure and mass flow rate) of the hot and cold fluid are equal. The hot fluid, flowing at 1 kg/s with sp. heat = 4 kJ/kg.K, enters the heat exchanger at 102 C while the cold fluid has an inlet temperature of 15 C. The overall heat transfer coefficient for the heat exchanger is estimated to be 1 kW/m^2.K and the corresponding heat transfer surface area is 5 m^2. Neglect heat transfer between the heat exchanger and the ambient. The heat exchanger is characterized by the following relation 2ε=1−Exp(−2NTU). The exit temp (in C) for the cold fluid is A. 45 B. 55 C. 65 D. 75