A well-insulated shell-and-tube heat exchanger is used to heat water (cp = 4.18 kJ/kg C) in

Question:

A well-insulated shell-and-tube heat exchanger is used to heat water (cp = 4.18 kJ/kg • °C) in the tubes from 20 to 70°C at a rate of 4.5 kg/s. Heat is supplied by hot oil (cp = 2.30 kJ/kg • °C) that enters the shell side at 170°C at a rate of 10 kg/s. Disregarding any heat loss from the heat exchanger, determine
(a) The exit temperature of oil and
(b) The rate of energy destruction in the heat exchanger. Take T0 = 25°C.