Improved heat recovery using twisted tube exchanger technology

Abstract

The geometrical features of twisted tube exchangers enhance the thermo-hydraulic performance for the same fluid velocity compared to conventional heat exchangers. The benefit of its use becomes evident in design as the required heat duty is transferred with smaller surface area for even lower pressure drop compared with conventional exchangers. This work introduces the development of a thermohydraulic model for the twisted tube geometry that relates pressure drop and heat transfer coefficient. Aspect ratio and twist pitch are the parameters that most influence the thermo-hydraulic performance of these exchangers. An alternative sizing approach using the concept of full use of pressure drop step is presented. The application to high viscosity fluids is discussed. The results show a reduction in surface area compared to conventional shell and tube exchangers of up to 45% and a pressure drop reduction of 15%.

Keywords

• Thermohydraulic model
• Twisted-tube
• Heat transfer enhancement
• Energy recovery
• Pressure drop