Heat exchanger network synthesis incorporating enhanced heat transfer techniques

Appropriate integration of tube- and shell-side enhanced heat transfer (EHT) techniques is essential for better thermal performance, lower heat transfer area requirement and reduced utility consumption in a heat exchanger network (HEN). In this study, EHT techniques have been integrated into grassroot HEN design to improve heat transfer rates and energy recovery. Based on performance and cost indices, an optimization model is proposed that identifies suitable tube-side and shell-side EHT techniques for implementation in grassroot HEN. The tube-side enhancement techniques considered include twisted-tape inserts, coiled-wire inserts, internal fins, the combination of coiled-wire inserts and internal fins, and the combination of twisted-tape and internal fins; external fins, helical baffles, and the combination of external fins and helical baffles are considered for the shell-side. Two examples are presented to demonstrate the capabilities of the models. The results obtained show that the proposed model ensures optimum selection of enhancement techniques, and savings in capital investment and utility costs. The study concludes that integration of enhancement devices into grassroot heat exchanger networks achieves capital investment and utility cost savings. (C) 2015 Published by Elsevier Ltd.