Heat Transfer Studies and Cost Analysis of a Shell-and-Tube Heat Exchanger using Aluminum Chips as Porous Medium

This paper investigates the cost reduction possibilities for a shell-and-tube heat exchanger using the passive heat transfer enhancement technique. Waste aluminum metal chips from machining process were used as the porous medium and were inserted inside the tubes of heat exchangers to enhance the tube side heat transfer. In flow through the porous medium, if the Reynolds number increases the rate of heat transfer will also increase at the expense of a reasonable pressure drop. Apart from the minimum pressure drop due to the presence of porous medium, an appreciable increase in heat transfer has been found. The total cost of the shell-and-tube heat exchanger with plain tubes and tubes with porous medium are analyzed and the cost to heat duty ratio is calculated. It is found that the use of waste metal chips as a porous medium in heat exchangers is advantageous from the standpoint of both the improvement of the heat transfer coefficient and the economy due to the use of waste metal chips. The conclusions are derived on the basis of the cost to heat duty ratio as a function of the Reynolds number.