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Maximising heat recovery Conserving energy saves money and reduces the environmental impact of processes. However, creating systems that are more energy-efficient is time consuming and costly. To address this, computer simulation of fluid-flow and heat transfer in tubular heat exchangers was used in two Defra LINK funded projects, to speed up the transition from design ideas to a much smaller number of prototypes built to test the ideas. 
The work involved collaboration with the University of Plymouth, Tetra Pak UK Ltd, ANSYS Europe Ltd, GlaxoSmithKline, Centura Foods and HJ Heinz Co. With potential application to many food processes, work initially compared computer predictions (based on CFD - computational fluid dynamics) with experimental measurements in commercial and laboratory heat exchange systems. Good agreement was obtained between measured and predicted values, and so the project team was able to explore the effects of design changes to exchangers - looking at features such as stagnation areas, the position of tube supports, tube diameter and baffles within the heat exchange shell. It was possible to identify design improvements and demonstrate that energy savings could be achieved by applying these to current tubular heat exchangers. In particular, computer simulation significantly speeded up the conversion from concept to commercial product, offering options for reducing energy use in processes that use tubular heat exchangers. A contrasting approach to making better use of waste heat was initiated as part of a Bridge LINK project - a pilot study to assess opportunities for capturing heat loss from systems such as ovens and boilers. This is a collaborative project between CCFRA and Bristol University that focuses on the potential of Stirling engines as the most likely means of converting 'low grade heat' to useable power. The project attracted considerable industrial interest reflecting the food industry's growing attention to the emergence of sustainable practices as a driver. Contact: Gary Tucker |