From the viewpoint of rational utilization of energy

the available energy of con-vective heat transfer enhancement in a tube was studied by energy analysis. The enhancement usually not only increases heat transfer

but also raises flow resistance. Since the heat transferred and the work done in flow

both are different forms of energy

Energy was used to combine heat transfer with flow resistance. Several dimensionless factors and a dimension-less equation about the available energy lost (or exergy lost )were presented to analyse and appraise the enhancement. The Kenics static mixer was taken as a example for study . The theoretical analysis and the example studied showed that this equation can be used as an analysis criterion for enhancement investigation and engineering application.