Comparing the Tube Fin Heat Exchangers to Metal Foam Heat Exchangers for Geothermal Applications

Abstract

This paper examines the application of two different heat transfer augmentation techniques to improve the performance of an air-cooled heat exchanger. The conventional finned-tube design is compared with a modern technique being the application of a metal foam heat exchanger applied as a layer to the outer surface of the tube. Both designs improve the heat transfer rate from the condensing fluid flowing in the tube bundle albeit at the expense of a higher pressure drop compared to the bare tube as our reference case. Considering the heat transfer enhancement as the benefit and the excess pressure drop as the cost, the two cases are compared against each other. In order to achieve this goal, results from two different sources have been compared being ANSYSFluent and ASPEN B-JAC. A number of correlations are also proposed to predict the cost (excess pressure drop) and the benefit (heat transfer augmentation) of the extended surface.