Question

4. Water (C = 4180 J/kg · °C) is to be heated by solar heated hot air (Cp = 1010 J/kg - °C) in a double pipe counter flow heat exchanger. Air enters the heat exchanger at 90°C at a rate of 0.3 kg/s, while water enters at 22°C at a rate of 0.1 kg/s. The overall heat transfer coefficient based on the inner side of the tube is given to be 80 W/m". °C. The length of the tuk is 12 m and the internal diameter of the tube is 1.2 cm. Determine the outlet temperatures of the water and the air. (Ans: 27.3° C, 82.7 C)​

Answer 1

Explanation:

effectiveness= 0.108

Q= 0.108*Qmax

Q= Ch(90-Tho)

Q=Cc(Tc-22)