Question: Consider the concentric-tube heat exchanger shown in the accompanying figure. A mixture of aqueous ethylene glycol solution arriving from a solar collector is passing through the inner tube. Water flows through the annulus as shown in the figure The average temperature of the water at the section shown is 15°C, with a corresponding heat transfer coefficient of h = 200 W/m2
• K. The average temperature of the ethylene glycol mixture is 48°C with an associated heat transfer coefficient of h = 150 W/m2
• K. In order to enhance the heat transfer rates between the fluids the outside surface of the inner tube is extended to form longitudinal fins, as shown in the figure.
Determine the temperature distribution inside the heat exchangers walls, assuming that the outside of the heat exchanger is perfectly insulated. Also, determine the heat transfer rate between the fluids.
